tools/perf/tests/bp_signal.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Inspired by breakpoint overflow test done by
   4  * Vince Weaver <vincent.weaver@maine.edu> for perf_event_tests
   5  * (git://github.com/deater/perf_event_tests)
   6  */
   7
   8 /*
   9  * Powerpc needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select
  10  * 'int-ll64.h' and avoid compile warnings when printing __u64 with %llu.
  11  */
  12 #define __SANE_USERSPACE_TYPES__
  13
  14 #include <stdlib.h>
  15 #include <stdio.h>
  16 #include <unistd.h>
  17 #include <string.h>
  18 #include <sys/ioctl.h>
  19 #include <time.h>
  20 #include <fcntl.h>
  21 #include <signal.h>
  22 #include <sys/mman.h>
  23 #include <linux/compiler.h>
  24 #include <linux/hw_breakpoint.h>
  25
  26 #include "tests.h"
  27 #include "debug.h"
  28 #include "perf.h"
  29 #include "cloexec.h"
  30
  31 static int fd1;
  32 static int fd2;
  33 static int fd3;
  34 static int overflows;
  35 static int overflows_2;
  36
  37 volatile long the_var;
  38
  39
  40 /*
  41  * Use ASM to ensure watchpoint and breakpoint can be triggered
  42  * at one instruction.
  43  */
  44 #if defined (__x86_64__)
  45 extern void __test_function(volatile long *ptr);
  46 asm (
  47         ".globl __test_function\n"
  48         "__test_function:\n"
  49         "incq (%rdi)\n"
  50         "ret\n");
  51 #elif defined (__aarch64__)
  52 extern void __test_function(volatile long *ptr);
  53 asm (
  54         ".globl __test_function\n"
  55         "__test_function:\n"
  56         "str x30, [x0]\n"
  57         "ret\n");
  58
  59 #else
  60 static void __test_function(volatile long *ptr)
  61 {
  62         *ptr = 0x1234;
  63 }
  64 #endif
  65
  66 static noinline int test_function(void)
  67 {
  68         __test_function(&the_var);
  69         the_var++;
  70         return time(NULL);
  71 }
  72
  73 static void sig_handler_2(int signum __maybe_unused,
  74                           siginfo_t *oh __maybe_unused,
  75                           void *uc __maybe_unused)
  76 {
  77         overflows_2++;
  78         if (overflows_2 > 10) {
  79                 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
  80                 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
  81                 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
  82         }
  83 }
  84
  85 static void sig_handler(int signum __maybe_unused,
  86                         siginfo_t *oh __maybe_unused,
  87                         void *uc __maybe_unused)
  88 {
  89         overflows++;
  90
  91         if (overflows > 10) {
  92                 /*
  93                  * This should be executed only once during
  94                  * this test, if we are here for the 10th
  95                  * time, consider this the recursive issue.
  96                  *
  97                  * We can get out of here by disable events,
  98                  * so no new SIGIO is delivered.
  99                  */
 100                 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
 101                 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
 102                 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
 103         }
 104 }
 105
 106 static int __event(bool is_x, void *addr, int sig)
 107 {
 108         struct perf_event_attr pe;
 109         int fd;
 110
 111         memset(&pe, 0, sizeof(struct perf_event_attr));
 112         pe.type = PERF_TYPE_BREAKPOINT;
 113         pe.size = sizeof(struct perf_event_attr);
 114
 115         pe.config = 0;
 116         pe.bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
 117         pe.bp_addr = (unsigned long) addr;
 118         pe.bp_len = sizeof(long);
 119
 120         pe.sample_period = 1;
 121         pe.sample_type = PERF_SAMPLE_IP;
 122         pe.wakeup_events = 1;
 123
 124         pe.disabled = 1;
 125         pe.exclude_kernel = 1;
 126         pe.exclude_hv = 1;
 127
 128         fd = sys_perf_event_open(&pe, 0, -1, -1,
 129                                  perf_event_open_cloexec_flag());
 130         if (fd < 0) {
 131                 pr_debug("failed opening event %llx\n", pe.config);
 132                 return TEST_FAIL;
 133         }
 134
 135         fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
 136         fcntl(fd, F_SETSIG, sig);
 137         fcntl(fd, F_SETOWN, getpid());
 138
 139         ioctl(fd, PERF_EVENT_IOC_RESET, 0);
 140
 141         return fd;
 142 }
 143
 144 static int bp_event(void *addr, int sig)
 145 {
 146         return __event(true, addr, sig);
 147 }
 148
 149 static int wp_event(void *addr, int sig)
 150 {
 151         return __event(false, addr, sig);
 152 }
 153
 154 static long long bp_count(int fd)
 155 {
 156         long long count;
 157         int ret;
 158
 159         ret = read(fd, &count, sizeof(long long));
 160         if (ret != sizeof(long long)) {
 161                 pr_debug("failed to read: %d\n", ret);
 162                 return TEST_FAIL;
 163         }
 164
 165         return count;
 166 }
 167
 168 int test__bp_signal(struct test *test __maybe_unused, int subtest __maybe_unused)
 169 {
 170         struct sigaction sa;
 171         long long count1, count2, count3;
 172
 173         /* setup SIGIO signal handler */
 174         memset(&sa, 0, sizeof(struct sigaction));
 175         sa.sa_sigaction = (void *) sig_handler;
 176         sa.sa_flags = SA_SIGINFO;
 177
 178         if (sigaction(SIGIO, &sa, NULL) < 0) {
 179                 pr_debug("failed setting up signal handler\n");
 180                 return TEST_FAIL;
 181         }
 182
 183         sa.sa_sigaction = (void *) sig_handler_2;
 184         if (sigaction(SIGUSR1, &sa, NULL) < 0) {
 185                 pr_debug("failed setting up signal handler 2\n");
 186                 return TEST_FAIL;
 187         }
 188
 189         /*
 190          * We create following events:
 191          *
 192          * fd1 - breakpoint event on __test_function with SIGIO
 193          *       signal configured. We should get signal
 194          *       notification each time the breakpoint is hit
 195          *
 196          * fd2 - breakpoint event on sig_handler with SIGUSR1
 197          *       configured. We should get SIGUSR1 each time when
 198          *       breakpoint is hit
 199          *
 200          * fd3 - watchpoint event on __test_function with SIGIO
 201          *       configured.
 202          *
 203          * Following processing should happen:
 204          *   Exec:               Action:                       Result:
 205          *   incq (%rdi)       - fd1 event breakpoint hit   -> count1 == 1
 206          *                     - SIGIO is delivered
 207          *   sig_handler       - fd2 event breakpoint hit   -> count2 == 1
 208          *                     - SIGUSR1 is delivered
 209          *   sig_handler_2                                  -> overflows_2 == 1  (nested signal)
 210          *   sys_rt_sigreturn  - return from sig_handler_2
 211          *   overflows++                                    -> overflows = 1
 212          *   sys_rt_sigreturn  - return from sig_handler
 213          *   incq (%rdi)       - fd3 event watchpoint hit   -> count3 == 1       (wp and bp in one insn)
 214          *                     - SIGIO is delivered
 215          *   sig_handler       - fd2 event breakpoint hit   -> count2 == 2
 216          *                     - SIGUSR1 is delivered
 217          *   sig_handler_2                                  -> overflows_2 == 2  (nested signal)
 218          *   sys_rt_sigreturn  - return from sig_handler_2
 219          *   overflows++                                    -> overflows = 2
 220          *   sys_rt_sigreturn  - return from sig_handler
 221          *   the_var++         - fd3 event watchpoint hit   -> count3 == 2       (standalone watchpoint)
 222          *                     - SIGIO is delivered
 223          *   sig_handler       - fd2 event breakpoint hit   -> count2 == 3
 224          *                     - SIGUSR1 is delivered
 225          *   sig_handler_2                                  -> overflows_2 == 3  (nested signal)
 226          *   sys_rt_sigreturn  - return from sig_handler_2
 227          *   overflows++                                    -> overflows == 3
 228          *   sys_rt_sigreturn  - return from sig_handler
 229          *
 230          * The test case check following error conditions:
 231          * - we get stuck in signal handler because of debug
 232          *   exception being triggered receursively due to
 233          *   the wrong RF EFLAG management
 234          *
 235          * - we never trigger the sig_handler breakpoint due
 236          *   to the rong RF EFLAG management
 237          *
 238          */
 239
 240         fd1 = bp_event(__test_function, SIGIO);
 241         fd2 = bp_event(sig_handler, SIGUSR1);
 242         fd3 = wp_event((void *)&the_var, SIGIO);
 243
 244         ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0);
 245         ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0);
 246         ioctl(fd3, PERF_EVENT_IOC_ENABLE, 0);
 247
 248         /*
 249          * Kick off the test by trigering 'fd1'
 250          * breakpoint.
 251          */
 252         test_function();
 253
 254         ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
 255         ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
 256         ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
 257
 258         count1 = bp_count(fd1);
 259         count2 = bp_count(fd2);
 260         count3 = bp_count(fd3);
 261
 262         close(fd1);
 263         close(fd2);
 264         close(fd3);
 265
 266         pr_debug("count1 %lld, count2 %lld, count3 %lld, overflow %d, overflows_2 %d\n",
 267                  count1, count2, count3, overflows, overflows_2);
 268
 269         if (count1 != 1) {
 270                 if (count1 == 11)
 271                         pr_debug("failed: RF EFLAG recursion issue detected\n");
 272                 else
 273                         pr_debug("failed: wrong count for bp1%lld\n", count1);
 274         }
 275
 276         if (overflows != 3)
 277                 pr_debug("failed: wrong overflow hit\n");
 278
 279         if (overflows_2 != 3)
 280                 pr_debug("failed: wrong overflow_2 hit\n");
 281
 282         if (count2 != 3)
 283                 pr_debug("failed: wrong count for bp2\n");
 284
 285         if (count3 != 2)
 286                 pr_debug("failed: wrong count for bp3\n");
 287
 288         return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ?
 289                 TEST_OK : TEST_FAIL;
 290 }
 291
 292 bool test__bp_signal_is_supported(void)
 293 {
 294 /*
 295  * The powerpc so far does not have support to even create
 296  * instruction breakpoint using the perf event interface.
 297  * Once it's there we can release this.
 298  */
 299 #if defined(__powerpc__) || defined(__s390x__)
 300         return false;
 301 #else
 302         return true;
 303 #endif
 304 }