1 files changed, 59 insertions, 0 deletions
diff --git a/tools/testing/selftests/powerpc/pmu/sampling_tests/bhrb_no_crash_wo_pmu_test.c b/tools/testing/selftests/powerpc/pmu/sampling_tests/bhrb_no_crash_wo_pmu_test.c
new file mode 100644
index 000000000000..4644c6782974
--- /dev/null
+++ b/tools/testing/selftests/powerpc/pmu/sampling_tests/bhrb_no_crash_wo_pmu_test.c
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2022, Athira Rajeev, IBM Corp.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "../event.h"
+#include "misc.h"
+#include "utils.h"
+
+/*
+ * A perf sampling test for making sure
+ * enabling branch stack doesn't crash in any
+ * environment, say:
+ *  - With generic compat PMU
+ *  - without any PMU registered
+ *  - With platform specific PMU
+ *  A fix for bhrb sampling crash was added in kernel
+ *  via commit: b460b512417a ("powerpc/perf: Fix crashes
+ *  with generic_compat_pmu & BHRB")
+ *
+ * This testcase exercises this code by doing branch
+ * stack enable for software event. s/w event is used
+ * since software event will work even in platform
+ * without PMU.
+ */
+static int bhrb_no_crash_wo_pmu_test(void)
+{
+	struct event event;
+
+	/*
+	 * Init the event for the sampling test.
+	 * This uses software event which works on
+	 * any platform.
+	 */
+	event_init_opts(&event, 0, PERF_TYPE_SOFTWARE, "cycles");
+
+	event.attr.sample_period = 1000;
+	event.attr.sample_type = PERF_SAMPLE_BRANCH_STACK;
+	event.attr.disabled = 1;
+
+	/*
+	 * Return code of event_open is not
+	 * considered since test just expects no crash from
+	 * using PERF_SAMPLE_BRANCH_STACK. Also for environment
+	 * like generic compat PMU, branch stack is unsupported.
+	 */
+	event_open(&event);
+
+	event_close(&event);
+	return 0;
+}
+
+int main(void)
+{
+	return test_harness(bhrb_no_crash_wo_pmu_test, "bhrb_no_crash_wo_pmu_test");
+}