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