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