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_buffer.c (3718B)

      1// SPDX-License-Identifier: GPL-2.0
      2#define _GNU_SOURCE
      3#include <pthread.h>
      4#include <sched.h>
      5#include <sys/socket.h>
      6#include <test_progs.h>
      7#include "test_perf_buffer.skel.h"
      8#include "bpf/libbpf_internal.h"
      9
     10static int duration;
     11
     12/* AddressSanitizer sometimes crashes due to data dereference below, due to
     13 * this being mmap()'ed memory. Disable instrumentation with
     14 * no_sanitize_address attribute
     15 */
     16__attribute__((no_sanitize_address))
     17static void on_sample(void *ctx, int cpu, void *data, __u32 size)
     18{
     19	int cpu_data = *(int *)data, duration = 0;
     20	cpu_set_t *cpu_seen = ctx;
     21
     22	if (cpu_data != cpu)
     23		CHECK(cpu_data != cpu, "check_cpu_data",
     24		      "cpu_data %d != cpu %d\n", cpu_data, cpu);
     25
     26	CPU_SET(cpu, cpu_seen);
     27}
     28
     29int trigger_on_cpu(int cpu)
     30{
     31	cpu_set_t cpu_set;
     32	int err;
     33
     34	CPU_ZERO(&cpu_set);
     35	CPU_SET(cpu, &cpu_set);
     36
     37	err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set), &cpu_set);
     38	if (err && CHECK(err, "set_affinity", "cpu #%d, err %d\n", cpu, err))
     39		return err;
     40
     41	usleep(1);
     42
     43	return 0;
     44}
     45
     46void serial_test_perf_buffer(void)
     47{
     48	int err, on_len, nr_on_cpus = 0, nr_cpus, i, j;
     49	int zero = 0, my_pid = getpid();
     50	struct test_perf_buffer *skel;
     51	cpu_set_t cpu_seen;
     52	struct perf_buffer *pb;
     53	int last_fd = -1, fd;
     54	bool *online;
     55
     56	nr_cpus = libbpf_num_possible_cpus();
     57	if (CHECK(nr_cpus < 0, "nr_cpus", "err %d\n", nr_cpus))
     58		return;
     59
     60	err = parse_cpu_mask_file("/sys/devices/system/cpu/online",
     61				  &online, &on_len);
     62	if (CHECK(err, "nr_on_cpus", "err %d\n", err))
     63		return;
     64
     65	for (i = 0; i < on_len; i++)
     66		if (online[i])
     67			nr_on_cpus++;
     68
     69	/* load program */
     70	skel = test_perf_buffer__open_and_load();
     71	if (CHECK(!skel, "skel_load", "skeleton open/load failed\n"))
     72		goto out_close;
     73
     74	err = bpf_map_update_elem(bpf_map__fd(skel->maps.my_pid_map), &zero, &my_pid, 0);
     75	if (!ASSERT_OK(err, "my_pid_update"))
     76		goto out_close;
     77
     78	/* attach probe */
     79	err = test_perf_buffer__attach(skel);
     80	if (CHECK(err, "attach_kprobe", "err %d\n", err))
     81		goto out_close;
     82
     83	/* set up perf buffer */
     84	pb = perf_buffer__new(bpf_map__fd(skel->maps.perf_buf_map), 1,
     85			      on_sample, NULL, &cpu_seen, NULL);
     86	if (!ASSERT_OK_PTR(pb, "perf_buf__new"))
     87		goto out_close;
     88
     89	CHECK(perf_buffer__epoll_fd(pb) < 0, "epoll_fd",
     90	      "bad fd: %d\n", perf_buffer__epoll_fd(pb));
     91
     92	/* trigger kprobe on every CPU */
     93	CPU_ZERO(&cpu_seen);
     94	for (i = 0; i < nr_cpus; i++) {
     95		if (i >= on_len || !online[i]) {
     96			printf("skipping offline CPU #%d\n", i);
     97			continue;
     98		}
     99
    100		if (trigger_on_cpu(i))
    101			goto out_close;
    102	}
    103
    104	/* read perf buffer */
    105	err = perf_buffer__poll(pb, 100);
    106	if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err))
    107		goto out_free_pb;
    108
    109	if (CHECK(CPU_COUNT(&cpu_seen) != nr_on_cpus, "seen_cpu_cnt",
    110		  "expect %d, seen %d\n", nr_on_cpus, CPU_COUNT(&cpu_seen)))
    111		goto out_free_pb;
    112
    113	if (CHECK(perf_buffer__buffer_cnt(pb) != nr_on_cpus, "buf_cnt",
    114		  "got %zu, expected %d\n", perf_buffer__buffer_cnt(pb), nr_on_cpus))
    115		goto out_close;
    116
    117	for (i = 0, j = 0; i < nr_cpus; i++) {
    118		if (i >= on_len || !online[i])
    119			continue;
    120
    121		fd = perf_buffer__buffer_fd(pb, j);
    122		CHECK(fd < 0 || last_fd == fd, "fd_check", "last fd %d == fd %d\n", last_fd, fd);
    123		last_fd = fd;
    124
    125		err = perf_buffer__consume_buffer(pb, j);
    126		if (CHECK(err, "drain_buf", "cpu %d, err %d\n", i, err))
    127			goto out_close;
    128
    129		CPU_CLR(i, &cpu_seen);
    130		if (trigger_on_cpu(i))
    131			goto out_close;
    132
    133		err = perf_buffer__consume_buffer(pb, j);
    134		if (CHECK(err, "consume_buf", "cpu %d, err %d\n", j, err))
    135			goto out_close;
    136
    137		if (CHECK(!CPU_ISSET(i, &cpu_seen), "cpu_seen", "cpu %d not seen\n", i))
    138			goto out_close;
    139		j++;
    140	}
    141
    142out_free_pb:
    143	perf_buffer__free(pb);
    144out_close:
    145	test_perf_buffer__destroy(skel);
    146	free(online);
    147}