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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intel-cqm.c (2837B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include "tests/tests.h"
      3#include "cloexec.h"
      4#include "debug.h"
      5#include "evlist.h"
      6#include "evsel.h"
      7#include "arch-tests.h"
      8#include <internal/lib.h> // page_size
      9
     10#include <signal.h>
     11#include <sys/mman.h>
     12#include <sys/wait.h>
     13#include <errno.h>
     14#include <string.h>
     15
     16static pid_t spawn(void)
     17{
     18	pid_t pid;
     19
     20	pid = fork();
     21	if (pid)
     22		return pid;
     23
     24	while(1)
     25		sleep(5);
     26	return 0;
     27}
     28
     29/*
     30 * Create an event group that contains both a sampled hardware
     31 * (cpu-cycles) and software (intel_cqm/llc_occupancy/) event. We then
     32 * wait for the hardware perf counter to overflow and generate a PMI,
     33 * which triggers an event read for both of the events in the group.
     34 *
     35 * Since reading Intel CQM event counters requires sending SMP IPIs, the
     36 * CQM pmu needs to handle the above situation gracefully, and return
     37 * the last read counter value to avoid triggering a WARN_ON_ONCE() in
     38 * smp_call_function_many() caused by sending IPIs from NMI context.
     39 */
     40int test__intel_cqm_count_nmi_context(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
     41{
     42	struct evlist *evlist = NULL;
     43	struct evsel *evsel = NULL;
     44	struct perf_event_attr pe;
     45	int i, fd[2], flag, ret;
     46	size_t mmap_len;
     47	void *event;
     48	pid_t pid;
     49	int err = TEST_FAIL;
     50
     51	flag = perf_event_open_cloexec_flag();
     52
     53	evlist = evlist__new();
     54	if (!evlist) {
     55		pr_debug("evlist__new failed\n");
     56		return TEST_FAIL;
     57	}
     58
     59	ret = parse_events(evlist, "intel_cqm/llc_occupancy/", NULL);
     60	if (ret) {
     61		pr_debug("parse_events failed, is \"intel_cqm/llc_occupancy/\" available?\n");
     62		err = TEST_SKIP;
     63		goto out;
     64	}
     65
     66	evsel = evlist__first(evlist);
     67	if (!evsel) {
     68		pr_debug("evlist__first failed\n");
     69		goto out;
     70	}
     71
     72	memset(&pe, 0, sizeof(pe));
     73	pe.size = sizeof(pe);
     74
     75	pe.type = PERF_TYPE_HARDWARE;
     76	pe.config = PERF_COUNT_HW_CPU_CYCLES;
     77	pe.read_format = PERF_FORMAT_GROUP;
     78
     79	pe.sample_period = 128;
     80	pe.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_READ;
     81
     82	pid = spawn();
     83
     84	fd[0] = sys_perf_event_open(&pe, pid, -1, -1, flag);
     85	if (fd[0] < 0) {
     86		pr_debug("failed to open event\n");
     87		goto out;
     88	}
     89
     90	memset(&pe, 0, sizeof(pe));
     91	pe.size = sizeof(pe);
     92
     93	pe.type = evsel->attr.type;
     94	pe.config = evsel->attr.config;
     95
     96	fd[1] = sys_perf_event_open(&pe, pid, -1, fd[0], flag);
     97	if (fd[1] < 0) {
     98		pr_debug("failed to open event\n");
     99		goto out;
    100	}
    101
    102	/*
    103	 * Pick a power-of-two number of pages + 1 for the meta-data
    104	 * page (struct perf_event_mmap_page). See tools/perf/design.txt.
    105	 */
    106	mmap_len = page_size * 65;
    107
    108	event = mmap(NULL, mmap_len, PROT_READ, MAP_SHARED, fd[0], 0);
    109	if (event == (void *)(-1)) {
    110		pr_debug("failed to mmap %d\n", errno);
    111		goto out;
    112	}
    113
    114	sleep(1);
    115
    116	err = TEST_OK;
    117
    118	munmap(event, mmap_len);
    119
    120	for (i = 0; i < 2; i++)
    121		close(fd[i]);
    122
    123	kill(pid, SIGKILL);
    124	wait(NULL);
    125out:
    126	evlist__delete(evlist);
    127	return err;
    128}