1 files changed, 76 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_stacktrace_build_id.c b/tools/testing/selftests/bpf/progs/test_stacktrace_build_id.c
new file mode 100644
index 000000000000..d86c281e957f
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_stacktrace_build_id.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 Facebook
+
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+
+#ifndef PERF_MAX_STACK_DEPTH
+#define PERF_MAX_STACK_DEPTH         127
+#endif
+
+struct bpf_map_def SEC("maps") control_map = {
+	.type = BPF_MAP_TYPE_ARRAY,
+	.key_size = sizeof(__u32),
+	.value_size = sizeof(__u32),
+	.max_entries = 1,
+};
+
+struct bpf_map_def SEC("maps") stackid_hmap = {
+	.type = BPF_MAP_TYPE_HASH,
+	.key_size = sizeof(__u32),
+	.value_size = sizeof(__u32),
+	.max_entries = 16384,
+};
+
+struct bpf_map_def SEC("maps") stackmap = {
+	.type = BPF_MAP_TYPE_STACK_TRACE,
+	.key_size = sizeof(__u32),
+	.value_size = sizeof(struct bpf_stack_build_id)
+		* PERF_MAX_STACK_DEPTH,
+	.max_entries = 128,
+	.map_flags = BPF_F_STACK_BUILD_ID,
+};
+
+struct bpf_map_def SEC("maps") stack_amap = {
+	.type = BPF_MAP_TYPE_ARRAY,
+	.key_size = sizeof(__u32),
+	.value_size = sizeof(struct bpf_stack_build_id)
+		* PERF_MAX_STACK_DEPTH,
+	.max_entries = 128,
+};
+
+/* taken from /sys/kernel/debug/tracing/events/random/urandom_read/format */
+struct random_urandom_args {
+	unsigned long long pad;
+	int got_bits;
+	int pool_left;
+	int input_left;
+};
+
+SEC("tracepoint/random/urandom_read")
+int oncpu(struct random_urandom_args *args)
+{
+	__u32 max_len = sizeof(struct bpf_stack_build_id)
+			* PERF_MAX_STACK_DEPTH;
+	__u32 key = 0, val = 0, *value_p;
+	void *stack_p;
+
+	value_p = bpf_map_lookup_elem(&control_map, &key);
+	if (value_p && *value_p)
+		return 0; /* skip if non-zero *value_p */
+
+	/* The size of stackmap and stackid_hmap should be the same */
+	key = bpf_get_stackid(args, &stackmap, BPF_F_USER_STACK);
+	if ((int)key >= 0) {
+		bpf_map_update_elem(&stackid_hmap, &key, &val, 0);
+		stack_p = bpf_map_lookup_elem(&stack_amap, &key);
+		if (stack_p)
+			bpf_get_stack(args, stack_p, max_len,
+				      BPF_F_USER_STACK | BPF_F_USER_BUILD_ID);
+	}
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";
+__u32 _version SEC("version") = 1; /* ignored by tracepoints, required by libbpf.a */