tools/perf/tests/bp_signal.c

   1 /*
   2  * Inspired by breakpoint overflow test done by
   3  * Vince Weaver <vincent.weaver@maine.edu> for perf_event_tests
   4  * (git://github.com/deater/perf_event_tests)
   5  */
   6
   7 #include <stdlib.h>
   8 #include <stdio.h>
   9 #include <unistd.h>
  10 #include <string.h>
  11 #include <sys/ioctl.h>
  12 #include <time.h>
  13 #include <fcntl.h>
  14 #include <signal.h>
  15 #include <sys/mman.h>
  16 #include <linux/compiler.h>
  17 #include <linux/hw_breakpoint.h>
  18
  19 #include "tests.h"
  20 #include "debug.h"
  21 #include "perf.h"
  22
  23 static int fd1;
  24 static int fd2;
  25 static int overflows;
  26
  27 __attribute__ ((noinline))
  28 static int test_function(void)
  29 {
  30         return time(NULL);
  31 }
  32
  33 static void sig_handler(int signum __maybe_unused,
  34                         siginfo_t *oh __maybe_unused,
  35                         void *uc __maybe_unused)
  36 {
  37         overflows++;
  38
  39         if (overflows > 10) {
  40                 /*
  41                  * This should be executed only once during
  42                  * this test, if we are here for the 10th
  43                  * time, consider this the recursive issue.
  44                  *
  45                  * We can get out of here by disable events,
  46                  * so no new SIGIO is delivered.
  47                  */
  48                 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
  49                 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
  50         }
  51 }
  52
  53 static int bp_event(void *fn, int setup_signal)
  54 {
  55         struct perf_event_attr pe;
  56         int fd;
  57
  58         memset(&pe, 0, sizeof(struct perf_event_attr));
  59         pe.type = PERF_TYPE_BREAKPOINT;
  60         pe.size = sizeof(struct perf_event_attr);
  61
  62         pe.config = 0;
  63         pe.bp_type = HW_BREAKPOINT_X;
  64         pe.bp_addr = (unsigned long) fn;
  65         pe.bp_len = sizeof(long);
  66
  67         pe.sample_period = 1;
  68         pe.sample_type = PERF_SAMPLE_IP;
  69         pe.wakeup_events = 1;
  70
  71         pe.disabled = 1;
  72         pe.exclude_kernel = 1;
  73         pe.exclude_hv = 1;
  74
  75         fd = sys_perf_event_open(&pe, 0, -1, -1, 0);
  76         if (fd < 0) {
  77                 pr_debug("failed opening event %llx\n", pe.config);
  78                 return TEST_FAIL;
  79         }
  80
  81         if (setup_signal) {
  82                 fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
  83                 fcntl(fd, F_SETSIG, SIGIO);
  84                 fcntl(fd, F_SETOWN, getpid());
  85         }
  86
  87         ioctl(fd, PERF_EVENT_IOC_RESET, 0);
  88
  89         return fd;
  90 }
  91
  92 static long long bp_count(int fd)
  93 {
  94         long long count;
  95         int ret;
  96
  97         ret = read(fd, &count, sizeof(long long));
  98         if (ret != sizeof(long long)) {
  99                 pr_debug("failed to read: %d\n", ret);
 100                 return TEST_FAIL;
 101         }
 102
 103         return count;
 104 }
 105
 106 int test__bp_signal(void)
 107 {
 108         struct sigaction sa;
 109         long long count1, count2;
 110
 111         /* setup SIGIO signal handler */
 112         memset(&sa, 0, sizeof(struct sigaction));
 113         sa.sa_sigaction = (void *) sig_handler;
 114         sa.sa_flags = SA_SIGINFO;
 115
 116         if (sigaction(SIGIO, &sa, NULL) < 0) {
 117                 pr_debug("failed setting up signal handler\n");
 118                 return TEST_FAIL;
 119         }
 120
 121         /*
 122          * We create following events:
 123          *
 124          * fd1 - breakpoint event on test_function with SIGIO
 125          *       signal configured. We should get signal
 126          *       notification each time the breakpoint is hit
 127          *
 128          * fd2 - breakpoint event on sig_handler without SIGIO
 129          *       configured.
 130          *
 131          * Following processing should happen:
 132          *   - execute test_function
 133          *   - fd1 event breakpoint hit -> count1 == 1
 134          *   - SIGIO is delivered       -> overflows == 1
 135          *   - fd2 event breakpoint hit -> count2 == 1
 136          *
 137          * The test case check following error conditions:
 138          * - we get stuck in signal handler because of debug
 139          *   exception being triggered receursively due to
 140          *   the wrong RF EFLAG management
 141          *
 142          * - we never trigger the sig_handler breakpoint due
 143          *   to the rong RF EFLAG management
 144          *
 145          */
 146
 147         fd1 = bp_event(test_function, 1);
 148         fd2 = bp_event(sig_handler, 0);
 149
 150         ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0);
 151         ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0);
 152
 153         /*
 154          * Kick off the test by trigering 'fd1'
 155          * breakpoint.
 156          */
 157         test_function();
 158
 159         ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
 160         ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
 161
 162         count1 = bp_count(fd1);
 163         count2 = bp_count(fd2);
 164
 165         close(fd1);
 166         close(fd2);
 167
 168         pr_debug("count1 %lld, count2 %lld, overflow %d\n",
 169                  count1, count2, overflows);
 170
 171         if (count1 != 1) {
 172                 if (count1 == 11)
 173                         pr_debug("failed: RF EFLAG recursion issue detected\n");
 174                 else
 175                         pr_debug("failed: wrong count for bp1%lld\n", count1);
 176         }
 177
 178         if (overflows != 1)
 179                 pr_debug("failed: wrong overflow hit\n");
 180
 181         if (count2 != 1)
 182                 pr_debug("failed: wrong count for bp2\n");
 183
 184         return count1 == 1 && overflows == 1 && count2 == 1 ?
 185                 TEST_OK : TEST_FAIL;
 186 }