[PATCH v2 5/5] powerpc: kprobes: emulate instructions on kprobe handler re-entry
From: Naveen N. Rao <hidden>
Date: 2017-04-12 11:00:09
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
On kprobe handler re-entry, try to emulate the instruction rather than single stepping always. As a related change, remove the duplicate saving of msr as that is already done in set_current_kprobe() Acked-by: Ananth N Mavinakayanahalli <redacted> Signed-off-by: Naveen N. Rao <redacted> --- arch/powerpc/kernel/kprobes.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 8b48f7d046bd..005bd4a75902 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c@@ -273,10 +273,17 @@ int __kprobes kprobe_handler(struct pt_regs *regs) */ save_previous_kprobe(kcb); set_current_kprobe(p, regs, kcb); - kcb->kprobe_saved_msr = regs->msr; kprobes_inc_nmissed_count(p); prepare_singlestep(p, regs); kcb->kprobe_status = KPROBE_REENTER; + if (p->ainsn.boostable >= 0) { + ret = try_to_emulate(p, regs); + + if (ret > 0) { + restore_previous_kprobe(kcb); + return 1; + } + } return 1; } else { if (*addr != BREAKPOINT_INSTRUCTION) {
--
2.12.1