1 #include <linux/types.h> 2 #include <stdlib.h> 3 #include <unistd.h> 4 #include <stdio.h> 5 #include <ctype.h> 6 #include <string.h> 7 8 #include "parse-events.h" 9 #include "evlist.h" 10 #include "evsel.h" 11 #include "thread_map.h" 12 #include "cpumap.h" 13 #include "machine.h" 14 #include "event.h" 15 #include "thread.h" 16 17 #include "tests.h" 18 19 #define BUFSZ 1024 20 #define READLEN 128 21 22 struct state { 23 u64 done[1024]; 24 size_t done_cnt; 25 }; 26 27 static unsigned int hex(char c) 28 { 29 if (c >= '0' && c <= '9') 30 return c - '0'; 31 if (c >= 'a' && c <= 'f') 32 return c - 'a' + 10; 33 return c - 'A' + 10; 34 } 35 36 static void read_objdump_line(const char *line, size_t line_len, void **buf, 37 size_t *len) 38 { 39 const char *p; 40 size_t i; 41 42 /* Skip to a colon */ 43 p = strchr(line, ':'); 44 if (!p) 45 return; 46 i = p + 1 - line; 47 48 /* Read bytes */ 49 while (*len) { 50 char c1, c2; 51 52 /* Skip spaces */ 53 for (; i < line_len; i++) { 54 if (!isspace(line[i])) 55 break; 56 } 57 /* Get 2 hex digits */ 58 if (i >= line_len || !isxdigit(line[i])) 59 break; 60 c1 = line[i++]; 61 if (i >= line_len || !isxdigit(line[i])) 62 break; 63 c2 = line[i++]; 64 /* Followed by a space */ 65 if (i < line_len && line[i] && !isspace(line[i])) 66 break; 67 /* Store byte */ 68 *(unsigned char *)*buf = (hex(c1) << 4) | hex(c2); 69 *buf += 1; 70 *len -= 1; 71 } 72 } 73 74 static int read_objdump_output(FILE *f, void **buf, size_t *len) 75 { 76 char *line = NULL; 77 size_t line_len; 78 ssize_t ret; 79 int err = 0; 80 81 while (1) { 82 ret = getline(&line, &line_len, f); 83 if (feof(f)) 84 break; 85 if (ret < 0) { 86 pr_debug("getline failed\n"); 87 err = -1; 88 break; 89 } 90 read_objdump_line(line, ret, buf, len); 91 } 92 93 free(line); 94 95 return err; 96 } 97 98 static int read_via_objdump(const char *filename, u64 addr, void *buf, 99 size_t len) 100 { 101 char cmd[PATH_MAX * 2]; 102 const char *fmt; 103 FILE *f; 104 int ret; 105 106 fmt = "%s -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s"; 107 ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len, 108 filename); 109 if (ret <= 0 || (size_t)ret >= sizeof(cmd)) 110 return -1; 111 112 pr_debug("Objdump command is: %s\n", cmd); 113 114 /* Ignore objdump errors */ 115 strcat(cmd, " 2>/dev/null"); 116 117 f = popen(cmd, "r"); 118 if (!f) { 119 pr_debug("popen failed\n"); 120 return -1; 121 } 122 123 ret = read_objdump_output(f, &buf, &len); 124 if (len) { 125 pr_debug("objdump read too few bytes\n"); 126 if (!ret) 127 ret = len; 128 } 129 130 pclose(f); 131 132 return ret; 133 } 134 135 static int read_object_code(u64 addr, size_t len, u8 cpumode, 136 struct thread *thread, struct state *state) 137 { 138 struct addr_location al; 139 unsigned char buf1[BUFSZ]; 140 unsigned char buf2[BUFSZ]; 141 size_t ret_len; 142 u64 objdump_addr; 143 int ret; 144 145 pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr); 146 147 thread__find_addr_map(thread, cpumode, MAP__FUNCTION, addr, &al); 148 if (!al.map || !al.map->dso) { 149 pr_debug("thread__find_addr_map failed\n"); 150 return -1; 151 } 152 153 pr_debug("File is: %s\n", al.map->dso->long_name); 154 155 if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS && 156 !dso__is_kcore(al.map->dso)) { 157 pr_debug("Unexpected kernel address - skipping\n"); 158 return 0; 159 } 160 161 pr_debug("On file address is: %#"PRIx64"\n", al.addr); 162 163 if (len > BUFSZ) 164 len = BUFSZ; 165 166 /* Do not go off the map */ 167 if (addr + len > al.map->end) 168 len = al.map->end - addr; 169 170 /* Read the object code using perf */ 171 ret_len = dso__data_read_offset(al.map->dso, thread->mg->machine, 172 al.addr, buf1, len); 173 if (ret_len != len) { 174 pr_debug("dso__data_read_offset failed\n"); 175 return -1; 176 } 177 178 /* 179 * Converting addresses for use by objdump requires more information. 180 * map__load() does that. See map__rip_2objdump() for details. 181 */ 182 if (map__load(al.map, NULL)) 183 return -1; 184 185 /* objdump struggles with kcore - try each map only once */ 186 if (dso__is_kcore(al.map->dso)) { 187 size_t d; 188 189 for (d = 0; d < state->done_cnt; d++) { 190 if (state->done[d] == al.map->start) { 191 pr_debug("kcore map tested already"); 192 pr_debug(" - skipping\n"); 193 return 0; 194 } 195 } 196 if (state->done_cnt >= ARRAY_SIZE(state->done)) { 197 pr_debug("Too many kcore maps - skipping\n"); 198 return 0; 199 } 200 state->done[state->done_cnt++] = al.map->start; 201 } 202 203 /* Read the object code using objdump */ 204 objdump_addr = map__rip_2objdump(al.map, al.addr); 205 ret = read_via_objdump(al.map->dso->long_name, objdump_addr, buf2, len); 206 if (ret > 0) { 207 /* 208 * The kernel maps are inaccurate - assume objdump is right in 209 * that case. 210 */ 211 if (cpumode == PERF_RECORD_MISC_KERNEL || 212 cpumode == PERF_RECORD_MISC_GUEST_KERNEL) { 213 len -= ret; 214 if (len) { 215 pr_debug("Reducing len to %zu\n", len); 216 } else if (dso__is_kcore(al.map->dso)) { 217 /* 218 * objdump cannot handle very large segments 219 * that may be found in kcore. 220 */ 221 pr_debug("objdump failed for kcore"); 222 pr_debug(" - skipping\n"); 223 return 0; 224 } else { 225 return -1; 226 } 227 } 228 } 229 if (ret < 0) { 230 pr_debug("read_via_objdump failed\n"); 231 return -1; 232 } 233 234 /* The results should be identical */ 235 if (memcmp(buf1, buf2, len)) { 236 pr_debug("Bytes read differ from those read by objdump\n"); 237 return -1; 238 } 239 pr_debug("Bytes read match those read by objdump\n"); 240 241 return 0; 242 } 243 244 static int process_sample_event(struct machine *machine, 245 struct perf_evlist *evlist, 246 union perf_event *event, struct state *state) 247 { 248 struct perf_sample sample; 249 struct thread *thread; 250 u8 cpumode; 251 int ret; 252 253 if (perf_evlist__parse_sample(evlist, event, &sample)) { 254 pr_debug("perf_evlist__parse_sample failed\n"); 255 return -1; 256 } 257 258 thread = machine__findnew_thread(machine, sample.pid, sample.tid); 259 if (!thread) { 260 pr_debug("machine__findnew_thread failed\n"); 261 return -1; 262 } 263 264 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK; 265 266 ret = read_object_code(sample.ip, READLEN, cpumode, thread, state); 267 thread__put(thread); 268 return ret; 269 } 270 271 static int process_event(struct machine *machine, struct perf_evlist *evlist, 272 union perf_event *event, struct state *state) 273 { 274 if (event->header.type == PERF_RECORD_SAMPLE) 275 return process_sample_event(machine, evlist, event, state); 276 277 if (event->header.type == PERF_RECORD_THROTTLE || 278 event->header.type == PERF_RECORD_UNTHROTTLE) 279 return 0; 280 281 if (event->header.type < PERF_RECORD_MAX) { 282 int ret; 283 284 ret = machine__process_event(machine, event, NULL); 285 if (ret < 0) 286 pr_debug("machine__process_event failed, event type %u\n", 287 event->header.type); 288 return ret; 289 } 290 291 return 0; 292 } 293 294 static int process_events(struct machine *machine, struct perf_evlist *evlist, 295 struct state *state) 296 { 297 union perf_event *event; 298 int i, ret; 299 300 for (i = 0; i < evlist->nr_mmaps; i++) { 301 while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) { 302 ret = process_event(machine, evlist, event, state); 303 perf_evlist__mmap_consume(evlist, i); 304 if (ret < 0) 305 return ret; 306 } 307 } 308 return 0; 309 } 310 311 static int comp(const void *a, const void *b) 312 { 313 return *(int *)a - *(int *)b; 314 } 315 316 static void do_sort_something(void) 317 { 318 int buf[40960], i; 319 320 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) 321 buf[i] = ARRAY_SIZE(buf) - i - 1; 322 323 qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp); 324 325 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) { 326 if (buf[i] != i) { 327 pr_debug("qsort failed\n"); 328 break; 329 } 330 } 331 } 332 333 static void sort_something(void) 334 { 335 int i; 336 337 for (i = 0; i < 10; i++) 338 do_sort_something(); 339 } 340 341 static void syscall_something(void) 342 { 343 int pipefd[2]; 344 int i; 345 346 for (i = 0; i < 1000; i++) { 347 if (pipe(pipefd) < 0) { 348 pr_debug("pipe failed\n"); 349 break; 350 } 351 close(pipefd[1]); 352 close(pipefd[0]); 353 } 354 } 355 356 static void fs_something(void) 357 { 358 const char *test_file_name = "temp-perf-code-reading-test-file--"; 359 FILE *f; 360 int i; 361 362 for (i = 0; i < 1000; i++) { 363 f = fopen(test_file_name, "w+"); 364 if (f) { 365 fclose(f); 366 unlink(test_file_name); 367 } 368 } 369 } 370 371 static void do_something(void) 372 { 373 fs_something(); 374 375 sort_something(); 376 377 syscall_something(); 378 } 379 380 enum { 381 TEST_CODE_READING_OK, 382 TEST_CODE_READING_NO_VMLINUX, 383 TEST_CODE_READING_NO_KCORE, 384 TEST_CODE_READING_NO_ACCESS, 385 TEST_CODE_READING_NO_KERNEL_OBJ, 386 }; 387 388 static int do_test_code_reading(bool try_kcore) 389 { 390 struct machines machines; 391 struct machine *machine; 392 struct thread *thread; 393 struct record_opts opts = { 394 .mmap_pages = UINT_MAX, 395 .user_freq = UINT_MAX, 396 .user_interval = ULLONG_MAX, 397 .freq = 4000, 398 .target = { 399 .uses_mmap = true, 400 }, 401 }; 402 struct state state = { 403 .done_cnt = 0, 404 }; 405 struct thread_map *threads = NULL; 406 struct cpu_map *cpus = NULL; 407 struct perf_evlist *evlist = NULL; 408 struct perf_evsel *evsel = NULL; 409 int err = -1, ret; 410 pid_t pid; 411 struct map *map; 412 bool have_vmlinux, have_kcore, excl_kernel = false; 413 414 pid = getpid(); 415 416 machines__init(&machines); 417 machine = &machines.host; 418 419 ret = machine__create_kernel_maps(machine); 420 if (ret < 0) { 421 pr_debug("machine__create_kernel_maps failed\n"); 422 goto out_err; 423 } 424 425 /* Force the use of kallsyms instead of vmlinux to try kcore */ 426 if (try_kcore) 427 symbol_conf.kallsyms_name = "/proc/kallsyms"; 428 429 /* Load kernel map */ 430 map = machine->vmlinux_maps[MAP__FUNCTION]; 431 ret = map__load(map, NULL); 432 if (ret < 0) { 433 pr_debug("map__load failed\n"); 434 goto out_err; 435 } 436 have_vmlinux = dso__is_vmlinux(map->dso); 437 have_kcore = dso__is_kcore(map->dso); 438 439 /* 2nd time through we just try kcore */ 440 if (try_kcore && !have_kcore) 441 return TEST_CODE_READING_NO_KCORE; 442 443 /* No point getting kernel events if there is no kernel object */ 444 if (!have_vmlinux && !have_kcore) 445 excl_kernel = true; 446 447 threads = thread_map__new_by_tid(pid); 448 if (!threads) { 449 pr_debug("thread_map__new_by_tid failed\n"); 450 goto out_err; 451 } 452 453 ret = perf_event__synthesize_thread_map(NULL, threads, 454 perf_event__process, machine, false, 500); 455 if (ret < 0) { 456 pr_debug("perf_event__synthesize_thread_map failed\n"); 457 goto out_err; 458 } 459 460 thread = machine__findnew_thread(machine, pid, pid); 461 if (!thread) { 462 pr_debug("machine__findnew_thread failed\n"); 463 goto out_put; 464 } 465 466 cpus = cpu_map__new(NULL); 467 if (!cpus) { 468 pr_debug("cpu_map__new failed\n"); 469 goto out_put; 470 } 471 472 while (1) { 473 const char *str; 474 475 evlist = perf_evlist__new(); 476 if (!evlist) { 477 pr_debug("perf_evlist__new failed\n"); 478 goto out_put; 479 } 480 481 perf_evlist__set_maps(evlist, cpus, threads); 482 483 if (excl_kernel) 484 str = "cycles:u"; 485 else 486 str = "cycles"; 487 pr_debug("Parsing event '%s'\n", str); 488 ret = parse_events(evlist, str, NULL); 489 if (ret < 0) { 490 pr_debug("parse_events failed\n"); 491 goto out_put; 492 } 493 494 perf_evlist__config(evlist, &opts); 495 496 evsel = perf_evlist__first(evlist); 497 498 evsel->attr.comm = 1; 499 evsel->attr.disabled = 1; 500 evsel->attr.enable_on_exec = 0; 501 502 ret = perf_evlist__open(evlist); 503 if (ret < 0) { 504 if (!excl_kernel) { 505 excl_kernel = true; 506 perf_evlist__set_maps(evlist, NULL, NULL); 507 perf_evlist__delete(evlist); 508 evlist = NULL; 509 continue; 510 } 511 pr_debug("perf_evlist__open failed\n"); 512 goto out_put; 513 } 514 break; 515 } 516 517 ret = perf_evlist__mmap(evlist, UINT_MAX, false); 518 if (ret < 0) { 519 pr_debug("perf_evlist__mmap failed\n"); 520 goto out_put; 521 } 522 523 perf_evlist__enable(evlist); 524 525 do_something(); 526 527 perf_evlist__disable(evlist); 528 529 ret = process_events(machine, evlist, &state); 530 if (ret < 0) 531 goto out_put; 532 533 if (!have_vmlinux && !have_kcore && !try_kcore) 534 err = TEST_CODE_READING_NO_KERNEL_OBJ; 535 else if (!have_vmlinux && !try_kcore) 536 err = TEST_CODE_READING_NO_VMLINUX; 537 else if (excl_kernel) 538 err = TEST_CODE_READING_NO_ACCESS; 539 else 540 err = TEST_CODE_READING_OK; 541 out_put: 542 thread__put(thread); 543 out_err: 544 545 if (evlist) { 546 perf_evlist__delete(evlist); 547 } else { 548 cpu_map__put(cpus); 549 thread_map__put(threads); 550 } 551 machines__destroy_kernel_maps(&machines); 552 machine__delete_threads(machine); 553 machines__exit(&machines); 554 555 return err; 556 } 557 558 int test__code_reading(void) 559 { 560 int ret; 561 562 ret = do_test_code_reading(false); 563 if (!ret) 564 ret = do_test_code_reading(true); 565 566 switch (ret) { 567 case TEST_CODE_READING_OK: 568 return 0; 569 case TEST_CODE_READING_NO_VMLINUX: 570 fprintf(stderr, " (no vmlinux)"); 571 return 0; 572 case TEST_CODE_READING_NO_KCORE: 573 fprintf(stderr, " (no kcore)"); 574 return 0; 575 case TEST_CODE_READING_NO_ACCESS: 576 fprintf(stderr, " (no access)"); 577 return 0; 578 case TEST_CODE_READING_NO_KERNEL_OBJ: 579 fprintf(stderr, " (no kernel obj)"); 580 return 0; 581 default: 582 return -1; 583 }; 584 } 585