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 #include <perf/cpumap.h> 12 #include <perf/evlist.h> 13 14 #include "debug.h" 15 #include "dso.h" 16 #include "parse-events.h" 17 #include "evlist.h" 18 #include "evsel.h" 19 #include "thread_map.h" 20 #include "cpumap.h" 21 #include "machine.h" 22 #include "map.h" 23 #include "symbol.h" 24 #include "event.h" 25 #include "record.h" 26 #include "thread.h" 27 28 #include "tests.h" 29 30 #include <linux/ctype.h> 31 32 #define BUFSZ 1024 33 #define READLEN 128 34 35 struct state { 36 u64 done[1024]; 37 size_t done_cnt; 38 }; 39 40 static unsigned int hex(char c) 41 { 42 if (c >= '0' && c <= '9') 43 return c - '0'; 44 if (c >= 'a' && c <= 'f') 45 return c - 'a' + 10; 46 return c - 'A' + 10; 47 } 48 49 static size_t read_objdump_chunk(const char **line, unsigned char **buf, 50 size_t *buf_len) 51 { 52 size_t bytes_read = 0; 53 unsigned char *chunk_start = *buf; 54 55 /* Read bytes */ 56 while (*buf_len > 0) { 57 char c1, c2; 58 59 /* Get 2 hex digits */ 60 c1 = *(*line)++; 61 if (!isxdigit(c1)) 62 break; 63 c2 = *(*line)++; 64 if (!isxdigit(c2)) 65 break; 66 67 /* Store byte and advance buf */ 68 **buf = (hex(c1) << 4) | hex(c2); 69 (*buf)++; 70 (*buf_len)--; 71 bytes_read++; 72 73 /* End of chunk? */ 74 if (isspace(**line)) 75 break; 76 } 77 78 /* 79 * objdump will display raw insn as LE if code endian 80 * is LE and bytes_per_chunk > 1. In that case reverse 81 * the chunk we just read. 82 * 83 * see disassemble_bytes() at binutils/objdump.c for details 84 * how objdump chooses display endian) 85 */ 86 if (bytes_read > 1 && !bigendian()) { 87 unsigned char *chunk_end = chunk_start + bytes_read - 1; 88 unsigned char tmp; 89 90 while (chunk_start < chunk_end) { 91 tmp = *chunk_start; 92 *chunk_start = *chunk_end; 93 *chunk_end = tmp; 94 chunk_start++; 95 chunk_end--; 96 } 97 } 98 99 return bytes_read; 100 } 101 102 static size_t read_objdump_line(const char *line, unsigned char *buf, 103 size_t buf_len) 104 { 105 const char *p; 106 size_t ret, bytes_read = 0; 107 108 /* Skip to a colon */ 109 p = strchr(line, ':'); 110 if (!p) 111 return 0; 112 p++; 113 114 /* Skip initial spaces */ 115 while (*p) { 116 if (!isspace(*p)) 117 break; 118 p++; 119 } 120 121 do { 122 ret = read_objdump_chunk(&p, &buf, &buf_len); 123 bytes_read += ret; 124 p++; 125 } while (ret > 0); 126 127 /* return number of successfully read bytes */ 128 return bytes_read; 129 } 130 131 static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr) 132 { 133 char *line = NULL; 134 size_t line_len, off_last = 0; 135 ssize_t ret; 136 int err = 0; 137 u64 addr, last_addr = start_addr; 138 139 while (off_last < *len) { 140 size_t off, read_bytes, written_bytes; 141 unsigned char tmp[BUFSZ]; 142 143 ret = getline(&line, &line_len, f); 144 if (feof(f)) 145 break; 146 if (ret < 0) { 147 pr_debug("getline failed\n"); 148 err = -1; 149 break; 150 } 151 152 /* read objdump data into temporary buffer */ 153 read_bytes = read_objdump_line(line, tmp, sizeof(tmp)); 154 if (!read_bytes) 155 continue; 156 157 if (sscanf(line, "%"PRIx64, &addr) != 1) 158 continue; 159 if (addr < last_addr) { 160 pr_debug("addr going backwards, read beyond section?\n"); 161 break; 162 } 163 last_addr = addr; 164 165 /* copy it from temporary buffer to 'buf' according 166 * to address on current objdump line */ 167 off = addr - start_addr; 168 if (off >= *len) 169 break; 170 written_bytes = MIN(read_bytes, *len - off); 171 memcpy(buf + off, tmp, written_bytes); 172 off_last = off + written_bytes; 173 } 174 175 /* len returns number of bytes that could not be read */ 176 *len -= off_last; 177 178 free(line); 179 180 return err; 181 } 182 183 static int read_via_objdump(const char *filename, u64 addr, void *buf, 184 size_t len) 185 { 186 char cmd[PATH_MAX * 2]; 187 const char *fmt; 188 FILE *f; 189 int ret; 190 191 fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s"; 192 ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len, 193 filename); 194 if (ret <= 0 || (size_t)ret >= sizeof(cmd)) 195 return -1; 196 197 pr_debug("Objdump command is: %s\n", cmd); 198 199 /* Ignore objdump errors */ 200 strcat(cmd, " 2>/dev/null"); 201 202 f = popen(cmd, "r"); 203 if (!f) { 204 pr_debug("popen failed\n"); 205 return -1; 206 } 207 208 ret = read_objdump_output(f, buf, &len, addr); 209 if (len) { 210 pr_debug("objdump read too few bytes: %zd\n", len); 211 if (!ret) 212 ret = len; 213 } 214 215 pclose(f); 216 217 return ret; 218 } 219 220 static void dump_buf(unsigned char *buf, size_t len) 221 { 222 size_t i; 223 224 for (i = 0; i < len; i++) { 225 pr_debug("0x%02x ", buf[i]); 226 if (i % 16 == 15) 227 pr_debug("\n"); 228 } 229 pr_debug("\n"); 230 } 231 232 static int read_object_code(u64 addr, size_t len, u8 cpumode, 233 struct thread *thread, struct state *state) 234 { 235 struct addr_location al; 236 unsigned char buf1[BUFSZ]; 237 unsigned char buf2[BUFSZ]; 238 size_t ret_len; 239 u64 objdump_addr; 240 const char *objdump_name; 241 char decomp_name[KMOD_DECOMP_LEN]; 242 bool decomp = false; 243 int ret; 244 245 pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr); 246 247 if (!thread__find_map(thread, cpumode, addr, &al) || !al.map->dso) { 248 if (cpumode == PERF_RECORD_MISC_HYPERVISOR) { 249 pr_debug("Hypervisor address can not be resolved - skipping\n"); 250 return 0; 251 } 252 253 pr_debug("thread__find_map failed\n"); 254 return -1; 255 } 256 257 pr_debug("File is: %s\n", al.map->dso->long_name); 258 259 if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS && 260 !dso__is_kcore(al.map->dso)) { 261 pr_debug("Unexpected kernel address - skipping\n"); 262 return 0; 263 } 264 265 pr_debug("On file address is: %#"PRIx64"\n", al.addr); 266 267 if (len > BUFSZ) 268 len = BUFSZ; 269 270 /* Do not go off the map */ 271 if (addr + len > al.map->end) 272 len = al.map->end - addr; 273 274 /* Read the object code using perf */ 275 ret_len = dso__data_read_offset(al.map->dso, thread->mg->machine, 276 al.addr, buf1, len); 277 if (ret_len != len) { 278 pr_debug("dso__data_read_offset failed\n"); 279 return -1; 280 } 281 282 /* 283 * Converting addresses for use by objdump requires more information. 284 * map__load() does that. See map__rip_2objdump() for details. 285 */ 286 if (map__load(al.map)) 287 return -1; 288 289 /* objdump struggles with kcore - try each map only once */ 290 if (dso__is_kcore(al.map->dso)) { 291 size_t d; 292 293 for (d = 0; d < state->done_cnt; d++) { 294 if (state->done[d] == al.map->start) { 295 pr_debug("kcore map tested already"); 296 pr_debug(" - skipping\n"); 297 return 0; 298 } 299 } 300 if (state->done_cnt >= ARRAY_SIZE(state->done)) { 301 pr_debug("Too many kcore maps - skipping\n"); 302 return 0; 303 } 304 state->done[state->done_cnt++] = al.map->start; 305 } 306 307 objdump_name = al.map->dso->long_name; 308 if (dso__needs_decompress(al.map->dso)) { 309 if (dso__decompress_kmodule_path(al.map->dso, objdump_name, 310 decomp_name, 311 sizeof(decomp_name)) < 0) { 312 pr_debug("decompression failed\n"); 313 return -1; 314 } 315 316 decomp = true; 317 objdump_name = decomp_name; 318 } 319 320 /* Read the object code using objdump */ 321 objdump_addr = map__rip_2objdump(al.map, al.addr); 322 ret = read_via_objdump(objdump_name, objdump_addr, buf2, len); 323 324 if (decomp) 325 unlink(objdump_name); 326 327 if (ret > 0) { 328 /* 329 * The kernel maps are inaccurate - assume objdump is right in 330 * that case. 331 */ 332 if (cpumode == PERF_RECORD_MISC_KERNEL || 333 cpumode == PERF_RECORD_MISC_GUEST_KERNEL) { 334 len -= ret; 335 if (len) { 336 pr_debug("Reducing len to %zu\n", len); 337 } else if (dso__is_kcore(al.map->dso)) { 338 /* 339 * objdump cannot handle very large segments 340 * that may be found in kcore. 341 */ 342 pr_debug("objdump failed for kcore"); 343 pr_debug(" - skipping\n"); 344 return 0; 345 } else { 346 return -1; 347 } 348 } 349 } 350 if (ret < 0) { 351 pr_debug("read_via_objdump failed\n"); 352 return -1; 353 } 354 355 /* The results should be identical */ 356 if (memcmp(buf1, buf2, len)) { 357 pr_debug("Bytes read differ from those read by objdump\n"); 358 pr_debug("buf1 (dso):\n"); 359 dump_buf(buf1, len); 360 pr_debug("buf2 (objdump):\n"); 361 dump_buf(buf2, len); 362 return -1; 363 } 364 pr_debug("Bytes read match those read by objdump\n"); 365 366 return 0; 367 } 368 369 static int process_sample_event(struct machine *machine, 370 struct evlist *evlist, 371 union perf_event *event, struct state *state) 372 { 373 struct perf_sample sample; 374 struct thread *thread; 375 int ret; 376 377 if (perf_evlist__parse_sample(evlist, event, &sample)) { 378 pr_debug("perf_evlist__parse_sample failed\n"); 379 return -1; 380 } 381 382 thread = machine__findnew_thread(machine, sample.pid, sample.tid); 383 if (!thread) { 384 pr_debug("machine__findnew_thread failed\n"); 385 return -1; 386 } 387 388 ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state); 389 thread__put(thread); 390 return ret; 391 } 392 393 static int process_event(struct machine *machine, struct evlist *evlist, 394 union perf_event *event, struct state *state) 395 { 396 if (event->header.type == PERF_RECORD_SAMPLE) 397 return process_sample_event(machine, evlist, event, state); 398 399 if (event->header.type == PERF_RECORD_THROTTLE || 400 event->header.type == PERF_RECORD_UNTHROTTLE) 401 return 0; 402 403 if (event->header.type < PERF_RECORD_MAX) { 404 int ret; 405 406 ret = machine__process_event(machine, event, NULL); 407 if (ret < 0) 408 pr_debug("machine__process_event failed, event type %u\n", 409 event->header.type); 410 return ret; 411 } 412 413 return 0; 414 } 415 416 static int process_events(struct machine *machine, struct evlist *evlist, 417 struct state *state) 418 { 419 union perf_event *event; 420 struct perf_mmap *md; 421 int i, ret; 422 423 for (i = 0; i < evlist->nr_mmaps; i++) { 424 md = &evlist->mmap[i]; 425 if (perf_mmap__read_init(md) < 0) 426 continue; 427 428 while ((event = perf_mmap__read_event(md)) != NULL) { 429 ret = process_event(machine, evlist, event, state); 430 perf_mmap__consume(md); 431 if (ret < 0) 432 return ret; 433 } 434 perf_mmap__read_done(md); 435 } 436 return 0; 437 } 438 439 static int comp(const void *a, const void *b) 440 { 441 return *(int *)a - *(int *)b; 442 } 443 444 static void do_sort_something(void) 445 { 446 int buf[40960], i; 447 448 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) 449 buf[i] = ARRAY_SIZE(buf) - i - 1; 450 451 qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp); 452 453 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) { 454 if (buf[i] != i) { 455 pr_debug("qsort failed\n"); 456 break; 457 } 458 } 459 } 460 461 static void sort_something(void) 462 { 463 int i; 464 465 for (i = 0; i < 10; i++) 466 do_sort_something(); 467 } 468 469 static void syscall_something(void) 470 { 471 int pipefd[2]; 472 int i; 473 474 for (i = 0; i < 1000; i++) { 475 if (pipe(pipefd) < 0) { 476 pr_debug("pipe failed\n"); 477 break; 478 } 479 close(pipefd[1]); 480 close(pipefd[0]); 481 } 482 } 483 484 static void fs_something(void) 485 { 486 const char *test_file_name = "temp-perf-code-reading-test-file--"; 487 FILE *f; 488 int i; 489 490 for (i = 0; i < 1000; i++) { 491 f = fopen(test_file_name, "w+"); 492 if (f) { 493 fclose(f); 494 unlink(test_file_name); 495 } 496 } 497 } 498 499 static const char *do_determine_event(bool excl_kernel) 500 { 501 const char *event = excl_kernel ? "cycles:u" : "cycles"; 502 503 #ifdef __s390x__ 504 char cpuid[128], model[16], model_c[16], cpum_cf_v[16]; 505 unsigned int family; 506 int ret, cpum_cf_a; 507 508 if (get_cpuid(cpuid, sizeof(cpuid))) 509 goto out_clocks; 510 ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c, 511 model, cpum_cf_v, &cpum_cf_a); 512 if (ret != 5) /* Not available */ 513 goto out_clocks; 514 if (excl_kernel && (cpum_cf_a & 4)) 515 return event; 516 if (!excl_kernel && (cpum_cf_a & 2)) 517 return event; 518 519 /* Fall through: missing authorization */ 520 out_clocks: 521 event = excl_kernel ? "cpu-clock:u" : "cpu-clock"; 522 523 #endif 524 return event; 525 } 526 527 static void do_something(void) 528 { 529 fs_something(); 530 531 sort_something(); 532 533 syscall_something(); 534 } 535 536 enum { 537 TEST_CODE_READING_OK, 538 TEST_CODE_READING_NO_VMLINUX, 539 TEST_CODE_READING_NO_KCORE, 540 TEST_CODE_READING_NO_ACCESS, 541 TEST_CODE_READING_NO_KERNEL_OBJ, 542 }; 543 544 static int do_test_code_reading(bool try_kcore) 545 { 546 struct machine *machine; 547 struct thread *thread; 548 struct record_opts opts = { 549 .mmap_pages = UINT_MAX, 550 .user_freq = UINT_MAX, 551 .user_interval = ULLONG_MAX, 552 .freq = 500, 553 .target = { 554 .uses_mmap = true, 555 }, 556 }; 557 struct state state = { 558 .done_cnt = 0, 559 }; 560 struct perf_thread_map *threads = NULL; 561 struct perf_cpu_map *cpus = NULL; 562 struct evlist *evlist = NULL; 563 struct evsel *evsel = NULL; 564 int err = -1, ret; 565 pid_t pid; 566 struct map *map; 567 bool have_vmlinux, have_kcore, excl_kernel = false; 568 569 pid = getpid(); 570 571 machine = machine__new_host(); 572 machine->env = &perf_env; 573 574 ret = machine__create_kernel_maps(machine); 575 if (ret < 0) { 576 pr_debug("machine__create_kernel_maps failed\n"); 577 goto out_err; 578 } 579 580 /* Force the use of kallsyms instead of vmlinux to try kcore */ 581 if (try_kcore) 582 symbol_conf.kallsyms_name = "/proc/kallsyms"; 583 584 /* Load kernel map */ 585 map = machine__kernel_map(machine); 586 ret = map__load(map); 587 if (ret < 0) { 588 pr_debug("map__load failed\n"); 589 goto out_err; 590 } 591 have_vmlinux = dso__is_vmlinux(map->dso); 592 have_kcore = dso__is_kcore(map->dso); 593 594 /* 2nd time through we just try kcore */ 595 if (try_kcore && !have_kcore) 596 return TEST_CODE_READING_NO_KCORE; 597 598 /* No point getting kernel events if there is no kernel object */ 599 if (!have_vmlinux && !have_kcore) 600 excl_kernel = true; 601 602 threads = thread_map__new_by_tid(pid); 603 if (!threads) { 604 pr_debug("thread_map__new_by_tid failed\n"); 605 goto out_err; 606 } 607 608 ret = perf_event__synthesize_thread_map(NULL, threads, 609 perf_event__process, machine, false); 610 if (ret < 0) { 611 pr_debug("perf_event__synthesize_thread_map failed\n"); 612 goto out_err; 613 } 614 615 thread = machine__findnew_thread(machine, pid, pid); 616 if (!thread) { 617 pr_debug("machine__findnew_thread failed\n"); 618 goto out_put; 619 } 620 621 cpus = perf_cpu_map__new(NULL); 622 if (!cpus) { 623 pr_debug("perf_cpu_map__new failed\n"); 624 goto out_put; 625 } 626 627 while (1) { 628 const char *str; 629 630 evlist = evlist__new(); 631 if (!evlist) { 632 pr_debug("perf_evlist__new failed\n"); 633 goto out_put; 634 } 635 636 perf_evlist__set_maps(&evlist->core, cpus, threads); 637 638 str = do_determine_event(excl_kernel); 639 pr_debug("Parsing event '%s'\n", str); 640 ret = parse_events(evlist, str, NULL); 641 if (ret < 0) { 642 pr_debug("parse_events failed\n"); 643 goto out_put; 644 } 645 646 perf_evlist__config(evlist, &opts, NULL); 647 648 evsel = perf_evlist__first(evlist); 649 650 evsel->core.attr.comm = 1; 651 evsel->core.attr.disabled = 1; 652 evsel->core.attr.enable_on_exec = 0; 653 654 ret = evlist__open(evlist); 655 if (ret < 0) { 656 if (!excl_kernel) { 657 excl_kernel = true; 658 /* 659 * Both cpus and threads are now owned by evlist 660 * and will be freed by following perf_evlist__set_maps 661 * call. Getting refference to keep them alive. 662 */ 663 perf_cpu_map__get(cpus); 664 perf_thread_map__get(threads); 665 perf_evlist__set_maps(&evlist->core, NULL, NULL); 666 evlist__delete(evlist); 667 evlist = NULL; 668 continue; 669 } 670 671 if (verbose > 0) { 672 char errbuf[512]; 673 perf_evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf)); 674 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf); 675 } 676 677 goto out_put; 678 } 679 break; 680 } 681 682 ret = perf_evlist__mmap(evlist, UINT_MAX); 683 if (ret < 0) { 684 pr_debug("perf_evlist__mmap failed\n"); 685 goto out_put; 686 } 687 688 evlist__enable(evlist); 689 690 do_something(); 691 692 evlist__disable(evlist); 693 694 ret = process_events(machine, evlist, &state); 695 if (ret < 0) 696 goto out_put; 697 698 if (!have_vmlinux && !have_kcore && !try_kcore) 699 err = TEST_CODE_READING_NO_KERNEL_OBJ; 700 else if (!have_vmlinux && !try_kcore) 701 err = TEST_CODE_READING_NO_VMLINUX; 702 else if (excl_kernel) 703 err = TEST_CODE_READING_NO_ACCESS; 704 else 705 err = TEST_CODE_READING_OK; 706 out_put: 707 thread__put(thread); 708 out_err: 709 710 if (evlist) { 711 evlist__delete(evlist); 712 } else { 713 perf_cpu_map__put(cpus); 714 perf_thread_map__put(threads); 715 } 716 machine__delete_threads(machine); 717 machine__delete(machine); 718 719 return err; 720 } 721 722 int test__code_reading(struct test *test __maybe_unused, int subtest __maybe_unused) 723 { 724 int ret; 725 726 ret = do_test_code_reading(false); 727 if (!ret) 728 ret = do_test_code_reading(true); 729 730 switch (ret) { 731 case TEST_CODE_READING_OK: 732 return 0; 733 case TEST_CODE_READING_NO_VMLINUX: 734 pr_debug("no vmlinux\n"); 735 return 0; 736 case TEST_CODE_READING_NO_KCORE: 737 pr_debug("no kcore\n"); 738 return 0; 739 case TEST_CODE_READING_NO_ACCESS: 740 pr_debug("no access\n"); 741 return 0; 742 case TEST_CODE_READING_NO_KERNEL_OBJ: 743 pr_debug("no kernel obj\n"); 744 return 0; 745 default: 746 return -1; 747 }; 748 } 749