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); 295