selftests/powerpc/pmu: Add interface test for extended reg support

The testcase uses check_extended_regs_support and
perf_get_platform_reg_mask function to check if the
platform has extended reg support. This will help to
check if sampling pmu selftest is enabled or not for
a given platform.

Signed-off-by: Kajol Jain <[e-mail]>
Signed-off-by: Athira Rajeev <[e-mail]>
Signed-off-by: Madhavan Srinivasan <[e-mail]>
Link: https://patch.msgid.link/[e-mail]

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

···
 		   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 mmcr1_sel_unit_cache_test mmcra_bhrb_disable_no_branch_test
+		   bhrb_filter_map_test mmcr1_sel_unit_cache_test mmcra_bhrb_disable_no_branch_test \
+		   check_extended_reg_test
 
 top_srcdir = ../../../../../..
 include ../../../lib.mk

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

···
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2024, Kajol Jain, IBM Corp.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "../event.h"
+#include "misc.h"
+#include "utils.h"
+
+/*
+ * A perf sampling test to check extended
+ * reg support.
+ */
+static int check_extended_reg_test(void)
+{
+	/* Check for platform support for the test */
+	SKIP_IF(!have_hwcap2(PPC_FEATURE2_ARCH_3_00));
+
+	 /* Skip for Generic compat PMU */
+	SKIP_IF(check_for_generic_compat_pmu());
+
+	/* Check if platform supports extended regs */
+	platform_extended_mask = perf_get_platform_reg_mask();
+	FAIL_IF(check_extended_regs_support());
+
+	return 0;
+}
+
+int main(void)
+{
+	return test_harness(check_extended_reg_test, "check_extended_reg_test");
+}

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

···
 }
 
 /* Return the extended regs mask value */
-static u64 perf_get_platform_reg_mask(void)
+u64 perf_get_platform_reg_mask(void)
 {
 	if (have_hwcap2(PPC_FEATURE2_ARCH_3_1))
 		return PERF_POWER10_MASK;

tools/testing/selftests/powerpc/pmu/sampling_tests/misc.h

···
 extern u64 platform_extended_mask;
 extern int check_pvr_for_sampling_tests(void);
 extern int platform_check_for_tests(void);
+extern int check_extended_regs_support(void);
+extern u64 perf_get_platform_reg_mask(void);
 
 /*
  * Event code field extraction macro.