Re: [PATCH v2 5/5] powerpc: kprobes: emulate instructions on kprobe handler re-entry

2017-04-12 Thread Naveen N. Rao 
On 2017/04/13 01:37PM, Masami Hiramatsu wrote:
> On Wed, 12 Apr 2017 16:28:28 +0530
> "Naveen N. Rao"  wrote:
> 
> > 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()
> 
> If so, this part might be separated as a cleanup patch...

Sure, thanks for the review!

- Naveen

Re: [PATCH v2 5/5] powerpc: kprobes: emulate instructions on kprobe handler re-entry

2017-04-12 Thread Masami Hiramatsu 
On Wed, 12 Apr 2017 16:28:28 +0530
"Naveen N. Rao"  wrote:

> 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()

If so, this part might be separated as a cleanup patch...

Thanks,

> 
> Acked-by: Ananth N Mavinakayanahalli 
> Signed-off-by: Naveen N. Rao 
> ---
>  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
> 


-- 
Masami Hiramatsu

[PATCH v2 5/5] powerpc: kprobes: emulate instructions on kprobe handler re-entry

2017-04-12 Thread Naveen N. Rao 
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 
Signed-off-by: Naveen N. Rao 
---
 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