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powerpc/kprobes: Remove resume_execution() in kprobes 

emulate_step() in kprobe_handler() would've already determined if the
probed instruction can be emulated. We single-step in hardware only if
the instruction couldn't be emulated. resume_execution() therefore is
superfluous -- all we need is to fix up the instruction pointer after
single-stepping.

Thanks to Paul Mackerras for catching this.

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Ananth N Mavinakayanahalli 2010-05-27 19:19:20 +00:00 committed by Benjamin Herrenschmidt
parent 83aea945c2
commit db97bc7f99
1 changed files with 2 additions and 12 deletions
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14
arch/powerpc/kernel/kprobes.c
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@ -378,17 +378,6 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
* single-stepped a copy of the instruction. The address of this
* copy is p->ainsn.insn.
*/
static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
{
int ret;
unsigned int insn = *p->ainsn.insn;
regs->nip = (unsigned long)p->addr;
ret = emulate_step(regs, insn);
if (ret == 0)
regs->nip = (unsigned long)p->addr + 4;
}
static int __kprobes post_kprobe_handler(struct pt_regs *regs)
{
struct kprobe *cur = kprobe_running();
@ -406,7 +395,8 @@ static int __kprobes post_kprobe_handler(struct pt_regs *regs)
cur->post_handler(cur, regs, 0);
}
resume_execution(cur, regs);
/* Adjust nip to after the single-stepped instruction */
regs->nip = (unsigned long)cur->addr + 4;
regs->msr |= kcb->kprobe_saved_msr;
/*Restore back the original saved kprobes variables and continue. */