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 "event.h"
  29 #include "perf-sys.h"
  30 #include "cloexec.h"
  31
  32 static int fd1;
  33 static int fd2;
  34 static int fd3;
  35 static int overflows;
  36 static int overflows_2;
  37
  38 volatile long the_var;
  39
  40
  41 /*
  42  * Use ASM to ensure watchpoint and breakpoint can be triggered
  43  * at one instruction.
  44  */
  45 #if defined (__x86_64__)
  46 extern void __test_function(volatile long *ptr);
  47 asm (
  48         ".pushsection .text;"
  49         ".globl __test_function\n"
  50         ".type __test_function, @function;"
  51         "__test_function:\n"
  52         "incq (%rdi)\n"
  53         "ret\n"
  54         ".popsection\n");
  55 #else
  56 static void __test_function(volatile long *ptr)
  57 {
  58         *ptr = 0x1234;
  59 }
  60 #endif
  61
  62 static noinline int test_function(void)
  63 {
  64         __test_function(&the_var);
  65         the_var++;
  66         return time(NULL);
  67 }
  68
  69 static void sig_handler_2(int signum __maybe_unused,
  70                           siginfo_t *oh __maybe_unused,
  71                           void *uc __maybe_unused)
  72 {
  73         overflows_2++;
  74         if (overflows_2 > 10) {
  75                 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
  76                 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
  77                 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
  78         }
  79 }
  80
  81 static void sig_handler(int signum __maybe_unused,
  82                         siginfo_t *oh __maybe_unused,
  83                         void *uc __maybe_unused)
  84 {
  85         overflows++;
  86
  87         if (overflows > 10) {
  88                 /*
  89                  * This should be executed only once during
  90                  * this test, if we are here for the 10th
  91                  * time, consider this the recursive issue.
  92                  *
  93                  * We can get out of here by disable events,
  94                  * so no new SIGIO is delivered.
  95                  */
  96                 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
  97                 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
  98                 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
  99         }
 100 }
 101
 102 static int __event(bool is_x, void *addr, int sig)
 103 {
 104         struct perf_event_attr pe;
 105         int fd;
 106
 107         memset(&pe, 0, sizeof(struct perf_event_attr));
 108         pe.type = PERF_TYPE_BREAKPOINT;
 109         pe.size = sizeof(struct perf_event_attr);
 110
 111         pe.config = 0;
 112         pe.bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
 113         pe.bp_addr = (unsigned long) addr;
 114         pe.bp_len = sizeof(long);
 115
 116         pe.sample_period = 1;
 117         pe.sample_type = PERF_SAMPLE_IP;
 118         pe.wakeup_events = 1;
 119
 120         pe.disabled = 1;
 121         pe.exclude_kernel = 1;
 122         pe.exclude_hv = 1;
 123
 124         fd = sys_perf_event_open(&pe, 0, -1, -1,
 125                                  perf_event_open_cloexec_flag());
 126         if (fd < 0) {
 127                 pr_debug("failed opening event %llx\n", pe.config);
 128                 return TEST_FAIL;
 129         }
 130
 131         fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
 132         fcntl(fd, F_SETSIG, sig);
 133         fcntl(fd, F_SETOWN, getpid());
 134
 135         ioctl(fd, PERF_EVENT_IOC_RESET, 0);
 136
 137         return fd;
 138 }
 139
 140 static int bp_event(void *addr, int sig)
 141 {
 142         return __event(true, addr, sig);
 143 }
 144
 145 static int wp_event(void *addr, int sig)
 146 {
 147         return __event(false, addr, sig);
 148 }
 149
 150 static long long bp_count(int fd)
 151 {
 152         long long count;
 153         int ret;
 154
 155         ret = read(fd, &count, sizeof(long long));
 156         if (ret != sizeof(long long)) {
 157                 pr_debug("failed to read: %d\n", ret);
 158                 return TEST_FAIL;
 159         }
 160
 161         return count;
 162 }
 163
 164 int test__bp_signal(struct test *test __maybe_unused, int subtest __maybe_unused)
 165 {
 166         struct sigaction sa;
 167         long long count1, count2, count3;
 168
 169         /* setup SIGIO signal handler */
 170         memset(&sa, 0, sizeof(struct sigaction));
 171         sa.sa_sigaction = (void *) sig_handler;
 172         sa.sa_flags = SA_SIGINFO;
 173
 174         if (sigaction(SIGIO, &sa, NULL) < 0) {
 175                 pr_debug("failed setting up signal handler\n");
 176                 return TEST_FAIL;
 177         }
 178
 179         sa.sa_sigaction = (void *) sig_handler_2;
 180         if (sigaction(SIGUSR1, &sa, NULL) < 0) {
 181                 pr_debug("failed setting up signal handler 2\n");
 182                 return TEST_FAIL;
 183         }
 184
 185         /*
 186          * We create following events:
 187          *
 188          * fd1 - breakpoint event on __test_function with SIGIO
 189          *       signal configured. We should get signal
 190          *       notification each time the breakpoint is hit
 191          *
 192          * fd2 - breakpoint event on sig_handler with SIGUSR1
 193          *       configured. We should get SIGUSR1 each time when
 194          *       breakpoint is hit
 195          *
 196          * fd3 - watchpoint event on __test_function with SIGIO
 197          *       configured.
 198          *
 199          * Following processing should happen:
 200          *   Exec:               Action:                       Result:
 201          *   incq (%rdi)       - fd1 event breakpoint hit   -> count1 == 1
 202          *                     - SIGIO is delivered
 203          *   sig_handler       - fd2 event breakpoint hit   -> count2 == 1
 204          *                     - SIGUSR1 is delivered
 205          *   sig_handler_2                                  -> overflows_2 == 1  (nested signal)
 206          *   sys_rt_sigreturn  - return from sig_handler_2
 207          *   overflows++                                    -> overflows = 1
 208          *   sys_rt_sigreturn  - return from sig_handler
 209          *   incq (%rdi)       - fd3 event watchpoint hit   -> count3 == 1       (wp and bp in one insn)
 210          *                     - SIGIO is delivered
 211          *   sig_handler       - fd2 event breakpoint hit   -> count2 == 2
 212          *                     - SIGUSR1 is delivered
 213          *   sig_handler_2                                  -> overflows_2 == 2  (nested signal)
 214          *   sys_rt_sigreturn  - return from sig_handler_2
 215          *   overflows++                                    -> overflows = 2
 216          *   sys_rt_sigreturn  - return from sig_handler
 217          *   the_var++         - fd3 event watchpoint hit   -> count3 == 2       (standalone watchpoint)
 218          *                     - SIGIO is delivered
 219          *   sig_handler       - fd2 event breakpoint hit   -> count2 == 3
 220          *                     - SIGUSR1 is delivered
 221          *   sig_handler_2                                  -> overflows_2 == 3  (nested signal)
 222          *   sys_rt_sigreturn  - return from sig_handler_2
 223          *   overflows++                                    -> overflows == 3
 224          *   sys_rt_sigreturn  - return from sig_handler
 225          *
 226          * The test case check following error conditions:
 227          * - we get stuck in signal handler because of debug
 228          *   exception being triggered receursively due to
 229          *   the wrong RF EFLAG management
 230          *
 231          * - we never trigger the sig_handler breakpoint due
 232          *   to the rong RF EFLAG management
 233          *
 234          */
 235
 236         fd1 = bp_event(__test_function, SIGIO);
 237         fd2 = bp_event(sig_handler, SIGUSR1);
 238         fd3 = wp_event((void *)&the_var, SIGIO);
 239
 240         ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0);
 241         ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0);
 242         ioctl(fd3, PERF_EVENT_IOC_ENABLE, 0);
 243
 244         /*
 245          * Kick off the test by trigering 'fd1'
 246          * breakpoint.
 247          */
 248         test_function();
 249
 250         ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
 251         ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
 252         ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
 253
 254         count1 = bp_count(fd1);
 255         count2 = bp_count(fd2);
 256         count3 = bp_count(fd3);
 257
 258         close(fd1);
 259         close(fd2);
 260         close(fd3);
 261
 262         pr_debug("count1 %lld, count2 %lld, count3 %lld, overflow %d, overflows_2 %d\n",
 263                  count1, count2, count3, overflows, overflows_2);
 264
 265         if (count1 != 1) {
 266                 if (count1 == 11)
 267                         pr_debug("failed: RF EFLAG recursion issue detected\n");
 268                 else
 269                         pr_debug("failed: wrong count for bp1: %lld, expected 1\n", count1);
 270         }
 271
 272         if (overflows != 3)
 273                 pr_debug("failed: wrong overflow (%d) hit, expected 3\n", overflows);
 274
 275         if (overflows_2 != 3)
 276                 pr_debug("failed: wrong overflow_2 (%d) hit, expected 3\n", overflows_2);
 277
 278         if (count2 != 3)
 279                 pr_debug("failed: wrong count for bp2 (%lld), expected 3\n", count2);
 280
 281         if (count3 != 2)
 282                 pr_debug("failed: wrong count for bp3 (%lld), expected 2\n", count3);
 283
 284         return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ?
 285                 TEST_OK : TEST_FAIL;
 286 }
 287
 288 bool test__bp_signal_is_supported(void)
 289 {
 290         /*
 291          * PowerPC and S390 do not support creation of instruction
 292          * breakpoints using the perf_event interface.
 293          *
 294          * ARM requires explicit rounding down of the instruction
 295          * pointer in Thumb mode, and then requires the single-step
 296          * to be handled explicitly in the overflow handler to avoid
 297          * stepping into the SIGIO handler and getting stuck on the
 298          * breakpointed instruction.
 299          *
 300          * Since arm64 has the same issue with arm for the single-step
 301          * handling, this case also gets stuck on the breakpointed
 302          * instruction.
 303          *
 304          * Just disable the test for these architectures until these
 305          * issues are resolved.
 306          */
 307 #if defined(__powerpc__) || defined(__s390x__) || defined(__arm__) || \
 308     defined(__aarch64__)
 309         return false;
 310 #else
 311         return true;
 312 #endif
 313 }