selftests/powerpc/pmu: Add selftest for group constraint check when using same PMC

Testcase for group constraint check when using events with same PMC.
Multiple events in a group asking for same PMC should fail. Testcase
uses "0x22C040" on PMC2 as leader and also subling which is expected to
fail. Using PMC1 for sibling event should pass the test.

Signed-off-by: Athira Rajeev <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

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

···
 # SPDX-License-Identifier: GPL-2.0
 CFLAGS += -m64
 
-TEST_GEN_PROGS := group_constraint_pmc56_test group_pmc56_exclude_constraints_test group_constraint_pmc_count_test
+TEST_GEN_PROGS := group_constraint_pmc56_test group_pmc56_exclude_constraints_test group_constraint_pmc_count_test \
+	group_constraint_repeat_test
 
 top_srcdir = ../../../../../..
 include ../../../lib.mk

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

···
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2022, Athira Rajeev, IBM Corp.
+ */
+
+#include <stdio.h>
+#include "../event.h"
+#include "../sampling_tests/misc.h"
+
+/* The processor's L1 data cache was reloaded */
+#define EventCode1 0x21C040
+#define EventCode2 0x22C040
+
+/*
+ * Testcase for group constraint check
+ * when using events with same PMC.
+ * Multiple events in a group shouldn't
+ * ask for same PMC. If so it should fail.
+ */
+
+static int group_constraint_repeat(void)
+{
+	struct event event, leader;
+
+	/* Check for platform support for the test */
+	SKIP_IF(platform_check_for_tests());
+
+	/*
+	 * Two events in a group using same PMC
+	 * should fail to get scheduled. Usei same PMC2
+	 * for leader and sibling event which is expected
+	 * to fail.
+	 */
+	event_init(&leader, EventCode1);
+	FAIL_IF(event_open(&leader));
+
+	event_init(&event, EventCode1);
+
+	/* Expected to fail since sibling event is requesting same PMC as leader */
+	FAIL_IF(!event_open_with_group(&event, leader.fd));
+
+	event_init(&event, EventCode2);
+
+	/* Expected to pass since sibling event is requesting different PMC */
+	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_repeat, "group_constraint_repeat");
+}