1 #include <errno.h> 2 #include <linux/kernel.h> 3 #include <linux/types.h> 4 #include <inttypes.h> 5 #include <stdlib.h> 6 #include <unistd.h> 7 #include <stdio.h> 8 #include <string.h> 9 #include <sys/param.h> 10 11 #include "parse-events.h" 12 #include "evlist.h" 13 #include "evsel.h" 14 #include "thread_map.h" 15 #include "cpumap.h" 16 #include "machine.h" 17 #include "event.h" 18 #include "thread.h" 19 20 #include "tests.h" 21 22 #include "sane_ctype.h" 23 24 #define BUFSZ 1024 25 #define READLEN 128 26 27 struct state { 28 u64 done[1024]; 29 size_t done_cnt; 30 }; 31 32 static unsigned int hex(char c) 33 { 34 if (c >= '0' && c <= '9') 35 return c - '0'; 36 if (c >= 'a' && c <= 'f') 37 return c - 'a' + 10; 38 return c - 'A' + 10; 39 } 40 41 static size_t read_objdump_chunk(const char **line, unsigned char **buf, 42 size_t *buf_len) 43 { 44 size_t bytes_read = 0; 45 unsigned char *chunk_start = *buf; 46 47 /* Read bytes */ 48 while (*buf_len > 0) { 49 char c1, c2; 50 51 /* Get 2 hex digits */ 52 c1 = *(*line)++; 53 if (!isxdigit(c1)) 54 break; 55 c2 = *(*line)++; 56 if (!isxdigit(c2)) 57 break; 58 59 /* Store byte and advance buf */ 60 **buf = (hex(c1) << 4) | hex(c2); 61 (*buf)++; 62 (*buf_len)--; 63 bytes_read++; 64 65 /* End of chunk? */ 66 if (isspace(**line)) 67 break; 68 } 69 70 /* 71 * objdump will display raw insn as LE if code endian 72 * is LE and bytes_per_chunk > 1. In that case reverse 73 * the chunk we just read. 74 * 75 * see disassemble_bytes() at binutils/objdump.c for details 76 * how objdump chooses display endian) 77 */ 78 if (bytes_read > 1 && !bigendian()) { 79 unsigned char *chunk_end = chunk_start + bytes_read - 1; 80 unsigned char tmp; 81 82 while (chunk_start < chunk_end) { 83 tmp = *chunk_start; 84 *chunk_start = *chunk_end; 85 *chunk_end = tmp; 86 chunk_start++; 87 chunk_end--; 88 } 89 } 90 91 return bytes_read; 92 } 93 94 static size_t read_objdump_line(const char *line, unsigned char *buf, 95 size_t buf_len) 96 { 97 const char *p; 98 size_t ret, bytes_read = 0; 99 100 /* Skip to a colon */ 101 p = strchr(line, ':'); 102 if (!p) 103 return 0; 104 p++; 105 106 /* Skip initial spaces */ 107 while (*p) { 108 if (!isspace(*p)) 109 break; 110 p++; 111 } 112 113 do { 114 ret = read_objdump_chunk(&p, &buf, &buf_len); 115 bytes_read += ret; 116 p++; 117 } while (ret > 0); 118 119 /* return number of successfully read bytes */ 120 return bytes_read; 121 } 122 123 static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr) 124 { 125 char *line = NULL; 126 size_t line_len, off_last = 0; 127 ssize_t ret; 128 int err = 0; 129 u64 addr, last_addr = start_addr; 130 131 while (off_last < *len) { 132 size_t off, read_bytes, written_bytes; 133 unsigned char tmp[BUFSZ]; 134 135 ret = getline(&line, &line_len, f); 136 if (feof(f)) 137 break; 138 if (ret < 0) { 139 pr_debug("getline failed\n"); 140 err = -1; 141 break; 142 } 143 144 /* read objdump data into temporary buffer */ 145 read_bytes = read_objdump_line(line, tmp, sizeof(tmp)); 146 if (!read_bytes) 147 continue; 148 149 if (sscanf(line, "%"PRIx64, &addr) != 1) 150 continue; 151 if (addr < last_addr) { 152 pr_debug("addr going backwards, read beyond section?\n"); 153 break; 154 } 155 last_addr = addr; 156 157 /* copy it from temporary buffer to 'buf' according 158 * to address on current objdump line */ 159 off = addr - start_addr; 160 if (off >= *len) 161 break; 162 written_bytes = MIN(read_bytes, *len - off); 163 memcpy(buf + off, tmp, written_bytes); 164 off_last = off + written_bytes; 165 } 166 167 /* len returns number of bytes that could not be read */ 168 *len -= off_last; 169 170 free(line); 171 172 return err; 173 } 174 175 static int read_via_objdump(const char *filename, u64 addr, void *buf, 176 size_t len) 177 { 178 char cmd[PATH_MAX * 2]; 179 const char *fmt; 180 FILE *f; 181 int ret; 182 183 fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s"; 184 ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len, 185 filename); 186 if (ret <= 0 || (size_t)ret >= sizeof(cmd)) 187 return -1; 188 189 pr_debug("Objdump command is: %s\n", cmd); 190 191 /* Ignore objdump errors */ 192 strcat(cmd, " 2>/dev/null"); 193 194 f = popen(cmd, "r"); 195 if (!f) { 196 pr_debug("popen failed\n"); 197 return -1; 198 } 199 200 ret = read_objdump_output(f, buf, &len, addr); 201 if (len) { 202 pr_debug("objdump read too few bytes: %zd\n", len); 203 if (!ret) 204 ret = len; 205 } 206 207 pclose(f); 208 209 return ret; 210 } 211 212 static void dump_buf(unsigned char *buf, size_t len) 213 { 214 size_t i; 215 216 for (i = 0; i < len; i++) { 217 pr_debug("0x%02x ", buf[i]); 218 if (i % 16 == 15) 219 pr_debug("\n"); 220 } 221 pr_debug("\n"); 222 } 223 224 static int read_object_code(u64 addr, size_t len, u8 cpumode, 225 struct thread *thread, struct state *state) 226 { 227 struct addr_location al; 228 unsigned char buf1[BUFSZ]; 229 unsigned char buf2[BUFSZ]; 230 size_t ret_len; 231 u64 objdump_addr; 232 const char *objdump_name; 233 char decomp_name[KMOD_DECOMP_LEN]; 234 int ret; 235 236 pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr); 237 238 thread__find_addr_map(thread, cpumode, MAP__FUNCTION, addr, &al); 239 if (!al.map || !al.map->dso) { 240 if (cpumode == PERF_RECORD_MISC_HYPERVISOR) { 241 pr_debug("Hypervisor address can not be resolved - skipping\n"); 242 return 0; 243 } 244 245 pr_debug("thread__find_addr_map failed\n"); 246 return -1; 247 } 248 249 pr_debug("File is: %s\n", al.map->dso->long_name); 250 251 if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS && 252 !dso__is_kcore(al.map->dso)) { 253 pr_debug("Unexpected kernel address - skipping\n"); 254 return 0; 255 } 256 257 pr_debug("On file address is: %#"PRIx64"\n", al.addr); 258 259 if (len > BUFSZ) 260 len = BUFSZ; 261 262 /* Do not go off the map */ 263 if (addr + len > al.map->end) 264 len = al.map->end - addr; 265 266 /* Read the object code using perf */ 267 ret_len = dso__data_read_offset(al.map->dso, thread->mg->machine, 268 al.addr, buf1, len); 269 if (ret_len != len) { 270 pr_debug("dso__data_read_offset failed\n"); 271 return -1; 272 } 273 274 /* 275 * Converting addresses for use by objdump requires more information. 276 * map__load() does that. See map__rip_2objdump() for details. 277 */ 278 if (map__load(al.map)) 279 return -1; 280 281 /* objdump struggles with kcore - try each map only once */ 282 if (dso__is_kcore(al.map->dso)) { 283 size_t d; 284 285 for (d = 0; d < state->done_cnt; d++) { 286 if (state->done[d] == al.map->start) { 287 pr_debug("kcore map tested already"); 288 pr_debug(" - skipping\n"); 289 return 0; 290 } 291 } 292 if (state->done_cnt >= ARRAY_SIZE(state->done)) { 293 pr_debug("Too many kcore maps - skipping\n"); 294 return 0; 295 } 296 state->done[state->done_cnt++] = al.map->start; 297 } 298 299 objdump_name = al.map->dso->long_name; 300 if (dso__needs_decompress(al.map->dso)) { 301 if (dso__decompress_kmodule_path(al.map->dso, objdump_name, 302 decomp_name, 303 sizeof(decomp_name)) < 0) { 304 pr_debug("decompression failed\n"); 305 return -1; 306 } 307 308 objdump_name = decomp_name; 309 } 310 311 /* Read the object code using objdump */ 312 objdump_addr = map__rip_2objdump(al.map, al.addr); 313 ret = read_via_objdump(objdump_name, objdump_addr, buf2, len); 314 315 if (dso__needs_decompress(al.map->dso)) 316 unlink(objdump_name); 317 318 if (ret > 0) { 319 /* 320 * The kernel maps are inaccurate - assume objdump is right in 321 * that case. 322 */ 323 if (cpumode == PERF_RECORD_MISC_KERNEL || 324 cpumode == PERF_RECORD_MISC_GUEST_KERNEL) { 325 len -= ret; 326 if (len) { 327 pr_debug("Reducing len to %zu\n", len); 328 } else if (dso__is_kcore(al.map->dso)) { 329 /* 330 * objdump cannot handle very large segments 331 * that may be found in kcore. 332 */ 333 pr_debug("objdump failed for kcore"); 334 pr_debug(" - skipping\n"); 335 return 0; 336 } else { 337 return -1; 338 } 339 } 340 } 341 if (ret < 0) { 342 pr_debug("read_via_objdump failed\n"); 343 return -1; 344 } 345 346 /* The results should be identical */ 347 if (memcmp(buf1, buf2, len)) { 348 pr_debug("Bytes read differ from those read by objdump\n"); 349 pr_debug("buf1 (dso):\n"); 350 dump_buf(buf1, len); 351 pr_debug("buf2 (objdump):\n"); 352 dump_buf(buf2, len); 353 return -1; 354 } 355 pr_debug("Bytes read match those read by objdump\n"); 356 357 return 0; 358 } 359 360 static int process_sample_event(struct machine *machine, 361 struct perf_evlist *evlist, 362 union perf_event *event, struct state *state) 363 { 364 struct perf_sample sample; 365 struct thread *thread; 366 int ret; 367 368 if (perf_evlist__parse_sample(evlist, event, &sample)) { 369 pr_debug("perf_evlist__parse_sample failed\n"); 370 return -1; 371 } 372 373 thread = machine__findnew_thread(machine, sample.pid, sample.tid); 374 if (!thread) { 375 pr_debug("machine__findnew_thread failed\n"); 376 return -1; 377 } 378 379 ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state); 380 thread__put(thread); 381 return ret; 382 } 383 384 static int process_event(struct machine *machine, struct perf_evlist *evlist, 385 union perf_event *event, struct state *state) 386 { 387 if (event->header.type == PERF_RECORD_SAMPLE) 388 return process_sample_event(machine, evlist, event, state); 389 390 if (event->header.type == PERF_RECORD_THROTTLE || 391 event->header.type == PERF_RECORD_UNTHROTTLE) 392 return 0; 393 394 if (event->header.type < PERF_RECORD_MAX) { 395 int ret; 396 397 ret = machine__process_event(machine, event, NULL); 398 if (ret < 0) 399 pr_debug("machine__process_event failed, event type %u\n", 400 event->header.type); 401 return ret; 402 } 403 404 return 0; 405 } 406 407 static int process_events(struct machine *machine, struct perf_evlist *evlist, 408 struct state *state) 409 { 410 union perf_event *event; 411 int i, ret; 412 413 for (i = 0; i < evlist->nr_mmaps; i++) { 414 while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) { 415 ret = process_event(machine, evlist, event, state); 416 perf_evlist__mmap_consume(evlist, i); 417 if (ret < 0) 418 return ret; 419 } 420 } 421 return 0; 422 } 423 424 static int comp(const void *a, const void *b) 425 { 426 return *(int *)a - *(int *)b; 427 } 428 429 static void do_sort_something(void) 430 { 431 int buf[40960], i; 432 433 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) 434 buf[i] = ARRAY_SIZE(buf) - i - 1; 435 436 qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp); 437 438 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) { 439 if (buf[i] != i) { 440 pr_debug("qsort failed\n"); 441 break; 442 } 443 } 444 } 445 446 static void sort_something(void) 447 { 448 int i; 449 450 for (i = 0; i < 10; i++) 451 do_sort_something(); 452 } 453 454 static void syscall_something(void) 455 { 456 int pipefd[2]; 457 int i; 458 459 for (i = 0; i < 1000; i++) { 460 if (pipe(pipefd) < 0) { 461 pr_debug("pipe failed\n"); 462 break; 463 } 464 close(pipefd[1]); 465 close(pipefd[0]); 466 } 467 } 468 469 static void fs_something(void) 470 { 471 const char *test_file_name = "temp-perf-code-reading-test-file--"; 472 FILE *f; 473 int i; 474 475 for (i = 0; i < 1000; i++) { 476 f = fopen(test_file_name, "w+"); 477 if (f) { 478 fclose(f); 479 unlink(test_file_name); 480 } 481 } 482 } 483 484 static void do_something(void) 485 { 486 fs_something(); 487 488 sort_something(); 489 490 syscall_something(); 491 } 492 493 enum { 494 TEST_CODE_READING_OK, 495 TEST_CODE_READING_NO_VMLINUX, 496 TEST_CODE_READING_NO_KCORE, 497 TEST_CODE_READING_NO_ACCESS, 498 TEST_CODE_READING_NO_KERNEL_OBJ, 499 }; 500 501 static int do_test_code_reading(bool try_kcore) 502 { 503 struct machine *machine; 504 struct thread *thread; 505 struct record_opts opts = { 506 .mmap_pages = UINT_MAX, 507 .user_freq = UINT_MAX, 508 .user_interval = ULLONG_MAX, 509 .freq = 500, 510 .target = { 511 .uses_mmap = true, 512 }, 513 }; 514 struct state state = { 515 .done_cnt = 0, 516 }; 517 struct thread_map *threads = NULL; 518 struct cpu_map *cpus = NULL; 519 struct perf_evlist *evlist = NULL; 520 struct perf_evsel *evsel = NULL; 521 int err = -1, ret; 522 pid_t pid; 523 struct map *map; 524 bool have_vmlinux, have_kcore, excl_kernel = false; 525 526 pid = getpid(); 527 528 machine = machine__new_host(); 529 530 ret = machine__create_kernel_maps(machine); 531 if (ret < 0) { 532 pr_debug("machine__create_kernel_maps failed\n"); 533 goto out_err; 534 } 535 536 /* Force the use of kallsyms instead of vmlinux to try kcore */ 537 if (try_kcore) 538 symbol_conf.kallsyms_name = "/proc/kallsyms"; 539 540 /* Load kernel map */ 541 map = machine__kernel_map(machine); 542 ret = map__load(map); 543 if (ret < 0) { 544 pr_debug("map__load failed\n"); 545 goto out_err; 546 } 547 have_vmlinux = dso__is_vmlinux(map->dso); 548 have_kcore = dso__is_kcore(map->dso); 549 550 /* 2nd time through we just try kcore */ 551 if (try_kcore && !have_kcore) 552 return TEST_CODE_READING_NO_KCORE; 553 554 /* No point getting kernel events if there is no kernel object */ 555 if (!have_vmlinux && !have_kcore) 556 excl_kernel = true; 557 558 threads = thread_map__new_by_tid(pid); 559 if (!threads) { 560 pr_debug("thread_map__new_by_tid failed\n"); 561 goto out_err; 562 } 563 564 ret = perf_event__synthesize_thread_map(NULL, threads, 565 perf_event__process, machine, false, 500); 566 if (ret < 0) { 567 pr_debug("perf_event__synthesize_thread_map failed\n"); 568 goto out_err; 569 } 570 571 thread = machine__findnew_thread(machine, pid, pid); 572 if (!thread) { 573 pr_debug("machine__findnew_thread failed\n"); 574 goto out_put; 575 } 576 577 cpus = cpu_map__new(NULL); 578 if (!cpus) { 579 pr_debug("cpu_map__new failed\n"); 580 goto out_put; 581 } 582 583 while (1) { 584 const char *str; 585 586 evlist = perf_evlist__new(); 587 if (!evlist) { 588 pr_debug("perf_evlist__new failed\n"); 589 goto out_put; 590 } 591 592 perf_evlist__set_maps(evlist, cpus, threads); 593 594 if (excl_kernel) 595 str = "cycles:u"; 596 else 597 str = "cycles"; 598 pr_debug("Parsing event '%s'\n", str); 599 ret = parse_events(evlist, str, NULL); 600 if (ret < 0) { 601 pr_debug("parse_events failed\n"); 602 goto out_put; 603 } 604 605 perf_evlist__config(evlist, &opts, NULL); 606 607 evsel = perf_evlist__first(evlist); 608 609 evsel->attr.comm = 1; 610 evsel->attr.disabled = 1; 611 evsel->attr.enable_on_exec = 0; 612 613 ret = perf_evlist__open(evlist); 614 if (ret < 0) { 615 if (!excl_kernel) { 616 excl_kernel = true; 617 /* 618 * Both cpus and threads are now owned by evlist 619 * and will be freed by following perf_evlist__set_maps 620 * call. Getting refference to keep them alive. 621 */ 622 cpu_map__get(cpus); 623 thread_map__get(threads); 624 perf_evlist__set_maps(evlist, NULL, NULL); 625 perf_evlist__delete(evlist); 626 evlist = NULL; 627 continue; 628 } 629 630 if (verbose > 0) { 631 char errbuf[512]; 632 perf_evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf)); 633 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf); 634 } 635 636 goto out_put; 637 } 638 break; 639 } 640 641 ret = perf_evlist__mmap(evlist, UINT_MAX, false); 642 if (ret < 0) { 643 pr_debug("perf_evlist__mmap failed\n"); 644 goto out_put; 645 } 646 647 perf_evlist__enable(evlist); 648 649 do_something(); 650 651 perf_evlist__disable(evlist); 652 653 ret = process_events(machine, evlist, &state); 654 if (ret < 0) 655 goto out_put; 656 657 if (!have_vmlinux && !have_kcore && !try_kcore) 658 err = TEST_CODE_READING_NO_KERNEL_OBJ; 659 else if (!have_vmlinux && !try_kcore) 660 err = TEST_CODE_READING_NO_VMLINUX; 661 else if (excl_kernel) 662 err = TEST_CODE_READING_NO_ACCESS; 663 else 664 err = TEST_CODE_READING_OK; 665 out_put: 666 thread__put(thread); 667 out_err: 668 669 if (evlist) { 670 perf_evlist__delete(evlist); 671 } else { 672 cpu_map__put(cpus); 673 thread_map__put(threads); 674 } 675 machine__delete_threads(machine); 676 machine__delete(machine); 677 678 return err; 679 } 680 681 int test__code_reading(struct test *test __maybe_unused, int subtest __maybe_unused) 682 { 683 int ret; 684 685 ret = do_test_code_reading(false); 686 if (!ret) 687 ret = do_test_code_reading(true); 688 689 switch (ret) { 690 case TEST_CODE_READING_OK: 691 return 0; 692 case TEST_CODE_READING_NO_VMLINUX: 693 pr_debug("no vmlinux\n"); 694 return 0; 695 case TEST_CODE_READING_NO_KCORE: 696 pr_debug("no kcore\n"); 697 return 0; 698 case TEST_CODE_READING_NO_ACCESS: 699 pr_debug("no access\n"); 700 return 0; 701 case TEST_CODE_READING_NO_KERNEL_OBJ: 702 pr_debug("no kernel obj\n"); 703 return 0; 704 default: 705 return -1; 706 }; 707 } 708