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authorNicolas Pitre <nico@cam.org>2006-01-14 16:18:08 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2006-01-14 16:18:08 +0000
commit2dede2d8e925f4c2cb4e136b14df127685e15dd3 (patch)
tree271b3fb300c5ac143556295d10c6736430ebed85 /arch/arm/kernel/entry-header.S
parentda2b1cd61903c8e9796e76be2d606584f26a78e5 (diff)
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[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/kernel/entry-header.S')
-rw-r--r--arch/arm/kernel/entry-header.S1
1 files changed, 1 insertions, 0 deletions
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
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