perf pmu: Remove a hard coded cpu PMU assumption

The property of "cpu" when it has no cpu map is true on S390 with the
PMU cpum_cf. Rather than maintain a list of such PMUs, reuse the
is_core test result from the caller.

Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Thomas Richter <tmricht@linux.ibm.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: James Clark <james.clark@arm.com>
Cc: Mark Rutland <mark.rutland@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: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-perf-users@vger.kernel.org
Link: https://lore.kernel.org/r/20230623043843.4080180-2-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

tools/perf/util/pmu.c

@@ -551,7 +551,7 @@ static int pmu_alias_terms(struct perf_pmu_alias *alias,
  * Uncore PMUs have a "cpumask" file under sysfs. CPU PMUs (e.g. on arm/arm64)
  * may have a "cpus" file.
  */
-static struct perf_cpu_map *pmu_cpumask(int dirfd, const char *name)
+static struct perf_cpu_map *pmu_cpumask(int dirfd, const char *name, bool is_core)
 {
 	struct perf_cpu_map *cpus;
 	const char *templates[] = {
@@ -575,7 +575,8 @@ static struct perf_cpu_map *pmu_cpumask(int dirfd, const char *name)
 			return cpus;
 	}
 
-	return !strcmp(name, "cpu") ? perf_cpu_map__get(cpu_map__online()) : NULL;
+	/* Nothing found, for core PMUs assume this means all CPUs. */
+	return is_core ? perf_cpu_map__get(cpu_map__online()) : NULL;
 }
 
 static bool pmu_is_uncore(int dirfd, const char *name)
@@ -886,7 +887,8 @@ struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const char
 	if (!pmu)
 		return NULL;
 
-	pmu->cpus = pmu_cpumask(dirfd, name);
+	pmu->is_core = is_pmu_core(name);
+	pmu->cpus = pmu_cpumask(dirfd, name, pmu->is_core);
 	pmu->name = strdup(name);
 	if (!pmu->name)
 		goto err;
@@ -903,7 +905,6 @@ struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const char
 	}
 
 	pmu->type = type;
-	pmu->is_core = is_pmu_core(name);
 	pmu->is_uncore = pmu_is_uncore(dirfd, name);
 	if (pmu->is_uncore)
 		pmu->id = pmu_id(name);