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 size_t read_objdump_chunk(const char **line, unsigned char **buf, 37 size_t *buf_len) 38 { 39 size_t bytes_read = 0; 40 unsigned char *chunk_start = *buf; 41 42 /* Read bytes */ 43 while (*buf_len > 0) { 44 char c1, c2; 45 46 /* Get 2 hex digits */ 47 c1 = *(*line)++; 48 if (!isxdigit(c1)) 49 break; 50 c2 = *(*line)++; 51 if (!isxdigit(c2)) 52 break; 53 54 /* Store byte and advance buf */ 55 **buf = (hex(c1) << 4) | hex(c2); 56 (*buf)++; 57 (*buf_len)--; 58 bytes_read++; 59 60 /* End of chunk? */ 61 if (isspace(**line)) 62 break; 63 } 64 65 /* 66 * objdump will display raw insn as LE if code endian 67 * is LE and bytes_per_chunk > 1. In that case reverse 68 * the chunk we just read. 69 * 70 * see disassemble_bytes() at binutils/objdump.c for details 71 * how objdump chooses display endian) 72 */ 73 if (bytes_read > 1 && !bigendian()) { 74 unsigned char *chunk_end = chunk_start + bytes_read - 1; 75 unsigned char tmp; 76 77 while (chunk_start < chunk_end) { 78 tmp = *chunk_start; 79 *chunk_start = *chunk_end; 80 *chunk_end = tmp; 81 chunk_start++; 82 chunk_end--; 83 } 84 } 85 86 return bytes_read; 87 } 88 89 static size_t read_objdump_line(const char *line, unsigned char *buf, 90 size_t buf_len) 91 { 92 const char *p; 93 size_t ret, bytes_read = 0; 94 95 /* Skip to a colon */ 96 p = strchr(line, ':'); 97 if (!p) 98 return 0; 99 p++; 100 101 /* Skip initial spaces */ 102 while (*p) { 103 if (!isspace(*p)) 104 break; 105 p++; 106 } 107 108 do { 109 ret = read_objdump_chunk(&p, &buf, &buf_len); 110 bytes_read += ret; 111 p++; 112 } while (ret > 0); 113 114 /* return number of successfully read bytes */ 115 return bytes_read; 116 } 117 118 static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr) 119 { 120 char *line = NULL; 121 size_t line_len, off_last = 0; 122 ssize_t ret; 123 int err = 0; 124 u64 addr, last_addr = start_addr; 125 126 while (off_last < *len) { 127 size_t off, read_bytes, written_bytes; 128 unsigned char tmp[BUFSZ]; 129 130 ret = getline(&line, &line_len, f); 131 if (feof(f)) 132 break; 133 if (ret < 0) { 134 pr_debug("getline failed\n"); 135 err = -1; 136 break; 137 } 138 139 /* read objdump data into temporary buffer */ 140 read_bytes = read_objdump_line(line, tmp, sizeof(tmp)); 141 if (!read_bytes) 142 continue; 143 144 if (sscanf(line, "%"PRIx64, &addr) != 1) 145 continue; 146 if (addr < last_addr) { 147 pr_debug("addr going backwards, read beyond section?\n"); 148 break; 149 } 150 last_addr = addr; 151 152 /* copy it from temporary buffer to 'buf' according 153 * to address on current objdump line */ 154 off = addr - start_addr; 155 if (off >= *len) 156 break; 157 written_bytes = MIN(read_bytes, *len - off); 158 memcpy(buf + off, tmp, written_bytes); 159 off_last = off + written_bytes; 160 } 161 162 /* len returns number of bytes that could not be read */ 163 *len -= off_last; 164 165 free(line); 166 167 return err; 168 } 169 170 static int read_via_objdump(const char *filename, u64 addr, void *buf, 171 size_t len) 172 { 173 char cmd[PATH_MAX * 2]; 174 const char *fmt; 175 FILE *f; 176 int ret; 177 178 fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s"; 179 ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len, 180 filename); 181 if (ret <= 0 || (size_t)ret >= sizeof(cmd)) 182 return -1; 183 184 pr_debug("Objdump command is: %s\n", cmd); 185 186 /* Ignore objdump errors */ 187 strcat(cmd, " 2>/dev/null"); 188 189 f = popen(cmd, "r"); 190 if (!f) { 191 pr_debug("popen failed\n"); 192 return -1; 193 } 194 195 ret = read_objdump_output(f, buf, &len, addr); 196 if (len) { 197 pr_debug("objdump read too few bytes: %zd\n", len); 198 if (!ret) 199 ret = len; 200 } 201 202 pclose(f); 203 204 return ret; 205 } 206 207 static void dump_buf(unsigned char *buf, size_t len) 208 { 209 size_t i; 210 211 for (i = 0; i < len; i++) { 212 pr_debug("0x%02x ", buf[i]); 213 if (i % 16 == 15) 214 pr_debug("\n"); 215 } 216 pr_debug("\n"); 217 } 218 219 static int read_object_code(u64 addr, size_t len, u8 cpumode, 220 struct thread *thread, struct state *state) 221 { 222 struct addr_location al; 223 unsigned char buf1[BUFSZ]; 224 unsigned char buf2[BUFSZ]; 225 size_t ret_len; 226 u64 objdump_addr; 227 int ret; 228 229 pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr); 230 231 thread__find_addr_map(thread, cpumode, MAP__FUNCTION, addr, &al); 232 if (!al.map || !al.map->dso) { 233 pr_debug("thread__find_addr_map failed\n"); 234 return -1; 235 } 236 237 pr_debug("File is: %s\n", al.map->dso->long_name); 238 239 if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS && 240 !dso__is_kcore(al.map->dso)) { 241 pr_debug("Unexpected kernel address - skipping\n"); 242 return 0; 243 } 244 245 pr_debug("On file address is: %#"PRIx64"\n", al.addr); 246 247 if (len > BUFSZ) 248 len = BUFSZ; 249 250 /* Do not go off the map */ 251 if (addr + len > al.map->end) 252 len = al.map->end - addr; 253 254 /* Read the object code using perf */ 255 ret_len = dso__data_read_offset(al.map->dso, thread->mg->machine, 256 al.addr, buf1, len); 257 if (ret_len != len) { 258 pr_debug("dso__data_read_offset failed\n"); 259 return -1; 260 } 261 262 /* 263 * Converting addresses for use by objdump requires more information. 264 * map__load() does that. See map__rip_2objdump() for details. 265 */ 266 if (map__load(al.map)) 267 return -1; 268 269 /* objdump struggles with kcore - try each map only once */ 270 if (dso__is_kcore(al.map->dso)) { 271 size_t d; 272 273 for (d = 0; d < state->done_cnt; d++) { 274 if (state->done[d] == al.map->start) { 275 pr_debug("kcore map tested already"); 276 pr_debug(" - skipping\n"); 277 return 0; 278 } 279 } 280 if (state->done_cnt >= ARRAY_SIZE(state->done)) { 281 pr_debug("Too many kcore maps - skipping\n"); 282 return 0; 283 } 284 state->done[state->done_cnt++] = al.map->start; 285 } 286 287 /* Read the object code using objdump */ 288 objdump_addr = map__rip_2objdump(al.map, al.addr); 289 ret = read_via_objdump(al.map->dso->long_name, objdump_addr, buf2, len); 290 if (ret > 0) { 291 /* 292 * The kernel maps are inaccurate - assume objdump is right in 293 * that case. 294 */ 295 if (cpumode == PERF_RECORD_MISC_KERNEL || 296 cpumode == PERF_RECORD_MISC_GUEST_KERNEL) { 297 len -= ret; 298 if (len) { 299 pr_debug("Reducing len to %zu\n", len); 300 } else if (dso__is_kcore(al.map->dso)) { 301 /* 302 * objdump cannot handle very large segments 303 * that may be found in kcore. 304 */ 305 pr_debug("objdump failed for kcore"); 306 pr_debug(" - skipping\n"); 307 return 0; 308 } else { 309 return -1; 310 } 311 } 312 } 313 if (ret < 0) { 314 pr_debug("read_via_objdump failed\n"); 315 return -1; 316 } 317 318 /* The results should be identical */ 319 if (memcmp(buf1, buf2, len)) { 320 pr_debug("Bytes read differ from those read by objdump\n"); 321 pr_debug("buf1 (dso):\n"); 322 dump_buf(buf1, len); 323 pr_debug("buf2 (objdump):\n"); 324 dump_buf(buf2, len); 325 return -1; 326 } 327 pr_debug("Bytes read match those read by objdump\n"); 328 329 return 0; 330 } 331 332 static int process_sample_event(struct machine *machine, 333 struct perf_evlist *evlist, 334 union perf_event *event, struct state *state) 335 { 336 struct perf_sample sample; 337 struct thread *thread; 338 int ret; 339 340 if (perf_evlist__parse_sample(evlist, event, &sample)) { 341 pr_debug("perf_evlist__parse_sample failed\n"); 342 return -1; 343 } 344 345 thread = machine__findnew_thread(machine, sample.pid, sample.tid); 346 if (!thread) { 347 pr_debug("machine__findnew_thread failed\n"); 348 return -1; 349 } 350 351 ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state); 352 thread__put(thread); 353 return ret; 354 } 355 356 static int process_event(struct machine *machine, struct perf_evlist *evlist, 357 union perf_event *event, struct state *state) 358 { 359 if (event->header.type == PERF_RECORD_SAMPLE) 360 return process_sample_event(machine, evlist, event, state); 361 362 if (event->header.type == PERF_RECORD_THROTTLE || 363 event->header.type == PERF_RECORD_UNTHROTTLE) 364 return 0; 365 366 if (event->header.type < PERF_RECORD_MAX) { 367 int ret; 368 369 ret = machine__process_event(machine, event, NULL); 370 if (ret < 0) 371 pr_debug("machine__process_event failed, event type %u\n", 372 event->header.type); 373 return ret; 374 } 375 376 return 0; 377 } 378 379 static int process_events(struct machine *machine, struct perf_evlist *evlist, 380 struct state *state) 381 { 382 union perf_event *event; 383 int i, ret; 384 385 for (i = 0; i < evlist->nr_mmaps; i++) { 386 while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) { 387 ret = process_event(machine, evlist, event, state); 388 perf_evlist__mmap_consume(evlist, i); 389 if (ret < 0) 390 return ret; 391 } 392 } 393 return 0; 394 } 395 396 static int comp(const void *a, const void *b) 397 { 398 return *(int *)a - *(int *)b; 399 } 400 401 static void do_sort_something(void) 402 { 403 int buf[40960], i; 404 405 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) 406 buf[i] = ARRAY_SIZE(buf) - i - 1; 407 408 qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp); 409 410 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) { 411 if (buf[i] != i) { 412 pr_debug("qsort failed\n"); 413 break; 414 } 415 } 416 } 417 418 static void sort_something(void) 419 { 420 int i; 421 422 for (i = 0; i < 10; i++) 423 do_sort_something(); 424 } 425 426 static void syscall_something(void) 427 { 428 int pipefd[2]; 429 int i; 430 431 for (i = 0; i < 1000; i++) { 432 if (pipe(pipefd) < 0) { 433 pr_debug("pipe failed\n"); 434 break; 435 } 436 close(pipefd[1]); 437 close(pipefd[0]); 438 } 439 } 440 441 static void fs_something(void) 442 { 443 const char *test_file_name = "temp-perf-code-reading-test-file--"; 444 FILE *f; 445 int i; 446 447 for (i = 0; i < 1000; i++) { 448 f = fopen(test_file_name, "w+"); 449 if (f) { 450 fclose(f); 451 unlink(test_file_name); 452 } 453 } 454 } 455 456 static void do_something(void) 457 { 458 fs_something(); 459 460 sort_something(); 461 462 syscall_something(); 463 } 464 465 enum { 466 TEST_CODE_READING_OK, 467 TEST_CODE_READING_NO_VMLINUX, 468 TEST_CODE_READING_NO_KCORE, 469 TEST_CODE_READING_NO_ACCESS, 470 TEST_CODE_READING_NO_KERNEL_OBJ, 471 }; 472 473 static int do_test_code_reading(bool try_kcore) 474 { 475 struct machine *machine; 476 struct thread *thread; 477 struct record_opts opts = { 478 .mmap_pages = UINT_MAX, 479 .user_freq = UINT_MAX, 480 .user_interval = ULLONG_MAX, 481 .freq = 500, 482 .target = { 483 .uses_mmap = true, 484 }, 485 }; 486 struct state state = { 487 .done_cnt = 0, 488 }; 489 struct thread_map *threads = NULL; 490 struct cpu_map *cpus = NULL; 491 struct perf_evlist *evlist = NULL; 492 struct perf_evsel *evsel = NULL; 493 int err = -1, ret; 494 pid_t pid; 495 struct map *map; 496 bool have_vmlinux, have_kcore, excl_kernel = false; 497 498 pid = getpid(); 499 500 machine = machine__new_host(); 501 502 ret = machine__create_kernel_maps(machine); 503 if (ret < 0) { 504 pr_debug("machine__create_kernel_maps failed\n"); 505 goto out_err; 506 } 507 508 /* Force the use of kallsyms instead of vmlinux to try kcore */ 509 if (try_kcore) 510 symbol_conf.kallsyms_name = "/proc/kallsyms"; 511 512 /* Load kernel map */ 513 map = machine__kernel_map(machine); 514 ret = map__load(map); 515 if (ret < 0) { 516 pr_debug("map__load failed\n"); 517 goto out_err; 518 } 519 have_vmlinux = dso__is_vmlinux(map->dso); 520 have_kcore = dso__is_kcore(map->dso); 521 522 /* 2nd time through we just try kcore */ 523 if (try_kcore && !have_kcore) 524 return TEST_CODE_READING_NO_KCORE; 525 526 /* No point getting kernel events if there is no kernel object */ 527 if (!have_vmlinux && !have_kcore) 528 excl_kernel = true; 529 530 threads = thread_map__new_by_tid(pid); 531 if (!threads) { 532 pr_debug("thread_map__new_by_tid failed\n"); 533 goto out_err; 534 } 535 536 ret = perf_event__synthesize_thread_map(NULL, threads, 537 perf_event__process, machine, false, 500); 538 if (ret < 0) { 539 pr_debug("perf_event__synthesize_thread_map failed\n"); 540 goto out_err; 541 } 542 543 thread = machine__findnew_thread(machine, pid, pid); 544 if (!thread) { 545 pr_debug("machine__findnew_thread failed\n"); 546 goto out_put; 547 } 548 549 cpus = cpu_map__new(NULL); 550 if (!cpus) { 551 pr_debug("cpu_map__new failed\n"); 552 goto out_put; 553 } 554 555 while (1) { 556 const char *str; 557 558 evlist = perf_evlist__new(); 559 if (!evlist) { 560 pr_debug("perf_evlist__new failed\n"); 561 goto out_put; 562 } 563 564 perf_evlist__set_maps(evlist, cpus, threads); 565 566 if (excl_kernel) 567 str = "cycles:u"; 568 else 569 str = "cycles"; 570 pr_debug("Parsing event '%s'\n", str); 571 ret = parse_events(evlist, str, NULL); 572 if (ret < 0) { 573 pr_debug("parse_events failed\n"); 574 goto out_put; 575 } 576 577 perf_evlist__config(evlist, &opts, NULL); 578 579 evsel = perf_evlist__first(evlist); 580 581 evsel->attr.comm = 1; 582 evsel->attr.disabled = 1; 583 evsel->attr.enable_on_exec = 0; 584 585 ret = perf_evlist__open(evlist); 586 if (ret < 0) { 587 if (!excl_kernel) { 588 excl_kernel = true; 589 /* 590 * Both cpus and threads are now owned by evlist 591 * and will be freed by following perf_evlist__set_maps 592 * call. Getting refference to keep them alive. 593 */ 594 cpu_map__get(cpus); 595 thread_map__get(threads); 596 perf_evlist__set_maps(evlist, NULL, NULL); 597 perf_evlist__delete(evlist); 598 evlist = NULL; 599 continue; 600 } 601 602 if (verbose > 0) { 603 char errbuf[512]; 604 perf_evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf)); 605 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf); 606 } 607 608 goto out_put; 609 } 610 break; 611 } 612 613 ret = perf_evlist__mmap(evlist, UINT_MAX, false); 614 if (ret < 0) { 615 pr_debug("perf_evlist__mmap failed\n"); 616 goto out_put; 617 } 618 619 perf_evlist__enable(evlist); 620 621 do_something(); 622 623 perf_evlist__disable(evlist); 624 625 ret = process_events(machine, evlist, &state); 626 if (ret < 0) 627 goto out_put; 628 629 if (!have_vmlinux && !have_kcore && !try_kcore) 630 err = TEST_CODE_READING_NO_KERNEL_OBJ; 631 else if (!have_vmlinux && !try_kcore) 632 err = TEST_CODE_READING_NO_VMLINUX; 633 else if (excl_kernel) 634 err = TEST_CODE_READING_NO_ACCESS; 635 else 636 err = TEST_CODE_READING_OK; 637 out_put: 638 thread__put(thread); 639 out_err: 640 641 if (evlist) { 642 perf_evlist__delete(evlist); 643 } else { 644 cpu_map__put(cpus); 645 thread_map__put(threads); 646 } 647 machine__delete_threads(machine); 648 machine__delete(machine); 649 650 return err; 651 } 652 653 int test__code_reading(int subtest __maybe_unused) 654 { 655 int ret; 656 657 ret = do_test_code_reading(false); 658 if (!ret) 659 ret = do_test_code_reading(true); 660 661 switch (ret) { 662 case TEST_CODE_READING_OK: 663 return 0; 664 case TEST_CODE_READING_NO_VMLINUX: 665 pr_debug("no vmlinux\n"); 666 return 0; 667 case TEST_CODE_READING_NO_KCORE: 668 pr_debug("no kcore\n"); 669 return 0; 670 case TEST_CODE_READING_NO_ACCESS: 671 pr_debug("no access\n"); 672 return 0; 673 case TEST_CODE_READING_NO_KERNEL_OBJ: 674 pr_debug("no kernel obj\n"); 675 return 0; 676 default: 677 return -1; 678 }; 679 } 680