6 files changed, 129 insertions, 1 deletions
diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build
index 0b2b8305c965..4afb6319ed51 100644
--- a/tools/perf/tests/Build
+++ b/tools/perf/tests/Build
@@ -50,6 +50,7 @@ perf-y += perf-hooks.o
 perf-y += clang.o
 perf-y += unit_number__scnprintf.o
 perf-y += mem2node.o
+perf-y += map_groups.o
 
 $(OUTPUT)tests/llvm-src-base.c: tests/bpf-script-example.c tests/Build
 	$(call rule_mkdir)
diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
index 9852b5d624a5..941c5456d625 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -290,6 +290,10 @@ static struct test generic_tests[] = {
 		.func = test__mem2node,
 	},
 	{
+		.desc = "map_groups__merge_in",
+		.func = test__map_groups__merge_in,
+	},
+	{
 		.func = NULL,
 	},
 };
diff --git a/tools/perf/tests/map_groups.c b/tools/perf/tests/map_groups.c
new file mode 100644
index 000000000000..70d96acc6dcf
--- /dev/null
+++ b/tools/perf/tests/map_groups.c
@@ -0,0 +1,120 @@
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include "tests.h"
+#include "map.h"
+#include "map_groups.h"
+#include "dso.h"
+#include "debug.h"
+
+struct map_def {
+	const char *name;
+	u64 start;
+	u64 end;
+};
+
+static int check_maps(struct map_def *merged, unsigned int size, struct map_groups *mg)
+{
+	struct map *map;
+	unsigned int i = 0;
+
+	map = map_groups__first(mg);
+	while (map) {
+		TEST_ASSERT_VAL("wrong map start",  map->start == merged[i].start);
+		TEST_ASSERT_VAL("wrong map end",    map->end == merged[i].end);
+		TEST_ASSERT_VAL("wrong map name",  !strcmp(map->dso->name, merged[i].name));
+		TEST_ASSERT_VAL("wrong map refcnt", refcount_read(&map->refcnt) == 2);
+
+		i++;
+		map = map_groups__next(map);
+
+		TEST_ASSERT_VAL("less maps expected", (map && i < size) || (!map && i == size));
+	}
+
+	return TEST_OK;
+}
+
+int test__map_groups__merge_in(struct test *t __maybe_unused, int subtest __maybe_unused)
+{
+	struct map_groups mg;
+	unsigned int i;
+	struct map_def bpf_progs[] = {
+		{ "bpf_prog_1", 200, 300 },
+		{ "bpf_prog_2", 500, 600 },
+		{ "bpf_prog_3", 800, 900 },
+	};
+	struct map_def merged12[] = {
+		{ "kcore1",     100,  200 },
+		{ "bpf_prog_1", 200,  300 },
+		{ "kcore1",     300,  500 },
+		{ "bpf_prog_2", 500,  600 },
+		{ "kcore1",     600,  800 },
+		{ "bpf_prog_3", 800,  900 },
+		{ "kcore1",     900, 1000 },
+	};
+	struct map_def merged3[] = {
+		{ "kcore1",      100,  200 },
+		{ "bpf_prog_1",  200,  300 },
+		{ "kcore1",      300,  500 },
+		{ "bpf_prog_2",  500,  600 },
+		{ "kcore1",      600,  800 },
+		{ "bpf_prog_3",  800,  900 },
+		{ "kcore1",      900, 1000 },
+		{ "kcore3",     1000, 1100 },
+	};
+	struct map *map_kcore1, *map_kcore2, *map_kcore3;
+	int ret;
+
+	map_groups__init(&mg, NULL);
+
+	for (i = 0; i < ARRAY_SIZE(bpf_progs); i++) {
+		struct map *map;
+
+		map = dso__new_map(bpf_progs[i].name);
+		TEST_ASSERT_VAL("failed to create map", map);
+
+		map->start = bpf_progs[i].start;
+		map->end   = bpf_progs[i].end;
+		map_groups__insert(&mg, map);
+		map__put(map);
+	}
+
+	map_kcore1 = dso__new_map("kcore1");
+	TEST_ASSERT_VAL("failed to create map", map_kcore1);
+
+	map_kcore2 = dso__new_map("kcore2");
+	TEST_ASSERT_VAL("failed to create map", map_kcore2);
+
+	map_kcore3 = dso__new_map("kcore3");
+	TEST_ASSERT_VAL("failed to create map", map_kcore3);
+
+	/* kcore1 map overlaps over all bpf maps */
+	map_kcore1->start = 100;
+	map_kcore1->end   = 1000;
+
+	/* kcore2 map hides behind bpf_prog_2 */
+	map_kcore2->start = 550;
+	map_kcore2->end   = 570;
+
+	/* kcore3 map hides behind bpf_prog_3, kcore1 and adds new map */
+	map_kcore3->start = 880;
+	map_kcore3->end   = 1100;
+
+	ret = map_groups__merge_in(&mg, map_kcore1);
+	TEST_ASSERT_VAL("failed to merge map", !ret);
+
+	ret = check_maps(merged12, ARRAY_SIZE(merged12), &mg);
+	TEST_ASSERT_VAL("merge check failed", !ret);
+
+	ret = map_groups__merge_in(&mg, map_kcore2);
+	TEST_ASSERT_VAL("failed to merge map", !ret);
+
+	ret = check_maps(merged12, ARRAY_SIZE(merged12), &mg);
+	TEST_ASSERT_VAL("merge check failed", !ret);
+
+	ret = map_groups__merge_in(&mg, map_kcore3);
+	TEST_ASSERT_VAL("failed to merge map", !ret);
+
+	ret = check_maps(merged3, ARRAY_SIZE(merged3), &mg);
+	TEST_ASSERT_VAL("merge check failed", !ret);
+	return TEST_OK;
+}
diff --git a/tools/perf/tests/tests.h b/tools/perf/tests/tests.h
index 399f18ca71a3..e5e3a57cd373 100644
--- a/tools/perf/tests/tests.h
+++ b/tools/perf/tests/tests.h
@@ -107,6 +107,7 @@ const char *test__clang_subtest_get_desc(int subtest);
 int test__clang_subtest_get_nr(void);
 int test__unit_number__scnprint(struct test *test, int subtest);
 int test__mem2node(struct test *t, int subtest);
+int test__map_groups__merge_in(struct test *t, int subtest);
 
 bool test__bp_signal_is_supported(void);
 bool test__wp_is_supported(void);
diff --git a/tools/perf/util/map_groups.h b/tools/perf/util/map_groups.h
index 4dcda33e0fdf..5f25efa6d6bc 100644
--- a/tools/perf/util/map_groups.h
+++ b/tools/perf/util/map_groups.h
@@ -88,4 +88,6 @@ int map_groups__fixup_overlappings(struct map_groups *mg, struct map *map, FILE
 
 struct map *map_groups__find_by_name(struct map_groups *mg, const char *name);
 
+int map_groups__merge_in(struct map_groups *kmaps, struct map *new_map);
+
 #endif // __PERF_MAP_GROUPS_H
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 29780fcd049c..f4540f8bbed1 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1170,7 +1170,7 @@ static int kcore_mapfn(u64 start, u64 len, u64 pgoff, void *data)
  * Merges map into map_groups by splitting the new map
  * within the existing map regions.
  */
-static int map_groups__merge_in(struct map_groups *kmaps, struct map *new_map)
+int map_groups__merge_in(struct map_groups *kmaps, struct map *new_map)
 {
 	struct map *old_map;
 	LIST_HEAD(merged);