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