selftests/powerpc/pmu/: Add interface test for mmcr2_l2l3 field

The testcases uses event code 0x010000046080 to verify the l2l3 bit
setting for Monitor Mode Control Register 2 (MMCR2). check if this bit
is set correctly via perf interface in ISA v3.1 platform.
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
[mpe: Add error checking, drop GET_MMCR_FIELD, add to .gitignore]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220127072012.662451-18-kjain@linux.ibm.com

tools/testing/selftests/powerpc/pmu/sampling_tests/.gitignore

@@ -5,3 +5,4 @@ mmcr0_pmcjce_test
 mmcr0_fc56_pmc1ce_test
 mmcr0_fc56_pmc56_test
 mmcr1_comb_test
+mmcr2_l2l3_test

tools/testing/selftests/powerpc/pmu/sampling_tests/Makefile

@@ -3,7 +3,7 @@ CFLAGS += -m64
 
 TEST_GEN_PROGS := mmcr0_exceptionbits_test mmcr0_cc56run_test mmcr0_pmccext_test \
 		   mmcr0_pmcjce_test mmcr0_fc56_pmc1ce_test mmcr0_fc56_pmc56_test \
-		   mmcr1_comb_test
+		   mmcr1_comb_test mmcr2_l2l3_test
 
 top_srcdir = ../../../../../..
 include ../../../lib.mk

tools/testing/selftests/powerpc/pmu/sampling_tests/mmcr2_l2l3_test.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2022, Madhavan Srinivasan, IBM Corp.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "../event.h"
+#include "misc.h"
+#include "utils.h"
+
+/* All successful D-side store dispatches for this thread */
+#define EventCode 0x010000046080
+
+#define MALLOC_SIZE     (0x10000 * 10)  /* Ought to be enough .. */
+
+/*
+ * A perf sampling test for mmcr2
+ * fields : l2l3
+ */
+static int mmcr2_l2l3(void)
+{
+	struct event event;
+	u64 *intr_regs;
+	char *p;
+	int i;
+
+	/* Check for platform support for the test */
+	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;
+	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 */
+	p = malloc(MALLOC_SIZE);
+	FAIL_IF(!p);
+
+	for (i = 0; i < MALLOC_SIZE; i += 0x10000)
+		p[i] = i;
+
+	FAIL_IF(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 l2l3 field of MMCR2 match with
+	 * corresponding event code field
+	 */
+	FAIL_IF(EV_CODE_EXTRACT(event.attr.config, l2l3) !=
+		get_mmcr2_l2l3(get_reg_value(intr_regs, "MMCR2"), 4));
+
+	event_close(&event);
+	free(p);
+
+	return 0;
+}
+
+int main(void)
+{
+	return test_harness(mmcr2_l2l3, "mmcr2_l2l3");
+}