GNU Linux-libre 4.19.211-gnu1
[releases.git] / tools / perf / util / perf-hooks.c
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 <setjmp.h>
12 #include <linux/err.h>
13 #include <linux/kernel.h>
14 #include "util/util.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 }