1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2021 Facebook */
3#include "vmlinux.h"
4#include <bpf/bpf_helpers.h>
5#include <bpf/bpf_tracing.h>
6
7#if __has_attribute(btf_decl_tag)
8#define __tag1 __attribute__((btf_decl_tag("tag1")))
9#define __tag2 __attribute__((btf_decl_tag("tag2")))
10volatile const bool skip_tests __tag1 __tag2 = false;
11#else
12#define __tag1
13#define __tag2
14volatile const bool skip_tests = true;
15#endif
16
17struct key_t {
18 int a;
19 int b __tag1 __tag2;
20 int c;
21} __tag1 __tag2;
22
23typedef struct {
24 int a;
25 int b;
26} value_t __tag1 __tag2;
27
28struct {
29 __uint(type, BPF_MAP_TYPE_HASH);
30 __uint(max_entries, 3);
31 __type(key, struct key_t);
32 __type(value, value_t);
33} hashmap1 SEC(".maps");
34
35
36static __noinline int foo(int x __tag1 __tag2) __tag1 __tag2
37{
38 struct key_t key;
39 value_t val = {};
40
41 key.a = key.b = key.c = x;
42 bpf_map_update_elem(&hashmap1, &key, &val, 0);
43 return 0;
44}
45
46SEC("fentry/bpf_fentry_test1")
47int BPF_PROG(sub, int x)
48{
49 return foo(x);
50}
51

source code of linux/tools/testing/selftests/bpf/progs/test_btf_decl_tag.c