[libcpu-riscv]: [common64 virt64]:Fix the normal startup of the SMP architecture.

Tests conducted on bsp: qemu-virt64-riscv. Currently, the command line cannot start normally.
This is because the SMP architecture requires scheduling information update operations;
secondly, it does not yet support context switching operations within interrupts.

Solution: In the two functions (rt_hw_context_switch_to and rt_hw_context_switch)
in context_gcc.S, add a call to rt_cpus_lock_status_restore to update the scheduler information.

For the second issue, if scheduling is triggered in an interrupt, pcpu->irq_switch_flag will
be set to 1; thus, rt_scheduler_do_irq_switch is called in interrupt_gcc.S to determine
whether to perform context switching.

Signed-off-by: Mengchen Teng <[email protected]>

Author: Tm-C-mT

libcpu/risc-v/common64/context_gcc.S

@@ -69,14 +69,27 @@
 .endm
 
 /*
+ * #ifdef RT_USING_SMP
+ * void rt_hw_context_switch_to(rt_ubase_t to, stuct rt_thread *to_thread);
+ * #else
  * void rt_hw_context_switch_to(rt_ubase_t to);
- *
- * a0 --> to SP pointer
+ * #endif
+ * a0 --> to
+ * a1 --> to_thread
  */
 .globl rt_hw_context_switch_to
 rt_hw_context_switch_to:
     LOAD sp, (a0)
 
+#ifdef RT_USING_SMP
+    /*
+     * Pass the previous CPU lock status to 
+     * rt_cpus_lock_status_restore for restoration 
+     */ 
+    mv   a0,   a1
+    call  rt_cpus_lock_status_restore
+#endif
+
     call rt_thread_self
     mv s1, a0
 
@@ -88,10 +101,15 @@ rt_hw_context_switch_to:
     sret
 
 /*
+ * #ifdef RT_USING_SMP
+ * void rt_hw_context_switch(rt_ubase_t from, rt_ubase_t to, struct rt_thread *to_thread);
+ * #else
  * void rt_hw_context_switch(rt_ubase_t from, rt_ubase_t to);
+ * #endif
  *
  * a0 --> from SP pointer
  * a1 --> to SP pointer
+ * a2 --> to_thread
  *
  * It should only be used on local interrupt disable
  */
@@ -103,6 +121,15 @@ rt_hw_context_switch:
     // restore to thread SP
     LOAD sp, (a1)
 
+#ifdef RT_USING_SMP
+    /*
+     * Pass the previous CPU lock status to 
+     * rt_cpus_lock_status_restore for restoration 
+     */ 
+    mv   a0,   a2
+    call  rt_cpus_lock_status_restore
+#endif /*RT_USING_SMP*/
+
     // restore Address Space
     call rt_thread_self
     mv s1, a0

libcpu/risc-v/common64/cpuport.c

@@ -117,6 +117,18 @@ void rt_hw_context_switch_interrupt(rt_ubase_t from, rt_ubase_t to, rt_thread_t
 
     return;
 }
+#else
+void rt_hw_context_switch_interrupt(void *context, rt_ubase_t from, rt_ubase_t to, struct rt_thread *to_thread)
+{   
+    /* Perform architecture-specific context switch. This call will
+     * restore the target thread context and should not return when a
+     * switch is performed. The caller (scheduler) invoked this function
+     * in a context where local IRQs are disabled. */
+    rt_uint32_t level;
+    level = rt_hw_local_irq_disable();
+    rt_hw_context_switch((rt_ubase_t)from, (rt_ubase_t)to, to_thread);
+    rt_hw_local_irq_enable(level);
+}
 #endif /* end of RT_USING_SMP */
 
 /** shutdown CPU */

libcpu/risc-v/common64/interrupt_gcc.S

@@ -60,10 +60,17 @@ _handle_interrupt_and_exception:
     call    handle_trap
 
 _interrupt_exit:
+#ifndef RT_USING_SMP
     la      s0, rt_thread_switch_interrupt_flag
     lw      s2, 0(s0)
     beqz    s2, _resume_execution
     sw      zero, 0(s0)
+#else
+    mv      a0, sp
+    call    rt_scheduler_do_irq_switch
+    // if failed, jump to __resume_execution
+    j       _resume_execution
+#endif /* RT_USING_SMP */
 
 _context_switch:
     la      t0, rt_interrupt_from_thread

libcpu/risc-v/virt64/interrupt.c

@@ -94,6 +94,14 @@ void rt_hw_interrupt_init()
 }
 
 #ifdef RT_USING_SMP
+rt_bool_t rt_hw_interrupt_is_disabled(void)
+{
+    /* Determine the interrupt enable state */
+    rt_ubase_t sstatus;
+    __asm__ volatile("csrr %0, sstatus" : "=r"(sstatus));
+    return (sstatus & SSTATUS_SIE) == 0;
+}
+
 void rt_hw_spin_lock_init(rt_hw_spinlock_t *_lock)
 {