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 "map.h" 19 #include "symbol.h" 20 #include "event.h" 21 #include "thread.h" 22 23 #include "tests.h" 24 25 #include "sane_ctype.h" 26 27 #define BUFSZ 1024 28 #define READLEN 128 29 30 struct state { 31 u64 done[1024]; 32 size_t done_cnt; 33 }; 34 35 static unsigned int hex(char c) 36 { 37 if (c >= '0' && c <= '9') 38 return c - '0'; 39 if (c >= 'a' && c <= 'f') 40 return c - 'a' + 10; 41 return c - 'A' + 10; 42 } 43 44 static size_t read_objdump_chunk(const char **line, unsigned char **buf, 45 size_t *buf_len) 46 { 47 size_t bytes_read = 0; 48 unsigned char *chunk_start = *buf; 49 50 /* Read bytes */ 51 while (*buf_len > 0) { 52 char c1, c2; 53 54 /* Get 2 hex digits */ 55 c1 = *(*line)++; 56 if (!isxdigit(c1)) 57 break; 58 c2 = *(*line)++; 59 if (!isxdigit(c2)) 60 break; 61 62 /* Store byte and advance buf */ 63 **buf = (hex(c1) << 4) | hex(c2); 64 (*buf)++; 65 (*buf_len)--; 66 bytes_read++; 67 68 /* End of chunk? */ 69 if (isspace(**line)) 70 break; 71 } 72 73 /* 74 * objdump will display raw insn as LE if code endian 75 * is LE and bytes_per_chunk > 1. In that case reverse 76 * the chunk we just read. 77 * 78 * see disassemble_bytes() at binutils/objdump.c for details 79 * how objdump chooses display endian) 80 */ 81 if (bytes_read > 1 && !bigendian()) { 82 unsigned char *chunk_end = chunk_start + bytes_read - 1; 83 unsigned char tmp; 84 85 while (chunk_start < chunk_end) { 86 tmp = *chunk_start; 87 *chunk_start = *chunk_end; 88 *chunk_end = tmp; 89 chunk_start++; 90 chunk_end--; 91 } 92 } 93 94 return bytes_read; 95 } 96 97 static size_t read_objdump_line(const char *line, unsigned char *buf, 98 size_t buf_len) 99 { 100 const char *p; 101 size_t ret, bytes_read = 0; 102 103 /* Skip to a colon */ 104 p = strchr(line, ':'); 105 if (!p) 106 return 0; 107 p++; 108 109 /* Skip initial spaces */ 110 while (*p) { 111 if (!isspace(*p)) 112 break; 113 p++; 114 } 115 116 do { 117 ret = read_objdump_chunk(&p, &buf, &buf_len); 118 bytes_read += ret; 119 p++; 120 } while (ret > 0); 121 122 /* return number of successfully read bytes */ 123 return bytes_read; 124 } 125 126 static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr) 127 { 128 char *line = NULL; 129 size_t line_len, off_last = 0; 130 ssize_t ret; 131 int err = 0; 132 u64 addr, last_addr = start_addr; 133 134 while (off_last < *len) { 135 size_t off, read_bytes, written_bytes; 136 unsigned char tmp[BUFSZ]; 137 138 ret = getline(&line, &line_len, f); 139 if (feof(f)) 140 break; 141 if (ret < 0) { 142 pr_debug("getline failed\n"); 143 err = -1; 144 break; 145 } 146 147 /* read objdump data into temporary buffer */ 148 read_bytes = read_objdump_line(line, tmp, sizeof(tmp)); 149 if (!read_bytes) 150 continue; 151 152 if (sscanf(line, "%"PRIx64, &addr) != 1) 153 continue; 154 if (addr < last_addr) { 155 pr_debug("addr going backwards, read beyond section?\n"); 156 break; 157 } 158 last_addr = addr; 159 160 /* copy it from temporary buffer to 'buf' according 161 * to address on current objdump line */ 162 off = addr - start_addr; 163 if (off >= *len) 164 break; 165 written_bytes = MIN(read_bytes, *len - off); 166 memcpy(buf + off, tmp, written_bytes); 167 off_last = off + written_bytes; 168 } 169 170 /* len returns number of bytes that could not be read */ 171 *len -= off_last; 172 173 free(line); 174 175 return err; 176 } 177 178 static int read_via_objdump(const char *filename, u64 addr, void *buf, 179 size_t len) 180 { 181 char cmd[PATH_MAX * 2]; 182 const char *fmt; 183 FILE *f; 184 int ret; 185 186 fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s"; 187 ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len, 188 filename); 189 if (ret <= 0 || (size_t)ret >= sizeof(cmd)) 190 return -1; 191 192 pr_debug("Objdump command is: %s\n", cmd); 193 194 /* Ignore objdump errors */ 195 strcat(cmd, " 2>/dev/null"); 196 197 f = popen(cmd, "r"); 198 if (!f) { 199 pr_debug("popen failed\n"); 200 return -1; 201 } 202 203 ret = read_objdump_output(f, buf, &len, addr); 204 if (len) { 205 pr_debug("objdump read too few bytes: %zd\n", len); 206 if (!ret) 207 ret = len; 208 } 209 210 pclose(f); 211 212 return ret; 213 } 214 215 static void dump_buf(unsigned char *buf, size_t len) 216 { 217 size_t i; 218 219 for (i = 0; i < len; i++) { 220 pr_debug("0x%02x ", buf[i]); 221 if (i % 16 == 15) 222 pr_debug("\n"); 223 } 224 pr_debug("\n"); 225 } 226 227 static int read_object_code(u64 addr, size_t len, u8 cpumode, 228 struct thread *thread, struct state *state) 229 { 230 struct addr_location al; 231 unsigned char buf1[BUFSZ]; 232 unsigned char buf2[BUFSZ]; 233 size_t ret_len; 234 u64 objdump_addr; 235 const char *objdump_name; 236 char decomp_name[KMOD_DECOMP_LEN]; 237 bool decomp = false; 238 int ret; 239 240 pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr); 241 242 if (!thread__find_map(thread, cpumode, addr, &al) || !al.map->dso) { 243 if (cpumode == PERF_RECORD_MISC_HYPERVISOR) { 244 pr_debug("Hypervisor address can not be resolved - skipping\n"); 245 return 0; 246 } 247 248 pr_debug("thread__find_map failed\n"); 249 return -1; 250 } 251 252 pr_debug("File is: %s\n", al.map->dso->long_name); 253 254 if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS && 255 !dso__is_kcore(al.map->dso)) { 256 pr_debug("Unexpected kernel address - skipping\n"); 257 return 0; 258 } 259 260 pr_debug("On file address is: %#"PRIx64"\n", al.addr); 261 262 if (len > BUFSZ) 263 len = BUFSZ; 264 265 /* Do not go off the map */ 266 if (addr + len > al.map->end) 267 len = al.map->end - addr; 268 269 /* Read the object code using perf */ 270 ret_len = dso__data_read_offset(al.map->dso, thread->mg->machine, 271 al.addr, buf1, len); 272 if (ret_len != len) { 273 pr_debug("dso__data_read_offset failed\n"); 274 return -1; 275 } 276 277 /* 278 * Converting addresses for use by objdump requires more information. 279 * map__load() does that. See map__rip_2objdump() for details. 280 */ 281 if (map__load(al.map)) 282 return -1; 283 284 /* objdump struggles with kcore - try each map only once */ 285 if (dso__is_kcore(al.map->dso)) { 286 size_t d; 287 288 for (d = 0; d < state->done_cnt; d++) { 289 if (state->done[d] == al.map->start) { 290 pr_debug("kcore map tested already"); 291 pr_debug(" - skipping\n"); 292 return 0; 293 } 294 } 295 if (state->done_cnt >= ARRAY_SIZE(state->done)) { 296 pr_debug("Too many kcore maps - skipping\n"); 297 return 0; 298 } 299 state->done[state->done_cnt++] = al.map->start; 300 } 301 302 objdump_name = al.map->dso->long_name; 303 if (dso__needs_decompress(al.map->dso)) { 304 if (dso__decompress_kmodule_path(al.map->dso, objdump_name, 305 decomp_name, 306 sizeof(decomp_name)) < 0) { 307 pr_debug("decompression failed\n"); 308 return -1; 309 } 310 311 decomp = true; 312 objdump_name = decomp_name; 313 } 314 315 /* Read the object code using objdump */ 316 objdump_addr = map__rip_2objdump(al.map, al.addr); 317 ret = read_via_objdump(objdump_name, objdump_addr, buf2, len); 318 319 if (decomp) 320 unlink(objdump_name); 321 322 if (ret > 0) { 323 /* 324 * The kernel maps are inaccurate - assume objdump is right in 325 * that case. 326 */ 327 if (cpumode == PERF_RECORD_MISC_KERNEL || 328 cpumode == PERF_RECORD_MISC_GUEST_KERNEL) { 329 len -= ret; 330 if (len) { 331 pr_debug("Reducing len to %zu\n", len); 332 } else if (dso__is_kcore(al.map->dso)) { 333 /* 334 * objdump cannot handle very large segments 335 * that may be found in kcore. 336 */ 337 pr_debug("objdump failed for kcore"); 338 pr_debug(" - skipping\n"); 339 return 0; 340 } else { 341 return -1; 342 } 343 } 344 } 345 if (ret < 0) { 346 pr_debug("read_via_objdump failed\n"); 347 return -1; 348 } 349 350 /* The results should be identical */ 351 if (memcmp(buf1, buf2, len)) { 352 pr_debug("Bytes read differ from those read by objdump\n"); 353 pr_debug("buf1 (dso):\n"); 354 dump_buf(buf1, len); 355 pr_debug("buf2 (objdump):\n"); 356 dump_buf(buf2, len); 357 return -1; 358 } 359 pr_debug("Bytes read match those read by objdump\n"); 360 361 return 0; 362 } 363 364 static int process_sample_event(struct machine *machine, 365 struct perf_evlist *evlist, 366 union perf_event *event, struct state *state) 367 { 368 struct perf_sample sample; 369 struct thread *thread; 370 int ret; 371 372 if (perf_evlist__parse_sample(evlist, event, &sample)) { 373 pr_debug("perf_evlist__parse_sample failed\n"); 374 return -1; 375 } 376 377 thread = machine__findnew_thread(machine, sample.pid, sample.tid); 378 if (!thread) { 379 pr_debug("machine__findnew_thread failed\n"); 380 return -1; 381 } 382 383 ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state); 384 thread__put(thread); 385 return ret; 386 } 387 388 static int process_event(struct machine *machine, struct perf_evlist *evlist, 389 union perf_event *event, struct state *state) 390 { 391 if (event->header.type == PERF_RECORD_SAMPLE) 392 return process_sample_event(machine, evlist, event, state); 393 394 if (event->header.type == PERF_RECORD_THROTTLE || 395 event->header.type == PERF_RECORD_UNTHROTTLE) 396 return 0; 397 398 if (event->header.type < PERF_RECORD_MAX) { 399 int ret; 400 401 ret = machine__process_event(machine, event, NULL); 402 if (ret < 0) 403 pr_debug("machine__process_event failed, event type %u\n", 404 event->header.type); 405 return ret; 406 } 407 408 return 0; 409 } 410 411 static int process_events(struct machine *machine, struct perf_evlist *evlist, 412 struct state *state) 413 { 414 union perf_event *event; 415 struct perf_mmap *md; 416 int i, ret; 417 418 for (i = 0; i < evlist->nr_mmaps; i++) { 419 md = &evlist->mmap[i]; 420 if (perf_mmap__read_init(md) < 0) 421 continue; 422 423 while ((event = perf_mmap__read_event(md)) != NULL) { 424 ret = process_event(machine, evlist, event, state); 425 perf_mmap__consume(md); 426 if (ret < 0) 427 return ret; 428 } 429 perf_mmap__read_done(md); 430 } 431 return 0; 432 } 433 434 static int comp(const void *a, const void *b) 435 { 436 return *(int *)a - *(int *)b; 437 } 438 439 static void do_sort_something(void) 440 { 441 int buf[40960], i; 442 443 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) 444 buf[i] = ARRAY_SIZE(buf) - i - 1; 445 446 qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp); 447 448 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) { 449 if (buf[i] != i) { 450 pr_debug("qsort failed\n"); 451 break; 452 } 453 } 454 } 455 456 static void sort_something(void) 457 { 458 int i; 459 460 for (i = 0; i < 10; i++) 461 do_sort_something(); 462 } 463 464 static void syscall_something(void) 465 { 466 int pipefd[2]; 467 int i; 468 469 for (i = 0; i < 1000; i++) { 470 if (pipe(pipefd) < 0) { 471 pr_debug("pipe failed\n"); 472 break; 473 } 474 close(pipefd[1]); 475 close(pipefd[0]); 476 } 477 } 478 479 static void fs_something(void) 480 { 481 const char *test_file_name = "temp-perf-code-reading-test-file--"; 482 FILE *f; 483 int i; 484 485 for (i = 0; i < 1000; i++) { 486 f = fopen(test_file_name, "w+"); 487 if (f) { 488 fclose(f); 489 unlink(test_file_name); 490 } 491 } 492 } 493 494 static const char *do_determine_event(bool excl_kernel) 495 { 496 const char *event = excl_kernel ? "cycles:u" : "cycles"; 497 498 #ifdef __s390x__ 499 char cpuid[128], model[16], model_c[16], cpum_cf_v[16]; 500 unsigned int family; 501 int ret, cpum_cf_a; 502 503 if (get_cpuid(cpuid, sizeof(cpuid))) 504 goto out_clocks; 505 ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c, 506 model, cpum_cf_v, &cpum_cf_a); 507 if (ret != 5) /* Not available */ 508 goto out_clocks; 509 if (excl_kernel && (cpum_cf_a & 4)) 510 return event; 511 if (!excl_kernel && (cpum_cf_a & 2)) 512 return event; 513 514 /* Fall through: missing authorization */ 515 out_clocks: 516 event = excl_kernel ? "cpu-clock:u" : "cpu-clock"; 517 518 #endif 519 return event; 520 } 521 522 static void do_something(void) 523 { 524 fs_something(); 525 526 sort_something(); 527 528 syscall_something(); 529 } 530 531 enum { 532 TEST_CODE_READING_OK, 533 TEST_CODE_READING_NO_VMLINUX, 534 TEST_CODE_READING_NO_KCORE, 535 TEST_CODE_READING_NO_ACCESS, 536 TEST_CODE_READING_NO_KERNEL_OBJ, 537 }; 538 539 static int do_test_code_reading(bool try_kcore) 540 { 541 struct machine *machine; 542 struct thread *thread; 543 struct record_opts opts = { 544 .mmap_pages = UINT_MAX, 545 .user_freq = UINT_MAX, 546 .user_interval = ULLONG_MAX, 547 .freq = 500, 548 .target = { 549 .uses_mmap = true, 550 }, 551 }; 552 struct state state = { 553 .done_cnt = 0, 554 }; 555 struct thread_map *threads = NULL; 556 struct cpu_map *cpus = NULL; 557 struct perf_evlist *evlist = NULL; 558 struct perf_evsel *evsel = NULL; 559 int err = -1, ret; 560 pid_t pid; 561 struct map *map; 562 bool have_vmlinux, have_kcore, excl_kernel = false; 563 564 pid = getpid(); 565 566 machine = machine__new_host(); 567 machine->env = &perf_env; 568 569 ret = machine__create_kernel_maps(machine); 570 if (ret < 0) { 571 pr_debug("machine__create_kernel_maps failed\n"); 572 goto out_err; 573 } 574 575 /* Force the use of kallsyms instead of vmlinux to try kcore */ 576 if (try_kcore) 577 symbol_conf.kallsyms_name = "/proc/kallsyms"; 578 579 /* Load kernel map */ 580 map = machine__kernel_map(machine); 581 ret = map__load(map); 582 if (ret < 0) { 583 pr_debug("map__load failed\n"); 584 goto out_err; 585 } 586 have_vmlinux = dso__is_vmlinux(map->dso); 587 have_kcore = dso__is_kcore(map->dso); 588 589 /* 2nd time through we just try kcore */ 590 if (try_kcore && !have_kcore) 591 return TEST_CODE_READING_NO_KCORE; 592 593 /* No point getting kernel events if there is no kernel object */ 594 if (!have_vmlinux && !have_kcore) 595 excl_kernel = true; 596 597 threads = thread_map__new_by_tid(pid); 598 if (!threads) { 599 pr_debug("thread_map__new_by_tid failed\n"); 600 goto out_err; 601 } 602 603 ret = perf_event__synthesize_thread_map(NULL, threads, 604 perf_event__process, machine, false); 605 if (ret < 0) { 606 pr_debug("perf_event__synthesize_thread_map failed\n"); 607 goto out_err; 608 } 609 610 thread = machine__findnew_thread(machine, pid, pid); 611 if (!thread) { 612 pr_debug("machine__findnew_thread failed\n"); 613 goto out_put; 614 } 615 616 cpus = cpu_map__new(NULL); 617 if (!cpus) { 618 pr_debug("cpu_map__new failed\n"); 619 goto out_put; 620 } 621 622 while (1) { 623 const char *str; 624 625 evlist = perf_evlist__new(); 626 if (!evlist) { 627 pr_debug("perf_evlist__new failed\n"); 628 goto out_put; 629 } 630 631 perf_evlist__set_maps(evlist, cpus, threads); 632 633 str = do_determine_event(excl_kernel); 634 pr_debug("Parsing event '%s'\n", str); 635 ret = parse_events(evlist, str, NULL); 636 if (ret < 0) { 637 pr_debug("parse_events failed\n"); 638 goto out_put; 639 } 640 641 perf_evlist__config(evlist, &opts, NULL); 642 643 evsel = perf_evlist__first(evlist); 644 645 evsel->attr.comm = 1; 646 evsel->attr.disabled = 1; 647 evsel->attr.enable_on_exec = 0; 648 649 ret = perf_evlist__open(evlist); 650 if (ret < 0) { 651 if (!excl_kernel) { 652 excl_kernel = true; 653 /* 654 * Both cpus and threads are now owned by evlist 655 * and will be freed by following perf_evlist__set_maps 656 * call. Getting refference to keep them alive. 657 */ 658 cpu_map__get(cpus); 659 thread_map__get(threads); 660 perf_evlist__set_maps(evlist, NULL, NULL); 661 perf_evlist__delete(evlist); 662 evlist = NULL; 663 continue; 664 } 665 666 if (verbose > 0) { 667 char errbuf[512]; 668 perf_evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf)); 669 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf); 670 } 671 672 goto out_put; 673 } 674 break; 675 } 676 677 ret = perf_evlist__mmap(evlist, UINT_MAX); 678 if (ret < 0) { 679 pr_debug("perf_evlist__mmap failed\n"); 680 goto out_put; 681 } 682 683 perf_evlist__enable(evlist); 684 685 do_something(); 686 687 perf_evlist__disable(evlist); 688 689 ret = process_events(machine, evlist, &state); 690 if (ret < 0) 691 goto out_put; 692 693 if (!have_vmlinux && !have_kcore && !try_kcore) 694 err = TEST_CODE_READING_NO_KERNEL_OBJ; 695 else if (!have_vmlinux && !try_kcore) 696 err = TEST_CODE_READING_NO_VMLINUX; 697 else if (excl_kernel) 698 err = TEST_CODE_READING_NO_ACCESS; 699 else 700 err = TEST_CODE_READING_OK; 701 out_put: 702 thread__put(thread); 703 out_err: 704 705 if (evlist) { 706 perf_evlist__delete(evlist); 707 } else { 708 cpu_map__put(cpus); 709 thread_map__put(threads); 710 } 711 machine__delete_threads(machine); 712 machine__delete(machine); 713 714 return err; 715 } 716 717 int test__code_reading(struct test *test __maybe_unused, int subtest __maybe_unused) 718 { 719 int ret; 720 721 ret = do_test_code_reading(false); 722 if (!ret) 723 ret = do_test_code_reading(true); 724 725 switch (ret) { 726 case TEST_CODE_READING_OK: 727 return 0; 728 case TEST_CODE_READING_NO_VMLINUX: 729 pr_debug("no vmlinux\n"); 730 return 0; 731 case TEST_CODE_READING_NO_KCORE: 732 pr_debug("no kcore\n"); 733 return 0; 734 case TEST_CODE_READING_NO_ACCESS: 735 pr_debug("no access\n"); 736 return 0; 737 case TEST_CODE_READING_NO_KERNEL_OBJ: 738 pr_debug("no kernel obj\n"); 739 return 0; 740 default: 741 return -1; 742 }; 743 } 744