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 /*
   8  * Powerpc needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select
   9  * 'int-ll64.h' and avoid compile warnings when printing __u64 with %llu.
  10  */
  11 #define __SANE_USERSPACE_TYPES__
  12
  13 #include <stdlib.h>
  14 #include <stdio.h>
  15 #include <unistd.h>
  16 #include <string.h>
  17 #include <sys/ioctl.h>
  18 #include <time.h>
  19 #include <fcntl.h>
  20 #include <signal.h>
  21 #include <sys/mman.h>
  22 #include <linux/compiler.h>
  23 #include <linux/hw_breakpoint.h>
  24
  25 #include "tests.h"
  26 #include "debug.h"
  27 #include "perf.h"
  28 #include "cloexec.h"
  29
  30 static int fd1;
  31 static int fd2;
  32 static int overflows;
  33
  34 __attribute__ ((noinline))
  35 static int test_function(void)
  36 {
  37         return time(NULL);
  38 }
  39
  40 static void sig_handler(int signum __maybe_unused,
  41                         siginfo_t *oh __maybe_unused,
  42                         void *uc __maybe_unused)
  43 {
  44         overflows++;
  45
  46         if (overflows > 10) {
  47                 /*
  48                  * This should be executed only once during
  49                  * this test, if we are here for the 10th
  50                  * time, consider this the recursive issue.
  51                  *
  52                  * We can get out of here by disable events,
  53                  * so no new SIGIO is delivered.
  54                  */
  55                 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
  56                 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
  57         }
  58 }
  59
  60 static int bp_event(void *fn, int setup_signal)
  61 {
  62         struct perf_event_attr pe;
  63         int fd;
  64
  65         memset(&pe, 0, sizeof(struct perf_event_attr));
  66         pe.type = PERF_TYPE_BREAKPOINT;
  67         pe.size = sizeof(struct perf_event_attr);
  68
  69         pe.config = 0;
  70         pe.bp_type = HW_BREAKPOINT_X;
  71         pe.bp_addr = (unsigned long) fn;
  72         pe.bp_len = sizeof(long);
  73
  74         pe.sample_period = 1;
  75         pe.sample_type = PERF_SAMPLE_IP;
  76         pe.wakeup_events = 1;
  77
  78         pe.disabled = 1;
  79         pe.exclude_kernel = 1;
  80         pe.exclude_hv = 1;
  81
  82         fd = sys_perf_event_open(&pe, 0, -1, -1,
  83                                  perf_event_open_cloexec_flag());
  84         if (fd < 0) {
  85                 pr_debug("failed opening event %llx\n", pe.config);
  86                 return TEST_FAIL;
  87         }
  88
  89         if (setup_signal) {
  90                 fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
  91                 fcntl(fd, F_SETSIG, SIGIO);
  92                 fcntl(fd, F_SETOWN, getpid());
  93         }
  94
  95         ioctl(fd, PERF_EVENT_IOC_RESET, 0);
  96
  97         return fd;
  98 }
  99
 100 static long long bp_count(int fd)
 101 {
 102         long long count;
 103         int ret;
 104
 105         ret = read(fd, &count, sizeof(long long));
 106         if (ret != sizeof(long long)) {
 107                 pr_debug("failed to read: %d\n", ret);
 108                 return TEST_FAIL;
 109         }
 110
 111         return count;
 112 }
 113
 114 int test__bp_signal(int subtest __maybe_unused)
 115 {
 116         struct sigaction sa;
 117         long long count1, count2;
 118
 119         /* setup SIGIO signal handler */
 120         memset(&sa, 0, sizeof(struct sigaction));
 121         sa.sa_sigaction = (void *) sig_handler;
 122         sa.sa_flags = SA_SIGINFO;
 123
 124         if (sigaction(SIGIO, &sa, NULL) < 0) {
 125                 pr_debug("failed setting up signal handler\n");
 126                 return TEST_FAIL;
 127         }
 128
 129         /*
 130          * We create following events:
 131          *
 132          * fd1 - breakpoint event on test_function with SIGIO
 133          *       signal configured. We should get signal
 134          *       notification each time the breakpoint is hit
 135          *
 136          * fd2 - breakpoint event on sig_handler without SIGIO
 137          *       configured.
 138          *
 139          * Following processing should happen:
 140          *   - execute test_function
 141          *   - fd1 event breakpoint hit -> count1 == 1
 142          *   - SIGIO is delivered       -> overflows == 1
 143          *   - fd2 event breakpoint hit -> count2 == 1
 144          *
 145          * The test case check following error conditions:
 146          * - we get stuck in signal handler because of debug
 147          *   exception being triggered receursively due to
 148          *   the wrong RF EFLAG management
 149          *
 150          * - we never trigger the sig_handler breakpoint due
 151          *   to the rong RF EFLAG management
 152          *
 153          */
 154
 155         fd1 = bp_event(test_function, 1);
 156         fd2 = bp_event(sig_handler, 0);
 157
 158         ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0);
 159         ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0);
 160
 161         /*
 162          * Kick off the test by trigering 'fd1'
 163          * breakpoint.
 164          */
 165         test_function();
 166
 167         ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
 168         ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
 169
 170         count1 = bp_count(fd1);
 171         count2 = bp_count(fd2);
 172
 173         close(fd1);
 174         close(fd2);
 175
 176         pr_debug("count1 %lld, count2 %lld, overflow %d\n",
 177                  count1, count2, overflows);
 178
 179         if (count1 != 1) {
 180                 if (count1 == 11)
 181                         pr_debug("failed: RF EFLAG recursion issue detected\n");
 182                 else
 183                         pr_debug("failed: wrong count for bp1%lld\n", count1);
 184         }
 185
 186         if (overflows != 1)
 187                 pr_debug("failed: wrong overflow hit\n");
 188
 189         if (count2 != 1)
 190                 pr_debug("failed: wrong count for bp2\n");
 191
 192         return count1 == 1 && overflows == 1 && count2 == 1 ?
 193                 TEST_OK : TEST_FAIL;
 194 }