From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F24B2C43603 for ; Wed, 18 Dec 2019 14:27:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CBCE7218AC for ; Wed, 18 Dec 2019 14:27:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727198AbfLRO1M (ORCPT ); Wed, 18 Dec 2019 09:27:12 -0500 Received: from mga01.intel.com ([192.55.52.88]:21667 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726856AbfLRO1M (ORCPT ); Wed, 18 Dec 2019 09:27:12 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Dec 2019 06:27:12 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,329,1571727600"; d="scan'208";a="240803857" Received: from ahunter-desktop.fi.intel.com ([10.237.72.76]) by fmsmga004.fm.intel.com with ESMTP; 18 Dec 2019 06:27:09 -0800 From: Adrian Hunter To: Peter Zijlstra Cc: Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , x86@kernel.org, Mark Rutland , Alexander Shishkin , Mathieu Poirier , Leo Yan , Arnaldo Carvalho de Melo , Jiri Olsa , linux-kernel@vger.kernel.org Subject: [PATCH 0/3] perf/x86: Add perf text poke event Date: Wed, 18 Dec 2019 16:26:15 +0200 Message-Id: <20191218142618.19332-1-adrian.hunter@intel.com> X-Mailer: git-send-email 2.17.1 Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Here are patches to add a text poke event to record changes to kernel text (i.e. self-modifying code) in order to support tracers like Intel PT decoding through jump labels. The first patch makes the kernel change and the subsequent patches are tools changes. The second patch adds support for updating perf tools' data cache with the changed bytes. The last patch is an Intel PT specific tools change. The patches are based on linux-next. Changes since RFC: Dropped 'flags' from the new event. The consensus seemed to be that text pokes should emply a scheme similar to x86's INT3 method instead. dropped tools patches already applied. Example: For jump labels, the kernel needs CONFIG_JUMP_LABEL=y and also an easy to flip jump label is in sysctl_schedstats() which needs CONFIG_SCHEDSTATS=y CONFIG_PROC_SYSCTL=y Also note the 'sudo perf record' is put into the background which, as written, needs sudo credential caching (otherwise the background task will stop awaiting the sudo password), hence the 'sudo echo' to start. Before: $ sudo echo $ sudo perf record -o perf.data.before --kcore -a -e intel_pt//k -m,64M & [1] 1640 $ cat /proc/sys/kernel/sched_schedstats 0 $ sudo bash -c 'echo 1 > /proc/sys/kernel/sched_schedstats' $ cat /proc/sys/kernel/sched_schedstats 1 $ sudo bash -c 'echo 0 > /proc/sys/kernel/sched_schedstats' $ cat /proc/sys/kernel/sched_schedstats 0 $ sudo kill 1640 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 16.635 MB perf.data.before ] $ perf script -i perf.data.before --itrace=e >/dev/null Warning: 1946 instruction trace errors After: $ sudo echo $ sudo perf record -o perf.data.after --kcore -a -e intel_pt//k -m,64M & [1] 1882 $ cat /proc/sys/kernel/sched_schedstats 0 $ sudo bash -c 'echo 1 > /proc/sys/kernel/sched_schedstats' $ cat /proc/sys/kernel/sched_schedstats 1 $ sudo bash -c 'echo 0 > /proc/sys/kernel/sched_schedstats' $ cat /proc/sys/kernel/sched_schedstats 0 $ sudo kill 1882 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 10.893 MB perf.data.after ] $ perf script -i perf.data.after --itrace=e $ Adrian Hunter (3): perf/x86: Add perf text poke event perf tools: Add support for PERF_RECORD_TEXT_POKE perf intel-pt: Add support for text poke events arch/x86/kernel/alternative.c | 37 ++++++++++++- include/linux/perf_event.h | 6 +++ include/uapi/linux/perf_event.h | 19 ++++++- kernel/events/core.c | 87 ++++++++++++++++++++++++++++++- tools/include/uapi/linux/perf_event.h | 19 ++++++- tools/perf/arch/x86/util/intel-pt.c | 4 ++ tools/perf/builtin-record.c | 45 ++++++++++++++++ tools/perf/lib/include/perf/event.h | 8 +++ tools/perf/util/event.c | 39 ++++++++++++++ tools/perf/util/event.h | 5 ++ tools/perf/util/evlist.h | 1 + tools/perf/util/intel-pt.c | 71 +++++++++++++++++++++++++ tools/perf/util/machine.c | 34 ++++++++++++ tools/perf/util/machine.h | 3 ++ tools/perf/util/perf_event_attr_fprintf.c | 1 + tools/perf/util/record.c | 10 ++++ tools/perf/util/record.h | 1 + tools/perf/util/session.c | 20 +++++++ tools/perf/util/tool.h | 3 +- 19 files changed, 408 insertions(+), 5 deletions(-) Regards Adrian