perf pmus: Ensure all PMUs are read for find_by_type

perf_pmus__find_by_type may be called for something like a raw event,
in which case the PMU isn't guaranteed to have been looked up. Add a
second check to make sure all PMUs are loaded.

Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ali Saidi <alisaidi@amazon.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Dmitrii Dolgov <9erthalion6@gmail.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jing Zhang <renyu.zj@linux.alibaba.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kang Minchul <tegongkang@gmail.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Ming Wang <wangming01@loongson.cn>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230527072210.2900565-32-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Author: captain5050

tools/perf/util/pmus.c

@@ -142,21 +142,34 @@ static void pmu_read_sysfs(bool core_only)
 	}
 }
 
-struct perf_pmu *perf_pmus__find_by_type(unsigned int type)
+static struct perf_pmu *__perf_pmus__find_by_type(unsigned int type)
 {
 	struct perf_pmu *pmu;
 
 	list_for_each_entry(pmu, &core_pmus, list) {
 		if (pmu->type == type)
 			return pmu;
 	}
+
 	list_for_each_entry(pmu, &other_pmus, list) {
 		if (pmu->type == type)
 			return pmu;
 	}
 	return NULL;
 }
 
+struct perf_pmu *perf_pmus__find_by_type(unsigned int type)
+{
+	struct perf_pmu *pmu = __perf_pmus__find_by_type(type);
+
+	if (pmu || read_sysfs_all_pmus)
+		return pmu;
+
+	pmu_read_sysfs(/*core_only=*/false);
+	pmu = __perf_pmus__find_by_type(type);
+	return pmu;
+}
+
 /*
  * pmu iterator: If pmu is NULL, we start at the begin, otherwise return the
  * next pmu. Returns NULL on end.