Subject: [PATCH 09/20] selftest/powerpc/pmu/: Add interface test for mmcr0 exception bits

From: Kajol Jain <[email-masked]>
Date: Thu, 27 Jan 2022 12:50:01 +0530

From: Athira Rajeev <[email-masked]>

The testcase uses "instructions" event to verify two
bits(PMAE and PMAO) in Monitor Mode Control Register 0
(MMCR0). At the time of interrupt, pmae bit ( which enables
performance monitor exception ) is expected to be cleared
and pmao (which indicates performance monitor alert) bit
is expected to be set in MMCR0. And testcases handles
these checks.

Signed-off-by: Athira Rajeev <[email-masked]>
---
 .../powerpc/pmu/sampling_tests/Makefile       |  6 +-
 .../sampling_tests/mmcr0_exceptionbits_test.c | 59 +++++++++++++++++++
 2 files changed, 63 insertions(+), 2 deletions(-)
 create mode 100644 tools/testing/selftests/powerpc/pmu/sampling_tests/mmcr0_exceptionbits_test.c

diff --git a/tools/testing/selftests/powerpc/pmu/sampling_tests/Makefile b/tools/testing/selftests/powerpc/pmu/sampling_tests/Makefile
index eb00c9f931ec..aee25c7037ac 100644
--- a/tools/testing/selftests/powerpc/pmu/sampling_tests/Makefile
+++ b/tools/testing/selftests/powerpc/pmu/sampling_tests/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 include ../../../../../../scripts/Kbuild.include
 
-all: $(TEST_GEN_PROGS)
+all: $(TEST_GEN_PROGS) mmcr0_exceptionbits_test.c
 
 noarg:
 	$(MAKE) -C ../../
@@ -12,9 +12,11 @@ CFLAGS += -m64 -I../../../../../lib/
 no-pie-option := $(call try-run, echo 'int main() { return 0; }' | \
 	$(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -no-pie -x c - -o "$$TMP", -no-pie)
 
+TEST_GEN_PROGS := mmcr0_exceptionbits_test
+
 LDFLAGS += $(no-pie-option)
 
 top_srcdir = ../../../../../..
 include ../../../lib.mk
 
-$(TEST_GEN_PROGS): ../../harness.c ../../utils.c ../event.c ../lib.c misc.c misc.h
+$(TEST_GEN_PROGS): ../../harness.c ../../utils.c ../event.c ../lib.c misc.c misc.h ../loop.S
diff --git a/tools/testing/selftests/powerpc/pmu/sampling_tests/mmcr0_exceptionbits_test.c b/tools/testing/selftests/powerpc/pmu/sampling_tests/mmcr0_exceptionbits_test.c
new file mode 100644
index 000000000000..4de0b40264c9
--- /dev/null
+++ b/tools/testing/selftests/powerpc/pmu/sampling_tests/mmcr0_exceptionbits_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"
+
+extern void thirty_two_instruction_loop(int loops);
+
+/*
+ * A perf sampling test for mmcr0
+ * fields : pmae, pmao.
+ */
+static int mmcr0_exceptionbits(void)
+{
+	struct event event;
+	u64 *intr_regs;
+
+	/* Check for platform support for the test */
+	SKIP_IF(check_pvr_for_sampling_tests());
+
+	/* Init the event for the sampling test */
+	event_init_sampling(&event, 0x500fa);
+	event.attr.sample_regs_intr = platform_extended_mask;
+	FAIL_IF(event_open(&event));
+	event.mmap_buffer = event_sample_buf_mmap(event.fd, 1);
+
+	event_enable(&event);
+
+	/* workload to make the event overflow */
+	thirty_two_instruction_loop(10000);
+
+	event_disable(&event);
+
+	/* Check for sample count */
+	FAIL_IF(!collect_samples(event.mmap_buffer));
+
+	intr_regs = get_intr_regs(&event, event.mmap_buffer);
+
+	/* Check for intr_regs */
+	FAIL_IF(!intr_regs);
+
+	/* Verify that pmae is cleared and pmao is set in MMCR0 */
+	FAIL_IF(GET_MMCR_FIELD(0, get_reg_value(intr_regs, "MMCR0"), 5, pmae));
+	FAIL_IF(!GET_MMCR_FIELD(0, get_reg_value(intr_regs, "MMCR0"), 5, pmao));
+
+	event_close(&event);
+	return 0;
+}
+
+int main(void)
+{
+	FAIL_IF(test_harness(mmcr0_exceptionbits, "mmcr0_exceptionbits"));
+}
-- 
2.27.0