[PATCH 5/5] perf test: Add kallsyms split test

[Namhyung Kim <namhyung@kernel.org>]

Add fake_root directory for /proc/{version,modules,kallsyms}.  The
kallsyms has a bad symbol in the module and it causes the main map
splitted.  The test ensures it only has two maps - kernel and the module
and it finds the initial map after the module without creating the split
maps like [kernel].0 and so on.

  $ perf test -vv "split kallsyms"
   69: split kallsyms:
  --- start ---
  test child forked, pid 921678
  try to find fake root directory
  maps__set_modules_path_dir: cannot open tests/fake_root/lib/modules/X.Y.Z dir
  Problems setting modules path maps, continuing anyway...
  Failed to open tests/fake_root/proc/kcore. Note /proc/kcore requires CAP_SYS_RAWIO capability to access.
  Using tests/fake_root/proc/kallsyms for symbols
  kernel map loaded - check symbol and map
  ---- end(0) ----
   69: split kallsyms                                                  : Ok

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/tests/Build                   |  1 +
 tools/perf/tests/builtin-test.c          |  1 +
 tools/perf/tests/fake_root/proc/kallsyms | 10 ++++
 tools/perf/tests/fake_root/proc/modules  |  1 +
 tools/perf/tests/fake_root/proc/version  |  1 +
 tools/perf/tests/kallsyms-split.c        | 72 ++++++++++++++++++++++++
 tools/perf/tests/tests.h                 |  1 +
 7 files changed, 87 insertions(+)
 create mode 100644 tools/perf/tests/fake_root/proc/kallsyms
 create mode 100644 tools/perf/tests/fake_root/proc/modules
 create mode 100644 tools/perf/tests/fake_root/proc/version
 create mode 100644 tools/perf/tests/kallsyms-split.c

diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build
index af67f8ef74b49c58..c2a67ce459417e0f 100644
--- a/tools/perf/tests/Build
+++ b/tools/perf/tests/Build
@@ -69,6 +69,7 @@ perf-test-y += util.o
 perf-test-y += hwmon_pmu.o
 perf-test-y += tool_pmu.o
 perf-test-y += subcmd-help.o
+perf-test-y += kallsyms-split.o
 
 ifeq ($(SRCARCH),$(filter $(SRCARCH),x86 arm arm64 powerpc))
 perf-test-$(CONFIG_DWARF_UNWIND) += dwarf-unwind.o
diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
index 9090e8238a447826..bd6ffa8e4578431a 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -140,6 +140,7 @@ static struct test_suite *generic_tests[] = {
 	&suite__symbols,
 	&suite__util,
 	&suite__subcmd_help,
+	&suite__kallsyms_split,
 	NULL,
 };
 
diff --git a/tools/perf/tests/fake_root/proc/kallsyms b/tools/perf/tests/fake_root/proc/kallsyms
new file mode 100644
index 0000000000000000..75d65639e6889c69
--- /dev/null
+++ b/tools/perf/tests/fake_root/proc/kallsyms
@@ -0,0 +1,10 @@
+ffffffffab200000 T _stext
+ffffffffab200010 T good_symbol
+ffffffffab200020 t bad_symbol
+ffffffffab200030 t main_symbol1
+ffffffffab200040 t main_symbol2
+ffffffffab200050 t main_symbol3
+ffffffffab200060 T _etext
+ffffffffcd000000 T start_module	[module]
+ffffffffab200020 u bad_symbol	[module]
+ffffffffcd000040 T end_module	[module]
diff --git a/tools/perf/tests/fake_root/proc/modules b/tools/perf/tests/fake_root/proc/modules
new file mode 100644
index 0000000000000000..608c6e2599f08d08
--- /dev/null
+++ b/tools/perf/tests/fake_root/proc/modules
@@ -0,0 +1 @@
+module 4096 1 - Live 0xffffffffcd000000
diff --git a/tools/perf/tests/fake_root/proc/version b/tools/perf/tests/fake_root/proc/version
new file mode 100644
index 0000000000000000..9de114d87d5e940e
--- /dev/null
+++ b/tools/perf/tests/fake_root/proc/version
@@ -0,0 +1 @@
+Linux version X.Y.Z (just for perf test)
diff --git a/tools/perf/tests/kallsyms-split.c b/tools/perf/tests/kallsyms-split.c
new file mode 100644
index 0000000000000000..b71a2ea6fa696895
--- /dev/null
+++ b/tools/perf/tests/kallsyms-split.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/compiler.h>
+#include <unistd.h>
+#include "util/dso.h"
+#include "util/map.h"
+#include "util/symbol.h"
+#include "util/debug.h"
+#include "util/machine.h"
+#include "tests.h"
+
+static int test__kallsyms_split(struct test_suite *test __maybe_unused,
+				int subtest __maybe_unused)
+{
+	struct machine m;
+	struct map *map = NULL;
+	int ret = TEST_FAIL;
+	const char *root_dirs[] = { "tests/fake_root", "tools/perf/tests/fake_root", "fake_root" };
+	unsigned int root_idx;
+
+	/* force to use /proc/kallsyms */
+	symbol_conf.ignore_vmlinux = true;
+	symbol_conf.ignore_vmlinux_buildid = true;
+
+	pr_debug("try to find fake root directory\n");
+	for (root_idx = 0; root_idx < ARRAY_SIZE(root_dirs); root_idx++) {
+		char buf[128];
+
+		scnprintf(buf, sizeof(buf), "%s/proc/kallsyms", root_dirs[root_idx]);
+		if (!access(buf, F_OK))
+			break;
+	}
+
+	if (root_idx == ARRAY_SIZE(root_dirs)) {
+		pr_debug("SKIP: cannot find the fake root directory and files\n");
+		return TEST_SKIP;
+	}
+
+	machine__init(&m, root_dirs[root_idx], HOST_KERNEL_ID);
+	if (machine__create_kernel_maps(&m) < 0) {
+		pr_debug("FAIL: failed to create kernel maps\n");
+		goto out;
+	}
+
+	if (map__load(machine__kernel_map(&m)) < 0) {
+		pr_debug("SKIP: failed to load kallsyms\n");
+		goto out;
+	}
+
+	pr_debug("kernel map loaded - check symbol and map\n");
+	if (maps__nr_maps(machine__kernel_maps(&m)) != 2) {
+		pr_debug("FAIL: it should have the kernel and a module, but has %u maps\n",
+			 maps__nr_maps(machine__kernel_maps(&m)));
+		goto out;
+	}
+
+	if (machine__find_kernel_symbol_by_name(&m, "main_symbol3", &map) == NULL) {
+		pr_debug("FAIL: failed to find a symbol\n");
+		goto out;
+	}
+
+	if (!RC_CHK_EQUAL(map, machine__kernel_map(&m))) {
+		pr_debug("FAIL: the symbol is not in the kernel map\n");
+		goto out;
+	}
+	ret = TEST_OK;
+
+out:
+	machine__exit(&m);
+	return ret;
+}
+
+DEFINE_SUITE("split kallsyms", kallsyms_split);
diff --git a/tools/perf/tests/tests.h b/tools/perf/tests/tests.h
index f5fba95b6f3ffbd3..cb67ddbd03753531 100644
--- a/tools/perf/tests/tests.h
+++ b/tools/perf/tests/tests.h
@@ -178,6 +178,7 @@ DECLARE_SUITE(event_groups);
 DECLARE_SUITE(symbols);
 DECLARE_SUITE(util);
 DECLARE_SUITE(subcmd_help);
+DECLARE_SUITE(kallsyms_split);
 
 /*
  * PowerPC and S390 do not support creation of instruction breakpoints using the
-- 
2.52.0.158.g65b55ccf14-goog