linux-kernel - [PATCH 0/4] perf cs-etm: Track exception level

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Message-Id: <20230524131958.2139331-1-james.clark@arm.com>
Date:   Wed, 24 May 2023 14:19:54 +0100
From:   James Clark <james.clark@....com>
To:     coresight@...ts.linaro.org, denik@...omium.org
Cc:     James Clark <james.clark@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach <mike.leach@...aro.org>,
        Leo Yan <leo.yan@...aro.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Ian Rogers <irogers@...gle.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        John Garry <john.g.garry@...cle.com>,
        Will Deacon <will@...nel.org>,
        linux-arm-kernel@...ts.infradead.org,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 0/4] perf cs-etm: Track exception level

Some fixes to support an issue reported by Denis Nikitin where decoding
trace that contains different EL1 and EL2 kernels can crash or go into
an infinite loop because the wrong kernel maps are used for the decode.

This still doesn't support distinguishing guest and host userspace,
we'd still have to fix the timestamps and do a bit more work to
correlate that. And I've removed PERF_RECORD_MISC_HYPERVISOR as a
possible outcome of cs_etm__cpu_mode(). As far as I know this could
never have been returned anyway because machine__is_host(machine) was
always true due to session.machines.host being hard coded. And I'm not
sure of the relevance of the difference between PERF_RECORD_MISC_KERNEL
and PERF_RECORD_MISC_HYPERVISOR in this scenario.

The first commit is a tidy up, second fixes a bug that I found when
comparing the exception level and thread of branch records, the third
is the main fix, and the last commit is some extra error checking. 

Applies to acme/perf-tools (4e111f0cf0)

James Clark (4):
  perf cs-etm: Only track threads instead of PID and TIDs
  perf cs-etm: Use previous thread for branch sample source IP
  perf cs-etm: Track exception level
  perf cs-etm: Add exception level consistency check

 .../perf/util/cs-etm-decoder/cs-etm-decoder.c |  13 +-
 .../perf/util/cs-etm-decoder/cs-etm-decoder.h |   4 +-
 tools/perf/util/cs-etm.c                      | 220 +++++++++---------
 tools/perf/util/cs-etm.h                      |   5 +-
 4 files changed, 126 insertions(+), 116 deletions(-)

-- 
2.34.1