lkml.org 
[lkml]   [2018]   [Apr]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v4 0/6] Coresight: Support panic kdump
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
>

\
 
 \ /
  Last update: 2018-04-02 18:41    [W:0.064 / U:2.284 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site