selftests/powerpc/pmu: Add selftest for mmcr1 pmcxsel/unit/cache fields

The testcase uses event code "0x21c040" to verify the settings for
different fields in Monitor Mode Control Register 1 (MMCR1). The fields
include PMCxSEL, PMCXCOMB PMCxUNIT, cache. Checks if these fields are
translated correctly via perf interface to MMCR1
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/20220610134113.62991-14-atrajeev@linux.vnet.ibm.com

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

@@ -7,7 +7,7 @@ TEST_GEN_PROGS := mmcr0_exceptionbits_test mmcr0_cc56run_test mmcr0_pmccext_test
 		   mmcr3_src_test mmcra_thresh_marked_sample_test mmcra_thresh_cmp_test \
 		   mmcra_bhrb_ind_call_test mmcra_bhrb_any_test mmcra_bhrb_cond_test \
 		   mmcra_bhrb_disable_test bhrb_no_crash_wo_pmu_test intr_regs_no_crash_wo_pmu_test \
-		   bhrb_filter_map_test
+		   bhrb_filter_map_test mmcr1_sel_unit_cache_test
 
 top_srcdir = ../../../../../..
 include ../../../lib.mk

tools/testing/selftests/powerpc/pmu/sampling_tests/mmcr1_sel_unit_cache_test.c

+// 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"
+
+#define MALLOC_SIZE     (0x10000 * 10)  /* Ought to be enough .. */
+
+/* The data cache was reloaded from local core's L3 due to a demand load */
+#define EventCode 0x21c040
+
+/*
+ * A perf sampling test for mmcr1
+ * fields : pmcxsel, unit, cache.
+ */
+static int mmcr1_sel_unit_cache(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());
+
+	p = malloc(MALLOC_SIZE);
+	FAIL_IF(!p);
+
+	/* Init the event for the sampling test */
+	event_init_sampling(&event, EventCode);
+	event.attr.sample_regs_intr = platform_extended_mask;
+	event.attr.sample_period = 1;
+	FAIL_IF(event_open(&event));
+	event.mmap_buffer = event_sample_buf_mmap(event.fd, 1);
+
+	event_enable(&event);
+
+	/* workload to make the event overflow */
+	for (i = 0; i < MALLOC_SIZE; i += 0x10000)
+		p[i] = i;
+
+	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  pmcxsel, unit and cache field of MMCR1
+	 * match with corresponding event code fields
+	 */
+	FAIL_IF(EV_CODE_EXTRACT(event.attr.config, pmcxsel) !=
+			get_mmcr1_pmcxsel(get_reg_value(intr_regs, "MMCR1"), 1));
+	FAIL_IF(EV_CODE_EXTRACT(event.attr.config, unit) !=
+			get_mmcr1_unit(get_reg_value(intr_regs, "MMCR1"), 1));
+	FAIL_IF(EV_CODE_EXTRACT(event.attr.config, cache) !=
+			get_mmcr1_cache(get_reg_value(intr_regs, "MMCR1"), 1));
+
+	free(p);
+	event_close(&event);
+	return 0;
+}
+
+int main(void)
+{
+	FAIL_IF(test_harness(mmcr1_sel_unit_cache, "mmcr1_sel_unit_cache"));
+}