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 #elif defined (__aarch64__) 53 extern void __test_function(volatile long *ptr); 54 asm ( 55 ".globl __test_function\n" 56 "__test_function:\n" 57 "str x30, [x0]\n" 58 "ret\n"); 59 60 #else 61 static void __test_function(volatile long *ptr) 62 { 63 *ptr = 0x1234; 64 } 65 #endif 66 67 static noinline int test_function(void) 68 { 69 __test_function(&the_var); 70 the_var++; 71 return time(NULL); 72 } 73 74 static void sig_handler_2(int signum __maybe_unused, 75 siginfo_t *oh __maybe_unused, 76 void *uc __maybe_unused) 77 { 78 overflows_2++; 79 if (overflows_2 > 10) { 80 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0); 81 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0); 82 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0); 83 } 84 } 85 86 static void sig_handler(int signum __maybe_unused, 87 siginfo_t *oh __maybe_unused, 88 void *uc __maybe_unused) 89 { 90 overflows++; 91 92 if (overflows > 10) { 93 /* 94 * This should be executed only once during 95 * this test, if we are here for the 10th 96 * time, consider this the recursive issue. 97 * 98 * We can get out of here by disable events, 99 * so no new SIGIO is delivered. 100 */ 101 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0); 102 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0); 103 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0); 104 } 105 } 106 107 static int __event(bool is_x, void *addr, int sig) 108 { 109 struct perf_event_attr pe; 110 int fd; 111 112 memset(&pe, 0, sizeof(struct perf_event_attr)); 113 pe.type = PERF_TYPE_BREAKPOINT; 114 pe.size = sizeof(struct perf_event_attr); 115 116 pe.config = 0; 117 pe.bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W; 118 pe.bp_addr = (unsigned long) addr; 119 pe.bp_len = sizeof(long); 120 121 pe.sample_period = 1; 122 pe.sample_type = PERF_SAMPLE_IP; 123 pe.wakeup_events = 1; 124 125 pe.disabled = 1; 126 pe.exclude_kernel = 1; 127 pe.exclude_hv = 1; 128 129 fd = sys_perf_event_open(&pe, 0, -1, -1, 130 perf_event_open_cloexec_flag()); 131 if (fd < 0) { 132 pr_debug("failed opening event %llx\n", pe.config); 133 return TEST_FAIL; 134 } 135 136 fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC); 137 fcntl(fd, F_SETSIG, sig); 138 fcntl(fd, F_SETOWN, getpid()); 139 140 ioctl(fd, PERF_EVENT_IOC_RESET, 0); 141 142 return fd; 143 } 144 145 static int bp_event(void *addr, int sig) 146 { 147 return __event(true, addr, sig); 148 } 149 150 static int wp_event(void *addr, int sig) 151 { 152 return __event(false, addr, sig); 153 } 154 155 static long long bp_count(int fd) 156 { 157 long long count; 158 int ret; 159 160 ret = read(fd, &count, sizeof(long long)); 161 if (ret != sizeof(long long)) { 162 pr_debug("failed to read: %d\n", ret); 163 return TEST_FAIL; 164 } 165 166 return count; 167 } 168 169 int test__bp_signal(struct test *test __maybe_unused, int subtest __maybe_unused) 170 { 171 struct sigaction sa; 172 long long count1, count2, count3; 173 174 /* setup SIGIO signal handler */ 175 memset(&sa, 0, sizeof(struct sigaction)); 176 sa.sa_sigaction = (void *) sig_handler; 177 sa.sa_flags = SA_SIGINFO; 178 179 if (sigaction(SIGIO, &sa, NULL) < 0) { 180 pr_debug("failed setting up signal handler\n"); 181 return TEST_FAIL; 182 } 183 184 sa.sa_sigaction = (void *) sig_handler_2; 185 if (sigaction(SIGUSR1, &sa, NULL) < 0) { 186 pr_debug("failed setting up signal handler 2\n"); 187 return TEST_FAIL; 188 } 189 190 /* 191 * We create following events: 192 * 193 * fd1 - breakpoint event on __test_function with SIGIO 194 * signal configured. We should get signal 195 * notification each time the breakpoint is hit 196 * 197 * fd2 - breakpoint event on sig_handler with SIGUSR1 198 * configured. We should get SIGUSR1 each time when 199 * breakpoint is hit 200 * 201 * fd3 - watchpoint event on __test_function with SIGIO 202 * configured. 203 * 204 * Following processing should happen: 205 * Exec: Action: Result: 206 * incq (%rdi) - fd1 event breakpoint hit -> count1 == 1 207 * - SIGIO is delivered 208 * sig_handler - fd2 event breakpoint hit -> count2 == 1 209 * - SIGUSR1 is delivered 210 * sig_handler_2 -> overflows_2 == 1 (nested signal) 211 * sys_rt_sigreturn - return from sig_handler_2 212 * overflows++ -> overflows = 1 213 * sys_rt_sigreturn - return from sig_handler 214 * incq (%rdi) - fd3 event watchpoint hit -> count3 == 1 (wp and bp in one insn) 215 * - SIGIO is delivered 216 * sig_handler - fd2 event breakpoint hit -> count2 == 2 217 * - SIGUSR1 is delivered 218 * sig_handler_2 -> overflows_2 == 2 (nested signal) 219 * sys_rt_sigreturn - return from sig_handler_2 220 * overflows++ -> overflows = 2 221 * sys_rt_sigreturn - return from sig_handler 222 * the_var++ - fd3 event watchpoint hit -> count3 == 2 (standalone watchpoint) 223 * - SIGIO is delivered 224 * sig_handler - fd2 event breakpoint hit -> count2 == 3 225 * - SIGUSR1 is delivered 226 * sig_handler_2 -> overflows_2 == 3 (nested signal) 227 * sys_rt_sigreturn - return from sig_handler_2 228 * overflows++ -> overflows == 3 229 * sys_rt_sigreturn - return from sig_handler 230 * 231 * The test case check following error conditions: 232 * - we get stuck in signal handler because of debug 233 * exception being triggered receursively due to 234 * the wrong RF EFLAG management 235 * 236 * - we never trigger the sig_handler breakpoint due 237 * to the rong RF EFLAG management 238 * 239 */ 240 241 fd1 = bp_event(__test_function, SIGIO); 242 fd2 = bp_event(sig_handler, SIGUSR1); 243 fd3 = wp_event((void *)&the_var, SIGIO); 244 245 ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0); 246 ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0); 247 ioctl(fd3, PERF_EVENT_IOC_ENABLE, 0); 248 249 /* 250 * Kick off the test by trigering 'fd1' 251 * breakpoint. 252 */ 253 test_function(); 254 255 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0); 256 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0); 257 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0); 258 259 count1 = bp_count(fd1); 260 count2 = bp_count(fd2); 261 count3 = bp_count(fd3); 262 263 close(fd1); 264 close(fd2); 265 close(fd3); 266 267 pr_debug("count1 %lld, count2 %lld, count3 %lld, overflow %d, overflows_2 %d\n", 268 count1, count2, count3, overflows, overflows_2); 269 270 if (count1 != 1) { 271 if (count1 == 11) 272 pr_debug("failed: RF EFLAG recursion issue detected\n"); 273 else 274 pr_debug("failed: wrong count for bp1%lld\n", count1); 275 } 276 277 if (overflows != 3) 278 pr_debug("failed: wrong overflow hit\n"); 279 280 if (overflows_2 != 3) 281 pr_debug("failed: wrong overflow_2 hit\n"); 282 283 if (count2 != 3) 284 pr_debug("failed: wrong count for bp2\n"); 285 286 if (count3 != 2) 287 pr_debug("failed: wrong count for bp3\n"); 288 289 return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ? 290 TEST_OK : TEST_FAIL; 291 } 292 293 bool test__bp_signal_is_supported(void) 294 { 295 /* 296 * PowerPC and S390 do not support creation of instruction 297 * breakpoints using the perf_event interface. 298 * 299 * ARM requires explicit rounding down of the instruction 300 * pointer in Thumb mode, and then requires the single-step 301 * to be handled explicitly in the overflow handler to avoid 302 * stepping into the SIGIO handler and getting stuck on the 303 * breakpointed instruction. 304 * 305 * Just disable the test for these architectures until these 306 * issues are resolved. 307 */ 308 #if defined(__powerpc__) || defined(__s390x__) || defined(__arm__) 309 return false; 310 #else 311 return true; 312 #endif 313 } 314