From: Mark Rutland Date: Thu, 17 Oct 2024 09:25:29 +0000 (+0100) Subject: arm64: pt_regs: assert pt_regs is a multiple of 16 bytes X-Git-Tag: v6.13-rc1~203^2~2^9~10 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c87df9cb9a216bc87951087a2592633cdc2737d4;p=thirdparty%2Fkernel%2Fstable.git arm64: pt_regs: assert pt_regs is a multiple of 16 bytes To ensure that the stack is correctly aligned when branching to C code, we require that struct pt_regs is a multiple of 16 bytes, as noted in a comment. Add an explicit assertion for this, so that any accidental violation of this requirement will be caught by the compiler. Signed-off-by: Mark Rutland Reviewed-by: Mark Brown Reviewed-by: Miroslav Benes Reviewed-by: Puranjay Mohan Cc: Ard Biesheuvel Cc: Josh Poimboeuf Cc: Kalesh Singh Cc: Madhavan T. Venkataraman Cc: Marc Zyngier Cc: Will Deacon Link: https://lore.kernel.org/r/20241017092538.1859841-2-mark.rutland@arm.com Signed-off-by: Catalin Marinas --- diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h index 0abe975d68a8e..10eca3a3fed49 100644 --- a/arch/arm64/include/asm/ptrace.h +++ b/arch/arm64/include/asm/ptrace.h @@ -149,8 +149,7 @@ static inline unsigned long pstate_to_compat_psr(const unsigned long pstate) /* * This struct defines the way the registers are stored on the stack during an - * exception. Note that sizeof(struct pt_regs) has to be a multiple of 16 (for - * stack alignment). struct user_pt_regs must form a prefix of struct pt_regs. + * exception. struct user_pt_regs must form a prefix of struct pt_regs. */ struct pt_regs { union { @@ -180,6 +179,9 @@ struct pt_regs { u64 exit_rcu; }; +/* For correct stack alignment, pt_regs has to be a multiple of 16 bytes. */ +static_assert(IS_ALIGNED(sizeof(struct pt_regs), 16)); + static inline bool in_syscall(struct pt_regs const *regs) { return regs->syscallno != NO_SYSCALL;