diff options
| author | Jon Medhurst <tixy@yxit.co.uk> | 2011-03-18 17:32:44 +0000 |
|---|---|---|
| committer | Tixy <tixy@medhuaa1.miniserver.com> | 2011-07-13 17:32:40 +0000 |
| commit | 594810621d9605dd40b6ce42e2e188a7dd6ba27c (patch) | |
| tree | b44f46bf562bec026a2758ec6516fb22bfada28d /arch/arm/kernel/entry-header.S | |
| parent | 620917de59eeb934b9f8cf35cc2d95c1ac8ed0fc (diff) | |
| download | lwn-594810621d9605dd40b6ce42e2e188a7dd6ba27c.tar.gz lwn-594810621d9605dd40b6ce42e2e188a7dd6ba27c.zip | |
ARM: Thumb-2: Fix exception return sequence to restore stack correctly
The implementation of svc_exit didn't take into account any stack hole
created by svc_entry; as happens with the undef handler when kprobes are
configured. The fix is to read the saved value of SP rather than trying
to calculate it.
Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Diffstat (limited to 'arch/arm/kernel/entry-header.S')
| -rw-r--r-- | arch/arm/kernel/entry-header.S | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S index 051166c2a932..83e29adced6c 100644 --- a/arch/arm/kernel/entry-header.S +++ b/arch/arm/kernel/entry-header.S @@ -121,15 +121,13 @@ .endm #else /* CONFIG_THUMB2_KERNEL */ .macro svc_exit, rpsr + ldr lr, [sp, #S_SP] @ top of the stack + ldrd r0, r1, [sp, #S_LR] @ calling lr and pc clrex @ clear the exclusive monitor - ldr r0, [sp, #S_SP] @ top of the stack - ldr r1, [sp, #S_PC] @ return address - tst r0, #4 @ orig stack 8-byte aligned? - stmdb r0, {r1, \rpsr} @ rfe context + stmdb lr!, {r0, r1, \rpsr} @ calling lr and rfe context ldmia sp, {r0 - r12} - ldr lr, [sp, #S_LR] - addeq sp, sp, #S_FRAME_SIZE - 8 @ aligned - addne sp, sp, #S_FRAME_SIZE - 4 @ not aligned + mov sp, lr + ldr lr, [sp], #4 rfeia sp! .endm |