projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| b31de018 WN |
1 | /* |
| 2 | * bpf-script-example.c | |
| 3 | * Test basic LLVM building | |
| 4 | */ | |
| d509db04 WN |
5 | #ifndef LINUX_VERSION_CODE |
| 6 | # error Need LINUX_VERSION_CODE | |
| 7 | # error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig' | |
| 8 | #endif | |
| 9 | #define BPF_ANY 0 | |
| 10 | #define BPF_MAP_TYPE_ARRAY 2 | |
| 11 | #define BPF_FUNC_map_lookup_elem 1 | |
| 12 | #define BPF_FUNC_map_update_elem 2 | |
| 13 | ||
| 14 | static void *(*bpf_map_lookup_elem)(void *map, void *key) = | |
| 15 | (void *) BPF_FUNC_map_lookup_elem; | |
| 16 | static void *(*bpf_map_update_elem)(void *map, void *key, void *value, int flags) = | |
| 17 | (void *) BPF_FUNC_map_update_elem; | |
| 18 | ||
| 19 | struct bpf_map_def { | |
| 20 | unsigned int type; | |
| 21 | unsigned int key_size; | |
| 22 | unsigned int value_size; | |
| 23 | unsigned int max_entries; | |
| 24 | }; | |
| 25 | ||
| 26 | #define SEC(NAME) __attribute__((section(NAME), used)) | |
| 27 | struct bpf_map_def SEC("maps") flip_table = { | |
| 28 | .type = BPF_MAP_TYPE_ARRAY, | |
| 29 | .key_size = sizeof(int), | |
| 30 | .value_size = sizeof(int), | |
| 31 | .max_entries = 1, | |
| 32 | }; | |
| 33 | ||
| 4ffde492 ACM |
34 | SEC("func=sys_epoll_wait") |
| 35 | int bpf_func__sys_epoll_wait(void *ctx) | |
| d509db04 WN |
36 | { |
| 37 | int ind =0; | |
| 38 | int *flag = bpf_map_lookup_elem(&flip_table, &ind); | |
| 39 | int new_flag; | |
| 40 | if (!flag) | |
| 41 | return 0; | |
| 42 | /* flip flag and store back */ | |
| 43 | new_flag = !*flag; | |
| 44 | bpf_map_update_elem(&flip_table, &ind, &new_flag, BPF_ANY); | |
| 45 | return new_flag; | |
| 46 | } | |
| 47 | char _license[] SEC("license") = "GPL"; | |
| 48 | int _version SEC("version") = LINUX_VERSION_CODE; |