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authorAnanth N Mavinakayanahalli <ananth@in.ibm.com>2006-04-28 17:38:42 +0530
committerPaul Mackerras <paulus@samba.org>2006-05-03 23:06:41 +1000
commit0ccde0a290b44b8296b82a7683b4c299eb51ba6b (patch)
treecc586aa319da07dcda8f91e3ee03d9da960d5fac /arch/powerpc
parent054d8ff37710efaebd1998ce94d366df315a354f (diff)
[PATCH] powerpc/kprobes: fix singlestep out-of-line
We currently single-step inline if the instruction on which a kprobe is inserted is a trap variant. - variants (such as tdnei, used by BUG()) typically evaluate a condition and cause a trap only if the condition is satisfied. - kprobes uses the unconditional "trap" (0x7fe00008) and single-stepping again on this instruction, resulting in another trap without evaluating the condition is obviously incorrect. Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/kernel/kprobes.c14
1 files changed, 7 insertions, 7 deletions
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 856ef1a832b..f78866367b7 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -90,15 +90,15 @@ void __kprobes arch_remove_kprobe(struct kprobe *p)
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
{
- kprobe_opcode_t insn = *p->ainsn.insn;
-
regs->msr |= MSR_SE;
- /* single step inline if it is a trap variant */
- if (is_trap(insn))
- regs->nip = (unsigned long)p->addr;
- else
- regs->nip = (unsigned long)p->ainsn.insn;
+ /*
+ * On powerpc we should single step on the original
+ * instruction even if the probed insn is a trap
+ * variant as values in regs could play a part in
+ * if the trap is taken or not
+ */
+ regs->nip = (unsigned long)p->ainsn.insn;
}
static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)