From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH 5/5] powerpc: kprobes: emulate instructions on kprobe handler re-entry
Date: Thu, 16 Feb 2017 16:22:43 +0530 [thread overview]
Message-ID: <8471fff08f4118b0dbec7893d86a01a2c8856f40.1487239680.git.naveen.n.rao@linux.vnet.ibm.com> (raw)
In-Reply-To: <49dae0da9b7cee3f1747b116cd59854ece84bf02.1487239680.git.naveen.n.rao@linux.vnet.ibm.com>
In-Reply-To: <49dae0da9b7cee3f1747b116cd59854ece84bf02.1487239680.git.naveen.n.rao@linux.vnet.ibm.com>
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 <ananth@linux.vnet.ibm.com>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
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) {
--
2.11.0
prev parent reply other threads:[~2017-02-16 10:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-16 10:52 [PATCH 1/5] powerpc: introduce a new helper to obtain function entry points Naveen N. Rao
2017-02-16 10:52 ` [PATCH 2/5] kprobes: convert kprobe_lookup_name() to a function Naveen N. Rao
2017-02-16 10:52 ` [PATCH 3/5] powerpc: kprobes: fix handling of function offsets on ABIv2 Naveen N. Rao
2017-02-16 10:52 ` [PATCH 4/5] powerpc: kprobes: factor out code to emulate instruction into a helper Naveen N. Rao
2017-02-16 10:52 ` Naveen N. Rao [this message]
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