cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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perf-hooks.c (2042B)

      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}