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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strncmp_bench.c (1079B)

      1// SPDX-License-Identifier: GPL-2.0
      2/* Copyright (C) 2021. Huawei Technologies Co., Ltd */
      3#include <linux/types.h>
      4#include <linux/bpf.h>
      5#include <bpf/bpf_helpers.h>
      6#include <bpf/bpf_tracing.h>
      7
      8#define STRNCMP_STR_SZ 4096
      9
     10/* Will be updated by benchmark before program loading */
     11const volatile unsigned int cmp_str_len = 1;
     12const char target[STRNCMP_STR_SZ];
     13
     14long hits = 0;
     15char str[STRNCMP_STR_SZ];
     16
     17char _license[] SEC("license") = "GPL";
     18
     19static __always_inline int local_strncmp(const char *s1, unsigned int sz,
     20					 const char *s2)
     21{
     22	int ret = 0;
     23	unsigned int i;
     24
     25	for (i = 0; i < sz; i++) {
     26		/* E.g. 0xff > 0x31 */
     27		ret = (unsigned char)s1[i] - (unsigned char)s2[i];
     28		if (ret || !s1[i])
     29			break;
     30	}
     31
     32	return ret;
     33}
     34
     35SEC("tp/syscalls/sys_enter_getpgid")
     36int strncmp_no_helper(void *ctx)
     37{
     38	if (local_strncmp(str, cmp_str_len + 1, target) < 0)
     39		__sync_add_and_fetch(&hits, 1);
     40	return 0;
     41}
     42
     43SEC("tp/syscalls/sys_enter_getpgid")
     44int strncmp_helper(void *ctx)
     45{
     46	if (bpf_strncmp(str, cmp_str_len + 1, target) < 0)
     47		__sync_add_and_fetch(&hits, 1);
     48	return 0;
     49}
     50