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 recursively due to 229 * the wrong RF EFLAG management 230 * 231 * - we never trigger the sig_handler breakpoint due 232 * to the wrong 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 triggering '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 } 314