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perf unwind: Use dynamic register set for DWARF unwind

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Architectures can detect availability of extra registers at runtime so
use this more complete set for unwinding. This will include the VG
register on arm64 in a later commit.

If the function isn't implemented then PERF_REGS_MASK is returned and
there is no change.

Committer notes:

Added util/perf_regs.c to tools/perf/util/python-ext-sources so that
'perf test python' passes, i.e. the perf python binding has all the
symbols it needs, addressing:

  $ perf test -v python
   19: 'import perf' in python                                         :
  --- start ---
  test child forked, pid 2037817
  python usage test: "echo "import sys ; sys.path.append('/tmp/build/perf/python'); import perf" | '/usr/bin/python3' "
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
  ImportError: /tmp/build/perf/python/perf.cpython-310-x86_64-linux-gnu.so: undefined symbol: arch__user_reg_mask
  test child finished with -1
  ---- end ----
  'import perf' in python: FAILED!
  $

Reviewed-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: James Clark <james.clark@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.garry@huawei.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20220525154114.718321-4-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
James Clark 2022-05-25 16:41:12 +01:00 committed by Arnaldo Carvalho de Melo
parent f450f11b2d
commit 721052048b
2 changed files with 2 additions and 1 deletions
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2
tools/perf/util/evsel.c
View File

@ -897,7 +897,7 @@ static void __evsel__config_callchain(struct evsel *evsel, struct record_opts *o
"specifying a subset with --user-regs may render DWARF unwinding unreliable, "
"so the minimal registers set (IP, SP) is explicitly forced.\n");
} else {
attr->sample_regs_user |= PERF_REGS_MASK;
attr->sample_regs_user |= arch__user_reg_mask();
}
attr->sample_stack_user = param->dump_size;
attr->exclude_callchain_user = 1;

1
tools/perf/util/python-ext-sources
View File

@ -38,5 +38,6 @@ util/units.c
util/affinity.c
util/rwsem.c
util/hashmap.c
util/perf_regs.c
util/pmu-hybrid.c
util/fncache.c