bp_signal_overflow.c

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// SPDX-License-Identifier: GPL-2.0
/*
 * Originally done by Vince Weaver <vincent.weaver@maine.edu> for
 * perf_event_tests (git://github.com/deater/perf_event_tests)
 */

/*
 * Powerpc needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select
 * 'int-ll64.h' and avoid compile warnings when printing __u64 with %llu.
 */
#define __SANE_USERSPACE_TYPES__

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
#include <time.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/mman.h>
#include <linux/compiler.h>
#include <linux/hw_breakpoint.h>

#include "tests.h"
#include "debug.h"
#include "perf.h"
#include "cloexec.h"

static int overflows;

static noinline int test_function(void)
{
    return time(NULL);
}

static void sig_handler(int signum __maybe_unused,
            siginfo_t *oh __maybe_unused,
            void *uc __maybe_unused)
{
    overflows++;
}

static long long bp_count(int fd)
{
    long long count;
    int ret;

    ret = read(fd, &count, sizeof(long long));
    if (ret != sizeof(long long)) {
        pr_debug("failed to read: %d\n", ret);
        return TEST_FAIL;
    }

    return count;
}

#define EXECUTIONS 10000
#define THRESHOLD  100

int test__bp_signal_overflow(struct test *test __maybe_unused, int subtest __maybe_unused)
{
    struct perf_event_attr pe;
    struct sigaction sa;
    long long count;
    int fd, i, fails = 0;

    /* setup SIGIO signal handler */
    memset(&sa, 0, sizeof(struct sigaction));
    sa.sa_sigaction = (void *) sig_handler;
    sa.sa_flags = SA_SIGINFO;

    if (sigaction(SIGIO, &sa, NULL) < 0) {
        pr_debug("failed setting up signal handler\n");
        return TEST_FAIL;
    }

    memset(&pe, 0, sizeof(struct perf_event_attr));
    pe.type = PERF_TYPE_BREAKPOINT;
    pe.size = sizeof(struct perf_event_attr);

    pe.config = 0;
    pe.bp_type = HW_BREAKPOINT_X;
    pe.bp_addr = (unsigned long) test_function;
    pe.bp_len = sizeof(long);

    pe.sample_period = THRESHOLD;
    pe.sample_type = PERF_SAMPLE_IP;
    pe.wakeup_events = 1;

    pe.disabled = 1;
    pe.exclude_kernel = 1;
    pe.exclude_hv = 1;

    fd = sys_perf_event_open(&pe, 0, -1, -1,
                 perf_event_open_cloexec_flag());
    if (fd < 0) {
        pr_debug("failed opening event %llx\n", pe.config);
        return TEST_FAIL;
    }

    fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
    fcntl(fd, F_SETSIG, SIGIO);
    fcntl(fd, F_SETOWN, getpid());

    ioctl(fd, PERF_EVENT_IOC_RESET, 0);
    ioctl(fd, PERF_EVENT_IOC_ENABLE, 0);

    for (i = 0; i < EXECUTIONS; i++)
        test_function();

    ioctl(fd, PERF_EVENT_IOC_DISABLE, 0);

    count = bp_count(fd);

    close(fd);

    pr_debug("count %lld, overflow %d\n",
         count, overflows);

    if (count != EXECUTIONS) {
        pr_debug("\tWrong number of executions %lld != %d\n",
        count, EXECUTIONS);
        fails++;
    }

    if (overflows != EXECUTIONS / THRESHOLD) {
        pr_debug("\tWrong number of overflows %d != %d\n",
        overflows, EXECUTIONS / THRESHOLD);
        fails++;
    }

    return fails ? TEST_FAIL : TEST_OK;
}