selftests/powerpc/pmu: Add interface test for mmcra_ifm field of indirect call type

The testcase uses "instructions" event to check if the
Instruction filtering mode(IFM) bits are programmed correctly
for indirect branch type. Testcase checks if IFM bits are
programmed correctly to Monitor Mode Control Register A (MMCRA)
via perf interface for ISA v3.1 platform.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220610134113.62991-6-atrajeev@linux.vnet.ibm.com

1 files changed, 69 insertions, 0 deletions

diff --git a/tools/testing/selftests/powerpc/pmu/sampling_tests/mmcra_bhrb_ind_call_test.c b/tools/testing/selftests/powerpc/pmu/sampling_tests/mmcra_bhrb_ind_call_test.c
new file mode 100644
index 000000000000..f0706730c099
--- /dev/null
+++ b/tools/testing/selftests/powerpc/pmu/sampling_tests/mmcra_bhrb_ind_call_test.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2022, Kajol Jain, IBM Corp.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "../event.h"
+#include "misc.h"
+#include "utils.h"
+
+extern void indirect_branch_loop(void);
+
+/* Instructions */
+#define EventCode 0x500fa
+
+/* ifm field for indirect branch mode */
+#define IFM_IND_BRANCH 0x2
+
+/*
+ * A perf sampling test for mmcra
+ * field: ifm for bhrb ind_call.
+ */
+static int mmcra_bhrb_ind_call_test(void)
+{
+	struct event event;
+	u64 *intr_regs;
+
+	/*
+	 * Check for platform support for the test.
+	 * This test is only aplicable on power10
+	 */
+	SKIP_IF(check_pvr_for_sampling_tests());
+	SKIP_IF(!have_hwcap2(PPC_FEATURE2_ARCH_3_1));
+
+	 /* Init the event for the sampling test */
+	event_init_sampling(&event, EventCode);
+	event.attr.sample_regs_intr = platform_extended_mask;
+	event.attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;
+	event.attr.branch_sample_type = PERF_SAMPLE_BRANCH_IND_CALL;
+	event.attr.exclude_kernel = 1;
+
+	FAIL_IF(event_open(&event));
+	event.mmap_buffer = event_sample_buf_mmap(event.fd, 1);
+
+	FAIL_IF(event_enable(&event));
+
+	/* workload to make the event overflow */
+	indirect_branch_loop();
+
+	FAIL_IF(event_disable(&event));
+
+	intr_regs = get_intr_regs(&event, event.mmap_buffer);
+
+	/* Check for intr_regs */
+	FAIL_IF(!intr_regs);
+
+	/* Verify that ifm bit is set properly in MMCRA */
+	FAIL_IF(get_mmcra_ifm(get_reg_value(intr_regs, "MMCRA"), 5) != IFM_IND_BRANCH);
+
+	event_close(&event);
+	return 0;
+}
+
+int main(void)
+{
+	return test_harness(mmcra_bhrb_ind_call_test, "mmcra_bhrb_ind_call_test");
+}