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 #include <perf/mmap.h> 14 15 #include "debug.h" 16 #include "dso.h" 17 #include "env.h" 18 #include "parse-events.h" 19 #include "evlist.h" 20 #include "evsel.h" 21 #include "thread_map.h" 22 #include "machine.h" 23 #include "map.h" 24 #include "symbol.h" 25 #include "event.h" 26 #include "record.h" 27 #include "util/mmap.h" 28 #include "util/string2.h" 29 #include "util/synthetic-events.h" 30 #include "util/util.h" 31 #include "thread.h" 32 33 #include "tests.h" 34 35 #include <linux/ctype.h> 36 37 #define BUFSZ 1024 38 #define READLEN 128 39 40 struct state { 41 u64 done[1024]; 42 size_t done_cnt; 43 }; 44 45 static size_t read_objdump_chunk(const char **line, unsigned char **buf, 46 size_t *buf_len) 47 { 48 size_t bytes_read = 0; 49 unsigned char *chunk_start = *buf; 50 51 /* Read bytes */ 52 while (*buf_len > 0) { 53 char c1, c2; 54 55 /* Get 2 hex digits */ 56 c1 = *(*line)++; 57 if (!isxdigit(c1)) 58 break; 59 c2 = *(*line)++; 60 if (!isxdigit(c2)) 61 break; 62 63 /* Store byte and advance buf */ 64 **buf = (hex(c1) << 4) | hex(c2); 65 (*buf)++; 66 (*buf_len)--; 67 bytes_read++; 68 69 /* End of chunk? */ 70 if (isspace(**line)) 71 break; 72 } 73 74 /* 75 * objdump will display raw insn as LE if code endian 76 * is LE and bytes_per_chunk > 1. In that case reverse 77 * the chunk we just read. 78 * 79 * see disassemble_bytes() at binutils/objdump.c for details 80 * how objdump chooses display endian) 81 */ 82 if (bytes_read > 1 && !host_is_bigendian()) { 83 unsigned char *chunk_end = chunk_start + bytes_read - 1; 84 unsigned char tmp; 85 86 while (chunk_start < chunk_end) { 87 tmp = *chunk_start; 88 *chunk_start = *chunk_end; 89 *chunk_end = tmp; 90 chunk_start++; 91 chunk_end--; 92 } 93 } 94 95 return bytes_read; 96 } 97 98 static size_t read_objdump_line(const char *line, unsigned char *buf, 99 size_t buf_len) 100 { 101 const char *p; 102 size_t ret, bytes_read = 0; 103 104 /* Skip to a colon */ 105 p = strchr(line, ':'); 106 if (!p) 107 return 0; 108 p++; 109 110 /* Skip initial spaces */ 111 while (*p) { 112 if (!isspace(*p)) 113 break; 114 p++; 115 } 116 117 do { 118 ret = read_objdump_chunk(&p, &buf, &buf_len); 119 bytes_read += ret; 120 p++; 121 } while (ret > 0); 122 123 /* return number of successfully read bytes */ 124 return bytes_read; 125 } 126 127 static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr) 128 { 129 char *line = NULL; 130 size_t line_len, off_last = 0; 131 ssize_t ret; 132 int err = 0; 133 u64 addr, last_addr = start_addr; 134 135 while (off_last < *len) { 136 size_t off, read_bytes, written_bytes; 137 unsigned char tmp[BUFSZ]; 138 139 ret = getline(&line, &line_len, f); 140 if (feof(f)) 141 break; 142 if (ret < 0) { 143 pr_debug("getline failed\n"); 144 err = -1; 145 break; 146 } 147 148 /* read objdump data into temporary buffer */ 149 read_bytes = read_objdump_line(line, tmp, sizeof(tmp)); 150 if (!read_bytes) 151 continue; 152 153 if (sscanf(line, "%"PRIx64, &addr) != 1) 154 continue; 155 if (addr < last_addr) { 156 pr_debug("addr going backwards, read beyond section?\n"); 157 break; 158 } 159 last_addr = addr; 160 161 /* copy it from temporary buffer to 'buf' according 162 * to address on current objdump line */ 163 off = addr - start_addr; 164 if (off >= *len) 165 break; 166 written_bytes = MIN(read_bytes, *len - off); 167 memcpy(buf + off, tmp, written_bytes); 168 off_last = off + written_bytes; 169 } 170 171 /* len returns number of bytes that could not be read */ 172 *len -= off_last; 173 174 free(line); 175 176 return err; 177 } 178 179 static int read_via_objdump(const char *filename, u64 addr, void *buf, 180 size_t len) 181 { 182 char cmd[PATH_MAX * 2]; 183 const char *fmt; 184 FILE *f; 185 int ret; 186 187 fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s"; 188 ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len, 189 filename); 190 if (ret <= 0 || (size_t)ret >= sizeof(cmd)) 191 return -1; 192 193 pr_debug("Objdump command is: %s\n", cmd); 194 195 /* Ignore objdump errors */ 196 strcat(cmd, " 2>/dev/null"); 197 198 f = popen(cmd, "r"); 199 if (!f) { 200 pr_debug("popen failed\n"); 201 return -1; 202 } 203 204 ret = read_objdump_output(f, buf, &len, addr); 205 if (len) { 206 pr_debug("objdump read too few bytes: %zd\n", len); 207 if (!ret) 208 ret = len; 209 } 210 211 pclose(f); 212 213 return ret; 214 } 215 216 static void dump_buf(unsigned char *buf, size_t len) 217 { 218 size_t i; 219 220 for (i = 0; i < len; i++) { 221 pr_debug("0x%02x ", buf[i]); 222 if (i % 16 == 15) 223 pr_debug("\n"); 224 } 225 pr_debug("\n"); 226 } 227 228 static int read_object_code(u64 addr, size_t len, u8 cpumode, 229 struct thread *thread, struct state *state) 230 { 231 struct addr_location al; 232 unsigned char buf1[BUFSZ] = {0}; 233 unsigned char buf2[BUFSZ] = {0}; 234 size_t ret_len; 235 u64 objdump_addr; 236 const char *objdump_name; 237 char decomp_name[KMOD_DECOMP_LEN]; 238 bool decomp = false; 239 int ret, err = 0; 240 struct dso *dso; 241 242 pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr); 243 244 addr_location__init(&al); 245 if (!thread__find_map(thread, cpumode, addr, &al) || !map__dso(al.map)) { 246 if (cpumode == PERF_RECORD_MISC_HYPERVISOR) { 247 pr_debug("Hypervisor address can not be resolved - skipping\n"); 248 goto out; 249 } 250 251 pr_debug("thread__find_map failed\n"); 252 err = -1; 253 goto out; 254 } 255 dso = map__dso(al.map); 256 pr_debug("File is: %s\n", dso->long_name); 257 258 if (dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS && !dso__is_kcore(dso)) { 259 pr_debug("Unexpected kernel address - skipping\n"); 260 goto out; 261 } 262 263 pr_debug("On file address is: %#"PRIx64"\n", al.addr); 264 265 if (len > BUFSZ) 266 len = BUFSZ; 267 268 /* Do not go off the map */ 269 if (addr + len > map__end(al.map)) 270 len = map__end(al.map) - addr; 271 272 /* Read the object code using perf */ 273 ret_len = dso__data_read_offset(dso, maps__machine(thread__maps(thread)), 274 al.addr, buf1, len); 275 if (ret_len != len) { 276 pr_debug("dso__data_read_offset failed\n"); 277 err = -1; 278 goto out; 279 } 280 281 /* 282 * Converting addresses for use by objdump requires more information. 283 * map__load() does that. See map__rip_2objdump() for details. 284 */ 285 if (map__load(al.map)) { 286 err = -1; 287 goto out; 288 } 289 290 /* objdump struggles with kcore - try each map only once */ 291 if (dso__is_kcore(dso)) { 292 size_t d; 293 294 for (d = 0; d < state->done_cnt; d++) { 295 if (state->done[d] == map__start(al.map)) { 296 pr_debug("kcore map tested already"); 297 pr_debug(" - skipping\n"); 298 goto out; 299 } 300 } 301 if (state->done_cnt >= ARRAY_SIZE(state->done)) { 302 pr_debug("Too many kcore maps - skipping\n"); 303 goto out; 304 } 305 state->done[state->done_cnt++] = map__start(al.map); 306 } 307 308 objdump_name = dso->long_name; 309 if (dso__needs_decompress(dso)) { 310 if (dso__decompress_kmodule_path(dso, objdump_name, 311 decomp_name, 312 sizeof(decomp_name)) < 0) { 313 pr_debug("decompression failed\n"); 314 err = -1; 315 goto out; 316 } 317 318 decomp = true; 319 objdump_name = decomp_name; 320 } 321 322 /* Read the object code using objdump */ 323 objdump_addr = map__rip_2objdump(al.map, al.addr); 324 ret = read_via_objdump(objdump_name, objdump_addr, buf2, len); 325 326 if (decomp) 327 unlink(objdump_name); 328 329 if (ret > 0) { 330 /* 331 * The kernel maps are inaccurate - assume objdump is right in 332 * that case. 333 */ 334 if (cpumode == PERF_RECORD_MISC_KERNEL || 335 cpumode == PERF_RECORD_MISC_GUEST_KERNEL) { 336 len -= ret; 337 if (len) { 338 pr_debug("Reducing len to %zu\n", len); 339 } else if (dso__is_kcore(dso)) { 340 /* 341 * objdump cannot handle very large segments 342 * that may be found in kcore. 343 */ 344 pr_debug("objdump failed for kcore"); 345 pr_debug(" - skipping\n"); 346 } else { 347 err = -1; 348 } 349 goto out; 350 } 351 } 352 if (ret < 0) { 353 pr_debug("read_via_objdump failed\n"); 354 err = -1; 355 goto out; 356 } 357 358 /* The results should be identical */ 359 if (memcmp(buf1, buf2, len)) { 360 pr_debug("Bytes read differ from those read by objdump\n"); 361 pr_debug("buf1 (dso):\n"); 362 dump_buf(buf1, len); 363 pr_debug("buf2 (objdump):\n"); 364 dump_buf(buf2, len); 365 err = -1; 366 goto out; 367 } 368 pr_debug("Bytes read match those read by objdump\n"); 369 out: 370 addr_location__exit(&al); 371 return err; 372 } 373 374 static int process_sample_event(struct machine *machine, 375 struct evlist *evlist, 376 union perf_event *event, struct state *state) 377 { 378 struct perf_sample sample; 379 struct thread *thread; 380 int ret; 381 382 if (evlist__parse_sample(evlist, event, &sample)) { 383 pr_debug("evlist__parse_sample failed\n"); 384 return -1; 385 } 386 387 thread = machine__findnew_thread(machine, sample.pid, sample.tid); 388 if (!thread) { 389 pr_debug("machine__findnew_thread failed\n"); 390 return -1; 391 } 392 393 ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state); 394 thread__put(thread); 395 return ret; 396 } 397 398 static int process_event(struct machine *machine, struct evlist *evlist, 399 union perf_event *event, struct state *state) 400 { 401 if (event->header.type == PERF_RECORD_SAMPLE) 402 return process_sample_event(machine, evlist, event, state); 403 404 if (event->header.type == PERF_RECORD_THROTTLE || 405 event->header.type == PERF_RECORD_UNTHROTTLE) 406 return 0; 407 408 if (event->header.type < PERF_RECORD_MAX) { 409 int ret; 410 411 ret = machine__process_event(machine, event, NULL); 412 if (ret < 0) 413 pr_debug("machine__process_event failed, event type %u\n", 414 event->header.type); 415 return ret; 416 } 417 418 return 0; 419 } 420 421 static int process_events(struct machine *machine, struct evlist *evlist, 422 struct state *state) 423 { 424 union perf_event *event; 425 struct mmap *md; 426 int i, ret; 427 428 for (i = 0; i < evlist->core.nr_mmaps; i++) { 429 md = &evlist->mmap[i]; 430 if (perf_mmap__read_init(&md->core) < 0) 431 continue; 432 433 while ((event = perf_mmap__read_event(&md->core)) != NULL) { 434 ret = process_event(machine, evlist, event, state); 435 perf_mmap__consume(&md->core); 436 if (ret < 0) 437 return ret; 438 } 439 perf_mmap__read_done(&md->core); 440 } 441 return 0; 442 } 443 444 static int comp(const void *a, const void *b) 445 { 446 return *(int *)a - *(int *)b; 447 } 448 449 static void do_sort_something(void) 450 { 451 int buf[40960], i; 452 453 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) 454 buf[i] = ARRAY_SIZE(buf) - i - 1; 455 456 qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp); 457 458 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) { 459 if (buf[i] != i) { 460 pr_debug("qsort failed\n"); 461 break; 462 } 463 } 464 } 465 466 static void sort_something(void) 467 { 468 int i; 469 470 for (i = 0; i < 10; i++) 471 do_sort_something(); 472 } 473 474 static void syscall_something(void) 475 { 476 int pipefd[2]; 477 int i; 478 479 for (i = 0; i < 1000; i++) { 480 if (pipe(pipefd) < 0) { 481 pr_debug("pipe failed\n"); 482 break; 483 } 484 close(pipefd[1]); 485 close(pipefd[0]); 486 } 487 } 488 489 static void fs_something(void) 490 { 491 const char *test_file_name = "temp-perf-code-reading-test-file--"; 492 FILE *f; 493 int i; 494 495 for (i = 0; i < 1000; i++) { 496 f = fopen(test_file_name, "w+"); 497 if (f) { 498 fclose(f); 499 unlink(test_file_name); 500 } 501 } 502 } 503 504 #ifdef __s390x__ 505 #include "header.h" // for get_cpuid() 506 #endif 507 508 static const char *do_determine_event(bool excl_kernel) 509 { 510 const char *event = excl_kernel ? "cycles:u" : "cycles"; 511 512 #ifdef __s390x__ 513 char cpuid[128], model[16], model_c[16], cpum_cf_v[16]; 514 unsigned int family; 515 int ret, cpum_cf_a; 516 517 if (get_cpuid(cpuid, sizeof(cpuid))) 518 goto out_clocks; 519 ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c, 520 model, cpum_cf_v, &cpum_cf_a); 521 if (ret != 5) /* Not available */ 522 goto out_clocks; 523 if (excl_kernel && (cpum_cf_a & 4)) 524 return event; 525 if (!excl_kernel && (cpum_cf_a & 2)) 526 return event; 527 528 /* Fall through: missing authorization */ 529 out_clocks: 530 event = excl_kernel ? "cpu-clock:u" : "cpu-clock"; 531 532 #endif 533 return event; 534 } 535 536 static void do_something(void) 537 { 538 fs_something(); 539 540 sort_something(); 541 542 syscall_something(); 543 } 544 545 enum { 546 TEST_CODE_READING_OK, 547 TEST_CODE_READING_NO_VMLINUX, 548 TEST_CODE_READING_NO_KCORE, 549 TEST_CODE_READING_NO_ACCESS, 550 TEST_CODE_READING_NO_KERNEL_OBJ, 551 }; 552 553 static int do_test_code_reading(bool try_kcore) 554 { 555 struct machine *machine; 556 struct thread *thread; 557 struct record_opts opts = { 558 .mmap_pages = UINT_MAX, 559 .user_freq = UINT_MAX, 560 .user_interval = ULLONG_MAX, 561 .freq = 500, 562 .target = { 563 .uses_mmap = true, 564 }, 565 }; 566 struct state state = { 567 .done_cnt = 0, 568 }; 569 struct perf_thread_map *threads = NULL; 570 struct perf_cpu_map *cpus = NULL; 571 struct evlist *evlist = NULL; 572 struct evsel *evsel = NULL; 573 int err = -1, ret; 574 pid_t pid; 575 struct map *map; 576 bool have_vmlinux, have_kcore, excl_kernel = false; 577 struct dso *dso; 578 579 pid = getpid(); 580 581 machine = machine__new_host(); 582 machine->env = &perf_env; 583 584 ret = machine__create_kernel_maps(machine); 585 if (ret < 0) { 586 pr_debug("machine__create_kernel_maps failed\n"); 587 goto out_err; 588 } 589 590 /* Force the use of kallsyms instead of vmlinux to try kcore */ 591 if (try_kcore) 592 symbol_conf.kallsyms_name = "/proc/kallsyms"; 593 594 /* Load kernel map */ 595 map = machine__kernel_map(machine); 596 ret = map__load(map); 597 if (ret < 0) { 598 pr_debug("map__load failed\n"); 599 goto out_err; 600 } 601 dso = map__dso(map); 602 have_vmlinux = dso__is_vmlinux(dso); 603 have_kcore = dso__is_kcore(dso); 604 605 /* 2nd time through we just try kcore */ 606 if (try_kcore && !have_kcore) 607 return TEST_CODE_READING_NO_KCORE; 608 609 /* No point getting kernel events if there is no kernel object */ 610 if (!have_vmlinux && !have_kcore) 611 excl_kernel = true; 612 613 threads = thread_map__new_by_tid(pid); 614 if (!threads) { 615 pr_debug("thread_map__new_by_tid failed\n"); 616 goto out_err; 617 } 618 619 ret = perf_event__synthesize_thread_map(NULL, threads, 620 perf_event__process, machine, 621 true, false); 622 if (ret < 0) { 623 pr_debug("perf_event__synthesize_thread_map failed\n"); 624 goto out_err; 625 } 626 627 thread = machine__findnew_thread(machine, pid, pid); 628 if (!thread) { 629 pr_debug("machine__findnew_thread failed\n"); 630 goto out_put; 631 } 632 633 cpus = perf_cpu_map__new(NULL); 634 if (!cpus) { 635 pr_debug("perf_cpu_map__new failed\n"); 636 goto out_put; 637 } 638 639 while (1) { 640 const char *str; 641 642 evlist = evlist__new(); 643 if (!evlist) { 644 pr_debug("evlist__new failed\n"); 645 goto out_put; 646 } 647 648 perf_evlist__set_maps(&evlist->core, cpus, threads); 649 650 str = do_determine_event(excl_kernel); 651 pr_debug("Parsing event '%s'\n", str); 652 ret = parse_event(evlist, str); 653 if (ret < 0) { 654 pr_debug("parse_events failed\n"); 655 goto out_put; 656 } 657 658 evlist__config(evlist, &opts, NULL); 659 660 evsel = evlist__first(evlist); 661 662 evsel->core.attr.comm = 1; 663 evsel->core.attr.disabled = 1; 664 evsel->core.attr.enable_on_exec = 0; 665 666 ret = evlist__open(evlist); 667 if (ret < 0) { 668 if (!excl_kernel) { 669 excl_kernel = true; 670 /* 671 * Both cpus and threads are now owned by evlist 672 * and will be freed by following perf_evlist__set_maps 673 * call. Getting reference to keep them alive. 674 */ 675 perf_cpu_map__get(cpus); 676 perf_thread_map__get(threads); 677 perf_evlist__set_maps(&evlist->core, NULL, NULL); 678 evlist__delete(evlist); 679 evlist = NULL; 680 continue; 681 } 682 683 if (verbose > 0) { 684 char errbuf[512]; 685 evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf)); 686 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf); 687 } 688 689 goto out_put; 690 } 691 break; 692 } 693 694 ret = evlist__mmap(evlist, UINT_MAX); 695 if (ret < 0) { 696 pr_debug("evlist__mmap failed\n"); 697 goto out_put; 698 } 699 700 evlist__enable(evlist); 701 702 do_something(); 703 704 evlist__disable(evlist); 705 706 ret = process_events(machine, evlist, &state); 707 if (ret < 0) 708 goto out_put; 709 710 if (!have_vmlinux && !have_kcore && !try_kcore) 711 err = TEST_CODE_READING_NO_KERNEL_OBJ; 712 else if (!have_vmlinux && !try_kcore) 713 err = TEST_CODE_READING_NO_VMLINUX; 714 else if (excl_kernel) 715 err = TEST_CODE_READING_NO_ACCESS; 716 else 717 err = TEST_CODE_READING_OK; 718 out_put: 719 thread__put(thread); 720 out_err: 721 evlist__delete(evlist); 722 perf_cpu_map__put(cpus); 723 perf_thread_map__put(threads); 724 machine__delete(machine); 725 726 return err; 727 } 728 729 static int test__code_reading(struct test_suite *test __maybe_unused, int subtest __maybe_unused) 730 { 731 int ret; 732 733 ret = do_test_code_reading(false); 734 if (!ret) 735 ret = do_test_code_reading(true); 736 737 switch (ret) { 738 case TEST_CODE_READING_OK: 739 return 0; 740 case TEST_CODE_READING_NO_VMLINUX: 741 pr_debug("no vmlinux\n"); 742 return 0; 743 case TEST_CODE_READING_NO_KCORE: 744 pr_debug("no kcore\n"); 745 return 0; 746 case TEST_CODE_READING_NO_ACCESS: 747 pr_debug("no access\n"); 748 return 0; 749 case TEST_CODE_READING_NO_KERNEL_OBJ: 750 pr_debug("no kernel obj\n"); 751 return 0; 752 default: 753 return -1; 754 }; 755 } 756 757 DEFINE_SUITE("Object code reading", code_reading); 758