ARM interrupt attribute warning doesn't have its own flag #34876
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bugzilla
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clang:diagnostics
New/improved warning or error message in Clang, but not in clang-tidy or static analyzer
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patch to fix this in: https://reviews.llvm.org/D74812 |
chrisnc
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May 12, 2024
This warning has two issues: - The interrupt attribute doesn't only change how volatile registers are treated; it also causes the function to return using an exception return instruction. This warning allows calls from one function with the interrupt attribute to another, and the diagnostic text suggests that not having the attribute on the callee is the problem. Actually making such a call will lead to a double exception return, which is unpredictable according to the ARM architecture manual section B9.1.1, "Restrictions on exception return instructions". Even on machines where an exception return from user/system mode is tolerated, if the callee's interrupt type is anything other than a supervisor call or secure monitor call, it will also return to a different address than a normal function would. For example, returning from an "IRQ" handler will return to lr - 4, which will generally result in calling the same function again. - It is part of the -Wextra diagnostic group and can't be individually disabled when using -Wextra, which also means the diagnostic text of this specific warning appears in the documentation of -Wextra. This change addresses both issues. Rather than check that the callee has the interrupt attribute, check that it uses the soft-float feature, which will prevent use of VFP state. The warning is also given its own diagnostic group. Closes llvm#34876.
chrisnc
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May 23, 2024
This warning has two issues: - The interrupt attribute doesn't only change how volatile registers are treated; it also causes the function to return using an exception return instruction. This warning allows calls from one function with the interrupt attribute to another, and the diagnostic text suggests that not having the attribute on the callee is the problem. Actually making such a call will lead to a double exception return, which is unpredictable according to the ARM architecture manual section B9.1.1, "Restrictions on exception return instructions". Even on machines where an exception return from user/system mode is tolerated, if the callee's interrupt type is anything other than a supervisor call or secure monitor call, it will also return to a different address than a normal function would. For example, returning from an "IRQ" handler will return to lr - 4, which will generally result in calling the same function again. - It is part of the -Wextra diagnostic group and can't be individually disabled when using -Wextra, which also means the diagnostic text of this specific warning appears in the documentation of -Wextra. This change addresses both issues. Rather than check that the callee has the interrupt attribute, check that it uses the soft-float feature, which will prevent use of VFP state. The warning is also given its own diagnostic group. Closes llvm#34876.
chrisnc
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May 29, 2024
This warning has two issues: - The interrupt attribute doesn't only change how volatile registers are treated; it also causes the function to return using an exception return instruction. This warning allows calls from one function with the interrupt attribute to another, and the diagnostic text suggests that not having the attribute on the callee is the problem. Actually making such a call will lead to a double exception return, which is unpredictable according to the ARM architecture manual section B9.1.1, "Restrictions on exception return instructions". Even on machines where an exception return from user/system mode is tolerated, if the callee's interrupt type is anything other than a supervisor call or secure monitor call, it will also return to a different address than a normal function would. For example, returning from an "IRQ" handler will return to lr - 4, which will generally result in calling the same function again. - It is part of the -Wextra diagnostic group and can't be individually disabled when using -Wextra, which also means the diagnostic text of this specific warning appears in the documentation of -Wextra. This change addresses both issues. Rather than check that the callee has the interrupt attribute, check that it uses the soft-float feature, which will prevent use of VFP state. The warning is also given its own diagnostic group. Closes llvm#34876.
chrisnc
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Jun 13, 2024
This warning has two issues: - The interrupt attribute doesn't only change how volatile registers are treated; it also causes the function to return using an exception return instruction. This warning allows calls from one function with the interrupt attribute to another, and the diagnostic text suggests that not having the attribute on the callee is the problem. Actually making such a call will lead to a double exception return, which is unpredictable according to the ARM architecture manual section B9.1.1, "Restrictions on exception return instructions". Even on machines where an exception return from user/system mode is tolerated, if the callee's interrupt type is anything other than a supervisor call or secure monitor call, it will also return to a different address than a normal function would. For example, returning from an "IRQ" handler will return to lr - 4, which will generally result in calling the same function again. - It is part of the -Wextra diagnostic group and can't be individually disabled when using -Wextra, which also means the diagnostic text of this specific warning appears in the documentation of -Wextra. This change addresses both issues. Rather than check that the callee has the interrupt attribute, check that it uses the soft-float feature, which will prevent use of VFP state. The warning is also given its own diagnostic group. Closes llvm#34876.
chrisnc
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Jun 13, 2024
This warning has two issues: - The interrupt attribute doesn't only change how volatile registers are treated; it also causes the function to return using an exception return instruction. This warning allows calls from one function with the interrupt attribute to another, and the diagnostic text suggests that not having the attribute on the callee is the problem. Actually making such a call will lead to a double exception return, which is unpredictable according to the ARM architecture manual section B9.1.1, "Restrictions on exception return instructions". Even on machines where an exception return from user/system mode is tolerated, if the callee's interrupt type is anything other than a supervisor call or secure monitor call, it will also return to a different address than a normal function would. For example, returning from an "IRQ" handler will return to lr - 4, which will generally result in calling the same function again. - It is part of the -Wextra diagnostic group and can't be individually disabled when using -Wextra, which also means the diagnostic text of this specific warning appears in the documentation of -Wextra. This change addresses both issues. Rather than check that the callee has the interrupt attribute, check that it uses the soft-float feature, which will prevent use of VFP state. The warning is also given its own diagnostic group. Closes llvm#34876.
chrisnc
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Jun 14, 2024
This warning has three issues: - The interrupt attribute causes the function to return using an exception return instruction. This warning allows calls from one function with the interrupt attribute to another, and the diagnostic text suggests that not having the attribute on the callee is a problem. Actually making such a call will lead to a double exception return, which is unpredictable according to the ARM architecture manual section B9.1.1, "Restrictions on exception return instructions". Even on machines where an exception return from user/system mode is tolerated, if the callee's interrupt type is anything other than a supervisor call or secure monitor call, it will also return to a different address than a normal function would. For example, returning from an "IRQ" handler will return to lr - 4, which will generally result in calling the same function again. - The interrupt attribute currently does not cause caller-saved VFP registers to be saved and restored if they are used, so putting __attribute__((interrupt)) on a called function doesn't prevent it from clobbering VFP state. - It is part of the -Wextra diagnostic group and can't be individually disabled when using -Wextra, which also means the diagnostic text of this specific warning appears in the documentation of -Wextra. This change addresses all three issues by instead generating a warning for any interrupt handler where the vfp feature is enabled. The warning is also given its own diagnostic group. Closes llvm#34876.
chrisnc
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Jun 23, 2024
This warning has three issues: - The interrupt attribute causes the function to return using an exception return instruction. This warning allows calls from one function with the interrupt attribute to another, and the diagnostic text suggests that not having the attribute on the callee is a problem. Actually making such a call will lead to a double exception return, which is unpredictable according to the ARM architecture manual section B9.1.1, "Restrictions on exception return instructions". Even on machines where an exception return from user/system mode is tolerated, if the callee's interrupt type is anything other than a supervisor call or secure monitor call, it will also return to a different address than a normal function would. For example, returning from an "IRQ" handler will return to lr - 4, which will generally result in calling the same function again. - The interrupt attribute currently does not cause caller-saved VFP registers to be saved and restored if they are used, so putting __attribute__((interrupt)) on a called function doesn't prevent it from clobbering VFP state. - It is part of the -Wextra diagnostic group and can't be individually disabled when using -Wextra, which also means the diagnostic text of this specific warning appears in the documentation of -Wextra. This change addresses all three issues by instead generating a warning for any interrupt handler where the vfp feature is enabled. The warning is also given its own diagnostic group. Closes llvm#34876.
chrisnc
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Jun 28, 2024
This warning has three issues: - The interrupt attribute causes the function to return using an exception return instruction. This warning allows calls from one function with the interrupt attribute to another, and the diagnostic text suggests that not having the attribute on the callee is a problem. Actually making such a call will lead to a double exception return, which is unpredictable according to the ARM architecture manual section B9.1.1, "Restrictions on exception return instructions". Even on machines where an exception return from user/system mode is tolerated, if the callee's interrupt type is anything other than a supervisor call or secure monitor call, it will also return to a different address than a normal function would. For example, returning from an "IRQ" handler will return to lr - 4, which will generally result in calling the same function again. - The interrupt attribute currently does not cause caller-saved VFP registers to be saved and restored if they are used, so putting __attribute__((interrupt)) on a called function doesn't prevent it from clobbering VFP state. - It is part of the -Wextra diagnostic group and can't be individually disabled when using -Wextra, which also means the diagnostic text of this specific warning appears in the documentation of -Wextra. This change addresses all three issues by instead generating a warning for any interrupt handler where the vfp feature is enabled. The warning is also given its own diagnostic group. Closes llvm#34876.
chrisnc
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Jul 2, 2024
This warning has three issues: - The interrupt attribute causes the function to return using an exception return instruction. This warning allows calls from one function with the interrupt attribute to another, and the diagnostic text suggests that not having the attribute on the callee is a problem. Actually making such a call will lead to a double exception return, which is unpredictable according to the ARM architecture manual section B9.1.1, "Restrictions on exception return instructions". Even on machines where an exception return from user/system mode is tolerated, if the callee's interrupt type is anything other than a supervisor call or secure monitor call, it will also return to a different address than a normal function would. For example, returning from an "IRQ" handler will return to lr - 4, which will generally result in calling the same function again. - The interrupt attribute currently does not cause caller-saved VFP registers to be saved and restored if they are used, so putting __attribute__((interrupt)) on a called function doesn't prevent it from clobbering VFP state. - It is part of the -Wextra diagnostic group and can't be individually disabled when using -Wextra, which also means the diagnostic text of this specific warning appears in the documentation of -Wextra. This change addresses all three issues by instead generating a warning for any interrupt handler where the vfp feature is enabled. The warning is also given its own diagnostic group. Closes llvm#34876.
chrisnc
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Jul 9, 2024
This warning has three issues: - The interrupt attribute causes the function to return using an exception return instruction. This warning allows calls from one function with the interrupt attribute to another, and the diagnostic text suggests that not having the attribute on the callee is a problem. Actually making such a call will lead to a double exception return, which is unpredictable according to the ARM architecture manual section B9.1.1, "Restrictions on exception return instructions". Even on machines where an exception return from user/system mode is tolerated, if the callee's interrupt type is anything other than a supervisor call or secure monitor call, it will also return to a different address than a normal function would. For example, returning from an "IRQ" handler will return to lr - 4, which will generally result in calling the same function again. - The interrupt attribute currently does not cause caller-saved VFP registers to be saved and restored if they are used, so putting __attribute__((interrupt)) on a called function doesn't prevent it from clobbering VFP state. - It is part of the -Wextra diagnostic group and can't be individually disabled when using -Wextra, which also means the diagnostic text of this specific warning appears in the documentation of -Wextra. This change addresses all three issues by instead generating a warning for any interrupt handler where the vfp feature is enabled. The warning is also given its own diagnostic group. Closes llvm#34876.
chrisnc
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Jul 10, 2024
This warning has three issues: - The interrupt attribute causes the function to return using an exception return instruction. This warning allows calls from one function with the interrupt attribute to another, and the diagnostic text suggests that not having the attribute on the callee is a problem. Actually making such a call will lead to a double exception return, which is unpredictable according to the ARM architecture manual section B9.1.1, "Restrictions on exception return instructions". Even on machines where an exception return from user/system mode is tolerated, if the callee's interrupt type is anything other than a supervisor call or secure monitor call, it will also return to a different address than a normal function would. For example, returning from an "IRQ" handler will return to lr - 4, which will generally result in calling the same function again. - The interrupt attribute currently does not cause caller-saved VFP registers to be saved and restored if they are used, so putting __attribute__((interrupt)) on a called function doesn't prevent it from clobbering VFP state. - It is part of the -Wextra diagnostic group and can't be individually disabled when using -Wextra, which also means the diagnostic text of this specific warning appears in the documentation of -Wextra. This change addresses all three issues by instead generating a warning for any interrupt handler where the vfp feature is enabled. The warning is also given its own diagnostic group. Closes llvm#34876.
chrisnc
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to chrisnc/llvm-project
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this issue
Jul 10, 2024
This warning has three issues: - The interrupt attribute causes the function to return using an exception return instruction. This warning allows calls from one function with the interrupt attribute to another, and the diagnostic text suggests that not having the attribute on the callee is a problem. Actually making such a call will lead to a double exception return, which is unpredictable according to the ARM architecture manual section B9.1.1, "Restrictions on exception return instructions". Even on machines where an exception return from user/system mode is tolerated, if the callee's interrupt type is anything other than a supervisor call or secure monitor call, it will also return to a different address than a normal function would. For example, returning from an "IRQ" handler will return to lr - 4, which will generally result in calling the same function again. - The interrupt attribute currently does not cause caller-saved VFP registers to be saved and restored if they are used, so putting __attribute__((interrupt)) on a called function doesn't prevent it from clobbering VFP state. - It is part of the -Wextra diagnostic group and can't be individually disabled when using -Wextra, which also means the diagnostic text of this specific warning appears in the documentation of -Wextra. This change addresses all three issues by instead generating a warning for any interrupt handler where the vfp feature is enabled. The warning is also given its own diagnostic group. Closes llvm#34876.
EugeneZelenko
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clang:diagnostics
aaryanshukla
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Jul 14, 2024
[clang][ARM] Fix warning for using VFP from interrupts. This warning has three issues: - The interrupt attribute causes the function to return using an exception return instruction. This warning allows calls from one function with the interrupt attribute to another, and the diagnostic text suggests that not having the attribute on the callee is a problem. Actually making such a call will lead to a double exception return, which is unpredictable according to the ARM architecture manual section B9.1.1, "Restrictions on exception return instructions". Even on machines where an exception return from user/system mode is tolerated, if the callee's interrupt type is anything other than a supervisor call or secure monitor call, it will also return to a different address than a normal function would. For example, returning from an "IRQ" handler will return to lr - 4, which will generally result in calling the same function again. - The interrupt attribute currently does not cause caller-saved VFP registers to be saved and restored if they are used, so putting __attribute__((interrupt)) on a called function doesn't prevent it from clobbering VFP state. - It is part of the -Wextra diagnostic group and can't be individually disabled when using -Wextra, which also means the diagnostic text of this specific warning appears in the documentation of -Wextra. This change addresses all three issues by instead generating a warning for any interrupt handler where the vfp feature is enabled. The warning is also given its own diagnostic group. Closes llvm#34876. [clang][ARM] Emit an error when an interrupt handler is called. Closes llvm#95359.
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Extended Description
https://reviews.llvm.org/D28820
Not sure what to call it. How about
-Warm-interrupt-safety?The text was updated successfully, but these errors were encountered: