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_link.c (2300B)

      1// SPDX-License-Identifier: GPL-2.0
      2/* Copyright (c) 2021 Facebook */
      3#define _GNU_SOURCE
      4#include <pthread.h>
      5#include <sched.h>
      6#include <test_progs.h>
      7#include "test_perf_link.skel.h"
      8
      9static void burn_cpu(void)
     10{
     11	volatile int j = 0;
     12	cpu_set_t cpu_set;
     13	int i, err;
     14
     15	/* generate some branches on cpu 0 */
     16	CPU_ZERO(&cpu_set);
     17	CPU_SET(0, &cpu_set);
     18	err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set), &cpu_set);
     19	ASSERT_OK(err, "set_thread_affinity");
     20
     21	/* spin the loop for a while (random high number) */
     22	for (i = 0; i < 1000000; ++i)
     23		++j;
     24}
     25
     26/* TODO: often fails in concurrent mode */
     27void serial_test_perf_link(void)
     28{
     29	struct test_perf_link *skel = NULL;
     30	struct perf_event_attr attr;
     31	int pfd = -1, link_fd = -1, err;
     32	int run_cnt_before, run_cnt_after;
     33	struct bpf_link_info info;
     34	__u32 info_len = sizeof(info);
     35
     36	/* create perf event */
     37	memset(&attr, 0, sizeof(attr));
     38	attr.size = sizeof(attr);
     39	attr.type = PERF_TYPE_SOFTWARE;
     40	attr.config = PERF_COUNT_SW_CPU_CLOCK;
     41	attr.freq = 1;
     42	attr.sample_freq = 1000;
     43	pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);
     44	if (!ASSERT_GE(pfd, 0, "perf_fd"))
     45		goto cleanup;
     46
     47	skel = test_perf_link__open_and_load();
     48	if (!ASSERT_OK_PTR(skel, "skel_load"))
     49		goto cleanup;
     50
     51	link_fd = bpf_link_create(bpf_program__fd(skel->progs.handler), pfd,
     52				  BPF_PERF_EVENT, NULL);
     53	if (!ASSERT_GE(link_fd, 0, "link_fd"))
     54		goto cleanup;
     55
     56	memset(&info, 0, sizeof(info));
     57	err = bpf_obj_get_info_by_fd(link_fd, &info, &info_len);
     58	if (!ASSERT_OK(err, "link_get_info"))
     59		goto cleanup;
     60
     61	ASSERT_EQ(info.type, BPF_LINK_TYPE_PERF_EVENT, "link_type");
     62	ASSERT_GT(info.id, 0, "link_id");
     63	ASSERT_GT(info.prog_id, 0, "link_prog_id");
     64
     65	/* ensure we get at least one perf_event prog execution */
     66	burn_cpu();
     67	ASSERT_GT(skel->bss->run_cnt, 0, "run_cnt");
     68
     69	/* perf_event is still active, but we close link and BPF program
     70	 * shouldn't be executed anymore
     71	 */
     72	close(link_fd);
     73	link_fd = -1;
     74
     75	/* make sure there are no stragglers */
     76	kern_sync_rcu();
     77
     78	run_cnt_before = skel->bss->run_cnt;
     79	burn_cpu();
     80	run_cnt_after = skel->bss->run_cnt;
     81
     82	ASSERT_EQ(run_cnt_before, run_cnt_after, "run_cnt_before_after");
     83
     84cleanup:
     85	if (link_fd >= 0)
     86		close(link_fd);
     87	if (pfd >= 0)
     88		close(pfd);
     89	test_perf_link__destroy(skel);
     90}