@@ -6,7 +6,7 @@ TEST_GEN_PROGS := mmcr0_exceptionbits_test mmcr0_cc56run_test mmcr0_pmccext_test
mmcr1_comb_test mmcr2_l2l3_test mmcr2_fcs_fch_test \
mmcr3_src_test mmcra_thresh_marked_sample_test mmcra_thresh_cmp_test \
mmcra_bhrb_ind_call_test mmcra_bhrb_any_test mmcra_bhrb_cond_test \
- mmcra_bhrb_disable_test
+ mmcra_bhrb_disable_test bhrb_no_crash_wo_pmu_test
top_srcdir = ../../../../../..
include ../../../lib.mk
new file mode 100644
@@ -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");
+}