perf tests: Add a test for the ARM 32-bit [vectors] page

perf on ARM requires CONFIG_KUSER_HELPERS to be turned on to allow some
independance with respect to the ARM CPU being used. Add a test which
tries to locate the [vectors] page, created when CONFIG_KUSER_HELPERS is
turned on to help asses the system's health.

Signed-off-by: Florian Fainelli <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Chris Healy <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Kim Phillips <[email protected]>
Cc: Lucas Stach <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ravi Bangoria <[email protected]>
Cc: Russell King <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Thomas Richter <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

tools/perf/arch/arm/tests/Build

@@ -1,4 +1,5 @@
 libperf-y += regs_load.o
 libperf-y += dwarf-unwind.o
+libperf-y += vectors-page.o
 
 libperf-y += arch-tests.o

tools/perf/arch/arm/tests/arch-tests.c

@@ -10,6 +10,10 @@ struct test arch_tests[] = {
 		.func = test__dwarf_unwind,
 	},
 #endif
+	{
+		.desc = "Vectors page",
+		.func = test__vectors_page,
+	},
 	{
 		.func = NULL,
 	},

tools/perf/arch/arm/tests/vectors-page.c

@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <string.h>
+#include <linux/compiler.h>
+
+#include "debug.h"
+#include "tests/tests.h"
+#include "util/find-map.c"
+
+#define VECTORS__MAP_NAME "[vectors]"
+
+int test__vectors_page(struct test *test __maybe_unused,
+		       int subtest __maybe_unused)
+{
+	void *start, *end;
+
+	if (find_map(&start, &end, VECTORS__MAP_NAME)) {
+		pr_err("%s not found, is CONFIG_KUSER_HELPERS enabled?\n",
+		       VECTORS__MAP_NAME);
+		return TEST_FAIL;
+	}
+
+	return TEST_OK;
+}

tools/perf/tests/tests.h

@@ -119,4 +119,9 @@ int test__arch_unwind_sample(struct perf_sample *sample,
 			     struct thread *thread);
 #endif
 #endif
+
+#if defined(__arm__)
+int test__vectors_page(struct test *test, int subtest);
+#endif
+
 #endif /* TESTS_H */