selftests/powerpc/pmu: Add selftest for event alternatives for power10

Platform specific PMU supports alternative event for some of the event
codes. During perf_event_open, it any event group doesn't match
constraint check criteria, further lookup is done to find alternative
event. Code checks to see if it is possible to schedule event as group
using alternative events.

Testcase exercises the alternative event find code for power10. Example,
Using PMC1 to PMC4 in a group and again trying to schedule
PM_CYC_ALT (0x0001e) will fail since this exceeds number of programmable
events in group. But since 0x600f4 is an alternative event for 0x0001e,
it is possible to use 0x0001e in the group. Testcase uses such
combination all events in power10 which has alternative event.
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220610134113.62991-28-atrajeev@linux.vnet.ibm.com

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

@@ -4,7 +4,7 @@ CFLAGS += -m64
 TEST_GEN_PROGS := group_constraint_pmc56_test group_pmc56_exclude_constraints_test group_constraint_pmc_count_test \
 	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
+	blacklisted_events_test event_alternatives_tests_p9 event_alternatives_tests_p10
 
 top_srcdir = ../../../../../..
 include ../../../lib.mk

tools/testing/selftests/powerpc/pmu/event_code_tests/event_alternatives_tests_p10.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"
+
+#define PM_RUN_CYC_ALT 0x200f4
+#define PM_INST_DISP 0x200f2
+#define PM_BR_2PATH 0x20036
+#define PM_LD_MISS_L1 0x3e054
+#define PM_RUN_INST_CMPL_ALT 0x400fa
+
+#define EventCode_1 0x100fc
+#define EventCode_2 0x200fa
+#define EventCode_3 0x300fc
+#define EventCode_4 0x400fc
+
+/*
+ * Check for event alternatives.
+ */
+
+static int event_alternatives_tests_p10(void)
+{
+	struct event *e, events[5];
+	int i;
+
+	/* Check for platform support for the test */
+	SKIP_IF(platform_check_for_tests());
+
+	/*
+	 * PVR check is used here since PMU specific data like
+	 * alternative events is handled by respective PMU driver
+	 * code and using PVR will work correctly for all cases
+	 * including generic compat mode.
+	 */
+	SKIP_IF(PVR_VER(mfspr(SPRN_PVR)) != POWER10);
+
+	SKIP_IF(check_for_generic_compat_pmu());
+
+	/*
+	 * Test for event alternative for 0x0001e
+	 * and 0x00002.
+	 */
+	e = &events[0];
+	event_init(e, 0x0001e);
+
+	e = &events[1];
+	event_init(e, EventCode_1);
+
+	e = &events[2];
+	event_init(e, EventCode_2);
+
+	e = &events[3];
+	event_init(e, EventCode_3);
+
+	e = &events[4];
+	event_init(e, EventCode_4);
+
+	FAIL_IF(event_open(&events[0]));
+
+	/*
+	 * Expected to pass since 0x0001e has alternative event
+	 * 0x600f4 in PMC6. So it can go in with other events
+	 * in PMC1 to PMC4.
+	 */
+	for (i = 1; i < 5; i++)
+		FAIL_IF(event_open_with_group(&events[i], events[0].fd));
+
+	for (i = 0; i < 5; i++)
+		event_close(&events[i]);
+
+	e = &events[0];
+	event_init(e, 0x00002);
+
+	e = &events[1];
+	event_init(e, EventCode_1);
+
+	e = &events[2];
+	event_init(e, EventCode_2);
+
+	e = &events[3];
+	event_init(e, EventCode_3);
+
+	e = &events[4];
+	event_init(e, EventCode_4);
+
+	FAIL_IF(event_open(&events[0]));
+
+	/*
+	 * Expected to pass since 0x00020 has alternative event
+	 * 0x500fa in PMC5. So it can go in with other events
+	 * in PMC1 to PMC4.
+	 */
+	for (i = 1; i < 5; i++)
+		FAIL_IF(event_open_with_group(&events[i], events[0].fd));
+
+	for (i = 0; i < 5; i++)
+		event_close(&events[i]);
+
+	return 0;
+}
+
+int main(void)
+{
+	return test_harness(event_alternatives_tests_p10, "event_alternatives_tests_p10");
+}