perf arm-spe: Introduce arm_spe__is_homogeneous()

Introduce the arm_spe__is_homogeneous() function, it uses to check if
Arm SPE is homogeneous cross all CPUs.

Signed-off-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20241003185322.192357-4-leo.yan@arm.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
(cherry picked from commit 56ae663)
Signed-off-by: Andrea Righi <arighi@nvidia.com>

Author: Leo-Yan

tools/perf/util/arm-spe.c

@@ -84,6 +84,7 @@ struct arm_spe {
 	u64				**metadata;
 	u64				metadata_ver;
 	u64				metadata_nr_cpu;
+	bool				is_homogeneous;
 };
 
 struct arm_spe_queue {
@@ -1401,6 +1402,30 @@ arm_spe_synth_events(struct arm_spe *spe, struct perf_session *session)
 	return 0;
 }
 
+static bool arm_spe__is_homogeneous(u64 **metadata, int nr_cpu)
+{
+	u64 midr;
+	int i;
+
+	if (!nr_cpu)
+		return false;
+
+	for (i = 0; i < nr_cpu; i++) {
+		if (!metadata[i])
+			return false;
+
+		if (i == 0) {
+			midr = metadata[i][ARM_SPE_CPU_MIDR];
+			continue;
+		}
+
+		if (midr != metadata[i][ARM_SPE_CPU_MIDR])
+			return false;
+	}
+
+	return true;
+}
+
 int arm_spe_process_auxtrace_info(union perf_event *event,
 				  struct perf_session *session)
 {
@@ -1446,6 +1471,7 @@ int arm_spe_process_auxtrace_info(union perf_event *event,
 	spe->metadata = metadata;
 	spe->metadata_ver = metadata_ver;
 	spe->metadata_nr_cpu = nr_cpu;
+	spe->is_homogeneous = arm_spe__is_homogeneous(metadata, nr_cpu);
 
 	spe->timeless_decoding = arm_spe__is_timeless_decoding(spe);