From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752813Ab2LKFs4 (ORCPT ); Tue, 11 Dec 2012 00:48:56 -0500 Received: from e23smtp02.au.ibm.com ([202.81.31.144]:35012 "EHLO e23smtp02.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752376Ab2LKFsy (ORCPT ); Tue, 11 Dec 2012 00:48:54 -0500 Message-ID: <50C6C930.90206@in.ibm.com> Date: Tue, 11 Dec 2012 11:18:32 +0530 From: "Suzuki K. Poulose" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: benh@kernel.crashing.org, Kumar Gala CC: "Suzuki K. Poulose" , bigeasy@linutronix.de, oleg@redhat.com, ananth@in.ibm.com, srikar@linux.vnet.ibm.com, peterz@infradead.org, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, anton@redhat.com, mingo@elte.hu Subject: Re: [PATCH v2 1/4] kprobes/powerpc: Do not disable External interrupts during single step References: <20121203150438.7727.74924.stgit@suzukikp> <20121203150720.7727.91582.stgit@suzukikp> In-Reply-To: <20121203150720.7727.91582.stgit@suzukikp> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12121105-5490-0000-0000-000002A0F7A1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/03/2012 08:37 PM, Suzuki K. Poulose wrote: > From: Suzuki K. Poulose > > External/Decrement exceptions have lower priority than the Debug Exception. > So, we don't have to disable the External interrupts before a single step. > However, on BookE, Critical Input Exception(CE) has higher priority than a > Debug Exception. Hence we mask them. > > Signed-off-by: Suzuki K. Poulose > Cc: Sebastian Andrzej Siewior > Cc: Ananth N Mavinakaynahalli > Cc: Kumar Gala > Cc: linuxppc-dev@ozlabs.org > --- > arch/powerpc/kernel/kprobes.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c > index e88c643..4901b34 100644 > --- a/arch/powerpc/kernel/kprobes.c > +++ b/arch/powerpc/kernel/kprobes.c > @@ -104,13 +104,13 @@ void __kprobes arch_remove_kprobe(struct kprobe *p) > > static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) > { > - /* We turn off async exceptions to ensure that the single step will > - * be for the instruction we have the kprobe on, if we dont its > - * possible we'd get the single step reported for an exception handler > - * like Decrementer or External Interrupt */ > - regs->msr &= ~MSR_EE; > regs->msr |= MSR_SINGLESTEP; > #ifdef CONFIG_PPC_ADV_DEBUG_REGS > + /* > + * We turn off Critical Input Exception(CE) to ensure that the single > + * step will be for the instruction we have the probe on; if we don't, > + * it is possible we'd get the single step reported for CE. > + */ > regs->msr &= ~MSR_CE; > mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM); > #ifdef CONFIG_PPC_47x > Ben, Kumar, Could you please review this patch ? Thanks Suzuki