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[PATCH] powerpc/kprobes: fix singlestep out-of-line

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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>
This commit is contained in:
Ananth N Mavinakayanahalli 2006-04-28 17:38:42 +05:30 committed by Paul Mackerras
parent 054d8ff377
commit 0ccde0a290
1 changed files with 7 additions and 7 deletions
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14
arch/powerpc/kernel/kprobes.c
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@ -90,15 +90,15 @@ void __kprobes arch_remove_kprobe(struct kprobe *p)
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
{ {
kprobe_opcode_t insn = *p->ainsn.insn;
regs->msr |= MSR_SE; regs->msr |= MSR_SE;
/* single step inline if it is a trap variant */ /*
if (is_trap(insn)) * On powerpc we should single step on the original
regs->nip = (unsigned long)p->addr; * instruction even if the probed insn is a trap
else * variant as values in regs could play a part in
regs->nip = (unsigned long)p->ainsn.insn; * if the trap is taken or not
*/
regs->nip = (unsigned long)p->ainsn.insn;
} }
static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)