diff options
| author | Nicolas Pitre <nico@cam.org> | 2006-01-14 16:18:08 +0000 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2006-01-14 16:18:08 +0000 |
| commit | 2dede2d8e925f4c2cb4e136b14df127685e15dd3 (patch) | |
| tree | 271b3fb300c5ac143556295d10c6736430ebed85 /arch/arm | |
| parent | da2b1cd61903c8e9796e76be2d606584f26a78e5 (diff) | |
[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 <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/kernel/entry-armv.S | 17 | ||||
| -rw-r--r-- | arch/arm/kernel/entry-header.S | 1 |
2 files changed, 18 insertions, 0 deletions
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index fb8e7f4c4b37..874e6bb79405 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -105,14 +105,24 @@ common_invalid: /* * SVC mode handlers */ + +#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) +#define SPFIX(code...) code +#else +#define SPFIX(code...) +#endif + .macro svc_entry sub sp, sp, #S_FRAME_SIZE + SPFIX( tst sp, #4 ) + SPFIX( bicne sp, sp, #4 ) stmib sp, {r1 - r12} ldmia r0, {r1 - r3} add r5, sp, #S_SP @ here for interlock avoidance mov r4, #-1 @ "" "" "" "" add r0, sp, #S_FRAME_SIZE @ "" "" "" "" + SPFIX( addne r0, r0, #4 ) str r1, [sp] @ save the "real" r0 copied @ from the exception stack @@ -303,7 +313,14 @@ __pabt_svc: /* * User mode handlers + * + * EABI note: sp_svc is always 64-bit aligned here, so should S_FRAME_SIZE */ + +#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) && (S_FRAME_SIZE & 7) +#error "sizeof(struct pt_regs) must be a multiple of 8" +#endif + .macro usr_entry sub sp, sp, #S_FRAME_SIZE stmib sp, {r1 - r12} diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S index 648cfff93138..55c99cdab7d6 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 |