From 2dede2d8e925f4c2cb4e136b14df127685e15dd3 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Sat, 14 Jan 2006 16:18:08 +0000 Subject: [ARM] 3102/1: ARM EABI: stack pointer must be 64-bit aligned after a CPU exception Patch from Nicolas Pitre The ARM EABI says that the stack pointer has to be 64-bit aligned for reasons already mentioned in patch #3101 when calling C functions. We therefore must verify and adjust sp accordingly when taking an exception from kernel mode since sp might not necessarily be 64-bit aligned if the exception occurs in the middle of a kernel function. If the exception occurs while in user mode then no sp fixup is needed as long as sizeof(struct pt_regs) as well as any additional syscall data stack space remain multiples of 8. Signed-off-by: Nicolas Pitre Signed-off-by: Russell King --- include/asm-arm/ptrace.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'include/asm-arm/ptrace.h') diff --git a/include/asm-arm/ptrace.h b/include/asm-arm/ptrace.h index 4377e22b7e1a..f40948d54448 100644 --- a/include/asm-arm/ptrace.h +++ b/include/asm-arm/ptrace.h @@ -60,9 +60,11 @@ #ifndef __ASSEMBLY__ -/* this struct defines the way the registers are stored on the - stack during a system call. */ - +/* + * This struct defines the way the registers are stored on the + * stack during a system call. Note that sizeof(struct pt_regs) + * has to be a multiple of 8. + */ struct pt_regs { long uregs[18]; }; -- cgit v1.2.3