From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751506AbdDMEiL (ORCPT ); Thu, 13 Apr 2017 00:38:11 -0400 Received: from mail.kernel.org ([198.145.29.136]:36852 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750775AbdDMEiJ (ORCPT ); Thu, 13 Apr 2017 00:38:09 -0400 Date: Thu, 13 Apr 2017 13:37:58 +0900 From: Masami Hiramatsu To: "Naveen N. Rao" Cc: Michael Ellerman , Ananth N Mavinakayanahalli , Masami Hiramatsu , Ingo Molnar , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 5/5] powerpc: kprobes: emulate instructions on kprobe handler re-entry Message-Id: <20170413133758.0f9e0c86bd3230dcd820f8e7@kernel.org> In-Reply-To: <7021f79a5738ecb25ee3e07931e927138e9493eb.1491991939.git.naveen.n.rao@linux.vnet.ibm.com> References: <7021f79a5738ecb25ee3e07931e927138e9493eb.1491991939.git.naveen.n.rao@linux.vnet.ibm.com> X-Mailer: Sylpheed 3.5.0 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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