1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * perf_hooks.c 4 * 5 * Copyright (C) 2016 Wang Nan <wangnan0@huawei.com> 6 * Copyright (C) 2016 Huawei Inc. 7 */ 8 9 #include <errno.h> 10 #include <stdlib.h> 11 #include <string.h> 12 #include <setjmp.h> 13 #include <linux/err.h> 14 #include <linux/kernel.h> 15 #include "util/debug.h" 16 #include "util/perf-hooks.h" 17 18 static sigjmp_buf jmpbuf; 19 static const struct perf_hook_desc *current_perf_hook; 20 21 void perf_hooks__invoke(const struct perf_hook_desc *desc) 22 { 23 if (!(desc && desc->p_hook_func && *desc->p_hook_func)) 24 return; 25 26 if (sigsetjmp(jmpbuf, 1)) { 27 pr_warning("Fatal error (SEGFAULT) in perf hook '%s'\n", 28 desc->hook_name); 29 *(current_perf_hook->p_hook_func) = NULL; 30 } else { 31 current_perf_hook = desc; 32 (**desc->p_hook_func)(desc->hook_ctx); 33 } 34 current_perf_hook = NULL; 35 } 36 37 void perf_hooks__recover(void) 38 { 39 if (current_perf_hook) 40 siglongjmp(jmpbuf, 1); 41 } 42 43 #define PERF_HOOK(name) \ 44 perf_hook_func_t __perf_hook_func_##name = NULL; \ 45 struct perf_hook_desc __perf_hook_desc_##name = \ 46 {.hook_name = #name, \ 47 .p_hook_func = &__perf_hook_func_##name, \ 48 .hook_ctx = NULL}; 49 #include "perf-hooks-list.h" 50 #undef PERF_HOOK 51 52 #define PERF_HOOK(name) \ 53 &__perf_hook_desc_##name, 54 55 static struct perf_hook_desc *perf_hooks[] = { 56 #include "perf-hooks-list.h" 57 }; 58 #undef PERF_HOOK 59 60 int perf_hooks__set_hook(const char *hook_name, 61 perf_hook_func_t hook_func, 62 void *hook_ctx) 63 { 64 unsigned int i; 65 66 for (i = 0; i < ARRAY_SIZE(perf_hooks); i++) { 67 if (strcmp(hook_name, perf_hooks[i]->hook_name) != 0) 68 continue; 69 70 if (*(perf_hooks[i]->p_hook_func)) 71 pr_warning("Overwrite existing hook: %s\n", hook_name); 72 *(perf_hooks[i]->p_hook_func) = hook_func; 73 perf_hooks[i]->hook_ctx = hook_ctx; 74 return 0; 75 } 76 return -ENOENT; 77 } 78 79 perf_hook_func_t perf_hooks__get_hook(const char *hook_name) 80 { 81 unsigned int i; 82 83 for (i = 0; i < ARRAY_SIZE(perf_hooks); i++) { 84 if (strcmp(hook_name, perf_hooks[i]->hook_name) != 0) 85 continue; 86 87 return *(perf_hooks[i]->p_hook_func); 88 } 89 return ERR_PTR(-ENOENT); 90 } 91