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authorTejun Heo <tj@kernel.org>2010-04-05 11:37:28 +0900
committerTejun Heo <tj@kernel.org>2010-04-05 11:37:28 +0900
commit336f5899d287f06d8329e208fc14ce50f7ec9698 (patch)
tree9b762d450d5eb248a6ff8317badb7e223d93ed58 /arch/arm/kernel/kprobes.c
parenta4ab2773205e8b94c18625455f85e3b6bb9d7ad6 (diff)
parentdb217dece3003df0841bacf9556b5c06aa097dae (diff)
Merge branch 'master' into export-slabh
Diffstat (limited to 'arch/arm/kernel/kprobes.c')
-rw-r--r--arch/arm/kernel/kprobes.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c
index 1fb932b4fec..2ba7deb3072 100644
--- a/arch/arm/kernel/kprobes.c
+++ b/arch/arm/kernel/kprobes.c
@@ -394,6 +394,14 @@ void __kprobes jprobe_return(void)
/*
* Setup an empty pt_regs. Fill SP and PC fields as
* they're needed by longjmp_break_handler.
+ *
+ * We allocate some slack between the original SP and start of
+ * our fabricated regs. To be precise we want to have worst case
+ * covered which is STMFD with all 16 regs so we allocate 2 *
+ * sizeof(struct_pt_regs)).
+ *
+ * This is to prevent any simulated instruction from writing
+ * over the regs when they are accessing the stack.
*/
"sub sp, %0, %1 \n\t"
"ldr r0, ="__stringify(JPROBE_MAGIC_ADDR)"\n\t"
@@ -411,7 +419,7 @@ void __kprobes jprobe_return(void)
"ldmia sp, {r0 - pc} \n\t"
:
: "r" (kcb->jprobe_saved_regs.ARM_sp),
- "I" (sizeof(struct pt_regs)),
+ "I" (sizeof(struct pt_regs) * 2),
"J" (offsetof(struct pt_regs, ARM_sp)),
"J" (offsetof(struct pt_regs, ARM_pc)),
"J" (offsetof(struct pt_regs, ARM_cpsr))