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 fd3;
  33 static int overflows;
  34 static int overflows_2;
  35
  36 volatile long the_var;
  37
  38
  39 /*
  40  * Use ASM to ensure watchpoint and breakpoint can be triggered
  41  * at one instruction.
  42  */
  43 #if defined (__x86_64__)
  44 extern void __test_function(volatile long *ptr);
  45 asm (
  46         ".globl __test_function\n"
  47         "__test_function:\n"
  48         "incq (%rdi)\n"
  49         "ret\n");
  50 #elif defined (__aarch64__)
  51 extern void __test_function(volatile long *ptr);
  52 asm (
  53         ".globl __test_function\n"
  54         "__test_function:\n"
  55         "str x30, [x0]\n"
  56         "ret\n");
  57
  58 #else
  59 static void __test_function(volatile long *ptr)
  60 {
  61         *ptr = 0x1234;
  62 }
  63 #endif
  64
  65 static noinline int test_function(void)
  66 {
  67         __test_function(&the_var);
  68         the_var++;
  69         return time(NULL);
  70 }
  71
  72 static void sig_handler_2(int signum __maybe_unused,
  73                           siginfo_t *oh __maybe_unused,
  74                           void *uc __maybe_unused)
  75 {
  76         overflows_2++;
  77         if (overflows_2 > 10) {
  78                 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
  79                 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
  80                 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
  81         }
  82 }
  83
  84 static void sig_handler(int signum __maybe_unused,
  85                         siginfo_t *oh __maybe_unused,
  86                         void *uc __maybe_unused)
  87 {
  88         overflows++;
  89
  90         if (overflows > 10) {
  91                 /*
  92                  * This should be executed only once during
  93                  * this test, if we are here for the 10th
  94                  * time, consider this the recursive issue.
  95                  *
  96                  * We can get out of here by disable events,
  97                  * so no new SIGIO is delivered.
  98                  */
  99                 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
 100                 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
 101                 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
 102         }
 103 }
 104
 105 static int __event(bool is_x, void *addr, int sig)
 106 {
 107         struct perf_event_attr pe;
 108         int fd;
 109
 110         memset(&pe, 0, sizeof(struct perf_event_attr));
 111         pe.type = PERF_TYPE_BREAKPOINT;
 112         pe.size = sizeof(struct perf_event_attr);
 113
 114         pe.config = 0;
 115         pe.bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
 116         pe.bp_addr = (unsigned long) addr;
 117         pe.bp_len = sizeof(long);
 118
 119         pe.sample_period = 1;
 120         pe.sample_type = PERF_SAMPLE_IP;
 121         pe.wakeup_events = 1;
 122
 123         pe.disabled = 1;
 124         pe.exclude_kernel = 1;
 125         pe.exclude_hv = 1;
 126
 127         fd = sys_perf_event_open(&pe, 0, -1, -1,
 128                                  perf_event_open_cloexec_flag());
 129         if (fd < 0) {
 130                 pr_debug("failed opening event %llx\n", pe.config);
 131                 return TEST_FAIL;
 132         }
 133
 134         fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
 135         fcntl(fd, F_SETSIG, sig);
 136         fcntl(fd, F_SETOWN, getpid());
 137
 138         ioctl(fd, PERF_EVENT_IOC_RESET, 0);
 139
 140         return fd;
 141 }
 142
 143 static int bp_event(void *addr, int sig)
 144 {
 145         return __event(true, addr, sig);
 146 }
 147
 148 static int wp_event(void *addr, int sig)
 149 {
 150         return __event(false, addr, sig);
 151 }
 152
 153 static long long bp_count(int fd)
 154 {
 155         long long count;
 156         int ret;
 157
 158         ret = read(fd, &count, sizeof(long long));
 159         if (ret != sizeof(long long)) {
 160                 pr_debug("failed to read: %d\n", ret);
 161                 return TEST_FAIL;
 162         }
 163
 164         return count;
 165 }
 166
 167 int test__bp_signal(struct test *test __maybe_unused, int subtest __maybe_unused)
 168 {
 169         struct sigaction sa;
 170         long long count1, count2, count3;
 171
 172         /* setup SIGIO signal handler */
 173         memset(&sa, 0, sizeof(struct sigaction));
 174         sa.sa_sigaction = (void *) sig_handler;
 175         sa.sa_flags = SA_SIGINFO;
 176
 177         if (sigaction(SIGIO, &sa, NULL) < 0) {
 178                 pr_debug("failed setting up signal handler\n");
 179                 return TEST_FAIL;
 180         }
 181
 182         sa.sa_sigaction = (void *) sig_handler_2;
 183         if (sigaction(SIGUSR1, &sa, NULL) < 0) {
 184                 pr_debug("failed setting up signal handler 2\n");
 185                 return TEST_FAIL;
 186         }
 187
 188         /*
 189          * We create following events:
 190          *
 191          * fd1 - breakpoint event on __test_function with SIGIO
 192          *       signal configured. We should get signal
 193          *       notification each time the breakpoint is hit
 194          *
 195          * fd2 - breakpoint event on sig_handler with SIGUSR1
 196          *       configured. We should get SIGUSR1 each time when
 197          *       breakpoint is hit
 198          *
 199          * fd3 - watchpoint event on __test_function with SIGIO
 200          *       configured.
 201          *
 202          * Following processing should happen:
 203          *   Exec:               Action:                       Result:
 204          *   incq (%rdi)       - fd1 event breakpoint hit   -> count1 == 1
 205          *                     - SIGIO is delivered
 206          *   sig_handler       - fd2 event breakpoint hit   -> count2 == 1
 207          *                     - SIGUSR1 is delivered
 208          *   sig_handler_2                                  -> overflows_2 == 1  (nested signal)
 209          *   sys_rt_sigreturn  - return from sig_handler_2
 210          *   overflows++                                    -> overflows = 1
 211          *   sys_rt_sigreturn  - return from sig_handler
 212          *   incq (%rdi)       - fd3 event watchpoint hit   -> count3 == 1       (wp and bp in one insn)
 213          *                     - SIGIO is delivered
 214          *   sig_handler       - fd2 event breakpoint hit   -> count2 == 2
 215          *                     - SIGUSR1 is delivered
 216          *   sig_handler_2                                  -> overflows_2 == 2  (nested signal)
 217          *   sys_rt_sigreturn  - return from sig_handler_2
 218          *   overflows++                                    -> overflows = 2
 219          *   sys_rt_sigreturn  - return from sig_handler
 220          *   the_var++         - fd3 event watchpoint hit   -> count3 == 2       (standalone watchpoint)
 221          *                     - SIGIO is delivered
 222          *   sig_handler       - fd2 event breakpoint hit   -> count2 == 3
 223          *                     - SIGUSR1 is delivered
 224          *   sig_handler_2                                  -> overflows_2 == 3  (nested signal)
 225          *   sys_rt_sigreturn  - return from sig_handler_2
 226          *   overflows++                                    -> overflows == 3
 227          *   sys_rt_sigreturn  - return from sig_handler
 228          *
 229          * The test case check following error conditions:
 230          * - we get stuck in signal handler because of debug
 231          *   exception being triggered receursively due to
 232          *   the wrong RF EFLAG management
 233          *
 234          * - we never trigger the sig_handler breakpoint due
 235          *   to the rong RF EFLAG management
 236          *
 237          */
 238
 239         fd1 = bp_event(__test_function, SIGIO);
 240         fd2 = bp_event(sig_handler, SIGUSR1);
 241         fd3 = wp_event((void *)&the_var, SIGIO);
 242
 243         ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0);
 244         ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0);
 245         ioctl(fd3, PERF_EVENT_IOC_ENABLE, 0);
 246
 247         /*
 248          * Kick off the test by trigering 'fd1'
 249          * breakpoint.
 250          */
 251         test_function();
 252
 253         ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
 254         ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
 255         ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
 256
 257         count1 = bp_count(fd1);
 258         count2 = bp_count(fd2);
 259         count3 = bp_count(fd3);
 260
 261         close(fd1);
 262         close(fd2);
 263         close(fd3);
 264
 265         pr_debug("count1 %lld, count2 %lld, count3 %lld, overflow %d, overflows_2 %d\n",
 266                  count1, count2, count3, overflows, overflows_2);
 267
 268         if (count1 != 1) {
 269                 if (count1 == 11)
 270                         pr_debug("failed: RF EFLAG recursion issue detected\n");
 271                 else
 272                         pr_debug("failed: wrong count for bp1%lld\n", count1);
 273         }
 274
 275         if (overflows != 3)
 276                 pr_debug("failed: wrong overflow hit\n");
 277
 278         if (overflows_2 != 3)
 279                 pr_debug("failed: wrong overflow_2 hit\n");
 280
 281         if (count2 != 3)
 282                 pr_debug("failed: wrong count for bp2\n");
 283
 284         if (count3 != 2)
 285                 pr_debug("failed: wrong count for bp3\n");
 286
 287         return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ?
 288                 TEST_OK : TEST_FAIL;
 289 }
 290
 291 bool test__bp_signal_is_supported(void)
 292 {
 293 /*
 294  * The powerpc so far does not have support to even create
 295  * instruction breakpoint using the perf event interface.
 296  * Once it's there we can release this.
 297  */
 298 #ifdef __powerpc__
 299         return false;
 300 #else
 301         return true;
 302 #endif
 303 }