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 --- arch/arm/kernel/entry-header.S | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/arm/kernel/entry-header.S') diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S index 648cfff9313..55c99cdab7d 100644 --- a/arch/arm/kernel/entry-header.S +++ b/arch/arm/kernel/entry-header.S @@ -19,6 +19,7 @@ @ @ Most of the stack format comes from struct pt_regs, but with @ the addition of 8 bytes for storing syscall args 5 and 6. +@ This _must_ remain a multiple of 8 for EABI. @ #define S_OFF 8 -- cgit v1.2.3