Add tests for perf event array with and without BPF_F_PRESERVE_ELEMS.
Add a perf event to array via fd mfd. Without BPF_F_PRESERVE_ELEMS, the
perf event is removed when mfd is closed. With BPF_F_PRESERVE_ELEMS, the
perf event is removed when the map is freed.
Signed-off-by: Song Liu <songliubraving@xxxxxx>
---
.../bpf/prog_tests/pe_preserve_elems.c | 66 +++++++++++++++++++
.../bpf/progs/test_pe_preserve_elems.c | 44 +++++++++++++
2 files changed, 110 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/pe_preserve_elems.c
create mode 100644 tools/testing/selftests/bpf/progs/test_pe_preserve_elems.c
diff --git a/tools/testing/selftests/bpf/prog_tests/pe_preserve_elems.c b/tools/testing/selftests/bpf/prog_tests/pe_preserve_elems.c
new file mode 100644
index 0000000000000..673d38395253b
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/pe_preserve_elems.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2019 Facebook */
+#include <test_progs.h>
+#include <linux/bpf.h>
+#include "test_pe_preserve_elems.skel.h"
+
+static int duration;
+
+static void test_one_map(struct bpf_map *map, struct bpf_program *prog,
+ bool has_share_pe)
+{
+ int err, key = 0, pfd = -1, mfd = bpf_map__fd(map);
+ DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts);
+ struct perf_event_attr attr = {
+ .size = sizeof(struct perf_event_attr),
+ .type = PERF_TYPE_SOFTWARE,
+ .config = PERF_COUNT_SW_CPU_CLOCK,
+ };
+
+ pfd = syscall(__NR_perf_event_open, &attr, 0 /* pid */,
+ -1 /* cpu 0 */, -1 /* group id */, 0 /* flags */);
+ if (CHECK(pfd < 0, "perf_event_open", "failed\n"))
+ return;
+
+ err = bpf_map_update_elem(mfd, &key, &pfd, BPF_ANY);
+ close(pfd);
+ if (CHECK(err < 0, "bpf_map_update_elem", "failed\n"))
+ return;
+
+ err = bpf_prog_test_run_opts(bpf_program__fd(prog), &opts);
+ if (CHECK(err < 0, "bpf_prog_test_run_opts", "failed\n"))
+ return;
+ if (CHECK(opts.retval != 0, "bpf_perf_event_read_value",
+ "failed with %d\n", opts.retval))
+ return;
+
+ /* closing mfd, prog still holds a reference on map */
+ close(mfd);
+
+ err = bpf_prog_test_run_opts(bpf_program__fd(prog), &opts);
+ if (CHECK(err < 0, "bpf_prog_test_run_opts", "failed\n"))
+ return;
+
+ if (has_share_pe) {
+ CHECK(opts.retval != 0, "bpf_perf_event_read_value",
+ "failed with %d\n", opts.retval);
+ } else {
+ CHECK(opts.retval != -ENOENT, "bpf_perf_event_read_value",
+ "should have failed with %d, but got %d\n", -ENOENT,
+ opts.retval);
+ }
+}
+
+void test_pe_preserve_elems(void)
+{
+ struct test_pe_preserve_elems *skel;
+
+ skel = test_pe_preserve_elems__open_and_load();
+ if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
+ return;
+
+ test_one_map(skel->maps.array_1, skel->progs.read_array_1, false);
+ test_one_map(skel->maps.array_2, skel->progs.read_array_2, true);
+
+ test_pe_preserve_elems__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_pe_preserve_elems.c b/tools/testing/selftests/bpf/progs/test_pe_preserve_elems.c
new file mode 100644
index 0000000000000..dc77e406de41f
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_pe_preserve_elems.c
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Facebook
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
+ __uint(max_entries, 1);
+ __uint(key_size, sizeof(int));
+ __uint(value_size, sizeof(int));
+} array_1 SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
+ __uint(max_entries, 1);
+ __uint(key_size, sizeof(int));
+ __uint(value_size, sizeof(int));
+ __uint(map_flags, BPF_F_PRESERVE_ELEMS);
+} array_2 SEC(".maps");
+
+SEC("raw_tp/sched_switch")
+int BPF_PROG(read_array_1)
+{
+ struct bpf_perf_event_value val;
+ long ret;
+
+ ret = bpf_perf_event_read_value(&array_1, 0, &val, sizeof(val));
+ bpf_printk("read_array_1 returns %ld", ret);
+ return ret;
+}
+
+SEC("raw_tp/task_rename")
+int BPF_PROG(read_array_2)
+{
+ struct bpf_perf_event_value val;
+ long ret;
+
+ ret = bpf_perf_event_read_value(&array_2, 0, &val, sizeof(val));
+ bpf_printk("read_array_2 returns %ld", ret);
+ return ret;
+}
+
+char LICENSE[] SEC("license") = "GPL";
--
2.24.1
