selftests/powerpc/pmu/: Add interface test for mmcr3_src fields

The testcase uses event code 0x1340000001c040 to verify the settings for
different src fields in Monitor Mode Control Register 3 (MMCR3). Checks
if these fields are translated correctly via perf interface to MMCR3 on
ISA v3.1 platform.

Signed-off-by: Kajol Jain <[e-mail]>
[mpe: Add error checking, drop GET_MMCR_FIELD, add to .gitignore]
Signed-off-by: Michael Ellerman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

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

···
 mmcr1_comb_test
 mmcr2_l2l3_test
 mmcr2_fcs_fch_test
+mmcr3_src_test

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

···
 
 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 mmcr2_l2l3_test mmcr2_fcs_fch_test
+		   mmcr1_comb_test mmcr2_l2l3_test mmcr2_fcs_fch_test \
+		   mmcr3_src_test
 
 top_srcdir = ../../../../../..
 include ../../../lib.mk

tools/testing/selftests/powerpc/pmu/sampling_tests/mmcr3_src_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 "misc.h"
+#include "utils.h"
+
+extern void thirty_two_instruction_loop_with_ll_sc(u64 loops, u64 *ll_sc_target);
+
+/* The data cache was reloaded from local core's L3 due to a demand load */
+#define EventCode 0x1340000001c040
+
+/*
+ * A perf sampling test for mmcr3
+ * fields.
+ */
+static int mmcr3_src(void)
+{
+	struct event event;
+	u64 *intr_regs;
+	u64 dummy;
+
+	/* 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 event overflow */
+	thirty_two_instruction_loop_with_ll_sc(1000000, &dummy);
+
+	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 src field of MMCR3 match with
+	 * corresponding event code field
+	 */
+	FAIL_IF(EV_CODE_EXTRACT(event.attr.config, mmcr3_src) !=
+		get_mmcr3_src(get_reg_value(intr_regs, "MMCR3"), 1));
+
+	event_close(&event);
+	return 0;
+}
+
+int main(void)
+{
+	return test_harness(mmcr3_src, "mmcr3_src");
+}