selftests/powerpc/pmu: Add selftest for group constraint check for MMCRA thresh_cmp field

Thresh compare bits for a event is used to program thresh compare field
in Monitor Mode Control Register A (MMCRA: 9-18 bits for power9 and
MMCRA: 8-18 bits for power10). When scheduling events as a group, all
events in that group should match value in thresh compare bits.
Otherwise event open for the sibling events will fail.

Testcase uses event code "0x401e0" as leader and another event "0x101ec"
as sibling event, and checks for thresh compare constraint via perf
interface.
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220610134113.62991-32-atrajeev@linux.vnet.ibm.com

tools/testing/selftests/powerpc/pmu/event_code_tests/Makefile

@@ -5,7 +5,7 @@ TEST_GEN_PROGS := group_constraint_pmc56_test group_pmc56_exclude_constraints_te
 	group_constraint_repeat_test group_constraint_radix_scope_qual_test reserved_bits_mmcra_sample_elig_mode_test \
 	group_constraint_mmcra_sample_test invalid_event_code_test reserved_bits_mmcra_thresh_ctl_test \
 	blacklisted_events_test event_alternatives_tests_p9 event_alternatives_tests_p10 generic_events_valid_test \
-	group_constraint_l2l3_sel_test group_constraint_cache_test
+	group_constraint_l2l3_sel_test group_constraint_cache_test group_constraint_thresh_cmp_test
 
 top_srcdir = ../../../../../..
 include ../../../lib.mk

tools/testing/selftests/powerpc/pmu/event_code_tests/group_constraint_thresh_cmp_test.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2022, Kajol Jain, IBM Corp.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "../event.h"
+#include "utils.h"
+#include "../sampling_tests/misc.h"
+
+/*
+ * Primary PMU events used here is PM_MRK_INST_CMPL (0x401e0) and
+ * PM_THRESH_MET (0x101ec)
+ * Threshold event selection used is issue to complete for cycles
+ * Sampling criteria is Load or Store only sampling
+ */
+#define p9_EventCode_1 0x13e35340401e0
+#define p9_EventCode_2 0x17d34340101ec
+#define p9_EventCode_3 0x13e35340101ec
+#define p10_EventCode_1 0x35340401e0
+#define p10_EventCode_2 0x35340101ec
+
+/*
+ * Testcase for group constraint check of thresh_cmp bits which is
+ * used to program thresh compare field in Monitor Mode Control Register A
+ * (MMCRA: 9-18 bits for power9 and MMCRA: 8-18 bits for power10).
+ * All events in the group should match thresh compare bits otherwise
+ * event_open for the group will fail.
+ */
+static int group_constraint_thresh_cmp(void)
+{
+	struct event event, leader;
+
+	/* Check for platform support for the test */
+	SKIP_IF(platform_check_for_tests());
+
+	if (have_hwcap2(PPC_FEATURE2_ARCH_3_1)) {
+		/* Init the events for the group contraint check for thresh_cmp bits */
+		event_init(&leader, p10_EventCode_1);
+
+		/* Add the thresh_cmp value for leader in config1 */
+		leader.attr.config1 = 1000;
+		FAIL_IF(event_open(&leader));
+
+		event_init(&event, p10_EventCode_2);
+
+		/* Add the different thresh_cmp value from the leader event in config1 */
+		event.attr.config1 = 2000;
+
+		/* Expected to fail as sibling and leader event request different thresh_cmp bits */
+		FAIL_IF(!event_open_with_group(&event, leader.fd));
+
+		event_close(&event);
+
+		/* Init the event for the group contraint thresh compare test */
+		event_init(&event, p10_EventCode_2);
+
+		/* Add the same thresh_cmp value for leader and sibling event in config1 */
+		event.attr.config1 = 1000;
+
+		/* Expected to succeed as sibling and leader event request same thresh_cmp bits */
+		FAIL_IF(event_open_with_group(&event, leader.fd));
+
+		event_close(&leader);
+		event_close(&event);
+	} else {
+		/* Init the events for the group contraint check for thresh_cmp bits */
+		event_init(&leader, p9_EventCode_1);
+		FAIL_IF(event_open(&leader));
+
+		event_init(&event, p9_EventCode_2);
+
+		/* Expected to fail as sibling and leader event request different thresh_cmp bits */
+		FAIL_IF(!event_open_with_group(&event, leader.fd));
+
+		event_close(&event);
+
+		/* Init the event for the group contraint thresh compare test */
+		event_init(&event, p9_EventCode_3);
+
+		/* Expected to succeed as sibling and leader event request same thresh_cmp bits */
+		FAIL_IF(event_open_with_group(&event, leader.fd));
+
+		event_close(&leader);
+		event_close(&event);
+	}
+
+	return 0;
+}
+
+int main(void)
+{
+	return test_harness(group_constraint_thresh_cmp, "group_constraint_thresh_cmp");
+}