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
18static sigjmp_buf jmpbuf;
19static const struct perf_hook_desc *current_perf_hook;
20
21void 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
37void perf_hooks__recover(void)
38{
39	if (current_perf_hook)
40		siglongjmp(jmpbuf, 1);
41}
42
43#define PERF_HOOK(name)					\
44perf_hook_func_t __perf_hook_func_##name = NULL;	\
45struct 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
55static struct perf_hook_desc *perf_hooks[] = {
56#include "perf-hooks-list.h"
57};
58#undef PERF_HOOK
59
60int 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
79perf_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