From 5f7d21b0011825058bc996153c22274cb43d5179 Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Wed, 11 Oct 2023 13:41:27 -0700
Subject: [PATCH 01/23] Verify installation of PendSV and SVCall handlers

---
 portable/GCC/ARM_CM4F/port.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/portable/GCC/ARM_CM4F/port.c b/portable/GCC/ARM_CM4F/port.c
index 3846a50f6a..859f76b245 100644
--- a/portable/GCC/ARM_CM4F/port.c
+++ b/portable/GCC/ARM_CM4F/port.c
@@ -62,6 +62,13 @@
 #define portNVIC_PENDSV_PRI                   ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 16UL )
 #define portNVIC_SYSTICK_PRI                  ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 24UL )
 
+/* Types and constants used to check for proper installation of the FreeRTOS
+ * interrupt handlers. */
+typedef void (* portISR_t)( void );
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xE000ED08 ) )
+#define portVECTOR_INDEX_SVC                  11
+#define portVECTOR_INDEX_PENDSV               14
+
 /* Constants required to check the validity of an interrupt priority. */
 #define portFIRST_USER_INTERRUPT_NUMBER       ( 16 )
 #define portNVIC_IP_REGISTERS_OFFSET_16       ( 0xE000E3F0 )
@@ -308,6 +315,7 @@ BaseType_t xPortStartScheduler( void )
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t * const pucFirstUserPriorityRegister = ( volatile uint8_t * const ) ( portNVIC_IP_REGISTERS_OFFSET_16 + portFIRST_USER_INTERRUPT_NUMBER );
         volatile uint8_t ucMaxPriorityValue;
+        const portISR_t * vectorTable = portSCB_VTOR_REG;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
          * functions can be called.  ISR safe functions are those that end in
@@ -383,6 +391,21 @@ BaseType_t xPortStartScheduler( void )
         /* Restore the clobbered interrupt priority register to its original
          * value. */
         *pucFirstUserPriorityRegister = ucOriginalPriority;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the system tick without using the SysTick
+         * timer.
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         * 
+         * Systems with a configurable base address for the vector table can
+         * also encounter assertion failures here if VTOR is not set correctly
+         * to point to the application's interrupt vector table. */
+        configASSERT( vectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
+        configASSERT( vectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
     }
     #endif /* configASSERT_DEFINED */
 

From 76814d00c6c646cbc0cc8491c0acbd5168d43e94 Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Wed, 11 Oct 2023 13:45:28 -0700
Subject: [PATCH 02/23] Make sure SVCall uses highest exception priority

---
 portable/GCC/ARM_CM4F/port.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/portable/GCC/ARM_CM4F/port.c b/portable/GCC/ARM_CM4F/port.c
index 859f76b245..970c9e333d 100644
--- a/portable/GCC/ARM_CM4F/port.c
+++ b/portable/GCC/ARM_CM4F/port.c
@@ -42,6 +42,7 @@
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG             ( *( ( volatile uint32_t * ) 0xe000e014 ) )
 #define portNVIC_SYSTICK_CURRENT_VALUE_REG    ( *( ( volatile uint32_t * ) 0xe000e018 ) )
+#define portNVIC_SHPR2_REG                    ( *( ( volatile uint32_t * ) 0xe000e01c ) )
 #define portNVIC_SHPR3_REG                    ( *( ( volatile uint32_t * ) 0xe000ed20 ) )
 /* ...then bits in the registers. */
 #define portNVIC_SYSTICK_CLK_BIT              ( 1UL << 2UL )
@@ -409,9 +410,11 @@ BaseType_t xPortStartScheduler( void )
     }
     #endif /* configASSERT_DEFINED */
 
-    /* Make PendSV and SysTick the lowest priority interrupts. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     /* Start the timer that generates the tick ISR.  Interrupts are disabled
      * here already. */

From 6237ca33b1d273c1a278432fdf4f6759c6fabf02 Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Thu, 12 Oct 2023 10:08:56 -0700
Subject: [PATCH 03/23] Fix style and update comments

---
 portable/GCC/ARM_CM4F/port.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/portable/GCC/ARM_CM4F/port.c b/portable/GCC/ARM_CM4F/port.c
index 970c9e333d..3e9f069f0d 100644
--- a/portable/GCC/ARM_CM4F/port.c
+++ b/portable/GCC/ARM_CM4F/port.c
@@ -38,6 +38,9 @@
     #error This port can only be used when the project options are configured to enable hardware floating point support.
 #endif
 
+/* Prototype to which all Interrupt Service Routines conform. */
+typedef void (* portISR_t)( void );
+
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG             ( *( ( volatile uint32_t * ) 0xe000e014 ) )
@@ -63,12 +66,10 @@
 #define portNVIC_PENDSV_PRI                   ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 16UL )
 #define portNVIC_SYSTICK_PRI                  ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 24UL )
 
-/* Types and constants used to check for proper installation of the FreeRTOS
- * interrupt handlers. */
-typedef void (* portISR_t)( void );
+/* Constants used to check the installation of the FreeRTOS interrupt handlers. */
 #define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xE000ED08 ) )
-#define portVECTOR_INDEX_SVC                  11
-#define portVECTOR_INDEX_PENDSV               14
+#define portVECTOR_INDEX_SVC                  ( 11 )
+#define portVECTOR_INDEX_PENDSV               ( 14 )
 
 /* Constants required to check the validity of an interrupt priority. */
 #define portFIRST_USER_INTERRUPT_NUMBER       ( 16 )
@@ -316,7 +317,7 @@ BaseType_t xPortStartScheduler( void )
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t * const pucFirstUserPriorityRegister = ( volatile uint8_t * const ) ( portNVIC_IP_REGISTERS_OFFSET_16 + portFIRST_USER_INTERRUPT_NUMBER );
         volatile uint8_t ucMaxPriorityValue;
-        const portISR_t * vectorTable = portSCB_VTOR_REG;
+        const portISR_t * const vectorTable = portSCB_VTOR_REG;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
          * functions can be called.  ISR safe functions are those that end in
@@ -395,16 +396,16 @@ BaseType_t xPortStartScheduler( void )
 
         /* Verify correct installation of the FreeRTOS handlers for SVCall and
          * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the system tick without using the SysTick
-         * timer.
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
          * Assertion failures here can be caused by incorrect installation of
          * the FreeRTOS handlers. For help installing the handlers, see
          * https://www.FreeRTOS.org/FAQHelp.html
-         * 
-         * Systems with a configurable base address for the vector table can
-         * also encounter assertion failures here if VTOR is not set correctly
-         * to point to the application's interrupt vector table. */
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
         configASSERT( vectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
         configASSERT( vectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
     }

From b957a080aabec189ac2a52daa1bcce79d4ce3019 Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Thu, 12 Oct 2023 19:59:49 -0700
Subject: [PATCH 04/23] Make equivalent changes to ARMv8-M

Delay replication (copy_files.py) to simplify review for now.
---
 portable/ARMv8M/non_secure/port.c | 50 +++++++++++++++++++++++--------
 1 file changed, 37 insertions(+), 13 deletions(-)

diff --git a/portable/ARMv8M/non_secure/port.c b/portable/ARMv8M/non_secure/port.c
index 52d68d3eaf..90e3cfd659 100644
--- a/portable/ARMv8M/non_secure/port.c
+++ b/portable/ARMv8M/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
 #define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC        ( 11 )
+#define portVECTOR_INDEX_PENDSV     ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1681,20 +1695,17 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
+        const portISR_t * const vectorTable = portSCB_VTOR_REG;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1728,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1756,15 +1766,29 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
 
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( vectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( vectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {

From efeba9648a76200c7f557877944eb2f7a24985f2 Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Thu, 12 Oct 2023 20:05:44 -0700
Subject: [PATCH 05/23] uncrustify

---
 portable/ARMv8M/non_secure/port.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/portable/ARMv8M/non_secure/port.c b/portable/ARMv8M/non_secure/port.c
index 90e3cfd659..ac2c843ae0 100644
--- a/portable/ARMv8M/non_secure/port.c
+++ b/portable/ARMv8M/non_secure/port.c
@@ -114,8 +114,8 @@ typedef void (* portISR_t)( void );
 /**
  * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
  */
-#define portVECTOR_INDEX_SVC        ( 11 )
-#define portVECTOR_INDEX_PENDSV     ( 14 )
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
 /*-----------------------------------------------------------*/
 
 /**
@@ -1780,7 +1780,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * VTOR is not set correctly to point to the application's vector table. */
         configASSERT( vectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
         configASSERT( vectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
-
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 

From 8fcb11f12683970264a9f9fa23d26f9b8cccccee Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Thu, 12 Oct 2023 20:51:27 -0700
Subject: [PATCH 06/23] match style of parenthesis usage

Style issue addressed here was previously existing
---
 portable/ARMv8M/non_secure/port.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/portable/ARMv8M/non_secure/port.c b/portable/ARMv8M/non_secure/port.c
index ac2c843ae0..4afcfef32b 100644
--- a/portable/ARMv8M/non_secure/port.c
+++ b/portable/ARMv8M/non_secure/port.c
@@ -107,7 +107,7 @@ typedef void (* portISR_t)( void );
  * @brief Constants required to manipulate the SCB.
  */
 #define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 

From f8565bc4d46cacc5bd57ecc72b3d10b298b07109 Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Fri, 13 Oct 2023 14:27:44 -0700
Subject: [PATCH 07/23] change vectorTable to pxVectorTable

---
 portable/ARMv8M/non_secure/port.c | 6 +++---
 portable/GCC/ARM_CM4F/port.c      | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/portable/ARMv8M/non_secure/port.c b/portable/ARMv8M/non_secure/port.c
index 4afcfef32b..0aea6033f9 100644
--- a/portable/ARMv8M/non_secure/port.c
+++ b/portable/ARMv8M/non_secure/port.c
@@ -1697,7 +1697,7 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
     {
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
-        const portISR_t * const vectorTable = portSCB_VTOR_REG;
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
          * functions can be called. ISR safe functions are those that end in
@@ -1778,8 +1778,8 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
          * VTOR is not set correctly to point to the application's vector table. */
-        configASSERT( vectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
-        configASSERT( vectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
diff --git a/portable/GCC/ARM_CM4F/port.c b/portable/GCC/ARM_CM4F/port.c
index 3e9f069f0d..6344dd5567 100644
--- a/portable/GCC/ARM_CM4F/port.c
+++ b/portable/GCC/ARM_CM4F/port.c
@@ -317,7 +317,7 @@ BaseType_t xPortStartScheduler( void )
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t * const pucFirstUserPriorityRegister = ( volatile uint8_t * const ) ( portNVIC_IP_REGISTERS_OFFSET_16 + portFIRST_USER_INTERRUPT_NUMBER );
         volatile uint8_t ucMaxPriorityValue;
-        const portISR_t * const vectorTable = portSCB_VTOR_REG;
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
          * functions can be called.  ISR safe functions are those that end in
@@ -406,8 +406,8 @@ BaseType_t xPortStartScheduler( void )
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
          * VTOR is not set correctly to point to the application's vector table. */
-        configASSERT( vectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
-        configASSERT( vectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
     }
     #endif /* configASSERT_DEFINED */
 

From 77b5aa7c52e4988fdde2de16bf6f450e4310f76e Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Fri, 13 Oct 2023 14:55:27 -0700
Subject: [PATCH 08/23] Fix typo in address of SHPR2 register

---
 portable/GCC/ARM_CM4F/port.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/portable/GCC/ARM_CM4F/port.c b/portable/GCC/ARM_CM4F/port.c
index 6344dd5567..fe0a96c2d4 100644
--- a/portable/GCC/ARM_CM4F/port.c
+++ b/portable/GCC/ARM_CM4F/port.c
@@ -45,7 +45,7 @@ typedef void (* portISR_t)( void );
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG             ( *( ( volatile uint32_t * ) 0xe000e014 ) )
 #define portNVIC_SYSTICK_CURRENT_VALUE_REG    ( *( ( volatile uint32_t * ) 0xe000e018 ) )
-#define portNVIC_SHPR2_REG                    ( *( ( volatile uint32_t * ) 0xe000e01c ) )
+#define portNVIC_SHPR2_REG                    ( *( ( volatile uint32_t * ) 0xe000ed1c ) )
 #define portNVIC_SHPR3_REG                    ( *( ( volatile uint32_t * ) 0xe000ed20 ) )
 /* ...then bits in the registers. */
 #define portNVIC_SYSTICK_CLK_BIT              ( 1UL << 2UL )

From cbe473a0d2c672b3715f500721adc24ba52dfa15 Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Fri, 13 Oct 2023 14:55:58 -0700
Subject: [PATCH 09/23] Make equivalent changes to ARMv6-M

---
 portable/GCC/ARM_CM0/port.c | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/portable/GCC/ARM_CM0/port.c b/portable/GCC/ARM_CM0/port.c
index 93e6d04895..0a16d86f13 100644
--- a/portable/GCC/ARM_CM0/port.c
+++ b/portable/GCC/ARM_CM0/port.c
@@ -34,11 +34,15 @@
 #include "FreeRTOS.h"
 #include "task.h"
 
+/* Prototype to which all Interrupt Service Routines conform. */
+typedef void (* portISR_t)( void );
+
 /* Constants required to manipulate the NVIC. */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG             ( *( ( volatile uint32_t * ) 0xe000e014 ) )
 #define portNVIC_SYSTICK_CURRENT_VALUE_REG    ( *( ( volatile uint32_t * ) 0xe000e018 ) )
 #define portNVIC_INT_CTRL_REG                 ( *( ( volatile uint32_t * ) 0xe000ed04 ) )
+#define portNVIC_SHPR2_REG                    ( *( ( volatile uint32_t * ) 0xe000ed1c ) )
 #define portNVIC_SHPR3_REG                    ( *( ( volatile uint32_t * ) 0xe000ed20 ) )
 #define portNVIC_SYSTICK_CLK_BIT              ( 1UL << 2UL )
 #define portNVIC_SYSTICK_INT_BIT              ( 1UL << 1UL )
@@ -51,6 +55,11 @@
 #define portNVIC_PENDSV_PRI                   ( portMIN_INTERRUPT_PRIORITY << 16UL )
 #define portNVIC_SYSTICK_PRI                  ( portMIN_INTERRUPT_PRIORITY << 24UL )
 
+/* Constants used to check the installation of the FreeRTOS interrupt handlers. */
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portVECTOR_INDEX_SVC                  ( 11 )
+#define portVECTOR_INDEX_PENDSV               ( 14 )
+
 /* Constants required to set up the initial stack. */
 #define portINITIAL_XPSR                      ( 0x01000000 )
 
@@ -231,9 +240,32 @@ void vPortStartFirstTask( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    #if ( configASSERT_DEFINED == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
+    }
+    #endif /* configASSERT_DEFINED */
+
+    /* Make PendSV and SysTick the lowest priority interrupt, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     /* Start the timer that generates the tick ISR.  Interrupts are disabled
      * here already. */

From f8b89faf3cf7786ac80de08555c8217ee1bc013c Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Sun, 15 Oct 2023 21:35:00 -0700
Subject: [PATCH 10/23] Revert check of SVC handler installation on CM0

SVC is not used in the CM0 port, and some FreeRTOS demos do not install
the SVC vector.
---
 portable/GCC/ARM_CM0/port.c | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/portable/GCC/ARM_CM0/port.c b/portable/GCC/ARM_CM0/port.c
index 0a16d86f13..2adfdcceff 100644
--- a/portable/GCC/ARM_CM0/port.c
+++ b/portable/GCC/ARM_CM0/port.c
@@ -42,7 +42,6 @@ typedef void (* portISR_t)( void );
 #define portNVIC_SYSTICK_LOAD_REG             ( *( ( volatile uint32_t * ) 0xe000e014 ) )
 #define portNVIC_SYSTICK_CURRENT_VALUE_REG    ( *( ( volatile uint32_t * ) 0xe000e018 ) )
 #define portNVIC_INT_CTRL_REG                 ( *( ( volatile uint32_t * ) 0xe000ed04 ) )
-#define portNVIC_SHPR2_REG                    ( *( ( volatile uint32_t * ) 0xe000ed1c ) )
 #define portNVIC_SHPR3_REG                    ( *( ( volatile uint32_t * ) 0xe000ed20 ) )
 #define portNVIC_SYSTICK_CLK_BIT              ( 1UL << 2UL )
 #define portNVIC_SYSTICK_INT_BIT              ( 1UL << 1UL )
@@ -57,7 +56,6 @@ typedef void (* portISR_t)( void );
 
 /* Constants used to check the installation of the FreeRTOS interrupt handlers. */
 #define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
-#define portVECTOR_INDEX_SVC                  ( 11 )
 #define portVECTOR_INDEX_PENDSV               ( 14 )
 
 /* Constants required to set up the initial stack. */
@@ -209,9 +207,6 @@ void vPortSVCHandler( void )
 
 void vPortStartFirstTask( void )
 {
-    /* The MSP stack is not reset as, unlike on M3/4 parts, there is no vector
-     * table offset register that can be used to locate the initial stack value.
-     * Not all M0 parts have the application vector table at address 0. */
     __asm volatile (
         "   .syntax unified             \n"
         "   ldr  r2, pxCurrentTCBConst2 \n"     /* Obtain location of pxCurrentTCB. */
@@ -242,12 +237,15 @@ BaseType_t xPortStartScheduler( void )
 {
     #if ( configASSERT_DEFINED == 1 )
     {
+        /* Point pxVectorTable at the interrupt vector table.  Systems without
+         * a VTOR register provide the value zero in place of the VTOR register
+         * and provide the vector table itself at address 0x00000000. */
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
-         * timer by overriding the weak function vPortSetupTimerInterrupt().
+        /* Verify correct installation of the FreeRTOS handler for PendSV. Do
+         * not check the installation of the SysTick handler because the
+         * application may provide the OS tick without using the SysTick timer
+         * by overriding the weak function vPortSetupTimerInterrupt().
          *
          * Assertion failures here can be caused by incorrect installation of
          * the FreeRTOS handlers. For help installing the handlers, see
@@ -256,16 +254,13 @@ BaseType_t xPortStartScheduler( void )
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
          * VTOR is not set correctly to point to the application's vector table. */
-        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
         configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
     }
     #endif /* configASSERT_DEFINED */
 
-    /* Make PendSV and SysTick the lowest priority interrupt, and make SVCall
-     * the highest priority. */
+    /* Make PendSV and SysTick the lowest priority interrupt. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
-    portNVIC_SHPR2_REG = 0;
 
     /* Start the timer that generates the tick ISR.  Interrupts are disabled
      * here already. */

From 5c08b83b8d200daf7c61931a25494108ca6de660 Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Mon, 16 Oct 2023 13:11:33 -0700
Subject: [PATCH 11/23] Update preexisting comment about not resetting MSP

---
 portable/GCC/ARM_CM0/port.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/portable/GCC/ARM_CM0/port.c b/portable/GCC/ARM_CM0/port.c
index 2adfdcceff..9679c9e3c2 100644
--- a/portable/GCC/ARM_CM0/port.c
+++ b/portable/GCC/ARM_CM0/port.c
@@ -207,6 +207,9 @@ void vPortSVCHandler( void )
 
 void vPortStartFirstTask( void )
 {
+    /* Don't reset the MSP stack as is done on CM3/4 devices. The vector table
+     * in some CM0 devices cannot be modified and thus may not hold the
+     * application's initial MSP value. */
     __asm volatile (
         "   .syntax unified             \n"
         "   ldr  r2, pxCurrentTCBConst2 \n"     /* Obtain location of pxCurrentTCB. */
@@ -237,7 +240,7 @@ BaseType_t xPortStartScheduler( void )
 {
     #if ( configASSERT_DEFINED == 1 )
     {
-        /* Point pxVectorTable at the interrupt vector table.  Systems without
+        /* Point pxVectorTable at the interrupt vector table. Systems without
          * a VTOR register provide the value zero in place of the VTOR register
          * and provide the vector table itself at address 0x00000000. */
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;

From fde7256c0ade116f5da31210daa61f204a14bb45 Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Mon, 16 Oct 2023 13:54:10 -0700
Subject: [PATCH 12/23] Add configCHECK_HANDLER_INSTALLATION

---
 portable/ARMv8M/non_secure/port.c            | 36 +++++++++++---------
 portable/ARMv8M/non_secure/portmacrocommon.h | 14 ++++++++
 portable/GCC/ARM_CM0/port.c                  |  4 +--
 portable/GCC/ARM_CM0/portmacro.h             | 14 ++++++++
 portable/GCC/ARM_CM4F/port.c                 | 36 +++++++++++---------
 portable/GCC/ARM_CM4F/portmacro.h            | 14 ++++++++
 6 files changed, 84 insertions(+), 34 deletions(-)

diff --git a/portable/ARMv8M/non_secure/port.c b/portable/ARMv8M/non_secure/port.c
index 0aea6033f9..fe5a232db9 100644
--- a/portable/ARMv8M/non_secure/port.c
+++ b/portable/ARMv8M/non_secure/port.c
@@ -1693,11 +1693,30 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    } /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
-        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
          * functions can be called. ISR safe functions are those that end in
@@ -1765,21 +1784,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
-         * timer by overriding the weak function vPortSetupTimerInterrupt().
-         *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
-         *
-         * Systems with a configurable address for the interrupt vector table
-         * can also encounter assertion failures or even system faults here if
-         * VTOR is not set correctly to point to the application's vector table. */
-        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
-        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
diff --git a/portable/ARMv8M/non_secure/portmacrocommon.h b/portable/ARMv8M/non_secure/portmacrocommon.h
index 60ef37380a..dc096021f7 100644
--- a/portable/ARMv8M/non_secure/portmacrocommon.h
+++ b/portable/ARMv8M/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime Checks on Port Configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM0/port.c b/portable/GCC/ARM_CM0/port.c
index 9679c9e3c2..e990dd1c32 100644
--- a/portable/GCC/ARM_CM0/port.c
+++ b/portable/GCC/ARM_CM0/port.c
@@ -238,7 +238,7 @@ void vPortStartFirstTask( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
-    #if ( configASSERT_DEFINED == 1 )
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         /* Point pxVectorTable at the interrupt vector table. Systems without
          * a VTOR register provide the value zero in place of the VTOR register
@@ -259,7 +259,7 @@ BaseType_t xPortStartScheduler( void )
          * VTOR is not set correctly to point to the application's vector table. */
         configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
     }
-    #endif /* configASSERT_DEFINED */
+    #endif /* configCHECK_HANDLER_INSTALLATION */
 
     /* Make PendSV and SysTick the lowest priority interrupt. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
diff --git a/portable/GCC/ARM_CM0/portmacro.h b/portable/GCC/ARM_CM0/portmacro.h
index 3c55b5d0c4..606a94f4a7 100644
--- a/portable/GCC/ARM_CM0/portmacro.h
+++ b/portable/GCC/ARM_CM0/portmacro.h
@@ -143,6 +143,20 @@ extern void vClearInterruptMaskFromISR( uint32_t ulMask )  __attribute__( ( nake
 
 /*-----------------------------------------------------------*/
 
+/* Runtime Checks on Port Configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 portFORCE_INLINE static BaseType_t xPortIsInsideInterrupt( void )
 {
     uint32_t ulCurrentInterrupt;
diff --git a/portable/GCC/ARM_CM4F/port.c b/portable/GCC/ARM_CM4F/port.c
index fe0a96c2d4..cf667d3124 100644
--- a/portable/GCC/ARM_CM4F/port.c
+++ b/portable/GCC/ARM_CM4F/port.c
@@ -310,6 +310,26 @@ BaseType_t xPortStartScheduler( void )
      * /source/portable/GCC/ARM_CM7/r0p1 directory. */
     configASSERT( portCPUID != portCORTEX_M7_r0p1_ID );
     configASSERT( portCPUID != portCORTEX_M7_r0p0_ID );
+    
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
+    } /* configCHECK_HANDLER_INSTALLATION */
 
     #if ( configASSERT_DEFINED == 1 )
     {
@@ -317,7 +337,6 @@ BaseType_t xPortStartScheduler( void )
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t * const pucFirstUserPriorityRegister = ( volatile uint8_t * const ) ( portNVIC_IP_REGISTERS_OFFSET_16 + portFIRST_USER_INTERRUPT_NUMBER );
         volatile uint8_t ucMaxPriorityValue;
-        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
          * functions can be called.  ISR safe functions are those that end in
@@ -393,21 +412,6 @@ BaseType_t xPortStartScheduler( void )
         /* Restore the clobbered interrupt priority register to its original
          * value. */
         *pucFirstUserPriorityRegister = ucOriginalPriority;
-
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
-         * timer by overriding the weak function vPortSetupTimerInterrupt().
-         *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
-         *
-         * Systems with a configurable address for the interrupt vector table
-         * can also encounter assertion failures or even system faults here if
-         * VTOR is not set correctly to point to the application's vector table. */
-        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
-        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
     }
     #endif /* configASSERT_DEFINED */
 
diff --git a/portable/GCC/ARM_CM4F/portmacro.h b/portable/GCC/ARM_CM4F/portmacro.h
index 40b2d03e91..956f9ed0b7 100644
--- a/portable/GCC/ARM_CM4F/portmacro.h
+++ b/portable/GCC/ARM_CM4F/portmacro.h
@@ -133,6 +133,20 @@ extern void vPortExitCritical( void );
 #define portTASK_FUNCTION( vFunction, pvParameters )          void vFunction( void * pvParameters )
 /*-----------------------------------------------------------*/
 
+/* Runtime Checks on Port Configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /* Tickless idle/low power functionality. */
 #ifndef portSUPPRESS_TICKS_AND_SLEEP
     extern void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime );

From 5d3726fe14872f3983111fc35734f1ecfcdf347a Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Mon, 16 Oct 2023 14:46:28 -0700
Subject: [PATCH 13/23] clean up whitespace

---
 portable/GCC/ARM_CM4F/port.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/portable/GCC/ARM_CM4F/port.c b/portable/GCC/ARM_CM4F/port.c
index cf667d3124..f7b08f05e8 100644
--- a/portable/GCC/ARM_CM4F/port.c
+++ b/portable/GCC/ARM_CM4F/port.c
@@ -310,7 +310,7 @@ BaseType_t xPortStartScheduler( void )
      * /source/portable/GCC/ARM_CM7/r0p1 directory. */
     configASSERT( portCPUID != portCORTEX_M7_r0p1_ID );
     configASSERT( portCPUID != portCORTEX_M7_r0p0_ID );
-    
+
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;

From 830957d51f7fb3669752b258c40faadf051c6978 Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Tue, 17 Oct 2023 16:42:21 -0700
Subject: [PATCH 14/23] Add comment on configCHECK_HANDLER_INSTALLATION

---
 portable/ARMv8M/non_secure/port.c | 5 +++++
 portable/GCC/ARM_CM0/port.c       | 5 +++++
 portable/GCC/ARM_CM4F/port.c      | 5 +++++
 3 files changed, 15 insertions(+)

diff --git a/portable/ARMv8M/non_secure/port.c b/portable/ARMv8M/non_secure/port.c
index fe5a232db9..3fa316e1f6 100644
--- a/portable/ARMv8M/non_secure/port.c
+++ b/portable/ARMv8M/non_secure/port.c
@@ -1693,6 +1693,11 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
diff --git a/portable/GCC/ARM_CM0/port.c b/portable/GCC/ARM_CM0/port.c
index e990dd1c32..40c6b35460 100644
--- a/portable/GCC/ARM_CM0/port.c
+++ b/portable/GCC/ARM_CM0/port.c
@@ -238,6 +238,11 @@ void vPortStartFirstTask( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         /* Point pxVectorTable at the interrupt vector table. Systems without
diff --git a/portable/GCC/ARM_CM4F/port.c b/portable/GCC/ARM_CM4F/port.c
index f7b08f05e8..08a779e0f6 100644
--- a/portable/GCC/ARM_CM4F/port.c
+++ b/portable/GCC/ARM_CM4F/port.c
@@ -311,6 +311,11 @@ BaseType_t xPortStartScheduler( void )
     configASSERT( portCPUID != portCORTEX_M7_r0p1_ID );
     configASSERT( portCPUID != portCORTEX_M7_r0p0_ID );
 
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;

From a7588dc17f532f4a73c85b6c6f424bba25726717 Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Wed, 18 Oct 2023 21:41:03 -0700
Subject: [PATCH 15/23] Add closing #endif (oops)

---
 portable/ARMv8M/non_secure/port.c | 3 ++-
 portable/GCC/ARM_CM4F/port.c      | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/portable/ARMv8M/non_secure/port.c b/portable/ARMv8M/non_secure/port.c
index 3fa316e1f6..617e0c8689 100644
--- a/portable/ARMv8M/non_secure/port.c
+++ b/portable/ARMv8M/non_secure/port.c
@@ -1716,7 +1716,8 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * VTOR is not set correctly to point to the application's vector table. */
         configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
         configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
-    } /* configCHECK_HANDLER_INSTALLATION */
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
 
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
diff --git a/portable/GCC/ARM_CM4F/port.c b/portable/GCC/ARM_CM4F/port.c
index 08a779e0f6..4d92bb3a68 100644
--- a/portable/GCC/ARM_CM4F/port.c
+++ b/portable/GCC/ARM_CM4F/port.c
@@ -334,7 +334,8 @@ BaseType_t xPortStartScheduler( void )
          * VTOR is not set correctly to point to the application's vector table. */
         configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
         configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
-    } /* configCHECK_HANDLER_INSTALLATION */
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
 
     #if ( configASSERT_DEFINED == 1 )
     {

From 4c8ba4a9947d8f42f340e1d5852ee1a9957f9c6e Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Mon, 23 Oct 2023 15:32:15 -0700
Subject: [PATCH 16/23] Replicate to all Cortex M ports for GCC and IAR

---
 portable/ARMv8M/non_secure/portmacrocommon.h  |  2 +-
 portable/GCC/ARM_CM0/port.c                   |  2 +-
 portable/GCC/ARM_CM0/portmacro.h              |  2 +-
 portable/GCC/ARM_CM23/non_secure/port.c       | 63 ++++++++++++++-----
 .../GCC/ARM_CM23/non_secure/portmacrocommon.h | 14 +++++
 portable/GCC/ARM_CM23_NTZ/non_secure/port.c   | 63 ++++++++++++++-----
 .../ARM_CM23_NTZ/non_secure/portmacrocommon.h | 14 +++++
 portable/GCC/ARM_CM3/port.c                   | 39 +++++++++++-
 portable/GCC/ARM_CM3/portmacro.h              | 14 +++++
 portable/GCC/ARM_CM33/non_secure/port.c       | 63 ++++++++++++++-----
 .../GCC/ARM_CM33/non_secure/portmacrocommon.h | 14 +++++
 portable/GCC/ARM_CM33_NTZ/non_secure/port.c   | 63 ++++++++++++++-----
 .../ARM_CM33_NTZ/non_secure/portmacrocommon.h | 14 +++++
 portable/GCC/ARM_CM35P/non_secure/port.c      | 63 ++++++++++++++-----
 .../ARM_CM35P/non_secure/portmacrocommon.h    | 14 +++++
 portable/GCC/ARM_CM35P_NTZ/non_secure/port.c  | 63 ++++++++++++++-----
 .../non_secure/portmacrocommon.h              | 14 +++++
 portable/GCC/ARM_CM3_MPU/port.c               | 34 ++++++++++
 portable/GCC/ARM_CM3_MPU/portmacro.h          | 14 +++++
 portable/GCC/ARM_CM4F/portmacro.h             |  2 +-
 portable/GCC/ARM_CM4_MPU/port.c               | 34 ++++++++++
 portable/GCC/ARM_CM4_MPU/portmacro.h          | 14 +++++
 portable/GCC/ARM_CM55/non_secure/port.c       | 63 ++++++++++++++-----
 .../GCC/ARM_CM55/non_secure/portmacrocommon.h | 14 +++++
 portable/GCC/ARM_CM55_NTZ/non_secure/port.c   | 63 ++++++++++++++-----
 .../ARM_CM55_NTZ/non_secure/portmacrocommon.h | 14 +++++
 portable/GCC/ARM_CM85/non_secure/port.c       | 63 ++++++++++++++-----
 .../GCC/ARM_CM85/non_secure/portmacrocommon.h | 14 +++++
 portable/GCC/ARM_CM85_NTZ/non_secure/port.c   | 63 ++++++++++++++-----
 .../ARM_CM85_NTZ/non_secure/portmacrocommon.h | 14 +++++
 portable/IAR/ARM_CM0/port.c                   | 35 +++++++++++
 portable/IAR/ARM_CM0/portasm.s                |  8 +--
 portable/IAR/ARM_CM0/portmacro.h              | 14 +++++
 portable/IAR/ARM_CM23/non_secure/port.c       | 63 ++++++++++++++-----
 .../IAR/ARM_CM23/non_secure/portmacrocommon.h | 14 +++++
 portable/IAR/ARM_CM23_NTZ/non_secure/port.c   | 63 ++++++++++++++-----
 .../ARM_CM23_NTZ/non_secure/portmacrocommon.h | 14 +++++
 portable/IAR/ARM_CM3/port.c                   | 39 +++++++++++-
 portable/IAR/ARM_CM3/portmacro.h              | 14 +++++
 portable/IAR/ARM_CM33/non_secure/port.c       | 63 ++++++++++++++-----
 .../IAR/ARM_CM33/non_secure/portmacrocommon.h | 14 +++++
 portable/IAR/ARM_CM33_NTZ/non_secure/port.c   | 63 ++++++++++++++-----
 .../ARM_CM33_NTZ/non_secure/portmacrocommon.h | 14 +++++
 portable/IAR/ARM_CM35P/non_secure/port.c      | 63 ++++++++++++++-----
 .../ARM_CM35P/non_secure/portmacrocommon.h    | 14 +++++
 portable/IAR/ARM_CM35P_NTZ/non_secure/port.c  | 63 ++++++++++++++-----
 .../non_secure/portmacrocommon.h              | 14 +++++
 portable/IAR/ARM_CM4F/port.c                  | 39 +++++++++++-
 portable/IAR/ARM_CM4F/portmacro.h             | 14 +++++
 portable/IAR/ARM_CM4F_MPU/port.c              | 34 ++++++++++
 portable/IAR/ARM_CM4F_MPU/portmacro.h         | 14 +++++
 portable/IAR/ARM_CM55/non_secure/port.c       | 63 ++++++++++++++-----
 .../IAR/ARM_CM55/non_secure/portmacrocommon.h | 14 +++++
 portable/IAR/ARM_CM55_NTZ/non_secure/port.c   | 63 ++++++++++++++-----
 .../ARM_CM55_NTZ/non_secure/portmacrocommon.h | 14 +++++
 portable/IAR/ARM_CM85/non_secure/port.c       | 63 ++++++++++++++-----
 .../IAR/ARM_CM85/non_secure/portmacrocommon.h | 14 +++++
 portable/IAR/ARM_CM85_NTZ/non_secure/port.c   | 63 ++++++++++++++-----
 .../ARM_CM85_NTZ/non_secure/portmacrocommon.h | 14 +++++
 59 files changed, 1597 insertions(+), 311 deletions(-)

diff --git a/portable/ARMv8M/non_secure/portmacrocommon.h b/portable/ARMv8M/non_secure/portmacrocommon.h
index dc096021f7..083eea5cf0 100644
--- a/portable/ARMv8M/non_secure/portmacrocommon.h
+++ b/portable/ARMv8M/non_secure/portmacrocommon.h
@@ -370,7 +370,7 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime Checks on Port Configuration */
+/* Runtime checks on port configuration */
 #ifndef configCHECK_HANDLER_INSTALLATION
     #if ( configASSERT_DEFINED == 1 )
         #define configCHECK_HANDLER_INSTALLATION    1
diff --git a/portable/GCC/ARM_CM0/port.c b/portable/GCC/ARM_CM0/port.c
index 40c6b35460..d7ccee29ac 100644
--- a/portable/GCC/ARM_CM0/port.c
+++ b/portable/GCC/ARM_CM0/port.c
@@ -266,7 +266,7 @@ BaseType_t xPortStartScheduler( void )
     }
     #endif /* configCHECK_HANDLER_INSTALLATION */
 
-    /* Make PendSV and SysTick the lowest priority interrupt. */
+    /* Make PendSV and SysTick the lowest priority interrupts. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
 
diff --git a/portable/GCC/ARM_CM0/portmacro.h b/portable/GCC/ARM_CM0/portmacro.h
index 606a94f4a7..f967a70a75 100644
--- a/portable/GCC/ARM_CM0/portmacro.h
+++ b/portable/GCC/ARM_CM0/portmacro.h
@@ -143,7 +143,7 @@ extern void vClearInterruptMaskFromISR( uint32_t ulMask )  __attribute__( ( nake
 
 /*-----------------------------------------------------------*/
 
-/* Runtime Checks on Port Configuration */
+/* Runtime checks on port configuration */
 #ifndef configCHECK_HANDLER_INSTALLATION
     #if ( configASSERT_DEFINED == 1 )
         #define configCHECK_HANDLER_INSTALLATION    1
diff --git a/portable/GCC/ARM_CM23/non_secure/port.c b/portable/GCC/ARM_CM23/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/GCC/ARM_CM23/non_secure/port.c
+++ b/portable/GCC/ARM_CM23/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/GCC/ARM_CM23/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM23/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/GCC/ARM_CM23/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM23/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM23_NTZ/non_secure/port.c b/portable/GCC/ARM_CM23_NTZ/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/GCC/ARM_CM23_NTZ/non_secure/port.c
+++ b/portable/GCC/ARM_CM23_NTZ/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/GCC/ARM_CM23_NTZ/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM23_NTZ/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/GCC/ARM_CM23_NTZ/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM23_NTZ/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM3/port.c b/portable/GCC/ARM_CM3/port.c
index 483f81324a..88246336e8 100644
--- a/portable/GCC/ARM_CM3/port.c
+++ b/portable/GCC/ARM_CM3/port.c
@@ -34,10 +34,14 @@
 #include "FreeRTOS.h"
 #include "task.h"
 
+/* Prototype to which all Interrupt Service Routines conform. */
+typedef void (* portISR_t)( void );
+
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG             ( *( ( volatile uint32_t * ) 0xe000e014 ) )
 #define portNVIC_SYSTICK_CURRENT_VALUE_REG    ( *( ( volatile uint32_t * ) 0xe000e018 ) )
+#define portNVIC_SHPR2_REG                    ( *( ( volatile uint32_t * ) 0xe000ed1c ) )
 #define portNVIC_SHPR3_REG                    ( *( ( volatile uint32_t * ) 0xe000ed20 ) )
 /* ...then bits in the registers. */
 #define portNVIC_SYSTICK_CLK_BIT              ( 1UL << 2UL )
@@ -52,6 +56,11 @@
 #define portNVIC_PENDSV_PRI                   ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 16UL )
 #define portNVIC_SYSTICK_PRI                  ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 24UL )
 
+/* Constants used to check the installation of the FreeRTOS interrupt handlers. */
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xE000ED08 ) )
+#define portVECTOR_INDEX_SVC                  ( 11 )
+#define portVECTOR_INDEX_PENDSV               ( 14 )
+
 /* Constants required to check the validity of an interrupt priority. */
 #define portFIRST_USER_INTERRUPT_NUMBER       ( 16 )
 #define portNVIC_IP_REGISTERS_OFFSET_16       ( 0xE000E3F0 )
@@ -259,6 +268,32 @@ static void prvPortStartFirstTask( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( configASSERT_DEFINED == 1 )
     {
         volatile uint8_t ucOriginalPriority;
@@ -343,9 +378,11 @@ BaseType_t xPortStartScheduler( void )
     }
     #endif /* configASSERT_DEFINED */
 
-    /* Make PendSV and SysTick the lowest priority interrupts. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     /* Start the timer that generates the tick ISR.  Interrupts are disabled
      * here already. */
diff --git a/portable/GCC/ARM_CM3/portmacro.h b/portable/GCC/ARM_CM3/portmacro.h
index 5d91d2139e..ac843131fd 100644
--- a/portable/GCC/ARM_CM3/portmacro.h
+++ b/portable/GCC/ARM_CM3/portmacro.h
@@ -130,6 +130,20 @@ extern void vPortExitCritical( void );
 #define portTASK_FUNCTION( vFunction, pvParameters )          void vFunction( void * pvParameters )
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /* Tickless idle/low power functionality. */
 #ifndef portSUPPRESS_TICKS_AND_SLEEP
     extern void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime );
diff --git a/portable/GCC/ARM_CM33/non_secure/port.c b/portable/GCC/ARM_CM33/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/GCC/ARM_CM33/non_secure/port.c
+++ b/portable/GCC/ARM_CM33/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/GCC/ARM_CM33/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM33/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/GCC/ARM_CM33/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM33/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM33_NTZ/non_secure/port.c b/portable/GCC/ARM_CM33_NTZ/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/GCC/ARM_CM33_NTZ/non_secure/port.c
+++ b/portable/GCC/ARM_CM33_NTZ/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/GCC/ARM_CM33_NTZ/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM33_NTZ/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/GCC/ARM_CM33_NTZ/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM33_NTZ/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM35P/non_secure/port.c b/portable/GCC/ARM_CM35P/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/GCC/ARM_CM35P/non_secure/port.c
+++ b/portable/GCC/ARM_CM35P/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/GCC/ARM_CM35P/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM35P/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/GCC/ARM_CM35P/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM35P/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM35P_NTZ/non_secure/port.c b/portable/GCC/ARM_CM35P_NTZ/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/GCC/ARM_CM35P_NTZ/non_secure/port.c
+++ b/portable/GCC/ARM_CM35P_NTZ/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/GCC/ARM_CM35P_NTZ/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM35P_NTZ/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/GCC/ARM_CM35P_NTZ/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM35P_NTZ/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM3_MPU/port.c b/portable/GCC/ARM_CM3_MPU/port.c
index ea2b9355e2..916b84e823 100644
--- a/portable/GCC/ARM_CM3_MPU/port.c
+++ b/portable/GCC/ARM_CM3_MPU/port.c
@@ -57,6 +57,9 @@
     #define configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS    1
 #endif
 
+/* Prototype to which all Interrupt Service Routines conform. */
+typedef void (* portISR_t)( void );
+
 /* Constants required to access and manipulate the NVIC. */
 #define portNVIC_SYSTICK_CTRL_REG                 ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG                 ( *( ( volatile uint32_t * ) 0xe000e014 ) )
@@ -94,6 +97,11 @@
 #define portINITIAL_CONTROL_IF_UNPRIVILEGED       ( 0x03 )
 #define portINITIAL_CONTROL_IF_PRIVILEGED         ( 0x02 )
 
+/* Constants used to check the installation of the FreeRTOS interrupt handlers. */
+#define portSCB_VTOR_REG                          ( *( ( portISR_t ** ) 0xE000ED08 ) )
+#define portVECTOR_INDEX_SVC                      ( 11 )
+#define portVECTOR_INDEX_PENDSV                   ( 14 )
+
 /* Constants required to check the validity of an interrupt priority. */
 #define portFIRST_USER_INTERRUPT_NUMBER           ( 16 )
 #define portNVIC_IP_REGISTERS_OFFSET_16           ( 0xE000E3F0 )
@@ -787,6 +795,32 @@ static void prvRestoreContextOfFirstTask( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( configASSERT_DEFINED == 1 )
     {
         volatile uint8_t ucOriginalPriority;
diff --git a/portable/GCC/ARM_CM3_MPU/portmacro.h b/portable/GCC/ARM_CM3_MPU/portmacro.h
index d0822e1443..bdb528f802 100644
--- a/portable/GCC/ARM_CM3_MPU/portmacro.h
+++ b/portable/GCC/ARM_CM3_MPU/portmacro.h
@@ -215,6 +215,20 @@ extern void vPortExitCritical( void );
 #define portTASK_FUNCTION( vFunction, pvParameters )          void vFunction( void * pvParameters )
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /* Architecture specific optimisations. */
 #ifndef configUSE_PORT_OPTIMISED_TASK_SELECTION
     #define configUSE_PORT_OPTIMISED_TASK_SELECTION    1
diff --git a/portable/GCC/ARM_CM4F/portmacro.h b/portable/GCC/ARM_CM4F/portmacro.h
index 956f9ed0b7..25089af391 100644
--- a/portable/GCC/ARM_CM4F/portmacro.h
+++ b/portable/GCC/ARM_CM4F/portmacro.h
@@ -133,7 +133,7 @@ extern void vPortExitCritical( void );
 #define portTASK_FUNCTION( vFunction, pvParameters )          void vFunction( void * pvParameters )
 /*-----------------------------------------------------------*/
 
-/* Runtime Checks on Port Configuration */
+/* Runtime checks on port configuration */
 #ifndef configCHECK_HANDLER_INSTALLATION
     #if ( configASSERT_DEFINED == 1 )
         #define configCHECK_HANDLER_INSTALLATION    1
diff --git a/portable/GCC/ARM_CM4_MPU/port.c b/portable/GCC/ARM_CM4_MPU/port.c
index e2ef1f054b..710838d4a3 100644
--- a/portable/GCC/ARM_CM4_MPU/port.c
+++ b/portable/GCC/ARM_CM4_MPU/port.c
@@ -61,6 +61,9 @@
     #define configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS    1
 #endif
 
+/* Prototype to which all Interrupt Service Routines conform. */
+typedef void (* portISR_t)( void );
+
 /* Constants required to access and manipulate the NVIC. */
 #define portNVIC_SYSTICK_CTRL_REG                 ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG                 ( *( ( volatile uint32_t * ) 0xe000e014 ) )
@@ -108,6 +111,11 @@
 #define portINITIAL_CONTROL_IF_UNPRIVILEGED       ( 0x03 )
 #define portINITIAL_CONTROL_IF_PRIVILEGED         ( 0x02 )
 
+/* Constants used to check the installation of the FreeRTOS interrupt handlers. */
+#define portSCB_VTOR_REG                          ( *( ( portISR_t ** ) 0xE000ED08 ) )
+#define portVECTOR_INDEX_SVC                      ( 11 )
+#define portVECTOR_INDEX_PENDSV                   ( 14 )
+
 /* Constants required to check the validity of an interrupt priority. */
 #define portFIRST_USER_INTERRUPT_NUMBER           ( 16 )
 #define portNVIC_IP_REGISTERS_OFFSET_16           ( 0xE000E3F0 )
@@ -895,6 +903,32 @@ BaseType_t xPortStartScheduler( void )
         configASSERT( portCPUID != portCORTEX_M7_r0p0_ID );
     #endif
 
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( configASSERT_DEFINED == 1 )
     {
         volatile uint8_t ucOriginalPriority;
diff --git a/portable/GCC/ARM_CM4_MPU/portmacro.h b/portable/GCC/ARM_CM4_MPU/portmacro.h
index 1f62279b04..c532ce2781 100644
--- a/portable/GCC/ARM_CM4_MPU/portmacro.h
+++ b/portable/GCC/ARM_CM4_MPU/portmacro.h
@@ -309,6 +309,20 @@ extern void vPortExitCritical( void );
 #define portTASK_FUNCTION( vFunction, pvParameters )          void vFunction( void * pvParameters )
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /* Architecture specific optimisations. */
 #ifndef configUSE_PORT_OPTIMISED_TASK_SELECTION
     #define configUSE_PORT_OPTIMISED_TASK_SELECTION    1
diff --git a/portable/GCC/ARM_CM55/non_secure/port.c b/portable/GCC/ARM_CM55/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/GCC/ARM_CM55/non_secure/port.c
+++ b/portable/GCC/ARM_CM55/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/GCC/ARM_CM55/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM55/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/GCC/ARM_CM55/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM55/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM55_NTZ/non_secure/port.c b/portable/GCC/ARM_CM55_NTZ/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/GCC/ARM_CM55_NTZ/non_secure/port.c
+++ b/portable/GCC/ARM_CM55_NTZ/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/GCC/ARM_CM55_NTZ/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM55_NTZ/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/GCC/ARM_CM55_NTZ/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM55_NTZ/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM85/non_secure/port.c b/portable/GCC/ARM_CM85/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/GCC/ARM_CM85/non_secure/port.c
+++ b/portable/GCC/ARM_CM85/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/GCC/ARM_CM85/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM85/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/GCC/ARM_CM85/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM85/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM85_NTZ/non_secure/port.c b/portable/GCC/ARM_CM85_NTZ/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/GCC/ARM_CM85_NTZ/non_secure/port.c
+++ b/portable/GCC/ARM_CM85_NTZ/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/GCC/ARM_CM85_NTZ/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM85_NTZ/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/GCC/ARM_CM85_NTZ/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM85_NTZ/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM0/port.c b/portable/IAR/ARM_CM0/port.c
index f4d77120c0..62c0adcf8e 100644
--- a/portable/IAR/ARM_CM0/port.c
+++ b/portable/IAR/ARM_CM0/port.c
@@ -37,6 +37,9 @@
 #include "FreeRTOS.h"
 #include "task.h"
 
+/* Prototype to which all Interrupt Service Routines conform. */
+typedef void (* portISR_t)( void );
+
 /* Constants required to manipulate the NVIC. */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG             ( *( ( volatile uint32_t * ) 0xe000e014 ) )
@@ -53,6 +56,10 @@
 #define portNVIC_PENDSV_PRI                   ( portMIN_INTERRUPT_PRIORITY << 16UL )
 #define portNVIC_SYSTICK_PRI                  ( portMIN_INTERRUPT_PRIORITY << 24UL )
 
+/* Constants used to check the installation of the FreeRTOS interrupt handlers. */
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portVECTOR_INDEX_PENDSV               ( 14 )
+
 /* Constants required to set up the initial stack. */
 #define portINITIAL_XPSR                      ( 0x01000000 )
 
@@ -168,6 +175,34 @@ static void prvTaskExitError( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        /* Point pxVectorTable at the interrupt vector table. Systems without
+         * a VTOR register provide the value zero in place of the VTOR register
+         * and provide the vector table itself at address 0x00000000. */
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handler for PendSV. Do
+         * not check the installation of the SysTick handler because the
+         * application may provide the OS tick without using the SysTick timer
+         * by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     /* Make PendSV and SysTick the lowest priority interrupts. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
diff --git a/portable/IAR/ARM_CM0/portasm.s b/portable/IAR/ARM_CM0/portasm.s
index 768ce41cb8..ede4921353 100644
--- a/portable/IAR/ARM_CM0/portasm.s
+++ b/portable/IAR/ARM_CM0/portasm.s
@@ -91,15 +91,15 @@ xPortPendSVHandler:
 
 vPortSVCHandler;
     /* This function is no longer used, but retained for backward
-    compatibility. */
+     * compatibility. */
     bx lr
 
 /*-----------------------------------------------------------*/
 
 vPortStartFirstTask
-    /* The MSP stack is not reset as, unlike on M3/4 parts, there is no vector
-    table offset register that can be used to locate the initial stack value.
-    Not all M0 parts have the application vector table at address 0. */
+    /* Don't reset the MSP stack as is done on CM3/4 devices. The vector table
+     * in some CM0 devices cannot be modified and thus may not hold the
+     * application's initial MSP value. */
 
     ldr r3, =pxCurrentTCB   /* Obtain location of pxCurrentTCB. */
     ldr r1, [r3]
diff --git a/portable/IAR/ARM_CM0/portmacro.h b/portable/IAR/ARM_CM0/portmacro.h
index fa8438fecf..8f4cb30c52 100644
--- a/portable/IAR/ARM_CM0/portmacro.h
+++ b/portable/IAR/ARM_CM0/portmacro.h
@@ -141,6 +141,20 @@ extern void vClearInterruptMaskFromISR( uint32_t ulMask );
 
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 portFORCE_INLINE static BaseType_t xPortIsInsideInterrupt( void )
 {
     uint32_t ulCurrentInterrupt;
diff --git a/portable/IAR/ARM_CM23/non_secure/port.c b/portable/IAR/ARM_CM23/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/IAR/ARM_CM23/non_secure/port.c
+++ b/portable/IAR/ARM_CM23/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/IAR/ARM_CM23/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM23/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/IAR/ARM_CM23/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM23/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM23_NTZ/non_secure/port.c b/portable/IAR/ARM_CM23_NTZ/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/IAR/ARM_CM23_NTZ/non_secure/port.c
+++ b/portable/IAR/ARM_CM23_NTZ/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/IAR/ARM_CM23_NTZ/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM23_NTZ/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/IAR/ARM_CM23_NTZ/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM23_NTZ/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM3/port.c b/portable/IAR/ARM_CM3/port.c
index 1fbe96d44f..91fe02fe53 100644
--- a/portable/IAR/ARM_CM3/port.c
+++ b/portable/IAR/ARM_CM3/port.c
@@ -41,10 +41,14 @@
     #error configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0.  See http: /*www.FreeRTOS.org/RTOS-Cortex-M3-M4.html */
 #endif
 
+/* Prototype to which all Interrupt Service Routines conform. */
+typedef void (* portISR_t)( void );
+
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG             ( *( ( volatile uint32_t * ) 0xe000e014 ) )
 #define portNVIC_SYSTICK_CURRENT_VALUE_REG    ( *( ( volatile uint32_t * ) 0xe000e018 ) )
+#define portNVIC_SHPR2_REG                    ( *( ( volatile uint32_t * ) 0xe000ed1c ) )
 #define portNVIC_SHPR3_REG                    ( *( ( volatile uint32_t * ) 0xe000ed20 ) )
 /* ...then bits in the registers. */
 #define portNVIC_SYSTICK_CLK_BIT              ( 1UL << 2UL )
@@ -59,6 +63,11 @@
 #define portNVIC_PENDSV_PRI                   ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 16UL )
 #define portNVIC_SYSTICK_PRI                  ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 24UL )
 
+/* Constants used to check the installation of the FreeRTOS interrupt handlers. */
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xE000ED08 ) )
+#define portVECTOR_INDEX_SVC                  ( 11 )
+#define portVECTOR_INDEX_PENDSV               ( 14 )
+
 /* Constants required to check the validity of an interrupt priority. */
 #define portFIRST_USER_INTERRUPT_NUMBER       ( 16 )
 #define portNVIC_IP_REGISTERS_OFFSET_16       ( 0xE000E3F0 )
@@ -208,6 +217,32 @@ static void prvTaskExitError( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( configASSERT_DEFINED == 1 )
     {
         volatile uint8_t ucOriginalPriority;
@@ -292,9 +327,11 @@ BaseType_t xPortStartScheduler( void )
     }
     #endif /* configASSERT_DEFINED */
 
-    /* Make PendSV and SysTick the lowest priority interrupts. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     /* Start the timer that generates the tick ISR.  Interrupts are disabled
      * here already. */
diff --git a/portable/IAR/ARM_CM3/portmacro.h b/portable/IAR/ARM_CM3/portmacro.h
index c90a952e2b..cf1aaa668e 100644
--- a/portable/IAR/ARM_CM3/portmacro.h
+++ b/portable/IAR/ARM_CM3/portmacro.h
@@ -173,6 +173,20 @@ extern void vPortExitCritical( void );
 #define portTASK_FUNCTION( vFunction, pvParameters )          void vFunction( void * pvParameters )
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 #ifdef configASSERT
     void vPortValidateInterruptPriority( void );
     #define portASSERT_IF_INTERRUPT_PRIORITY_INVALID()    vPortValidateInterruptPriority()
diff --git a/portable/IAR/ARM_CM33/non_secure/port.c b/portable/IAR/ARM_CM33/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/IAR/ARM_CM33/non_secure/port.c
+++ b/portable/IAR/ARM_CM33/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/IAR/ARM_CM33/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM33/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/IAR/ARM_CM33/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM33/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM33_NTZ/non_secure/port.c b/portable/IAR/ARM_CM33_NTZ/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/IAR/ARM_CM33_NTZ/non_secure/port.c
+++ b/portable/IAR/ARM_CM33_NTZ/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/IAR/ARM_CM33_NTZ/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM33_NTZ/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/IAR/ARM_CM33_NTZ/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM33_NTZ/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM35P/non_secure/port.c b/portable/IAR/ARM_CM35P/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/IAR/ARM_CM35P/non_secure/port.c
+++ b/portable/IAR/ARM_CM35P/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/IAR/ARM_CM35P/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM35P/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/IAR/ARM_CM35P/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM35P/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM35P_NTZ/non_secure/port.c b/portable/IAR/ARM_CM35P_NTZ/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/IAR/ARM_CM35P_NTZ/non_secure/port.c
+++ b/portable/IAR/ARM_CM35P_NTZ/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/IAR/ARM_CM35P_NTZ/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM35P_NTZ/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/IAR/ARM_CM35P_NTZ/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM35P_NTZ/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM4F/port.c b/portable/IAR/ARM_CM4F/port.c
index effedcb14b..d75e48492d 100644
--- a/portable/IAR/ARM_CM4F/port.c
+++ b/portable/IAR/ARM_CM4F/port.c
@@ -45,10 +45,14 @@
     #error configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0.  See http: /*www.FreeRTOS.org/RTOS-Cortex-M3-M4.html */
 #endif
 
+/* Prototype to which all Interrupt Service Routines conform. */
+typedef void (* portISR_t)( void );
+
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG             ( *( ( volatile uint32_t * ) 0xe000e014 ) )
 #define portNVIC_SYSTICK_CURRENT_VALUE_REG    ( *( ( volatile uint32_t * ) 0xe000e018 ) )
+#define portNVIC_SHPR2_REG                    ( *( ( volatile uint32_t * ) 0xe000ed1c ) )
 #define portNVIC_SHPR3_REG                    ( *( ( volatile uint32_t * ) 0xe000ed20 ) )
 /* ...then bits in the registers. */
 #define portNVIC_SYSTICK_CLK_BIT              ( 1UL << 2UL )
@@ -69,6 +73,11 @@
 #define portNVIC_PENDSV_PRI                   ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 16UL )
 #define portNVIC_SYSTICK_PRI                  ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 24UL )
 
+/* Constants used to check the installation of the FreeRTOS interrupt handlers. */
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xE000ED08 ) )
+#define portVECTOR_INDEX_SVC                  ( 11 )
+#define portVECTOR_INDEX_PENDSV               ( 14 )
+
 /* Constants required to check the validity of an interrupt priority. */
 #define portFIRST_USER_INTERRUPT_NUMBER       ( 16 )
 #define portNVIC_IP_REGISTERS_OFFSET_16       ( 0xE000E3F0 )
@@ -246,6 +255,32 @@ BaseType_t xPortStartScheduler( void )
     configASSERT( portCPUID != portCORTEX_M7_r0p1_ID );
     configASSERT( portCPUID != portCORTEX_M7_r0p0_ID );
 
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( configASSERT_DEFINED == 1 )
     {
         volatile uint8_t ucOriginalPriority;
@@ -330,9 +365,11 @@ BaseType_t xPortStartScheduler( void )
     }
     #endif /* configASSERT_DEFINED */
 
-    /* Make PendSV and SysTick the lowest priority interrupts. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     /* Start the timer that generates the tick ISR.  Interrupts are disabled
      * here already. */
diff --git a/portable/IAR/ARM_CM4F/portmacro.h b/portable/IAR/ARM_CM4F/portmacro.h
index 20467efcbb..7b82c0c939 100644
--- a/portable/IAR/ARM_CM4F/portmacro.h
+++ b/portable/IAR/ARM_CM4F/portmacro.h
@@ -172,6 +172,20 @@ extern void vPortExitCritical( void );
 #define portTASK_FUNCTION( vFunction, pvParameters )          void vFunction( void * pvParameters )
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 #ifdef configASSERT
     void vPortValidateInterruptPriority( void );
     #define portASSERT_IF_INTERRUPT_PRIORITY_INVALID()    vPortValidateInterruptPriority()
diff --git a/portable/IAR/ARM_CM4F_MPU/port.c b/portable/IAR/ARM_CM4F_MPU/port.c
index 6db7bd796a..0a9d8272c5 100644
--- a/portable/IAR/ARM_CM4F_MPU/port.c
+++ b/portable/IAR/ARM_CM4F_MPU/port.c
@@ -68,6 +68,9 @@
     #define configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS    1
 #endif
 
+/* Prototype to which all Interrupt Service Routines conform. */
+typedef void (* portISR_t)( void );
+
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG                 ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG                 ( *( ( volatile uint32_t * ) 0xe000e014 ) )
@@ -109,6 +112,11 @@
 #define portNVIC_SYSTICK_PRI                      ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 24UL )
 #define portNVIC_SVC_PRI                          ( ( ( uint32_t ) configMAX_SYSCALL_INTERRUPT_PRIORITY - 1UL ) << 24UL )
 
+/* Constants used to check the installation of the FreeRTOS interrupt handlers. */
+#define portSCB_VTOR_REG                          ( *( ( portISR_t ** ) 0xE000ED08 ) )
+#define portVECTOR_INDEX_SVC                      ( 11 )
+#define portVECTOR_INDEX_PENDSV                   ( 14 )
+
 /* Constants required to check the validity of an interrupt priority. */
 #define portFIRST_USER_INTERRUPT_NUMBER           ( 16 )
 #define portNVIC_IP_REGISTERS_OFFSET_16           ( 0xE000E3F0 )
@@ -777,6 +785,32 @@ BaseType_t xPortStartScheduler( void )
         configASSERT( portCPUID != portCORTEX_M7_r0p0_ID );
     #endif
 
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( configASSERT_DEFINED == 1 )
     {
         volatile uint8_t ucOriginalPriority;
diff --git a/portable/IAR/ARM_CM4F_MPU/portmacro.h b/portable/IAR/ARM_CM4F_MPU/portmacro.h
index 98b087e11f..6dad44d93e 100644
--- a/portable/IAR/ARM_CM4F_MPU/portmacro.h
+++ b/portable/IAR/ARM_CM4F_MPU/portmacro.h
@@ -288,6 +288,20 @@ typedef struct MPU_SETTINGS
 #define portYIELD_FROM_ISR( x )    portEND_SWITCHING_ISR( x )
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /* Architecture specific optimisations. */
 #ifndef configUSE_PORT_OPTIMISED_TASK_SELECTION
     #define configUSE_PORT_OPTIMISED_TASK_SELECTION    1
diff --git a/portable/IAR/ARM_CM55/non_secure/port.c b/portable/IAR/ARM_CM55/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/IAR/ARM_CM55/non_secure/port.c
+++ b/portable/IAR/ARM_CM55/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/IAR/ARM_CM55/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM55/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/IAR/ARM_CM55/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM55/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM55_NTZ/non_secure/port.c b/portable/IAR/ARM_CM55_NTZ/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/IAR/ARM_CM55_NTZ/non_secure/port.c
+++ b/portable/IAR/ARM_CM55_NTZ/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/IAR/ARM_CM55_NTZ/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM55_NTZ/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/IAR/ARM_CM55_NTZ/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM55_NTZ/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM85/non_secure/port.c b/portable/IAR/ARM_CM85/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/IAR/ARM_CM85/non_secure/port.c
+++ b/portable/IAR/ARM_CM85/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/IAR/ARM_CM85/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM85/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/IAR/ARM_CM85/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM85/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM85_NTZ/non_secure/port.c b/portable/IAR/ARM_CM85_NTZ/non_secure/port.c
index 52d68d3eaf..617e0c8689 100644
--- a/portable/IAR/ARM_CM85_NTZ/non_secure/port.c
+++ b/portable/IAR/ARM_CM85_NTZ/non_secure/port.c
@@ -79,6 +79,12 @@
 #endif
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Prototype to which all Interrupt Service Routines conform.
+ */
+typedef void (* portISR_t)( void );
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to manipulate the NVIC.
  */
@@ -100,10 +106,18 @@
 /**
  * @brief Constants required to manipulate the SCB.
  */
-#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( volatile uint32_t * ) 0xe000ed24 )
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xe000ed08 ) )
+#define portSCB_SYS_HANDLER_CTRL_STATE_REG    ( *( ( volatile uint32_t * ) 0xe000ed24 ) )
 #define portSCB_MEM_FAULT_ENABLE_BIT          ( 1UL << 16UL )
 /*-----------------------------------------------------------*/
 
+/**
+ * @brief Constants used to check the installation of the FreeRTOS interrupt handlers.
+ */
+#define portVECTOR_INDEX_SVC       ( 11 )
+#define portVECTOR_INDEX_PENDSV    ( 14 )
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Constants required to check the validity of an interrupt priority.
  */
@@ -1679,22 +1693,44 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == SVC_Handler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == PendSV_Handler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) )
     {
-        volatile uint32_t ulOriginalPriority;
         volatile uint32_t ulImplementedPrioBits = 0;
         volatile uint8_t ucMaxPriorityValue;
 
         /* Determine the maximum priority from which ISR safe FreeRTOS API
-         * functions can be called.  ISR safe functions are those that end in
-         * "FromISR".  FreeRTOS maintains separate thread and ISR API functions to
+         * functions can be called. ISR safe functions are those that end in
+         * "FromISR". FreeRTOS maintains separate thread and ISR API functions to
          * ensure interrupt entry is as fast and simple as possible.
          *
-         * Save the interrupt priority value that is about to be clobbered. */
-        ulOriginalPriority = portNVIC_SHPR2_REG;
-
-        /* Determine the number of priority bits available.  First write to all
-         * possible bits. */
+         * First, determine the number of priority bits available. Write to all
+         * possible bits in the priority setting for SVCall. */
         portNVIC_SHPR2_REG = 0xFF000000;
 
         /* Read the value back to see how many bits stuck. */
@@ -1717,7 +1753,6 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 
         /* Calculate the maximum acceptable priority group value for the number
          * of bits read back. */
-
         while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
         {
             ulImplementedPrioBits++;
@@ -1755,16 +1790,14 @@ BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
          * register. */
         ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
         ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
-
-        /* Restore the clobbered interrupt priority register to its original
-         * value. */
-        portNVIC_SHPR2_REG = ulOriginalPriority;
     }
     #endif /* #if ( ( configASSERT_DEFINED == 1 ) && ( portHAS_ARMV8M_MAIN_EXTENSION == 1 ) ) */
 
-    /* Make PendSV, CallSV and SysTick the same priority as the kernel. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     #if ( configENABLE_MPU == 1 )
     {
diff --git a/portable/IAR/ARM_CM85_NTZ/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM85_NTZ/non_secure/portmacrocommon.h
index 60ef37380a..083eea5cf0 100644
--- a/portable/IAR/ARM_CM85_NTZ/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM85_NTZ/non_secure/portmacrocommon.h
@@ -370,6 +370,20 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
+/* Runtime checks on port configuration */
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #if ( configASSERT_DEFINED == 1 )
+        #define configCHECK_HANDLER_INSTALLATION    1
+    #else
+        #define configCHECK_HANDLER_INSTALLATION    0
+    #endif
+#else
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+/*-----------------------------------------------------------*/
+
 /**
  * @brief Tickless idle/low power functionality.
  */

From 9f58ab67ff77a261b9f1a98a62c972fe9e226fe2 Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Wed, 25 Oct 2023 14:09:44 -0700
Subject: [PATCH 17/23] Move macro check to FreeRTOS.h and simplify

---
 include/FreeRTOS.h                                 | 10 ++++++++++
 portable/ARMv8M/non_secure/portmacrocommon.h       | 14 --------------
 portable/GCC/ARM_CM0/portmacro.h                   | 14 --------------
 portable/GCC/ARM_CM23/non_secure/portmacrocommon.h | 14 --------------
 .../GCC/ARM_CM23_NTZ/non_secure/portmacrocommon.h  | 14 --------------
 portable/GCC/ARM_CM3/portmacro.h                   | 14 --------------
 portable/GCC/ARM_CM33/non_secure/portmacrocommon.h | 14 --------------
 .../GCC/ARM_CM33_NTZ/non_secure/portmacrocommon.h  | 14 --------------
 .../GCC/ARM_CM35P/non_secure/portmacrocommon.h     | 14 --------------
 .../GCC/ARM_CM35P_NTZ/non_secure/portmacrocommon.h | 14 --------------
 portable/GCC/ARM_CM3_MPU/portmacro.h               | 14 --------------
 portable/GCC/ARM_CM4F/portmacro.h                  | 14 --------------
 portable/GCC/ARM_CM4_MPU/portmacro.h               | 14 --------------
 portable/GCC/ARM_CM55/non_secure/portmacrocommon.h | 14 --------------
 .../GCC/ARM_CM55_NTZ/non_secure/portmacrocommon.h  | 14 --------------
 portable/GCC/ARM_CM85/non_secure/portmacrocommon.h | 14 --------------
 .../GCC/ARM_CM85_NTZ/non_secure/portmacrocommon.h  | 14 --------------
 portable/IAR/ARM_CM0/portmacro.h                   | 14 --------------
 portable/IAR/ARM_CM23/non_secure/portmacrocommon.h | 14 --------------
 .../IAR/ARM_CM23_NTZ/non_secure/portmacrocommon.h  | 14 --------------
 portable/IAR/ARM_CM3/portmacro.h                   | 14 --------------
 portable/IAR/ARM_CM33/non_secure/portmacrocommon.h | 14 --------------
 .../IAR/ARM_CM33_NTZ/non_secure/portmacrocommon.h  | 14 --------------
 .../IAR/ARM_CM35P/non_secure/portmacrocommon.h     | 14 --------------
 .../IAR/ARM_CM35P_NTZ/non_secure/portmacrocommon.h | 14 --------------
 portable/IAR/ARM_CM4F/portmacro.h                  | 14 --------------
 portable/IAR/ARM_CM4F_MPU/portmacro.h              | 14 --------------
 portable/IAR/ARM_CM55/non_secure/portmacrocommon.h | 14 --------------
 .../IAR/ARM_CM55_NTZ/non_secure/portmacrocommon.h  | 14 --------------
 portable/IAR/ARM_CM85/non_secure/portmacrocommon.h | 14 --------------
 .../IAR/ARM_CM85_NTZ/non_secure/portmacrocommon.h  | 14 --------------
 31 files changed, 10 insertions(+), 420 deletions(-)

diff --git a/include/FreeRTOS.h b/include/FreeRTOS.h
index b8153ac64d..8fcd932f22 100644
--- a/include/FreeRTOS.h
+++ b/include/FreeRTOS.h
@@ -365,6 +365,16 @@
     #define configPRECONDITION_DEFINED    1
 #endif
 
+#ifndef configCHECK_HANDLER_INSTALLATION
+    #define configCHECK_HANDLER_INSTALLATION    1
+#else
+    /* The application has explicitly defined configCHECK_HANDLER_INSTALLATION
+     * to 1. The checks work only if configASSERT() is defined. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
+    #endif
+#endif
+
 #ifndef portMEMORY_BARRIER
     #define portMEMORY_BARRIER()
 #endif
diff --git a/portable/ARMv8M/non_secure/portmacrocommon.h b/portable/ARMv8M/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/ARMv8M/non_secure/portmacrocommon.h
+++ b/portable/ARMv8M/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM0/portmacro.h b/portable/GCC/ARM_CM0/portmacro.h
index f967a70a75..3c55b5d0c4 100644
--- a/portable/GCC/ARM_CM0/portmacro.h
+++ b/portable/GCC/ARM_CM0/portmacro.h
@@ -143,20 +143,6 @@ extern void vClearInterruptMaskFromISR( uint32_t ulMask )  __attribute__( ( nake
 
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 portFORCE_INLINE static BaseType_t xPortIsInsideInterrupt( void )
 {
     uint32_t ulCurrentInterrupt;
diff --git a/portable/GCC/ARM_CM23/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM23/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/GCC/ARM_CM23/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM23/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM23_NTZ/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM23_NTZ/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/GCC/ARM_CM23_NTZ/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM23_NTZ/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM3/portmacro.h b/portable/GCC/ARM_CM3/portmacro.h
index ac843131fd..5d91d2139e 100644
--- a/portable/GCC/ARM_CM3/portmacro.h
+++ b/portable/GCC/ARM_CM3/portmacro.h
@@ -130,20 +130,6 @@ extern void vPortExitCritical( void );
 #define portTASK_FUNCTION( vFunction, pvParameters )          void vFunction( void * pvParameters )
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /* Tickless idle/low power functionality. */
 #ifndef portSUPPRESS_TICKS_AND_SLEEP
     extern void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime );
diff --git a/portable/GCC/ARM_CM33/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM33/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/GCC/ARM_CM33/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM33/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM33_NTZ/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM33_NTZ/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/GCC/ARM_CM33_NTZ/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM33_NTZ/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM35P/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM35P/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/GCC/ARM_CM35P/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM35P/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM35P_NTZ/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM35P_NTZ/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/GCC/ARM_CM35P_NTZ/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM35P_NTZ/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM3_MPU/portmacro.h b/portable/GCC/ARM_CM3_MPU/portmacro.h
index bdb528f802..d0822e1443 100644
--- a/portable/GCC/ARM_CM3_MPU/portmacro.h
+++ b/portable/GCC/ARM_CM3_MPU/portmacro.h
@@ -215,20 +215,6 @@ extern void vPortExitCritical( void );
 #define portTASK_FUNCTION( vFunction, pvParameters )          void vFunction( void * pvParameters )
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /* Architecture specific optimisations. */
 #ifndef configUSE_PORT_OPTIMISED_TASK_SELECTION
     #define configUSE_PORT_OPTIMISED_TASK_SELECTION    1
diff --git a/portable/GCC/ARM_CM4F/portmacro.h b/portable/GCC/ARM_CM4F/portmacro.h
index 25089af391..40b2d03e91 100644
--- a/portable/GCC/ARM_CM4F/portmacro.h
+++ b/portable/GCC/ARM_CM4F/portmacro.h
@@ -133,20 +133,6 @@ extern void vPortExitCritical( void );
 #define portTASK_FUNCTION( vFunction, pvParameters )          void vFunction( void * pvParameters )
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /* Tickless idle/low power functionality. */
 #ifndef portSUPPRESS_TICKS_AND_SLEEP
     extern void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime );
diff --git a/portable/GCC/ARM_CM4_MPU/portmacro.h b/portable/GCC/ARM_CM4_MPU/portmacro.h
index c532ce2781..1f62279b04 100644
--- a/portable/GCC/ARM_CM4_MPU/portmacro.h
+++ b/portable/GCC/ARM_CM4_MPU/portmacro.h
@@ -309,20 +309,6 @@ extern void vPortExitCritical( void );
 #define portTASK_FUNCTION( vFunction, pvParameters )          void vFunction( void * pvParameters )
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /* Architecture specific optimisations. */
 #ifndef configUSE_PORT_OPTIMISED_TASK_SELECTION
     #define configUSE_PORT_OPTIMISED_TASK_SELECTION    1
diff --git a/portable/GCC/ARM_CM55/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM55/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/GCC/ARM_CM55/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM55/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM55_NTZ/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM55_NTZ/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/GCC/ARM_CM55_NTZ/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM55_NTZ/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM85/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM85/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/GCC/ARM_CM85/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM85/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/GCC/ARM_CM85_NTZ/non_secure/portmacrocommon.h b/portable/GCC/ARM_CM85_NTZ/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/GCC/ARM_CM85_NTZ/non_secure/portmacrocommon.h
+++ b/portable/GCC/ARM_CM85_NTZ/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM0/portmacro.h b/portable/IAR/ARM_CM0/portmacro.h
index 8f4cb30c52..fa8438fecf 100644
--- a/portable/IAR/ARM_CM0/portmacro.h
+++ b/portable/IAR/ARM_CM0/portmacro.h
@@ -141,20 +141,6 @@ extern void vClearInterruptMaskFromISR( uint32_t ulMask );
 
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 portFORCE_INLINE static BaseType_t xPortIsInsideInterrupt( void )
 {
     uint32_t ulCurrentInterrupt;
diff --git a/portable/IAR/ARM_CM23/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM23/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/IAR/ARM_CM23/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM23/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM23_NTZ/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM23_NTZ/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/IAR/ARM_CM23_NTZ/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM23_NTZ/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM3/portmacro.h b/portable/IAR/ARM_CM3/portmacro.h
index cf1aaa668e..c90a952e2b 100644
--- a/portable/IAR/ARM_CM3/portmacro.h
+++ b/portable/IAR/ARM_CM3/portmacro.h
@@ -173,20 +173,6 @@ extern void vPortExitCritical( void );
 #define portTASK_FUNCTION( vFunction, pvParameters )          void vFunction( void * pvParameters )
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 #ifdef configASSERT
     void vPortValidateInterruptPriority( void );
     #define portASSERT_IF_INTERRUPT_PRIORITY_INVALID()    vPortValidateInterruptPriority()
diff --git a/portable/IAR/ARM_CM33/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM33/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/IAR/ARM_CM33/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM33/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM33_NTZ/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM33_NTZ/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/IAR/ARM_CM33_NTZ/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM33_NTZ/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM35P/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM35P/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/IAR/ARM_CM35P/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM35P/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM35P_NTZ/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM35P_NTZ/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/IAR/ARM_CM35P_NTZ/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM35P_NTZ/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM4F/portmacro.h b/portable/IAR/ARM_CM4F/portmacro.h
index 7b82c0c939..20467efcbb 100644
--- a/portable/IAR/ARM_CM4F/portmacro.h
+++ b/portable/IAR/ARM_CM4F/portmacro.h
@@ -172,20 +172,6 @@ extern void vPortExitCritical( void );
 #define portTASK_FUNCTION( vFunction, pvParameters )          void vFunction( void * pvParameters )
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 #ifdef configASSERT
     void vPortValidateInterruptPriority( void );
     #define portASSERT_IF_INTERRUPT_PRIORITY_INVALID()    vPortValidateInterruptPriority()
diff --git a/portable/IAR/ARM_CM4F_MPU/portmacro.h b/portable/IAR/ARM_CM4F_MPU/portmacro.h
index 6dad44d93e..98b087e11f 100644
--- a/portable/IAR/ARM_CM4F_MPU/portmacro.h
+++ b/portable/IAR/ARM_CM4F_MPU/portmacro.h
@@ -288,20 +288,6 @@ typedef struct MPU_SETTINGS
 #define portYIELD_FROM_ISR( x )    portEND_SWITCHING_ISR( x )
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /* Architecture specific optimisations. */
 #ifndef configUSE_PORT_OPTIMISED_TASK_SELECTION
     #define configUSE_PORT_OPTIMISED_TASK_SELECTION    1
diff --git a/portable/IAR/ARM_CM55/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM55/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/IAR/ARM_CM55/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM55/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM55_NTZ/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM55_NTZ/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/IAR/ARM_CM55_NTZ/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM55_NTZ/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM85/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM85/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/IAR/ARM_CM85/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM85/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */
diff --git a/portable/IAR/ARM_CM85_NTZ/non_secure/portmacrocommon.h b/portable/IAR/ARM_CM85_NTZ/non_secure/portmacrocommon.h
index 083eea5cf0..60ef37380a 100644
--- a/portable/IAR/ARM_CM85_NTZ/non_secure/portmacrocommon.h
+++ b/portable/IAR/ARM_CM85_NTZ/non_secure/portmacrocommon.h
@@ -370,20 +370,6 @@ extern void vClearInterruptMask( uint32_t ulMask ) /* __attribute__(( naked )) P
 #define portEXIT_CRITICAL()                       vPortExitCritical()
 /*-----------------------------------------------------------*/
 
-/* Runtime checks on port configuration */
-#ifndef configCHECK_HANDLER_INSTALLATION
-    #if ( configASSERT_DEFINED == 1 )
-        #define configCHECK_HANDLER_INSTALLATION    1
-    #else
-        #define configCHECK_HANDLER_INSTALLATION    0
-    #endif
-#else
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
-        #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
-    #endif
-#endif
-/*-----------------------------------------------------------*/
-
 /**
  * @brief Tickless idle/low power functionality.
  */

From 84b6981fe54f300561e8d49841753c5a32ff481b Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Wed, 25 Oct 2023 14:10:25 -0700
Subject: [PATCH 18/23] Replicate to Cortex-M7 r0p1

---
 portable/GCC/ARM_CM7/r0p1/port.c | 39 +++++++++++++++++++++++++++++++-
 portable/IAR/ARM_CM7/r0p1/port.c | 39 +++++++++++++++++++++++++++++++-
 2 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/portable/GCC/ARM_CM7/r0p1/port.c b/portable/GCC/ARM_CM7/r0p1/port.c
index c22a3592b7..a34b8067a9 100644
--- a/portable/GCC/ARM_CM7/r0p1/port.c
+++ b/portable/GCC/ARM_CM7/r0p1/port.c
@@ -38,10 +38,14 @@
     #error This port can only be used when the project options are configured to enable hardware floating point support.
 #endif
 
+/* Prototype to which all Interrupt Service Routines conform. */
+typedef void (* portISR_t)( void );
+
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG             ( *( ( volatile uint32_t * ) 0xe000e014 ) )
 #define portNVIC_SYSTICK_CURRENT_VALUE_REG    ( *( ( volatile uint32_t * ) 0xe000e018 ) )
+#define portNVIC_SHPR2_REG                    ( *( ( volatile uint32_t * ) 0xe000ed1c ) )
 #define portNVIC_SHPR3_REG                    ( *( ( volatile uint32_t * ) 0xe000ed20 ) )
 /* ...then bits in the registers. */
 #define portNVIC_SYSTICK_CLK_BIT              ( 1UL << 2UL )
@@ -56,6 +60,11 @@
 #define portNVIC_PENDSV_PRI                   ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 16UL )
 #define portNVIC_SYSTICK_PRI                  ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 24UL )
 
+/* Constants used to check the installation of the FreeRTOS interrupt handlers. */
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xE000ED08 ) )
+#define portVECTOR_INDEX_SVC                  ( 11 )
+#define portVECTOR_INDEX_PENDSV               ( 14 )
+
 /* Constants required to check the validity of an interrupt priority. */
 #define portFIRST_USER_INTERRUPT_NUMBER       ( 16 )
 #define portNVIC_IP_REGISTERS_OFFSET_16       ( 0xE000E3F0 )
@@ -290,6 +299,32 @@ static void prvPortStartFirstTask( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( configASSERT_DEFINED == 1 )
     {
         volatile uint8_t ucOriginalPriority;
@@ -374,9 +409,11 @@ BaseType_t xPortStartScheduler( void )
     }
     #endif /* configASSERT_DEFINED */
 
-    /* Make PendSV and SysTick the lowest priority interrupts. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     /* Start the timer that generates the tick ISR.  Interrupts are disabled
      * here already. */
diff --git a/portable/IAR/ARM_CM7/r0p1/port.c b/portable/IAR/ARM_CM7/r0p1/port.c
index 58129a4dfc..2ae2292787 100644
--- a/portable/IAR/ARM_CM7/r0p1/port.c
+++ b/portable/IAR/ARM_CM7/r0p1/port.c
@@ -45,10 +45,14 @@
     #error configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0.  See http: /*www.FreeRTOS.org/RTOS-Cortex-M3-M4.html */
 #endif
 
+/* Prototype to which all Interrupt Service Routines conform. */
+typedef void (* portISR_t)( void );
+
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG             ( *( ( volatile uint32_t * ) 0xe000e014 ) )
 #define portNVIC_SYSTICK_CURRENT_VALUE_REG    ( *( ( volatile uint32_t * ) 0xe000e018 ) )
+#define portNVIC_SHPR2_REG                    ( *( ( volatile uint32_t * ) 0xe000ed1c ) )
 #define portNVIC_SHPR3_REG                    ( *( ( volatile uint32_t * ) 0xe000ed20 ) )
 /* ...then bits in the registers. */
 #define portNVIC_SYSTICK_CLK_BIT              ( 1UL << 2UL )
@@ -63,6 +67,11 @@
 #define portNVIC_PENDSV_PRI                   ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 16UL )
 #define portNVIC_SYSTICK_PRI                  ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 24UL )
 
+/* Constants used to check the installation of the FreeRTOS interrupt handlers. */
+#define portSCB_VTOR_REG                      ( *( ( portISR_t ** ) 0xE000ED08 ) )
+#define portVECTOR_INDEX_SVC                  ( 11 )
+#define portVECTOR_INDEX_PENDSV               ( 14 )
+
 /* Constants required to check the validity of an interrupt priority. */
 #define portFIRST_USER_INTERRUPT_NUMBER       ( 16 )
 #define portNVIC_IP_REGISTERS_OFFSET_16       ( 0xE000E3F0 )
@@ -234,6 +243,32 @@ static void prvTaskExitError( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
+    /* Applications that route program control to the FreeRTOS interrupt
+     * handlers through intermediate handlers (indirect routing) should set
+     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, is preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Verify correct installation of the FreeRTOS handlers for SVCall and
+         * PendSV. Do not check the installation of the SysTick handler because
+         * the application may provide the OS tick without using the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here can be caused by incorrect installation of
+         * the FreeRTOS handlers. For help installing the handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( configASSERT_DEFINED == 1 )
     {
         volatile uint8_t ucOriginalPriority;
@@ -318,9 +353,11 @@ BaseType_t xPortStartScheduler( void )
     }
     #endif /* configASSERT_DEFINED */
 
-    /* Make PendSV and SysTick the lowest priority interrupts. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     /* Start the timer that generates the tick ISR.  Interrupts are disabled
      * here already. */

From 869f78e2b080f3d3b5550f26747c3c5b8b724a66 Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Wed, 25 Oct 2023 14:19:18 -0700
Subject: [PATCH 19/23] uncrustify

---
 include/FreeRTOS.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/FreeRTOS.h b/include/FreeRTOS.h
index 8fcd932f22..8edb991205 100644
--- a/include/FreeRTOS.h
+++ b/include/FreeRTOS.h
@@ -368,8 +368,9 @@
 #ifndef configCHECK_HANDLER_INSTALLATION
     #define configCHECK_HANDLER_INSTALLATION    1
 #else
-    /* The application has explicitly defined configCHECK_HANDLER_INSTALLATION
-     * to 1. The checks work only if configASSERT() is defined. */
+
+/* The application has explicitly defined configCHECK_HANDLER_INSTALLATION
+ * to 1. The checks work only if configASSERT() is defined. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
         #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
     #endif

From 2e6494b691e4904fa3cbf4addaa06b0b5da5ed97 Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Thu, 26 Oct 2023 08:51:52 -0700
Subject: [PATCH 20/23] Set SVC priority to zero in ARMv7-M MPU ports

---
 portable/GCC/ARM_CM3_MPU/port.c  | 9 ++++-----
 portable/GCC/ARM_CM4_MPU/port.c  | 8 +++-----
 portable/IAR/ARM_CM4F_MPU/port.c | 6 +++---
 3 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/portable/GCC/ARM_CM3_MPU/port.c b/portable/GCC/ARM_CM3_MPU/port.c
index 916b84e823..63de0573a0 100644
--- a/portable/GCC/ARM_CM3_MPU/port.c
+++ b/portable/GCC/ARM_CM3_MPU/port.c
@@ -89,7 +89,6 @@ typedef void (* portISR_t)( void );
 #define portMIN_INTERRUPT_PRIORITY                ( 255UL )
 #define portNVIC_PENDSV_PRI                       ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 16UL )
 #define portNVIC_SYSTICK_PRI                      ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 24UL )
-#define portNVIC_SVC_PRI                          ( ( ( uint32_t ) configMAX_SYSCALL_INTERRUPT_PRIORITY - 1UL ) << 24UL )
 
 /* Constants required to set up the initial stack. */
 #define portINITIAL_XPSR                          ( 0x01000000 )
@@ -420,7 +419,6 @@ void vSVCHandler_C( uint32_t * pulParam ) /* PRIVILEGED_FUNCTION */
     switch( ucSVCNumber )
     {
         case portSVC_START_SCHEDULER:
-            portNVIC_SHPR2_REG |= portNVIC_SVC_PRI;
             prvRestoreContextOfFirstTask();
             break;
 
@@ -905,11 +903,12 @@ BaseType_t xPortStartScheduler( void )
     }
     #endif /* configASSERT_DEFINED */
 
-    /* Make PendSV and SysTick the same priority as the kernel, and the SVC
-     * handler higher priority so it can be used to exit a critical section (where
-     * lower priorities are masked). */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
+
 
     /* Configure the regions in the MPU that are common to all tasks. */
     prvSetupMPU();
diff --git a/portable/GCC/ARM_CM4_MPU/port.c b/portable/GCC/ARM_CM4_MPU/port.c
index 710838d4a3..668ec6c0d7 100644
--- a/portable/GCC/ARM_CM4_MPU/port.c
+++ b/portable/GCC/ARM_CM4_MPU/port.c
@@ -99,7 +99,6 @@ typedef void (* portISR_t)( void );
 #define portMIN_INTERRUPT_PRIORITY                ( 255UL )
 #define portNVIC_PENDSV_PRI                       ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 16UL )
 #define portNVIC_SYSTICK_PRI                      ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 24UL )
-#define portNVIC_SVC_PRI                          ( ( ( uint32_t ) configMAX_SYSCALL_INTERRUPT_PRIORITY - 1UL ) << 24UL )
 
 /* Constants required to manipulate the VFP. */
 #define portFPCCR                                 ( ( volatile uint32_t * ) 0xe000ef34UL ) /* Floating point context control register. */
@@ -460,7 +459,6 @@ void vSVCHandler_C( uint32_t * pulParam ) /* PRIVILEGED_FUNCTION */
     switch( ucSVCNumber )
     {
         case portSVC_START_SCHEDULER:
-            portNVIC_SHPR2_REG |= portNVIC_SVC_PRI;
             prvRestoreContextOfFirstTask();
             break;
 
@@ -1013,11 +1011,11 @@ BaseType_t xPortStartScheduler( void )
     }
     #endif /* configASSERT_DEFINED */
 
-    /* Make PendSV and SysTick the same priority as the kernel, and the SVC
-     * handler higher priority so it can be used to exit a critical section (where
-     * lower priorities are masked). */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     /* Configure the regions in the MPU that are common to all tasks. */
     prvSetupMPU();
diff --git a/portable/IAR/ARM_CM4F_MPU/port.c b/portable/IAR/ARM_CM4F_MPU/port.c
index 0a9d8272c5..a8359a8465 100644
--- a/portable/IAR/ARM_CM4F_MPU/port.c
+++ b/portable/IAR/ARM_CM4F_MPU/port.c
@@ -110,7 +110,6 @@ typedef void (* portISR_t)( void );
 #define portMIN_INTERRUPT_PRIORITY                ( 255UL )
 #define portNVIC_PENDSV_PRI                       ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 16UL )
 #define portNVIC_SYSTICK_PRI                      ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 24UL )
-#define portNVIC_SVC_PRI                          ( ( ( uint32_t ) configMAX_SYSCALL_INTERRUPT_PRIORITY - 1UL ) << 24UL )
 
 /* Constants used to check the installation of the FreeRTOS interrupt handlers. */
 #define portSCB_VTOR_REG                          ( *( ( portISR_t ** ) 0xE000ED08 ) )
@@ -389,7 +388,6 @@ void vPortSVCHandler_C( uint32_t * pulParam ) /* PRIVILEGED_FUNCTION */
     switch( ucSVCNumber )
     {
         case portSVC_START_SCHEDULER:
-            portNVIC_SHPR2_REG |= portNVIC_SVC_PRI;
             vPortRestoreContextOfFirstTask();
             break;
 
@@ -895,9 +893,11 @@ BaseType_t xPortStartScheduler( void )
     }
     #endif /* configASSERT_DEFINED */
 
-    /* Make PendSV and SysTick the lowest priority interrupts. */
+    /* Make PendSV and SysTick the lowest priority interrupts, and make SVCall
+     * the highest priority. */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     /* Configure the regions in the MPU that are common to all tasks. */
     prvSetupMPU();

From cdf8cc5206a5a805f45b0687e736616846904d7b Mon Sep 17 00:00:00 2001
From: Gaurav Aggarwal <aggarg@amazon.com>
Date: Sat, 9 Dec 2023 17:51:21 +0530
Subject: [PATCH 21/23] Update comments

Also update the only remaining MPU port RVDS/ARM_CM4_MPU.

Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
---
 include/FreeRTOS.h                           |  4 +-
 portable/ARMv8M/non_secure/port.c            | 32 ++++++++-----
 portable/GCC/ARM_CM0/port.c                  | 47 +++++++++++--------
 portable/GCC/ARM_CM23/non_secure/port.c      | 32 ++++++++-----
 portable/GCC/ARM_CM23_NTZ/non_secure/port.c  | 32 ++++++++-----
 portable/GCC/ARM_CM3/port.c                  | 32 ++++++++-----
 portable/GCC/ARM_CM33/non_secure/port.c      | 32 ++++++++-----
 portable/GCC/ARM_CM33_NTZ/non_secure/port.c  | 32 ++++++++-----
 portable/GCC/ARM_CM35P/non_secure/port.c     | 32 ++++++++-----
 portable/GCC/ARM_CM35P_NTZ/non_secure/port.c | 32 ++++++++-----
 portable/GCC/ARM_CM3_MPU/port.c              | 32 ++++++++-----
 portable/GCC/ARM_CM4F/port.c                 | 32 ++++++++-----
 portable/GCC/ARM_CM4_MPU/port.c              | 32 ++++++++-----
 portable/GCC/ARM_CM55/non_secure/port.c      | 32 ++++++++-----
 portable/GCC/ARM_CM55_NTZ/non_secure/port.c  | 32 ++++++++-----
 portable/GCC/ARM_CM7/r0p1/port.c             | 32 ++++++++-----
 portable/GCC/ARM_CM85/non_secure/port.c      | 32 ++++++++-----
 portable/GCC/ARM_CM85_NTZ/non_secure/port.c  | 32 ++++++++-----
 portable/IAR/ARM_CM0/port.c                  | 39 +++++++++-------
 portable/IAR/ARM_CM23/non_secure/port.c      | 32 ++++++++-----
 portable/IAR/ARM_CM23_NTZ/non_secure/port.c  | 32 ++++++++-----
 portable/IAR/ARM_CM3/port.c                  | 32 ++++++++-----
 portable/IAR/ARM_CM33/non_secure/port.c      | 32 ++++++++-----
 portable/IAR/ARM_CM33_NTZ/non_secure/port.c  | 32 ++++++++-----
 portable/IAR/ARM_CM35P/non_secure/port.c     | 32 ++++++++-----
 portable/IAR/ARM_CM35P_NTZ/non_secure/port.c | 32 ++++++++-----
 portable/IAR/ARM_CM4F/port.c                 | 32 ++++++++-----
 portable/IAR/ARM_CM4F_MPU/port.c             | 32 ++++++++-----
 portable/IAR/ARM_CM55/non_secure/port.c      | 32 ++++++++-----
 portable/IAR/ARM_CM55_NTZ/non_secure/port.c  | 32 ++++++++-----
 portable/IAR/ARM_CM7/r0p1/port.c             | 32 ++++++++-----
 portable/IAR/ARM_CM85/non_secure/port.c      | 32 ++++++++-----
 portable/IAR/ARM_CM85_NTZ/non_secure/port.c  | 32 ++++++++-----
 portable/RVDS/ARM_CM4_MPU/port.c             | 49 ++++++++++++++++++--
 34 files changed, 697 insertions(+), 402 deletions(-)

diff --git a/include/FreeRTOS.h b/include/FreeRTOS.h
index cc02666e4b..b6caec77f7 100644
--- a/include/FreeRTOS.h
+++ b/include/FreeRTOS.h
@@ -370,8 +370,8 @@
 #else
 
 /* The application has explicitly defined configCHECK_HANDLER_INSTALLATION
- * to 1. The checks work only if configASSERT() is defined. */
-    #if ( configCHECK_HANDLER_INSTALLATION == 1 && configASSERT_DEFINED == 0 )
+ * to 1. The checks requires configASSERT() to be defined. */
+    #if ( ( configCHECK_HANDLER_INSTALLATION == 1 ) && ( configASSERT_DEFINED == 0 ) )
         #error You must define configASSERT() when configCHECK_HANDLER_INSTALLATION is 1.
     #endif
 #endif
diff --git a/portable/ARMv8M/non_secure/port.c b/portable/ARMv8M/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/ARMv8M/non_secure/port.c
+++ b/portable/ARMv8M/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM0/port.c b/portable/GCC/ARM_CM0/port.c
index d7ccee29ac..53bc33a410 100644
--- a/portable/GCC/ARM_CM0/port.c
+++ b/portable/GCC/ARM_CM0/port.c
@@ -34,8 +34,8 @@
 #include "FreeRTOS.h"
 #include "task.h"
 
-/* Prototype to which all Interrupt Service Routines conform. */
-typedef void (* portISR_t)( void );
+/* Prototype of all Interrupt Service Routines (ISRs). */
+typedef void ( * portISR_t )( void );
 
 /* Constants required to manipulate the NVIC. */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
@@ -215,12 +215,12 @@ void vPortStartFirstTask( void )
         "   ldr  r2, pxCurrentTCBConst2 \n"     /* Obtain location of pxCurrentTCB. */
         "   ldr  r3, [r2]               \n"
         "   ldr  r0, [r3]               \n"     /* The first item in pxCurrentTCB is the task top of stack. */
-        "   adds r0, #32                    \n" /* Discard everything up to r0. */
-        "   msr  psp, r0                    \n" /* This is now the new top of stack to use in the task. */
+        "   adds r0, #32                \n"     /* Discard everything up to r0. */
+        "   msr  psp, r0                \n"     /* This is now the new top of stack to use in the task. */
         "   movs r0, #2                 \n"     /* Switch to the psp stack. */
-        "   msr  CONTROL, r0                \n"
+        "   msr  CONTROL, r0            \n"
         "   isb                         \n"
-        "   pop  {r0-r5}                    \n" /* Pop the registers that are saved automatically. */
+        "   pop  {r0-r5}                \n"     /* Pop the registers that are saved automatically. */
         "   mov  lr, r5                 \n"     /* lr is now in r5. */
         "   pop  {r3}                   \n"     /* Return address is now in r3. */
         "   pop  {r2}                   \n"     /* Pop and discard XPSR. */
@@ -238,26 +238,33 @@ void vPortStartFirstTask( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the function xPortPendSVHandler for PendSV
+     *    interrupt.
+     * 2. Indirect Routing - Install separate handler for PendSV interrupt and
+     *    route program control from that handler to xPortPendSVHandler function.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
-        /* Point pxVectorTable at the interrupt vector table. Systems without
-         * a VTOR register provide the value zero in place of the VTOR register
-         * and provide the vector table itself at address 0x00000000. */
+        /* Point pxVectorTable to the interrupt vector table. Systems without
+         * a VTOR register provide the value zero in the VTOR register and
+         * the vector table itself is located at the address 0x00000000. */
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handler for PendSV. Do
-         * not check the installation of the SysTick handler because the
-         * application may provide the OS tick without using the SysTick timer
-         * by overriding the weak function vPortSetupTimerInterrupt().
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handler for PendSV interrupt. We do not check the installation of the
+         * SysTick handler because the application may choose to drive the RTOS
+         * tick using a timer other than the SysTick timer by overriding the
+         * weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handler. For help installing the FreeRTOS handler, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM23/non_secure/port.c b/portable/GCC/ARM_CM23/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/GCC/ARM_CM23/non_secure/port.c
+++ b/portable/GCC/ARM_CM23/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM23_NTZ/non_secure/port.c b/portable/GCC/ARM_CM23_NTZ/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/GCC/ARM_CM23_NTZ/non_secure/port.c
+++ b/portable/GCC/ARM_CM23_NTZ/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM3/port.c b/portable/GCC/ARM_CM3/port.c
index 88246336e8..8ce6fa6c4c 100644
--- a/portable/GCC/ARM_CM3/port.c
+++ b/portable/GCC/ARM_CM3/port.c
@@ -34,8 +34,8 @@
 #include "FreeRTOS.h"
 #include "task.h"
 
-/* Prototype to which all Interrupt Service Routines conform. */
-typedef void (* portISR_t)( void );
+/* Prototype of all Interrupt Service Routines (ISRs). */
+typedef void ( * portISR_t )( void );
 
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
@@ -268,23 +268,31 @@ static void prvPortStartFirstTask( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions vPortSVCHandler and
+     *    xPortPendSVHandler for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    vPortSVCHandler and xPortPendSVHandler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM33/non_secure/port.c b/portable/GCC/ARM_CM33/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/GCC/ARM_CM33/non_secure/port.c
+++ b/portable/GCC/ARM_CM33/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM33_NTZ/non_secure/port.c b/portable/GCC/ARM_CM33_NTZ/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/GCC/ARM_CM33_NTZ/non_secure/port.c
+++ b/portable/GCC/ARM_CM33_NTZ/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM35P/non_secure/port.c b/portable/GCC/ARM_CM35P/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/GCC/ARM_CM35P/non_secure/port.c
+++ b/portable/GCC/ARM_CM35P/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM35P_NTZ/non_secure/port.c b/portable/GCC/ARM_CM35P_NTZ/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/GCC/ARM_CM35P_NTZ/non_secure/port.c
+++ b/portable/GCC/ARM_CM35P_NTZ/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM3_MPU/port.c b/portable/GCC/ARM_CM3_MPU/port.c
index 99260cbd42..d8c18325c4 100644
--- a/portable/GCC/ARM_CM3_MPU/port.c
+++ b/portable/GCC/ARM_CM3_MPU/port.c
@@ -58,8 +58,8 @@
     #define configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS    1
 #endif
 
-/* Prototype to which all Interrupt Service Routines conform. */
-typedef void (* portISR_t)( void );
+/* Prototype of all Interrupt Service Routines (ISRs). */
+typedef void ( * portISR_t )( void );
 
 /* Constants required to access and manipulate the NVIC. */
 #define portNVIC_SYSTICK_CTRL_REG                 ( *( ( volatile uint32_t * ) 0xe000e010 ) )
@@ -743,23 +743,31 @@ static void prvRestoreContextOfFirstTask( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions vPortSVCHandler and
+     *    xPortPendSVHandler for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    vPortSVCHandler and xPortPendSVHandler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM4F/port.c b/portable/GCC/ARM_CM4F/port.c
index 4d92bb3a68..3e5151bdc5 100644
--- a/portable/GCC/ARM_CM4F/port.c
+++ b/portable/GCC/ARM_CM4F/port.c
@@ -38,8 +38,8 @@
     #error This port can only be used when the project options are configured to enable hardware floating point support.
 #endif
 
-/* Prototype to which all Interrupt Service Routines conform. */
-typedef void (* portISR_t)( void );
+/* Prototype of all Interrupt Service Routines (ISRs). */
+typedef void ( * portISR_t )( void );
 
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
@@ -311,23 +311,31 @@ BaseType_t xPortStartScheduler( void )
     configASSERT( portCPUID != portCORTEX_M7_r0p1_ID );
     configASSERT( portCPUID != portCORTEX_M7_r0p0_ID );
 
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions vPortSVCHandler and
+     *    xPortPendSVHandler for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    vPortSVCHandler and xPortPendSVHandler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM4_MPU/port.c b/portable/GCC/ARM_CM4_MPU/port.c
index f7e19d3ecb..0775cfbf89 100644
--- a/portable/GCC/ARM_CM4_MPU/port.c
+++ b/portable/GCC/ARM_CM4_MPU/port.c
@@ -62,8 +62,8 @@
     #define configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS    1
 #endif
 
-/* Prototype to which all Interrupt Service Routines conform. */
-typedef void (* portISR_t)( void );
+/* Prototype of all Interrupt Service Routines (ISRs). */
+typedef void ( * portISR_t )( void );
 
 /* Constants required to access and manipulate the NVIC. */
 #define portNVIC_SYSTICK_CTRL_REG                 ( *( ( volatile uint32_t * ) 0xe000e010 ) )
@@ -829,23 +829,31 @@ BaseType_t xPortStartScheduler( void )
         configASSERT( portCPUID != portCORTEX_M7_r0p0_ID );
     #endif
 
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions vPortSVCHandler and
+     *    xPortPendSVHandler for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    vPortSVCHandler and xPortPendSVHandler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM55/non_secure/port.c b/portable/GCC/ARM_CM55/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/GCC/ARM_CM55/non_secure/port.c
+++ b/portable/GCC/ARM_CM55/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM55_NTZ/non_secure/port.c b/portable/GCC/ARM_CM55_NTZ/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/GCC/ARM_CM55_NTZ/non_secure/port.c
+++ b/portable/GCC/ARM_CM55_NTZ/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM7/r0p1/port.c b/portable/GCC/ARM_CM7/r0p1/port.c
index a34b8067a9..3070445ab2 100644
--- a/portable/GCC/ARM_CM7/r0p1/port.c
+++ b/portable/GCC/ARM_CM7/r0p1/port.c
@@ -38,8 +38,8 @@
     #error This port can only be used when the project options are configured to enable hardware floating point support.
 #endif
 
-/* Prototype to which all Interrupt Service Routines conform. */
-typedef void (* portISR_t)( void );
+/* Prototype of all Interrupt Service Routines (ISRs). */
+typedef void ( * portISR_t )( void );
 
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
@@ -299,23 +299,31 @@ static void prvPortStartFirstTask( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions vPortSVCHandler and
+     *    xPortPendSVHandler for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    vPortSVCHandler and xPortPendSVHandler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM85/non_secure/port.c b/portable/GCC/ARM_CM85/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/GCC/ARM_CM85/non_secure/port.c
+++ b/portable/GCC/ARM_CM85/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/GCC/ARM_CM85_NTZ/non_secure/port.c b/portable/GCC/ARM_CM85_NTZ/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/GCC/ARM_CM85_NTZ/non_secure/port.c
+++ b/portable/GCC/ARM_CM85_NTZ/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/IAR/ARM_CM0/port.c b/portable/IAR/ARM_CM0/port.c
index 62c0adcf8e..571af1f96e 100644
--- a/portable/IAR/ARM_CM0/port.c
+++ b/portable/IAR/ARM_CM0/port.c
@@ -37,8 +37,8 @@
 #include "FreeRTOS.h"
 #include "task.h"
 
-/* Prototype to which all Interrupt Service Routines conform. */
-typedef void (* portISR_t)( void );
+/* Prototype of all Interrupt Service Routines (ISRs). */
+typedef void ( * portISR_t )( void );
 
 /* Constants required to manipulate the NVIC. */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
@@ -175,26 +175,33 @@ static void prvTaskExitError( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the function xPortPendSVHandler for PendSV
+     *    interrupt.
+     * 2. Indirect Routing - Install separate handler for PendSV interrupt and
+     *    route program control from that handler to xPortPendSVHandler function.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
-        /* Point pxVectorTable at the interrupt vector table. Systems without
-         * a VTOR register provide the value zero in place of the VTOR register
-         * and provide the vector table itself at address 0x00000000. */
+        /* Point pxVectorTable to the interrupt vector table. Systems without
+         * a VTOR register provide the value zero in the VTOR register and
+         * the vector table itself is located at the address 0x00000000. */
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handler for PendSV. Do
-         * not check the installation of the SysTick handler because the
-         * application may provide the OS tick without using the SysTick timer
-         * by overriding the weak function vPortSetupTimerInterrupt().
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handler for PendSV interrupt. We do not check the installation of the
+         * SysTick handler because the application may choose to drive the RTOS
+         * tick using a timer other than the SysTick timer by overriding the
+         * weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handler. For help installing the FreeRTOS handler, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/IAR/ARM_CM23/non_secure/port.c b/portable/IAR/ARM_CM23/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/IAR/ARM_CM23/non_secure/port.c
+++ b/portable/IAR/ARM_CM23/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/IAR/ARM_CM23_NTZ/non_secure/port.c b/portable/IAR/ARM_CM23_NTZ/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/IAR/ARM_CM23_NTZ/non_secure/port.c
+++ b/portable/IAR/ARM_CM23_NTZ/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/IAR/ARM_CM3/port.c b/portable/IAR/ARM_CM3/port.c
index 91fe02fe53..72f51debac 100644
--- a/portable/IAR/ARM_CM3/port.c
+++ b/portable/IAR/ARM_CM3/port.c
@@ -41,8 +41,8 @@
     #error configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0.  See http: /*www.FreeRTOS.org/RTOS-Cortex-M3-M4.html */
 #endif
 
-/* Prototype to which all Interrupt Service Routines conform. */
-typedef void (* portISR_t)( void );
+/* Prototype of all Interrupt Service Routines (ISRs). */
+typedef void ( * portISR_t )( void );
 
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
@@ -217,23 +217,31 @@ static void prvTaskExitError( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions vPortSVCHandler and
+     *    xPortPendSVHandler for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    vPortSVCHandler and xPortPendSVHandler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/IAR/ARM_CM33/non_secure/port.c b/portable/IAR/ARM_CM33/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/IAR/ARM_CM33/non_secure/port.c
+++ b/portable/IAR/ARM_CM33/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/IAR/ARM_CM33_NTZ/non_secure/port.c b/portable/IAR/ARM_CM33_NTZ/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/IAR/ARM_CM33_NTZ/non_secure/port.c
+++ b/portable/IAR/ARM_CM33_NTZ/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/IAR/ARM_CM35P/non_secure/port.c b/portable/IAR/ARM_CM35P/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/IAR/ARM_CM35P/non_secure/port.c
+++ b/portable/IAR/ARM_CM35P/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/IAR/ARM_CM35P_NTZ/non_secure/port.c b/portable/IAR/ARM_CM35P_NTZ/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/IAR/ARM_CM35P_NTZ/non_secure/port.c
+++ b/portable/IAR/ARM_CM35P_NTZ/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/IAR/ARM_CM4F/port.c b/portable/IAR/ARM_CM4F/port.c
index d75e48492d..112d657ce1 100644
--- a/portable/IAR/ARM_CM4F/port.c
+++ b/portable/IAR/ARM_CM4F/port.c
@@ -45,8 +45,8 @@
     #error configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0.  See http: /*www.FreeRTOS.org/RTOS-Cortex-M3-M4.html */
 #endif
 
-/* Prototype to which all Interrupt Service Routines conform. */
-typedef void (* portISR_t)( void );
+/* Prototype of all Interrupt Service Routines (ISRs). */
+typedef void ( * portISR_t )( void );
 
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
@@ -255,23 +255,31 @@ BaseType_t xPortStartScheduler( void )
     configASSERT( portCPUID != portCORTEX_M7_r0p1_ID );
     configASSERT( portCPUID != portCORTEX_M7_r0p0_ID );
 
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions vPortSVCHandler and
+     *    xPortPendSVHandler for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    vPortSVCHandler and xPortPendSVHandler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/IAR/ARM_CM4F_MPU/port.c b/portable/IAR/ARM_CM4F_MPU/port.c
index 6f8ef49897..e03699f996 100644
--- a/portable/IAR/ARM_CM4F_MPU/port.c
+++ b/portable/IAR/ARM_CM4F_MPU/port.c
@@ -69,8 +69,8 @@
     #define configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS    1
 #endif
 
-/* Prototype to which all Interrupt Service Routines conform. */
-typedef void (* portISR_t)( void );
+/* Prototype of all Interrupt Service Routines (ISRs). */
+typedef void ( * portISR_t )( void );
 
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG                 ( *( ( volatile uint32_t * ) 0xe000e010 ) )
@@ -719,23 +719,31 @@ BaseType_t xPortStartScheduler( void )
         configASSERT( portCPUID != portCORTEX_M7_r0p0_ID );
     #endif
 
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions vPortSVCHandler and
+     *    xPortPendSVHandler for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    vPortSVCHandler and xPortPendSVHandler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/IAR/ARM_CM55/non_secure/port.c b/portable/IAR/ARM_CM55/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/IAR/ARM_CM55/non_secure/port.c
+++ b/portable/IAR/ARM_CM55/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/IAR/ARM_CM55_NTZ/non_secure/port.c b/portable/IAR/ARM_CM55_NTZ/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/IAR/ARM_CM55_NTZ/non_secure/port.c
+++ b/portable/IAR/ARM_CM55_NTZ/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/IAR/ARM_CM7/r0p1/port.c b/portable/IAR/ARM_CM7/r0p1/port.c
index 2ae2292787..5b42ac93aa 100644
--- a/portable/IAR/ARM_CM7/r0p1/port.c
+++ b/portable/IAR/ARM_CM7/r0p1/port.c
@@ -45,8 +45,8 @@
     #error configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0.  See http: /*www.FreeRTOS.org/RTOS-Cortex-M3-M4.html */
 #endif
 
-/* Prototype to which all Interrupt Service Routines conform. */
-typedef void (* portISR_t)( void );
+/* Prototype of all Interrupt Service Routines (ISRs). */
+typedef void ( * portISR_t )( void );
 
 /* Constants required to manipulate the core.  Registers first... */
 #define portNVIC_SYSTICK_CTRL_REG             ( *( ( volatile uint32_t * ) 0xe000e010 ) )
@@ -243,23 +243,31 @@ static void prvTaskExitError( void )
  */
 BaseType_t xPortStartScheduler( void )
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions vPortSVCHandler and
+     *    xPortPendSVHandler for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    vPortSVCHandler and xPortPendSVHandler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/IAR/ARM_CM85/non_secure/port.c b/portable/IAR/ARM_CM85/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/IAR/ARM_CM85/non_secure/port.c
+++ b/portable/IAR/ARM_CM85/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/IAR/ARM_CM85_NTZ/non_secure/port.c b/portable/IAR/ARM_CM85_NTZ/non_secure/port.c
index 865b583c27..e7f7a6501e 100644
--- a/portable/IAR/ARM_CM85_NTZ/non_secure/port.c
+++ b/portable/IAR/ARM_CM85_NTZ/non_secure/port.c
@@ -81,9 +81,9 @@
 /*-----------------------------------------------------------*/
 
 /**
- * @brief Prototype to which all Interrupt Service Routines conform.
+ * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void (* portISR_t)( void );
+typedef void ( *portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
@@ -1612,23 +1612,31 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
 
 BaseType_t xPortStartScheduler( void ) /* PRIVILEGED_FUNCTION */
 {
-    /* Applications that route program control to the FreeRTOS interrupt
-     * handlers through intermediate handlers (indirect routing) should set
-     * configCHECK_HANDLER_INSTALLATION to 0 in FreeRTOSConfig.h. Direct
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions SVC_Handler and PendSV_Handler
+     *    for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    SVC_Handler and PendSV_Handler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
      * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
-     * is 1, is preferred when possible. */
+     * is 1, should be preferred when possible. */
     #if ( configCHECK_HANDLER_INSTALLATION == 1 )
     {
         const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
 
-        /* Verify correct installation of the FreeRTOS handlers for SVCall and
-         * PendSV. Do not check the installation of the SysTick handler because
-         * the application may provide the OS tick without using the SysTick
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
          * timer by overriding the weak function vPortSetupTimerInterrupt().
          *
-         * Assertion failures here can be caused by incorrect installation of
-         * the FreeRTOS handlers. For help installing the handlers, see
-         * https://www.FreeRTOS.org/FAQHelp.html
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
          *
          * Systems with a configurable address for the interrupt vector table
          * can also encounter assertion failures or even system faults here if
diff --git a/portable/RVDS/ARM_CM4_MPU/port.c b/portable/RVDS/ARM_CM4_MPU/port.c
index 566d4f7373..cc28db85dc 100644
--- a/portable/RVDS/ARM_CM4_MPU/port.c
+++ b/portable/RVDS/ARM_CM4_MPU/port.c
@@ -51,6 +51,9 @@
     #define configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS    1
 #endif
 
+/* Prototype of all Interrupt Service Routines (ISRs). */
+typedef void ( * portISR_t )( void );
+
 /* Constants required to access and manipulate the NVIC. */
 #define portNVIC_SYSTICK_CTRL_REG                 ( *( ( volatile uint32_t * ) 0xe000e010 ) )
 #define portNVIC_SYSTICK_LOAD_REG                 ( *( ( volatile uint32_t * ) 0xe000e014 ) )
@@ -87,7 +90,6 @@
 #define portMIN_INTERRUPT_PRIORITY                ( 255UL )
 #define portNVIC_PENDSV_PRI                       ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 16UL )
 #define portNVIC_SYSTICK_PRI                      ( ( ( uint32_t ) portMIN_INTERRUPT_PRIORITY ) << 24UL )
-#define portNVIC_SVC_PRI                          ( ( ( uint32_t ) configMAX_SYSCALL_INTERRUPT_PRIORITY - 1UL ) << 24UL )
 
 /* Constants required to manipulate the VFP. */
 #define portFPCCR                                 ( ( volatile uint32_t * ) 0xe000ef34UL ) /* Floating point context control register. */
@@ -99,6 +101,11 @@
 #define portINITIAL_CONTROL_IF_UNPRIVILEGED       ( 0x03 )
 #define portINITIAL_CONTROL_IF_PRIVILEGED         ( 0x02 )
 
+/* Constants used to check the installation of the FreeRTOS interrupt handlers. */
+#define portSCB_VTOR_REG                          ( *( ( portISR_t ** ) 0xE000ED08 ) )
+#define portVECTOR_INDEX_SVC                      ( 11 )
+#define portVECTOR_INDEX_PENDSV                   ( 14 )
+
 /* Constants required to check the validity of an interrupt priority. */
 #define portFIRST_USER_INTERRUPT_NUMBER           ( 16 )
 #define portNVIC_IP_REGISTERS_OFFSET_16           ( 0xE000E3F0 )
@@ -386,7 +393,6 @@ void vSVCHandler_C( uint32_t * pulParam )
     switch( ucSVCNumber )
     {
         case portSVC_START_SCHEDULER:
-            portNVIC_SHPR2_REG |= portNVIC_SVC_PRI;
             prvRestoreContextOfFirstTask();
             break;
 
@@ -822,6 +828,40 @@ BaseType_t xPortStartScheduler( void )
         configASSERT( portCPUID != portCORTEX_M7_r0p0_ID );
     #endif
 
+    /* An application can install FreeRTOS interrupt handlers in one of the
+     * folllowing ways:
+     * 1. Direct Routing - Install the functions vPortSVCHandler and
+     *    xPortPendSVHandler for SVCall and PendSV interrupts respectively.
+     * 2. Indirect Routing - Install separate handlers for SVCall and PendSV
+     *    interrupts and route program control from those handlers to
+     *    vPortSVCHandler and xPortPendSVHandler functions.
+     *
+     * Applications that use Indirect Routing must set
+     * configCHECK_HANDLER_INSTALLATION to 0 in their FreeRTOSConfig.h. Direct
+     * routing, which is validated here when configCHECK_HANDLER_INSTALLATION
+     * is 1, should be preferred when possible. */
+    #if ( configCHECK_HANDLER_INSTALLATION == 1 )
+    {
+        const portISR_t * const pxVectorTable = portSCB_VTOR_REG;
+
+        /* Validate that the application has correctly installed the FreeRTOS
+         * handlers for SVCall and PendSV interrupts. We do not check the
+         * installation of the SysTick handler because the application may
+         * choose to drive the RTOS tick using a timer other than the SysTick
+         * timer by overriding the weak function vPortSetupTimerInterrupt().
+         *
+         * Assertion failures here indicate incorrect installation of the
+         * FreeRTOS handlers. For help installing the FreeRTOS handlers, see
+         * https://www.FreeRTOS.org/FAQHelp.html.
+         *
+         * Systems with a configurable address for the interrupt vector table
+         * can also encounter assertion failures or even system faults here if
+         * VTOR is not set correctly to point to the application's vector table. */
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_SVC ] == vPortSVCHandler );
+        configASSERT( pxVectorTable[ portVECTOR_INDEX_PENDSV ] == xPortPendSVHandler );
+    }
+    #endif /* configCHECK_HANDLER_INSTALLATION */
+
     #if ( configASSERT_DEFINED == 1 )
     {
         volatile uint8_t ucOriginalPriority;
@@ -907,10 +947,11 @@ BaseType_t xPortStartScheduler( void )
     #endif /* configASSERT_DEFINED */
 
     /* Make PendSV and SysTick the same priority as the kernel, and the SVC
-     * handler higher priority so it can be used to exit a critical section (where
-     * lower priorities are masked). */
+     * handler highest priority so it can be used to exit a critical section
+     * (where lower priorities are masked). */
     portNVIC_SHPR3_REG |= portNVIC_PENDSV_PRI;
     portNVIC_SHPR3_REG |= portNVIC_SYSTICK_PRI;
+    portNVIC_SHPR2_REG = 0;
 
     /* Configure the regions in the MPU that are common to all tasks. */
     prvSetupMPU();

From eb825c9c050c16700e011894108699d5f2a66801 Mon Sep 17 00:00:00 2001
From: Gaurav Aggarwal <aggarg@amazon.com>
Date: Sat, 9 Dec 2023 18:25:34 +0530
Subject: [PATCH 22/23] Fix build errors

Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
---
 portable/IAR/ARM_CM0/port.c      | 4 ++++
 portable/IAR/ARM_CM3/port.c      | 5 +++++
 portable/IAR/ARM_CM4F/port.c     | 5 +++++
 portable/IAR/ARM_CM4F_MPU/port.c | 5 +++++
 portable/IAR/ARM_CM7/r0p1/port.c | 5 +++++
 portable/RVDS/ARM_CM4_MPU/port.c | 1 +
 6 files changed, 25 insertions(+)

diff --git a/portable/IAR/ARM_CM0/port.c b/portable/IAR/ARM_CM0/port.c
index 571af1f96e..1b9caa13ae 100644
--- a/portable/IAR/ARM_CM0/port.c
+++ b/portable/IAR/ARM_CM0/port.c
@@ -128,6 +128,10 @@ extern void vPortStartFirstTask( void );
  */
 static void prvTaskExitError( void );
 
+/*
+ * FreeRTOS handlers implemented in assembly.
+ */
+extern void xPortPendSVHandler( void );
 /*-----------------------------------------------------------*/
 
 /*
diff --git a/portable/IAR/ARM_CM3/port.c b/portable/IAR/ARM_CM3/port.c
index 72f51debac..4608268720 100644
--- a/portable/IAR/ARM_CM3/port.c
+++ b/portable/IAR/ARM_CM3/port.c
@@ -130,6 +130,11 @@ extern void vPortStartFirstTask( void );
  */
 static void prvTaskExitError( void );
 
+/*
+ * FreeRTOS handlers implemented in assembly.
+ */
+extern void vPortSVCHandler( void );
+extern void xPortPendSVHandler( void );
 /*-----------------------------------------------------------*/
 
 /* Each task maintains its own interrupt status in the critical nesting
diff --git a/portable/IAR/ARM_CM4F/port.c b/portable/IAR/ARM_CM4F/port.c
index 112d657ce1..763ff2a5cb 100644
--- a/portable/IAR/ARM_CM4F/port.c
+++ b/portable/IAR/ARM_CM4F/port.c
@@ -150,6 +150,11 @@ extern void vPortEnableVFP( void );
  */
 static void prvTaskExitError( void );
 
+/*
+ * FreeRTOS handlers implemented in assembly.
+ */
+extern void vPortSVCHandler( void );
+extern void xPortPendSVHandler( void );
 /*-----------------------------------------------------------*/
 
 /* Each task maintains its own interrupt status in the critical nesting
diff --git a/portable/IAR/ARM_CM4F_MPU/port.c b/portable/IAR/ARM_CM4F_MPU/port.c
index e03699f996..c3bab2671c 100644
--- a/portable/IAR/ARM_CM4F_MPU/port.c
+++ b/portable/IAR/ARM_CM4F_MPU/port.c
@@ -289,6 +289,11 @@ BaseType_t xPortIsTaskPrivileged( void ) PRIVILEGED_FUNCTION;
  */
 void vPortSwitchToUserMode( void );
 
+/*
+ * FreeRTOS handlers implemented in assembly.
+ */
+extern void vPortSVCHandler( void ) PRIVILEGED_FUNCTION;
+extern void xPortPendSVHandler( void ) PRIVILEGED_FUNCTION;
 /*-----------------------------------------------------------*/
 
 /* Each task maintains its own interrupt status in the critical nesting
diff --git a/portable/IAR/ARM_CM7/r0p1/port.c b/portable/IAR/ARM_CM7/r0p1/port.c
index 5b42ac93aa..2790028f42 100644
--- a/portable/IAR/ARM_CM7/r0p1/port.c
+++ b/portable/IAR/ARM_CM7/r0p1/port.c
@@ -144,6 +144,11 @@ extern void vPortEnableVFP( void );
  */
 static void prvTaskExitError( void );
 
+/*
+ * FreeRTOS handlers implemented in assembly.
+ */
+extern void vPortSVCHandler( void );
+extern void xPortPendSVHandler( void );
 /*-----------------------------------------------------------*/
 
 /* Each task maintains its own interrupt status in the critical nesting
diff --git a/portable/RVDS/ARM_CM4_MPU/port.c b/portable/RVDS/ARM_CM4_MPU/port.c
index cc28db85dc..af4ea632f0 100644
--- a/portable/RVDS/ARM_CM4_MPU/port.c
+++ b/portable/RVDS/ARM_CM4_MPU/port.c
@@ -1237,6 +1237,7 @@ __asm void vPortEnableVFP( void )
     orr r1, r1, #( 0xf << 20 ) /* Enable CP10 and CP11 coprocessors, then save back. */
     str r1, [ r0 ]
     bx r14
+    nop
 /* *INDENT-ON* */
 }
 /*-----------------------------------------------------------*/

From 53cfc6d234ac1d97743a7b0887f08f87373b038a Mon Sep 17 00:00:00 2001
From: Gaurav Aggarwal <aggarg@amazon.com>
Date: Sun, 10 Dec 2023 23:15:16 +0530
Subject: [PATCH 23/23] Fix formatting

Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
---
 portable/ARMv8M/non_secure/port.c            | 2 +-
 portable/GCC/ARM_CM23/non_secure/port.c      | 2 +-
 portable/GCC/ARM_CM23_NTZ/non_secure/port.c  | 2 +-
 portable/GCC/ARM_CM33/non_secure/port.c      | 2 +-
 portable/GCC/ARM_CM33_NTZ/non_secure/port.c  | 2 +-
 portable/GCC/ARM_CM35P/non_secure/port.c     | 2 +-
 portable/GCC/ARM_CM35P_NTZ/non_secure/port.c | 2 +-
 portable/GCC/ARM_CM55/non_secure/port.c      | 2 +-
 portable/GCC/ARM_CM55_NTZ/non_secure/port.c  | 2 +-
 portable/GCC/ARM_CM85/non_secure/port.c      | 2 +-
 portable/GCC/ARM_CM85_NTZ/non_secure/port.c  | 2 +-
 portable/IAR/ARM_CM23/non_secure/port.c      | 2 +-
 portable/IAR/ARM_CM23_NTZ/non_secure/port.c  | 2 +-
 portable/IAR/ARM_CM33/non_secure/port.c      | 2 +-
 portable/IAR/ARM_CM33_NTZ/non_secure/port.c  | 2 +-
 portable/IAR/ARM_CM35P/non_secure/port.c     | 2 +-
 portable/IAR/ARM_CM35P_NTZ/non_secure/port.c | 2 +-
 portable/IAR/ARM_CM55/non_secure/port.c      | 2 +-
 portable/IAR/ARM_CM55_NTZ/non_secure/port.c  | 2 +-
 portable/IAR/ARM_CM85/non_secure/port.c      | 2 +-
 portable/IAR/ARM_CM85_NTZ/non_secure/port.c  | 2 +-
 21 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/portable/ARMv8M/non_secure/port.c b/portable/ARMv8M/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/ARMv8M/non_secure/port.c
+++ b/portable/ARMv8M/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/GCC/ARM_CM23/non_secure/port.c b/portable/GCC/ARM_CM23/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/GCC/ARM_CM23/non_secure/port.c
+++ b/portable/GCC/ARM_CM23/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/GCC/ARM_CM23_NTZ/non_secure/port.c b/portable/GCC/ARM_CM23_NTZ/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/GCC/ARM_CM23_NTZ/non_secure/port.c
+++ b/portable/GCC/ARM_CM23_NTZ/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/GCC/ARM_CM33/non_secure/port.c b/portable/GCC/ARM_CM33/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/GCC/ARM_CM33/non_secure/port.c
+++ b/portable/GCC/ARM_CM33/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/GCC/ARM_CM33_NTZ/non_secure/port.c b/portable/GCC/ARM_CM33_NTZ/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/GCC/ARM_CM33_NTZ/non_secure/port.c
+++ b/portable/GCC/ARM_CM33_NTZ/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/GCC/ARM_CM35P/non_secure/port.c b/portable/GCC/ARM_CM35P/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/GCC/ARM_CM35P/non_secure/port.c
+++ b/portable/GCC/ARM_CM35P/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/GCC/ARM_CM35P_NTZ/non_secure/port.c b/portable/GCC/ARM_CM35P_NTZ/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/GCC/ARM_CM35P_NTZ/non_secure/port.c
+++ b/portable/GCC/ARM_CM35P_NTZ/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/GCC/ARM_CM55/non_secure/port.c b/portable/GCC/ARM_CM55/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/GCC/ARM_CM55/non_secure/port.c
+++ b/portable/GCC/ARM_CM55/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/GCC/ARM_CM55_NTZ/non_secure/port.c b/portable/GCC/ARM_CM55_NTZ/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/GCC/ARM_CM55_NTZ/non_secure/port.c
+++ b/portable/GCC/ARM_CM55_NTZ/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/GCC/ARM_CM85/non_secure/port.c b/portable/GCC/ARM_CM85/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/GCC/ARM_CM85/non_secure/port.c
+++ b/portable/GCC/ARM_CM85/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/GCC/ARM_CM85_NTZ/non_secure/port.c b/portable/GCC/ARM_CM85_NTZ/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/GCC/ARM_CM85_NTZ/non_secure/port.c
+++ b/portable/GCC/ARM_CM85_NTZ/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/IAR/ARM_CM23/non_secure/port.c b/portable/IAR/ARM_CM23/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/IAR/ARM_CM23/non_secure/port.c
+++ b/portable/IAR/ARM_CM23/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/IAR/ARM_CM23_NTZ/non_secure/port.c b/portable/IAR/ARM_CM23_NTZ/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/IAR/ARM_CM23_NTZ/non_secure/port.c
+++ b/portable/IAR/ARM_CM23_NTZ/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/IAR/ARM_CM33/non_secure/port.c b/portable/IAR/ARM_CM33/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/IAR/ARM_CM33/non_secure/port.c
+++ b/portable/IAR/ARM_CM33/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/IAR/ARM_CM33_NTZ/non_secure/port.c b/portable/IAR/ARM_CM33_NTZ/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/IAR/ARM_CM33_NTZ/non_secure/port.c
+++ b/portable/IAR/ARM_CM33_NTZ/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/IAR/ARM_CM35P/non_secure/port.c b/portable/IAR/ARM_CM35P/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/IAR/ARM_CM35P/non_secure/port.c
+++ b/portable/IAR/ARM_CM35P/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/IAR/ARM_CM35P_NTZ/non_secure/port.c b/portable/IAR/ARM_CM35P_NTZ/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/IAR/ARM_CM35P_NTZ/non_secure/port.c
+++ b/portable/IAR/ARM_CM35P_NTZ/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/IAR/ARM_CM55/non_secure/port.c b/portable/IAR/ARM_CM55/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/IAR/ARM_CM55/non_secure/port.c
+++ b/portable/IAR/ARM_CM55/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/IAR/ARM_CM55_NTZ/non_secure/port.c b/portable/IAR/ARM_CM55_NTZ/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/IAR/ARM_CM55_NTZ/non_secure/port.c
+++ b/portable/IAR/ARM_CM55_NTZ/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/IAR/ARM_CM85/non_secure/port.c b/portable/IAR/ARM_CM85/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/IAR/ARM_CM85/non_secure/port.c
+++ b/portable/IAR/ARM_CM85/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**
diff --git a/portable/IAR/ARM_CM85_NTZ/non_secure/port.c b/portable/IAR/ARM_CM85_NTZ/non_secure/port.c
index e7f7a6501e..a5ed7004a6 100644
--- a/portable/IAR/ARM_CM85_NTZ/non_secure/port.c
+++ b/portable/IAR/ARM_CM85_NTZ/non_secure/port.c
@@ -83,7 +83,7 @@
 /**
  * @brief Prototype of all Interrupt Service Routines (ISRs).
  */
-typedef void ( *portISR_t )( void );
+typedef void ( * portISR_t )( void );
 /*-----------------------------------------------------------*/
 
 /**