1 // SPDX-License-Identifier: GPL-2.0 2 #include <errno.h> 3 #include <linux/kernel.h> 4 #include <linux/types.h> 5 #include <inttypes.h> 6 #include <stdlib.h> 7 #include <unistd.h> 8 #include <stdio.h> 9 #include <string.h> 10 #include <sys/param.h> 11 12 #include "parse-events.h" 13 #include "evlist.h" 14 #include "evsel.h" 15 #include "thread_map.h" 16 #include "cpumap.h" 17 #include "machine.h" 18 #include "event.h" 19 #include "thread.h" 20 21 #include "tests.h" 22 23 #include "sane_ctype.h" 24 25 #define BUFSZ 1024 26 #define READLEN 128 27 28 struct state { 29 u64 done[1024]; 30 size_t done_cnt; 31 }; 32 33 static unsigned int hex(char c) 34 { 35 if (c >= '0' && c <= '9') 36 return c - '0'; 37 if (c >= 'a' && c <= 'f') 38 return c - 'a' + 10; 39 return c - 'A' + 10; 40 } 41 42 static size_t read_objdump_chunk(const char **line, unsigned char **buf, 43 size_t *buf_len) 44 { 45 size_t bytes_read = 0; 46 unsigned char *chunk_start = *buf; 47 48 /* Read bytes */ 49 while (*buf_len > 0) { 50 char c1, c2; 51 52 /* Get 2 hex digits */ 53 c1 = *(*line)++; 54 if (!isxdigit(c1)) 55 break; 56 c2 = *(*line)++; 57 if (!isxdigit(c2)) 58 break; 59 60 /* Store byte and advance buf */ 61 **buf = (hex(c1) << 4) | hex(c2); 62 (*buf)++; 63 (*buf_len)--; 64 bytes_read++; 65 66 /* End of chunk? */ 67 if (isspace(**line)) 68 break; 69 } 70 71 /* 72 * objdump will display raw insn as LE if code endian 73 * is LE and bytes_per_chunk > 1. In that case reverse 74 * the chunk we just read. 75 * 76 * see disassemble_bytes() at binutils/objdump.c for details 77 * how objdump chooses display endian) 78 */ 79 if (bytes_read > 1 && !bigendian()) { 80 unsigned char *chunk_end = chunk_start + bytes_read - 1; 81 unsigned char tmp; 82 83 while (chunk_start < chunk_end) { 84 tmp = *chunk_start; 85 *chunk_start = *chunk_end; 86 *chunk_end = tmp; 87 chunk_start++; 88 chunk_end--; 89 } 90 } 91 92 return bytes_read; 93 } 94 95 static size_t read_objdump_line(const char *line, unsigned char *buf, 96 size_t buf_len) 97 { 98 const char *p; 99 size_t ret, bytes_read = 0; 100 101 /* Skip to a colon */ 102 p = strchr(line, ':'); 103 if (!p) 104 return 0; 105 p++; 106 107 /* Skip initial spaces */ 108 while (*p) { 109 if (!isspace(*p)) 110 break; 111 p++; 112 } 113 114 do { 115 ret = read_objdump_chunk(&p, &buf, &buf_len); 116 bytes_read += ret; 117 p++; 118 } while (ret > 0); 119 120 /* return number of successfully read bytes */ 121 return bytes_read; 122 } 123 124 static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr) 125 { 126 char *line = NULL; 127 size_t line_len, off_last = 0; 128 ssize_t ret; 129 int err = 0; 130 u64 addr, last_addr = start_addr; 131 132 while (off_last < *len) { 133 size_t off, read_bytes, written_bytes; 134 unsigned char tmp[BUFSZ]; 135 136 ret = getline(&line, &line_len, f); 137 if (feof(f)) 138 break; 139 if (ret < 0) { 140 pr_debug("getline failed\n"); 141 err = -1; 142 break; 143 } 144 145 /* read objdump data into temporary buffer */ 146 read_bytes = read_objdump_line(line, tmp, sizeof(tmp)); 147 if (!read_bytes) 148 continue; 149 150 if (sscanf(line, "%"PRIx64, &addr) != 1) 151 continue; 152 if (addr < last_addr) { 153 pr_debug("addr going backwards, read beyond section?\n"); 154 break; 155 } 156 last_addr = addr; 157 158 /* copy it from temporary buffer to 'buf' according 159 * to address on current objdump line */ 160 off = addr - start_addr; 161 if (off >= *len) 162 break; 163 written_bytes = MIN(read_bytes, *len - off); 164 memcpy(buf + off, tmp, written_bytes); 165 off_last = off + written_bytes; 166 } 167 168 /* len returns number of bytes that could not be read */ 169 *len -= off_last; 170 171 free(line); 172 173 return err; 174 } 175 176 static int read_via_objdump(const char *filename, u64 addr, void *buf, 177 size_t len) 178 { 179 char cmd[PATH_MAX * 2]; 180 const char *fmt; 181 FILE *f; 182 int ret; 183 184 fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s"; 185 ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len, 186 filename); 187 if (ret <= 0 || (size_t)ret >= sizeof(cmd)) 188 return -1; 189 190 pr_debug("Objdump command is: %s\n", cmd); 191 192 /* Ignore objdump errors */ 193 strcat(cmd, " 2>/dev/null"); 194 195 f = popen(cmd, "r"); 196 if (!f) { 197 pr_debug("popen failed\n"); 198 return -1; 199 } 200 201 ret = read_objdump_output(f, buf, &len, addr); 202 if (len) { 203 pr_debug("objdump read too few bytes: %zd\n", len); 204 if (!ret) 205 ret = len; 206 } 207 208 pclose(f); 209 210 return ret; 211 } 212 213 static void dump_buf(unsigned char *buf, size_t len) 214 { 215 size_t i; 216 217 for (i = 0; i < len; i++) { 218 pr_debug("0x%02x ", buf[i]); 219 if (i % 16 == 15) 220 pr_debug("\n"); 221 } 222 pr_debug("\n"); 223 } 224 225 static int read_object_code(u64 addr, size_t len, u8 cpumode, 226 struct thread *thread, struct state *state) 227 { 228 struct addr_location al; 229 unsigned char buf1[BUFSZ]; 230 unsigned char buf2[BUFSZ]; 231 size_t ret_len; 232 u64 objdump_addr; 233 const char *objdump_name; 234 char decomp_name[KMOD_DECOMP_LEN]; 235 int ret; 236 237 pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr); 238 239 thread__find_addr_map(thread, cpumode, MAP__FUNCTION, addr, &al); 240 if (!al.map || !al.map->dso) { 241 if (cpumode == PERF_RECORD_MISC_HYPERVISOR) { 242 pr_debug("Hypervisor address can not be resolved - skipping\n"); 243 return 0; 244 } 245 246 pr_debug("thread__find_addr_map failed\n"); 247 return -1; 248 } 249 250 pr_debug("File is: %s\n", al.map->dso->long_name); 251 252 if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS && 253 !dso__is_kcore(al.map->dso)) { 254 pr_debug("Unexpected kernel address - skipping\n"); 255 return 0; 256 } 257 258 pr_debug("On file address is: %#"PRIx64"\n", al.addr); 259 260 if (len > BUFSZ) 261 len = BUFSZ; 262 263 /* Do not go off the map */ 264 if (addr + len > al.map->end) 265 len = al.map->end - addr; 266 267 /* Read the object code using perf */ 268 ret_len = dso__data_read_offset(al.map->dso, thread->mg->machine, 269 al.addr, buf1, len); 270 if (ret_len != len) { 271 pr_debug("dso__data_read_offset failed\n"); 272 return -1; 273 } 274 275 /* 276 * Converting addresses for use by objdump requires more information. 277 * map__load() does that. See map__rip_2objdump() for details. 278 */ 279 if (map__load(al.map)) 280 return -1; 281 282 /* objdump struggles with kcore - try each map only once */ 283 if (dso__is_kcore(al.map->dso)) { 284 size_t d; 285 286 for (d = 0; d < state->done_cnt; d++) { 287 if (state->done[d] == al.map->start) { 288 pr_debug("kcore map tested already"); 289 pr_debug(" - skipping\n"); 290 return 0; 291 } 292 } 293 if (state->done_cnt >= ARRAY_SIZE(state->done)) { 294 pr_debug("Too many kcore maps - skipping\n"); 295 return 0; 296 } 297 state->done[state->done_cnt++] = al.map->start; 298 } 299 300 objdump_name = al.map->dso->long_name; 301 if (dso__needs_decompress(al.map->dso)) { 302 if (dso__decompress_kmodule_path(al.map->dso, objdump_name, 303 decomp_name, 304 sizeof(decomp_name)) < 0) { 305 pr_debug("decompression failed\n"); 306 return -1; 307 } 308 309 objdump_name = decomp_name; 310 } 311 312 /* Read the object code using objdump */ 313 objdump_addr = map__rip_2objdump(al.map, al.addr); 314 ret = read_via_objdump(objdump_name, objdump_addr, buf2, len); 315 316 if (dso__needs_decompress(al.map->dso)) 317 unlink(objdump_name); 318 319 if (ret > 0) { 320 /* 321 * The kernel maps are inaccurate - assume objdump is right in 322 * that case. 323 */ 324 if (cpumode == PERF_RECORD_MISC_KERNEL || 325 cpumode == PERF_RECORD_MISC_GUEST_KERNEL) { 326 len -= ret; 327 if (len) { 328 pr_debug("Reducing len to %zu\n", len); 329 } else if (dso__is_kcore(al.map->dso)) { 330 /* 331 * objdump cannot handle very large segments 332 * that may be found in kcore. 333 */ 334 pr_debug("objdump failed for kcore"); 335 pr_debug(" - skipping\n"); 336 return 0; 337 } else { 338 return -1; 339 } 340 } 341 } 342 if (ret < 0) { 343 pr_debug("read_via_objdump failed\n"); 344 return -1; 345 } 346 347 /* The results should be identical */ 348 if (memcmp(buf1, buf2, len)) { 349 pr_debug("Bytes read differ from those read by objdump\n"); 350 pr_debug("buf1 (dso):\n"); 351 dump_buf(buf1, len); 352 pr_debug("buf2 (objdump):\n"); 353 dump_buf(buf2, len); 354 return -1; 355 } 356 pr_debug("Bytes read match those read by objdump\n"); 357 358 return 0; 359 } 360 361 static int process_sample_event(struct machine *machine, 362 struct perf_evlist *evlist, 363 union perf_event *event, struct state *state) 364 { 365 struct perf_sample sample; 366 struct thread *thread; 367 int ret; 368 369 if (perf_evlist__parse_sample(evlist, event, &sample)) { 370 pr_debug("perf_evlist__parse_sample failed\n"); 371 return -1; 372 } 373 374 thread = machine__findnew_thread(machine, sample.pid, sample.tid); 375 if (!thread) { 376 pr_debug("machine__findnew_thread failed\n"); 377 return -1; 378 } 379 380 ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state); 381 thread__put(thread); 382 return ret; 383 } 384 385 static int process_event(struct machine *machine, struct perf_evlist *evlist, 386 union perf_event *event, struct state *state) 387 { 388 if (event->header.type == PERF_RECORD_SAMPLE) 389 return process_sample_event(machine, evlist, event, state); 390 391 if (event->header.type == PERF_RECORD_THROTTLE || 392 event->header.type == PERF_RECORD_UNTHROTTLE) 393 return 0; 394 395 if (event->header.type < PERF_RECORD_MAX) { 396 int ret; 397 398 ret = machine__process_event(machine, event, NULL); 399 if (ret < 0) 400 pr_debug("machine__process_event failed, event type %u\n", 401 event->header.type); 402 return ret; 403 } 404 405 return 0; 406 } 407 408 static int process_events(struct machine *machine, struct perf_evlist *evlist, 409 struct state *state) 410 { 411 union perf_event *event; 412 int i, ret; 413 414 for (i = 0; i < evlist->nr_mmaps; i++) { 415 while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) { 416 ret = process_event(machine, evlist, event, state); 417 perf_evlist__mmap_consume(evlist, i); 418 if (ret < 0) 419 return ret; 420 } 421 } 422 return 0; 423 } 424 425 static int comp(const void *a, const void *b) 426 { 427 return *(int *)a - *(int *)b; 428 } 429 430 static void do_sort_something(void) 431 { 432 int buf[40960], i; 433 434 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) 435 buf[i] = ARRAY_SIZE(buf) - i - 1; 436 437 qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp); 438 439 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) { 440 if (buf[i] != i) { 441 pr_debug("qsort failed\n"); 442 break; 443 } 444 } 445 } 446 447 static void sort_something(void) 448 { 449 int i; 450 451 for (i = 0; i < 10; i++) 452 do_sort_something(); 453 } 454 455 static void syscall_something(void) 456 { 457 int pipefd[2]; 458 int i; 459 460 for (i = 0; i < 1000; i++) { 461 if (pipe(pipefd) < 0) { 462 pr_debug("pipe failed\n"); 463 break; 464 } 465 close(pipefd[1]); 466 close(pipefd[0]); 467 } 468 } 469 470 static void fs_something(void) 471 { 472 const char *test_file_name = "temp-perf-code-reading-test-file--"; 473 FILE *f; 474 int i; 475 476 for (i = 0; i < 1000; i++) { 477 f = fopen(test_file_name, "w+"); 478 if (f) { 479 fclose(f); 480 unlink(test_file_name); 481 } 482 } 483 } 484 485 static void do_something(void) 486 { 487 fs_something(); 488 489 sort_something(); 490 491 syscall_something(); 492 } 493 494 enum { 495 TEST_CODE_READING_OK, 496 TEST_CODE_READING_NO_VMLINUX, 497 TEST_CODE_READING_NO_KCORE, 498 TEST_CODE_READING_NO_ACCESS, 499 TEST_CODE_READING_NO_KERNEL_OBJ, 500 }; 501 502 static int do_test_code_reading(bool try_kcore) 503 { 504 struct machine *machine; 505 struct thread *thread; 506 struct record_opts opts = { 507 .mmap_pages = UINT_MAX, 508 .user_freq = UINT_MAX, 509 .user_interval = ULLONG_MAX, 510 .freq = 500, 511 .target = { 512 .uses_mmap = true, 513 }, 514 }; 515 struct state state = { 516 .done_cnt = 0, 517 }; 518 struct thread_map *threads = NULL; 519 struct cpu_map *cpus = NULL; 520 struct perf_evlist *evlist = NULL; 521 struct perf_evsel *evsel = NULL; 522 int err = -1, ret; 523 pid_t pid; 524 struct map *map; 525 bool have_vmlinux, have_kcore, excl_kernel = false; 526 527 pid = getpid(); 528 529 machine = machine__new_host(); 530 531 ret = machine__create_kernel_maps(machine); 532 if (ret < 0) { 533 pr_debug("machine__create_kernel_maps failed\n"); 534 goto out_err; 535 } 536 537 /* Force the use of kallsyms instead of vmlinux to try kcore */ 538 if (try_kcore) 539 symbol_conf.kallsyms_name = "/proc/kallsyms"; 540 541 /* Load kernel map */ 542 map = machine__kernel_map(machine); 543 ret = map__load(map); 544 if (ret < 0) { 545 pr_debug("map__load failed\n"); 546 goto out_err; 547 } 548 have_vmlinux = dso__is_vmlinux(map->dso); 549 have_kcore = dso__is_kcore(map->dso); 550 551 /* 2nd time through we just try kcore */ 552 if (try_kcore && !have_kcore) 553 return TEST_CODE_READING_NO_KCORE; 554 555 /* No point getting kernel events if there is no kernel object */ 556 if (!have_vmlinux && !have_kcore) 557 excl_kernel = true; 558 559 threads = thread_map__new_by_tid(pid); 560 if (!threads) { 561 pr_debug("thread_map__new_by_tid failed\n"); 562 goto out_err; 563 } 564 565 ret = perf_event__synthesize_thread_map(NULL, threads, 566 perf_event__process, machine, false, 500); 567 if (ret < 0) { 568 pr_debug("perf_event__synthesize_thread_map failed\n"); 569 goto out_err; 570 } 571 572 thread = machine__findnew_thread(machine, pid, pid); 573 if (!thread) { 574 pr_debug("machine__findnew_thread failed\n"); 575 goto out_put; 576 } 577 578 cpus = cpu_map__new(NULL); 579 if (!cpus) { 580 pr_debug("cpu_map__new failed\n"); 581 goto out_put; 582 } 583 584 while (1) { 585 const char *str; 586 587 evlist = perf_evlist__new(); 588 if (!evlist) { 589 pr_debug("perf_evlist__new failed\n"); 590 goto out_put; 591 } 592 593 perf_evlist__set_maps(evlist, cpus, threads); 594 595 if (excl_kernel) 596 str = "cycles:u"; 597 else 598 str = "cycles"; 599 pr_debug("Parsing event '%s'\n", str); 600 ret = parse_events(evlist, str, NULL); 601 if (ret < 0) { 602 pr_debug("parse_events failed\n"); 603 goto out_put; 604 } 605 606 perf_evlist__config(evlist, &opts, NULL); 607 608 evsel = perf_evlist__first(evlist); 609 610 evsel->attr.comm = 1; 611 evsel->attr.disabled = 1; 612 evsel->attr.enable_on_exec = 0; 613 614 ret = perf_evlist__open(evlist); 615 if (ret < 0) { 616 if (!excl_kernel) { 617 excl_kernel = true; 618 /* 619 * Both cpus and threads are now owned by evlist 620 * and will be freed by following perf_evlist__set_maps 621 * call. Getting refference to keep them alive. 622 */ 623 cpu_map__get(cpus); 624 thread_map__get(threads); 625 perf_evlist__set_maps(evlist, NULL, NULL); 626 perf_evlist__delete(evlist); 627 evlist = NULL; 628 continue; 629 } 630 631 if (verbose > 0) { 632 char errbuf[512]; 633 perf_evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf)); 634 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf); 635 } 636 637 goto out_put; 638 } 639 break; 640 } 641 642 ret = perf_evlist__mmap(evlist, UINT_MAX); 643 if (ret < 0) { 644 pr_debug("perf_evlist__mmap failed\n"); 645 goto out_put; 646 } 647 648 perf_evlist__enable(evlist); 649 650 do_something(); 651 652 perf_evlist__disable(evlist); 653 654 ret = process_events(machine, evlist, &state); 655 if (ret < 0) 656 goto out_put; 657 658 if (!have_vmlinux && !have_kcore && !try_kcore) 659 err = TEST_CODE_READING_NO_KERNEL_OBJ; 660 else if (!have_vmlinux && !try_kcore) 661 err = TEST_CODE_READING_NO_VMLINUX; 662 else if (excl_kernel) 663 err = TEST_CODE_READING_NO_ACCESS; 664 else 665 err = TEST_CODE_READING_OK; 666 out_put: 667 thread__put(thread); 668 out_err: 669 670 if (evlist) { 671 perf_evlist__delete(evlist); 672 } else { 673 cpu_map__put(cpus); 674 thread_map__put(threads); 675 } 676 machine__delete_threads(machine); 677 machine__delete(machine); 678 679 return err; 680 } 681 682 int test__code_reading(struct test *test __maybe_unused, int subtest __maybe_unused) 683 { 684 int ret; 685 686 ret = do_test_code_reading(false); 687 if (!ret) 688 ret = do_test_code_reading(true); 689 690 switch (ret) { 691 case TEST_CODE_READING_OK: 692 return 0; 693 case TEST_CODE_READING_NO_VMLINUX: 694 pr_debug("no vmlinux\n"); 695 return 0; 696 case TEST_CODE_READING_NO_KCORE: 697 pr_debug("no kcore\n"); 698 return 0; 699 case TEST_CODE_READING_NO_ACCESS: 700 pr_debug("no access\n"); 701 return 0; 702 case TEST_CODE_READING_NO_KERNEL_OBJ: 703 pr_debug("no kernel obj\n"); 704 return 0; 705 default: 706 return -1; 707 }; 708 } 709