1 files changed, 44 insertions, 0 deletions

diff --git a/tools/perf/tests/bpf-script-example.c b/tools/perf/tests/bpf-script-example.c
new file mode 100644
index 000000000000..410a70b93b93
--- /dev/null
+++ b/tools/perf/tests/bpf-script-example.c
@@ -0,0 +1,44 @@
+#ifndef LINUX_VERSION_CODE
+# error Need LINUX_VERSION_CODE
+# error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'
+#endif
+#define BPF_ANY 0
+#define BPF_MAP_TYPE_ARRAY 2
+#define BPF_FUNC_map_lookup_elem 1
+#define BPF_FUNC_map_update_elem 2
+
+static void *(*bpf_map_lookup_elem)(void *map, void *key) =
+        (void *) BPF_FUNC_map_lookup_elem;
+static void *(*bpf_map_update_elem)(void *map, void *key, void *value, int flags) =
+        (void *) BPF_FUNC_map_update_elem;
+
+struct bpf_map_def {
+        unsigned int type;
+        unsigned int key_size;
+        unsigned int value_size;
+        unsigned int max_entries;
+};
+
+#define SEC(NAME) __attribute__((section(NAME), used))
+struct bpf_map_def SEC("maps") flip_table = {
+        .type = BPF_MAP_TYPE_ARRAY,
+        .key_size = sizeof(int),
+        .value_size = sizeof(int),
+        .max_entries = 1,
+};
+
+SEC("func=sys_epoll_pwait")
+int bpf_func__sys_epoll_pwait(void *ctx)
+{
+        int ind =0;
+        int *flag = bpf_map_lookup_elem(&flip_table, &ind);
+        int new_flag;
+        if (!flag)
+                return 0;
+        /* flip flag and store back */
+        new_flag = !*flag;
+        bpf_map_update_elem(&flip_table, &ind, &new_flag, BPF_ANY);
+        return new_flag;
+}
+char _license[] SEC("license") = "GPL";
+int _version SEC("version") = LINUX_VERSION_CODE;