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[68.147.8.254]) by smtp.gmail.com with ESMTPSA id 5sm1976189pfh.133.2018.04.02.09.41.00 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 02 Apr 2018 09:41:00 -0700 (PDT) Date: Mon, 2 Apr 2018 10:40:58 -0600 From: Mathieu Poirier To: Leo Yan Cc: Jonathan Corbet , Greg Kroah-Hartman , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org, Kim Phillips , Mike Leach Subject: Re: [PATCH v4 0/6] Coresight: Support panic kdump Message-ID: <20180402164058.GA15452@xps15> References: <1522379724-30648-1-git-send-email-leo.yan@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1522379724-30648-1-git-send-email-leo.yan@linaro.org> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Hi Leo, Please see below (and in upcoming patches) my comments related to your latest work. Thanks, Mathieu On Fri, Mar 30, 2018 at 11:15:18AM +0800, Leo Yan wrote: > This patch set is to explore Coresight tracing data for postmortem > debugging. When kernel panic happens, the Coresight panic kdump can > help to save on-chip tracing data and tracer metadata into DRAM, later > relies on kdump and crash/perf tools to recovery tracing data for > "offline" analysis. > > The documentation is important to understand the purpose of Coresight > panic kdump, the implementation of framework and usage. Patches 0001 > and patch 0002 are used for creating new sub directory for placing > Coresight docs and add a new doc for Coresight panic kdump. > > Patch 0003 introduces the simple panic kdump framework which provides > helper functions can be used by Coresight devices, and it registers > panic notifier for dump tracing data. > > Patches 0004/0005 support panic kdump for ETB; Patch 0006 supports the > kdump for ETMv4. > > This patch set has been reworked by following suggestions at Linaro > HKG18 connect (mainly suggestions from Mathieu, thanks a lot!), and > it's rebased on acme git tree [1] with last commit 109d59b900e7 ('perf > vendor events s390: Add JSON files for IBM z14'). > > Due Coresight kdump data structure has been changed significantly, the > corresponding crash extension program also has been updated for this > reason [2]; furthermore the crash extension program is updated to > dynamically generate kernel buildid according to vmlinux elf info [3], > this is a fixing for the old code which uses hard-coded buildid value. > > This patch set has been verified on 96boards Hikey620 with Coresight > enabling by the sysFS interface. Also the updated crash extension > program has been verified to cowork with Coresight panic kdump and it > successfully extracts tracing data from the vmcore and finally can be > decoded by perf tool. > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git > [2] https://git.linaro.org/people/leo.yan/crash.git/tree/extensions/csdump.c > [3] https://git.linaro.org/people/leo.yan/crash.git/tree/extensions/csdump_buildid.c > > Changes from v3: > * Following Mathieu suggestion, reworked the panic kdump framework, > used kdump array to maintain source and sink device handlers; > * According to Mathieu suggestion, optimized panic notifier to > firstly dump panic CPU tracing data and then dump other CPUs tracing > data; > * Refined doc to reflect these implementation changes; > * Changed ETMv4 driver to add source device handler at probe phase; > * Refactored crash extension program to reflect kernel changes. > > Changes from v2: > * Add the two patches for documentation. > * Following Mathieu suggestion, reworked the panic kdump framework, > removed the useless flag "PRE_PANIC". > * According to comment, changed to add and delete kdump node operations > in sink enable/disable functions; > * According to Mathieu suggestion, handle kdump node > addition/deletion/updating separately for sysFS interface and perf > method. > > Changes from v1: > * Add support to dump ETMv4 meta data. > * Wrote 'crash' extension csdump.so so rely on it to generate 'perf' > format compatible file. > * Refactored panic dump driver to support pre & post panic dump. > > Changes from RFC: > * Follow Mathieu's suggestion, use general framework to support dump > functionality. > * Changed to use perf to analyse trace data. > > Leo Yan (6): > doc: Add Coresight documentation directory > doc: Add documentation for Coresight panic kdump > coresight: Support panic kdump functionality > coresight: tmc: Hook callback for panic kdump > coresight: Set and clear sink device handler for kdump node > coresight: etm4x: Support panic kdump > > Documentation/trace/coresight-cpu-debug.txt | 187 ---------- > Documentation/trace/coresight.txt | 383 --------------------- > .../trace/coresight/coresight-cpu-debug.txt | 187 ++++++++++ > .../trace/coresight/coresight-panic-kdump.txt | 130 +++++++ > Documentation/trace/coresight/coresight.txt | 383 +++++++++++++++++++++ Please use the -M option with git format-patch in order to prevent the metrics associated with the renaming of files to be tallied. > MAINTAINERS | 5 +- > drivers/hwtracing/coresight/Kconfig | 9 + > drivers/hwtracing/coresight/Makefile | 1 + > drivers/hwtracing/coresight/coresight-etm-perf.c | 5 + > drivers/hwtracing/coresight/coresight-etm4x.c | 27 ++ > drivers/hwtracing/coresight/coresight-etm4x.h | 15 + > .../hwtracing/coresight/coresight-panic-kdump.c | 199 +++++++++++ > drivers/hwtracing/coresight/coresight-priv.h | 12 + > drivers/hwtracing/coresight/coresight-tmc-etf.c | 30 ++ > drivers/hwtracing/coresight/coresight.c | 16 +- > include/linux/coresight.h | 4 + > 16 files changed, 1019 insertions(+), 574 deletions(-) > delete mode 100644 Documentation/trace/coresight-cpu-debug.txt > delete mode 100644 Documentation/trace/coresight.txt > create mode 100644 Documentation/trace/coresight/coresight-cpu-debug.txt > create mode 100644 Documentation/trace/coresight/coresight-panic-kdump.txt > create mode 100644 Documentation/trace/coresight/coresight.txt > create mode 100644 drivers/hwtracing/coresight/coresight-panic-kdump.c > > -- > 2.7.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html