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