perf pmu: Add hybrid helper functions

The functions perf_pmu__is_hybrid and perf_pmu__find_hybrid_pmu
can be used to identify the hybrid platform and return the found
hybrid cpu pmu. All the detected hybrid pmus have been saved in
'perf_pmu__hybrid_pmus' list. So we just need to search this list.

perf_pmu__hybrid_type_to_pmu converts the user specified string
to hybrid pmu name. This is used to support the '--cputype' option
in next patches.

perf_pmu__has_hybrid checks the existing of hybrid pmu. Note that,
we have to define it in pmu.c (make pmu-hybrid.c no more symbol
dependency), otherwise perf test python would be failed.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210427070139.25256-7-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/pmu-hybrid.c

@@ -47,3 +47,43 @@ bool perf_pmu__hybrid_mounted(const char *name)
 
 	return true;
 }
+
+struct perf_pmu *perf_pmu__find_hybrid_pmu(const char *name)
+{
+	struct perf_pmu *pmu;
+
+	if (!name)
+		return NULL;
+
+	perf_pmu__for_each_hybrid_pmu(pmu) {
+		if (!strcmp(name, pmu->name))
+			return pmu;
+	}
+
+	return NULL;
+}
+
+bool perf_pmu__is_hybrid(const char *name)
+{
+	return perf_pmu__find_hybrid_pmu(name) != NULL;
+}
+
+char *perf_pmu__hybrid_type_to_pmu(const char *type)
+{
+	char *pmu_name = NULL;
+
+	if (asprintf(&pmu_name, "cpu_%s", type) < 0)
+		return NULL;
+
+	if (perf_pmu__is_hybrid(pmu_name))
+		return pmu_name;
+
+	/*
+	 * pmu may be not scanned, check the sysfs.
+	 */
+	if (perf_pmu__hybrid_mounted(pmu_name))
+		return pmu_name;
+
+	free(pmu_name);
+	return NULL;
+}

tools/perf/util/pmu-hybrid.h

@@ -15,4 +15,8 @@ extern struct list_head perf_pmu__hybrid_pmus;
 
 bool perf_pmu__hybrid_mounted(const char *name);
 
+struct perf_pmu *perf_pmu__find_hybrid_pmu(const char *name);
+bool perf_pmu__is_hybrid(const char *name);
+char *perf_pmu__hybrid_type_to_pmu(const char *type);
+
 #endif /* __PMU_HYBRID_H */

tools/perf/util/pmu.c

@@ -40,6 +40,7 @@ int perf_pmu_parse(struct list_head *list, char *name);
 extern FILE *perf_pmu_in;
 
 static LIST_HEAD(pmus);
+static bool hybrid_scanned;
 
 /*
  * Parse & process all the sysfs attributes located under
@@ -1861,3 +1862,13 @@ void perf_pmu__warn_invalid_config(struct perf_pmu *pmu, __u64 config,
 		   "'%llx' not supported by kernel)!\n",
 		   name ?: "N/A", buf, config);
 }
+
+bool perf_pmu__has_hybrid(void)
+{
+	if (!hybrid_scanned) {
+		hybrid_scanned = true;
+		perf_pmu__scan(NULL);
+	}
+
+	return !list_empty(&perf_pmu__hybrid_pmus);
+}

tools/perf/util/pmu.h

@@ -132,4 +132,6 @@ int perf_pmu__caps_parse(struct perf_pmu *pmu);
 void perf_pmu__warn_invalid_config(struct perf_pmu *pmu, __u64 config,
 				   char *name);
 
+bool perf_pmu__has_hybrid(void);
+
 #endif /* __PMU_H */