From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751298AbdGQDVM (ORCPT ); Sun, 16 Jul 2017 23:21:12 -0400 Received: from mail-pg0-f47.google.com ([74.125.83.47]:33332 "EHLO mail-pg0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751253AbdGQDVL (ORCPT ); Sun, 16 Jul 2017 23:21:11 -0400 Subject: Re: [PATCH V2 0/4] ARM64: Fix irq generation between breakpoint and step exception To: linux-arm-kernel@lists.infradead.org, mark.rutland@arm.com References: Cc: will.deacon@arm.com, huawei.libin@huawei.com, Alexander Shishkin , Arnaldo Carvalho de Melo , Ingo Molnar , linux-kernel@vger.kernel.org, Peter Zijlstra From: Pratyush Anand Message-ID: <45e8f432-8786-2cb1-421e-e4093167c57a@redhat.com> Date: Mon, 17 Jul 2017 08:51:04 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 07 July 2017 05:33 PM, Pratyush Anand wrote: > v1 was here http://marc.info/?l=linux-arm-kernel&m=149910958418708&w=2 > > v1 -> v2: > - patch 1 of v1 has been modified to patch 1-3 of v2. > - Introduced a new event attribute step_needed and implemented > hw_breakpoint_needs_single_step() (patch 1) > - Replaced usage of is_default_overflow_handler() with > hw_breakpoint_needs_single_step(). (patch 2) > - Modified sample test to set set step_needed bit field (patch 3) > > samples/hw_breakpoint/data_breakpoint.c passes with x86_64 but fails with > ARM64. Even though it has been NAKed previously on upstream [1, 2], I have > tried to come up with patches which can resolve it for ARM64 as well. > > I noticed that even perf step exception can go into an infinite loop if CPU > receives an interrupt while executing breakpoint/watchpoint handler. So, > event though we are not concerned about above test, we will have to find a > solution for the perf issue. > > This patchset attempts to resolve both the issue. Please review. Any comments/feedback? > > [1] http://marc.info/?l=linux-arm-kernel&m=149580777524910&w=2 > [2] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-April/425266.html > > Pratyush Anand (4): > hw_breakpoint: Add step_needed event attribute > arm64: use hw_breakpoint_needs_single_step() to decide if step is > needed > hw-breakpoint: sample test: set step_needed bit field > arm64: disable irq between breakpoint and step exception > > arch/arm64/kernel/debug-monitors.c | 3 +++ > arch/arm64/kernel/hw_breakpoint.c | 10 +++++----- > arch/arm64/mm/fault.c | 22 ++++++++++++++++++---- > include/linux/hw_breakpoint.h | 6 ++++++ > include/uapi/linux/perf_event.h | 3 ++- > kernel/events/core.c | 2 ++ > samples/hw_breakpoint/data_breakpoint.c | 1 + > tools/include/uapi/linux/perf_event.h | 3 ++- > 8 files changed, 39 insertions(+), 11 deletions(-) > -- Pratyush