LXR linux/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 <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