1 files changed, 48 insertions, 0 deletions
diff --git a/kernel/tools/perf/tests/bpf-script-example.c b/kernel/tools/perf/tests/bpf-script-example.c
new file mode 100644
index 000000000..0ec9c2c03
--- /dev/null
+++ b/kernel/tools/perf/tests/bpf-script-example.c
@@ -0,0 +1,48 @@
+/*
+ * bpf-script-example.c
+ * Test basic LLVM building
+ */
+#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;