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Commit db97bc7f authored by Ananth N Mavinakayanahalli's avatar Ananth N Mavinakayanahalli Committed by Benjamin Herrenschmidt
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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: default avatarAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 83aea945

arch/powerpc/kernel/kprobes.c

+2 −12
Original line number Diff line number Diff line
@@ -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. */