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>
* single-stepped a copy of the instruction. The address of this
* copy is p->ainsn.insn.
*/
* 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();
static int __kprobes post_kprobe_handler(struct pt_regs *regs)
{
struct kprobe *cur = kprobe_running();
cur->post_handler(cur, regs, 0);
}
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. */
regs->msr |= kcb->kprobe_saved_msr;
/*Restore back the original saved kprobes variables and continue. */