6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: James Clark james.clark@arm.com
[ Upstream commit 3d0f5f456a5786573ba6a3358178c8db580e4b85 ]
pmu__find_core_pmu() more logically belongs in pmus.c because it iterates over all PMUs, so move it to pmus.c
At the same time rename it to perf_pmus__find_core_pmu() to match the naming convention in this file.
list_prepare_entry() can't be used in perf_pmus__scan_core() anymore now that it's called from the same compilation unit. This is with -O2 (specifically -O1 -ftree-vrp -finline-functions -finline-small-functions) which allow the bounds of the array access to be determined at compile time. list_prepare_entry() subtracts the offset of the 'list' member in struct perf_pmu from &core_pmus, which isn't a struct perf_pmu. The compiler sees that pmu results in &core_pmus - 8 and refuses to compile. At runtime this works because list_for_each_entry_continue() always adds the offset back again before dereferencing ->next, but it's technically undefined behavior. With -fsanitize=undefined an additional warning is generated.
Using list_first_entry_or_null() to get the first entry here avoids doing &core_pmus - 8 but has the same result and fixes both the compile warning and the undefined behavior warning. There are other uses of list_prepare_entry() in pmus.c, but the compiler doesn't seem to be able to see that they can also be called with &core_pmus, so I won't change any at this time.
Signed-off-by: James Clark james.clark@arm.com Reviewed-by: Ian Rogers irogers@google.com Reviewed-by: John Garry john.g.garry@oracle.com Cc: Ravi Bangoria ravi.bangoria@amd.com Cc: Eduard Zingerman eddyz87@gmail.com Cc: Will Deacon will@kernel.org Cc: Leo Yan leo.yan@linaro.org Cc: Mike Leach mike.leach@linaro.org Cc: Jing Zhang renyu.zj@linux.alibaba.com Cc: Haixin Yu yuhaixin.yhx@linux.alibaba.com Cc: Kan Liang kan.liang@linux.intel.com Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20230913153355.138331-2-james.clark@arm.com Signed-off-by: Namhyung Kim namhyung@kernel.org Stable-dep-of: d9c5f5f94c2d ("perf pmu: Count sys and cpuid JSON events separately") Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/arch/arm64/util/pmu.c | 6 +++--- tools/perf/tests/expr.c | 2 +- tools/perf/util/expr.c | 2 +- tools/perf/util/pmu.c | 17 ----------------- tools/perf/util/pmu.h | 2 +- tools/perf/util/pmus.c | 20 +++++++++++++++++++- 6 files changed, 25 insertions(+), 24 deletions(-)
diff --git a/tools/perf/arch/arm64/util/pmu.c b/tools/perf/arch/arm64/util/pmu.c index 615084eb88d8c..3d9330feebd28 100644 --- a/tools/perf/arch/arm64/util/pmu.c +++ b/tools/perf/arch/arm64/util/pmu.c @@ -10,7 +10,7 @@
const struct pmu_metrics_table *pmu_metrics_table__find(void) { - struct perf_pmu *pmu = pmu__find_core_pmu(); + struct perf_pmu *pmu = perf_pmus__find_core_pmu();
if (pmu) return perf_pmu__find_metrics_table(pmu); @@ -20,7 +20,7 @@ const struct pmu_metrics_table *pmu_metrics_table__find(void)
const struct pmu_events_table *pmu_events_table__find(void) { - struct perf_pmu *pmu = pmu__find_core_pmu(); + struct perf_pmu *pmu = perf_pmus__find_core_pmu();
if (pmu) return perf_pmu__find_events_table(pmu); @@ -32,7 +32,7 @@ double perf_pmu__cpu_slots_per_cycle(void) { char path[PATH_MAX]; unsigned long long slots = 0; - struct perf_pmu *pmu = pmu__find_core_pmu(); + struct perf_pmu *pmu = perf_pmus__find_core_pmu();
if (pmu) { perf_pmu__pathname_scnprintf(path, sizeof(path), diff --git a/tools/perf/tests/expr.c b/tools/perf/tests/expr.c index b177d09078038..cea4a506197db 100644 --- a/tools/perf/tests/expr.c +++ b/tools/perf/tests/expr.c @@ -76,7 +76,7 @@ static int test__expr(struct test_suite *t __maybe_unused, int subtest __maybe_u struct expr_parse_ctx *ctx; bool is_intel = false; char strcmp_cpuid_buf[256]; - struct perf_pmu *pmu = pmu__find_core_pmu(); + struct perf_pmu *pmu = perf_pmus__find_core_pmu(); char *cpuid = perf_pmu__getcpuid(pmu); char *escaped_cpuid1, *escaped_cpuid2;
diff --git a/tools/perf/util/expr.c b/tools/perf/util/expr.c index 80cf2478f98fc..b8875aac8f870 100644 --- a/tools/perf/util/expr.c +++ b/tools/perf/util/expr.c @@ -527,7 +527,7 @@ double expr__strcmp_cpuid_str(const struct expr_parse_ctx *ctx __maybe_unused, bool compute_ids __maybe_unused, const char *test_id) { double ret; - struct perf_pmu *pmu = pmu__find_core_pmu(); + struct perf_pmu *pmu = perf_pmus__find_core_pmu(); char *cpuid = perf_pmu__getcpuid(pmu);
if (!cpuid) diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index 86bfdf5db2135..72b7a1d3225f6 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -2058,20 +2058,3 @@ void perf_pmu__delete(struct perf_pmu *pmu) zfree(&pmu->id); free(pmu); } - -struct perf_pmu *pmu__find_core_pmu(void) -{ - struct perf_pmu *pmu = NULL; - - while ((pmu = perf_pmus__scan_core(pmu))) { - /* - * The cpumap should cover all CPUs. Otherwise, some CPUs may - * not support some events or have different event IDs. - */ - if (RC_CHK_ACCESS(pmu->cpus)->nr != cpu__max_cpu().cpu) - return NULL; - - return pmu; - } - return NULL; -} diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h index 6a4e170c61d6b..45079f26abf60 100644 --- a/tools/perf/util/pmu.h +++ b/tools/perf/util/pmu.h @@ -264,6 +264,6 @@ int perf_pmu__pathname_fd(int dirfd, const char *pmu_name, const char *filename, 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); -struct perf_pmu *pmu__find_core_pmu(void); +struct perf_pmu *perf_pmus__find_core_pmu(void);
#endif /* __PMU_H */ diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c index 6631367c756fd..cec869cbe163a 100644 --- a/tools/perf/util/pmus.c +++ b/tools/perf/util/pmus.c @@ -10,6 +10,7 @@ #include <pthread.h> #include <string.h> #include <unistd.h> +#include "cpumap.h" #include "debug.h" #include "evsel.h" #include "pmus.h" @@ -268,7 +269,7 @@ struct perf_pmu *perf_pmus__scan_core(struct perf_pmu *pmu) { if (!pmu) { pmu_read_sysfs(/*core_only=*/true); - pmu = list_prepare_entry(pmu, &core_pmus, list); + return list_first_entry_or_null(&core_pmus, typeof(*pmu), list); } list_for_each_entry_continue(pmu, &core_pmus, list) return pmu; @@ -592,3 +593,20 @@ struct perf_pmu *evsel__find_pmu(const struct evsel *evsel) } return pmu; } + +struct perf_pmu *perf_pmus__find_core_pmu(void) +{ + struct perf_pmu *pmu = NULL; + + while ((pmu = perf_pmus__scan_core(pmu))) { + /* + * The cpumap should cover all CPUs. Otherwise, some CPUs may + * not support some events or have different event IDs. + */ + if (RC_CHK_ACCESS(pmu->cpus)->nr != cpu__max_cpu().cpu) + return NULL; + + return pmu; + } + return NULL; +}