diff options
| author | Ian Rogers <irogers@google.com> | 2023-06-27 11:28:34 -0700 |
|---|---|---|
| committer | Namhyung Kim <namhyung@kernel.org> | 2023-06-27 23:38:39 -0700 |
| commit | 628eaa4e877af8230ef7326d378e15d511c506ba (patch) | |
| tree | e2fb65c08dcc3f0ae94370e41dc672cc0f1d2ee3 /tools | |
| parent | ad5f604e186ac08d12c401e34ea96c09c38ddbc5 (diff) | |
| download | linux-stable-628eaa4e877af8230ef7326d378e15d511c506ba.tar.gz linux-stable-628eaa4e877af8230ef7326d378e15d511c506ba.tar.bz2 linux-stable-628eaa4e877af8230ef7326d378e15d511c506ba.zip | |
perf pmus: Add placeholder core PMU
If loading a core PMU fails, legacy hardware/cache events may segv due
to there being no PMU. Create a placeholder empty PMU for this
case. This was discussed in:
https://lore.kernel.org/lkml/20230614151625.2077-1-yangjihong1@huawei.com/
Reported-by: Yang Jihong <yangjihong1@huawei.com>
Tested-by: Yang Jihong <yangjihong1@huawei.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: James Clark <james.clark@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/r/20230627182834.117565-1-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/perf/util/pmu.c | 25 | ||||
| -rw-r--r-- | tools/perf/util/pmu.h | 1 | ||||
| -rw-r--r-- | tools/perf/util/pmus.c | 7 |
3 files changed, 32 insertions, 1 deletions
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index 8d5ecd4ff1a9..7f984a7f16ca 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -928,6 +928,31 @@ err: return NULL; } +/* Creates the PMU when sysfs scanning fails. */ +struct perf_pmu *perf_pmu__create_placeholder_core_pmu(struct list_head *core_pmus) +{ + struct perf_pmu *pmu = zalloc(sizeof(*pmu)); + + if (!pmu) + return NULL; + + pmu->name = strdup("cpu"); + if (!pmu->name) { + free(pmu); + return NULL; + } + + pmu->is_core = true; + pmu->type = PERF_TYPE_RAW; + pmu->cpus = cpu_map__online(); + + INIT_LIST_HEAD(&pmu->format); + INIT_LIST_HEAD(&pmu->aliases); + INIT_LIST_HEAD(&pmu->caps); + list_add_tail(&pmu->list, core_pmus); + return pmu; +} + void perf_pmu__warn_invalid_formats(struct perf_pmu *pmu) { struct perf_pmu_format *format; diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h index 8807a624e918..203b92860e3c 100644 --- a/tools/perf/util/pmu.h +++ b/tools/perf/util/pmu.h @@ -286,6 +286,7 @@ int perf_pmu__event_source_devices_fd(void); int perf_pmu__pathname_fd(int dirfd, const char *pmu_name, const char *filename, int flags); struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const char *lookup_name); +struct perf_pmu *perf_pmu__create_placeholder_core_pmu(struct list_head *core_pmus); void perf_pmu__delete(struct perf_pmu *pmu); #endif /* __PMU_H */ diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c index 0866dee3fc62..3cd9de42139e 100644 --- a/tools/perf/util/pmus.c +++ b/tools/perf/util/pmus.c @@ -153,7 +153,12 @@ static void pmu_read_sysfs(bool core_only) closedir(dir); if (core_only) { - read_sysfs_core_pmus = true; + if (!list_empty(&core_pmus)) + read_sysfs_core_pmus = true; + else { + if (perf_pmu__create_placeholder_core_pmu(&core_pmus)) + read_sysfs_core_pmus = true; + } } else { read_sysfs_core_pmus = true; read_sysfs_all_pmus = true; |