1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun // Copyright (c) 2019 Facebook
3*4882a593Smuzhiyun
4*4882a593Smuzhiyun #include <linux/bpf.h>
5*4882a593Smuzhiyun #include <stdint.h>
6*4882a593Smuzhiyun #include <bpf/bpf_helpers.h>
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun char _license[] SEC("license") = "GPL";
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun struct {
11*4882a593Smuzhiyun __uint(type, BPF_MAP_TYPE_ARRAY);
12*4882a593Smuzhiyun __uint(max_entries, 4096);
13*4882a593Smuzhiyun __uint(map_flags, BPF_F_MMAPABLE | BPF_F_RDONLY_PROG);
14*4882a593Smuzhiyun __type(key, __u32);
15*4882a593Smuzhiyun __type(value, char);
16*4882a593Smuzhiyun } rdonly_map SEC(".maps");
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun struct {
19*4882a593Smuzhiyun __uint(type, BPF_MAP_TYPE_ARRAY);
20*4882a593Smuzhiyun __uint(max_entries, 512 * 4); /* at least 4 pages of data */
21*4882a593Smuzhiyun __uint(map_flags, BPF_F_MMAPABLE);
22*4882a593Smuzhiyun __type(key, __u32);
23*4882a593Smuzhiyun __type(value, __u64);
24*4882a593Smuzhiyun } data_map SEC(".maps");
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun __u64 in_val = 0;
27*4882a593Smuzhiyun __u64 out_val = 0;
28*4882a593Smuzhiyun
29*4882a593Smuzhiyun SEC("raw_tracepoint/sys_enter")
test_mmap(void * ctx)30*4882a593Smuzhiyun int test_mmap(void *ctx)
31*4882a593Smuzhiyun {
32*4882a593Smuzhiyun int zero = 0, one = 1, two = 2, far = 1500;
33*4882a593Smuzhiyun __u64 val, *p;
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun out_val = in_val;
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun /* data_map[2] = in_val; */
38*4882a593Smuzhiyun bpf_map_update_elem(&data_map, &two, (const void *)&in_val, 0);
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun /* data_map[1] = data_map[0] * 2; */
41*4882a593Smuzhiyun p = bpf_map_lookup_elem(&data_map, &zero);
42*4882a593Smuzhiyun if (p) {
43*4882a593Smuzhiyun val = (*p) * 2;
44*4882a593Smuzhiyun bpf_map_update_elem(&data_map, &one, &val, 0);
45*4882a593Smuzhiyun }
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun /* data_map[far] = in_val * 3; */
48*4882a593Smuzhiyun val = in_val * 3;
49*4882a593Smuzhiyun bpf_map_update_elem(&data_map, &far, &val, 0);
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun return 0;
52*4882a593Smuzhiyun }
53*4882a593Smuzhiyun
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