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 "trace-event.h" 20 #include "evlist.h" 21 #include "evsel.h" 22 #include "thread_map.h" 23 #include "machine.h" 24 #include "map.h" 25 #include "symbol.h" 26 #include "event.h" 27 #include "record.h" 28 #include "util/mmap.h" 29 #include "util/synthetic-events.h" 30 #include "thread.h" 31 32 #include "tests.h" 33 34 #include <linux/ctype.h> 35 36 #define BUFSZ 1024 37 #define READLEN 128 38 39 struct state { 40 u64 done[1024]; 41 size_t done_cnt; 42 }; 43 44 static unsigned int hex(char c) 45 { 46 if (c >= '0' && c <= '9') 47 return c - '0'; 48 if (c >= 'a' && c <= 'f') 49 return c - 'a' + 10; 50 return c - 'A' + 10; 51 } 52 53 static size_t read_objdump_chunk(const char **line, unsigned char **buf, 54 size_t *buf_len) 55 { 56 size_t bytes_read = 0; 57 unsigned char *chunk_start = *buf; 58 59 /* Read bytes */ 60 while (*buf_len > 0) { 61 char c1, c2; 62 63 /* Get 2 hex digits */ 64 c1 = *(*line)++; 65 if (!isxdigit(c1)) 66 break; 67 c2 = *(*line)++; 68 if (!isxdigit(c2)) 69 break; 70 71 /* Store byte and advance buf */ 72 **buf = (hex(c1) << 4) | hex(c2); 73 (*buf)++; 74 (*buf_len)--; 75 bytes_read++; 76 77 /* End of chunk? */ 78 if (isspace(**line)) 79 break; 80 } 81 82 /* 83 * objdump will display raw insn as LE if code endian 84 * is LE and bytes_per_chunk > 1. In that case reverse 85 * the chunk we just read. 86 * 87 * see disassemble_bytes() at binutils/objdump.c for details 88 * how objdump chooses display endian) 89 */ 90 if (bytes_read > 1 && !bigendian()) { 91 unsigned char *chunk_end = chunk_start + bytes_read - 1; 92 unsigned char tmp; 93 94 while (chunk_start < chunk_end) { 95 tmp = *chunk_start; 96 *chunk_start = *chunk_end; 97 *chunk_end = tmp; 98 chunk_start++; 99 chunk_end--; 100 } 101 } 102 103 return bytes_read; 104 } 105 106 static size_t read_objdump_line(const char *line, unsigned char *buf, 107 size_t buf_len) 108 { 109 const char *p; 110 size_t ret, bytes_read = 0; 111 112 /* Skip to a colon */ 113 p = strchr(line, ':'); 114 if (!p) 115 return 0; 116 p++; 117 118 /* Skip initial spaces */ 119 while (*p) { 120 if (!isspace(*p)) 121 break; 122 p++; 123 } 124 125 do { 126 ret = read_objdump_chunk(&p, &buf, &buf_len); 127 bytes_read += ret; 128 p++; 129 } while (ret > 0); 130 131 /* return number of successfully read bytes */ 132 return bytes_read; 133 } 134 135 static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr) 136 { 137 char *line = NULL; 138 size_t line_len, off_last = 0; 139 ssize_t ret; 140 int err = 0; 141 u64 addr, last_addr = start_addr; 142 143 while (off_last < *len) { 144 size_t off, read_bytes, written_bytes; 145 unsigned char tmp[BUFSZ]; 146 147 ret = getline(&line, &line_len, f); 148 if (feof(f)) 149 break; 150 if (ret < 0) { 151 pr_debug("getline failed\n"); 152 err = -1; 153 break; 154 } 155 156 /* read objdump data into temporary buffer */ 157 read_bytes = read_objdump_line(line, tmp, sizeof(tmp)); 158 if (!read_bytes) 159 continue; 160 161 if (sscanf(line, "%"PRIx64, &addr) != 1) 162 continue; 163 if (addr < last_addr) { 164 pr_debug("addr going backwards, read beyond section?\n"); 165 break; 166 } 167 last_addr = addr; 168 169 /* copy it from temporary buffer to 'buf' according 170 * to address on current objdump line */ 171 off = addr - start_addr; 172 if (off >= *len) 173 break; 174 written_bytes = MIN(read_bytes, *len - off); 175 memcpy(buf + off, tmp, written_bytes); 176 off_last = off + written_bytes; 177 } 178 179 /* len returns number of bytes that could not be read */ 180 *len -= off_last; 181 182 free(line); 183 184 return err; 185 } 186 187 static int read_via_objdump(const char *filename, u64 addr, void *buf, 188 size_t len) 189 { 190 char cmd[PATH_MAX * 2]; 191 const char *fmt; 192 FILE *f; 193 int ret; 194 195 fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s"; 196 ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len, 197 filename); 198 if (ret <= 0 || (size_t)ret >= sizeof(cmd)) 199 return -1; 200 201 pr_debug("Objdump command is: %s\n", cmd); 202 203 /* Ignore objdump errors */ 204 strcat(cmd, " 2>/dev/null"); 205 206 f = popen(cmd, "r"); 207 if (!f) { 208 pr_debug("popen failed\n"); 209 return -1; 210 } 211 212 ret = read_objdump_output(f, buf, &len, addr); 213 if (len) { 214 pr_debug("objdump read too few bytes: %zd\n", len); 215 if (!ret) 216 ret = len; 217 } 218 219 pclose(f); 220 221 return ret; 222 } 223 224 static void dump_buf(unsigned char *buf, size_t len) 225 { 226 size_t i; 227 228 for (i = 0; i < len; i++) { 229 pr_debug("0x%02x ", buf[i]); 230 if (i % 16 == 15) 231 pr_debug("\n"); 232 } 233 pr_debug("\n"); 234 } 235 236 static int read_object_code(u64 addr, size_t len, u8 cpumode, 237 struct thread *thread, struct state *state) 238 { 239 struct addr_location al; 240 unsigned char buf1[BUFSZ]; 241 unsigned char buf2[BUFSZ]; 242 size_t ret_len; 243 u64 objdump_addr; 244 const char *objdump_name; 245 char decomp_name[KMOD_DECOMP_LEN]; 246 bool decomp = false; 247 int ret; 248 249 pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr); 250 251 if (!thread__find_map(thread, cpumode, addr, &al) || !al.map->dso) { 252 if (cpumode == PERF_RECORD_MISC_HYPERVISOR) { 253 pr_debug("Hypervisor address can not be resolved - skipping\n"); 254 return 0; 255 } 256 257 pr_debug("thread__find_map failed\n"); 258 return -1; 259 } 260 261 pr_debug("File is: %s\n", al.map->dso->long_name); 262 263 if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS && 264 !dso__is_kcore(al.map->dso)) { 265 pr_debug("Unexpected kernel address - skipping\n"); 266 return 0; 267 } 268 269 pr_debug("On file address is: %#"PRIx64"\n", al.addr); 270 271 if (len > BUFSZ) 272 len = BUFSZ; 273 274 /* Do not go off the map */ 275 if (addr + len > al.map->end) 276 len = al.map->end - addr; 277 278 /* Read the object code using perf */ 279 ret_len = dso__data_read_offset(al.map->dso, thread->maps->machine, 280 al.addr, buf1, len); 281 if (ret_len != len) { 282 pr_debug("dso__data_read_offset failed\n"); 283 return -1; 284 } 285 286 /* 287 * Converting addresses for use by objdump requires more information. 288 * map__load() does that. See map__rip_2objdump() for details. 289 */ 290 if (map__load(al.map)) 291 return -1; 292 293 /* objdump struggles with kcore - try each map only once */ 294 if (dso__is_kcore(al.map->dso)) { 295 size_t d; 296 297 for (d = 0; d < state->done_cnt; d++) { 298 if (state->done[d] == al.map->start) { 299 pr_debug("kcore map tested already"); 300 pr_debug(" - skipping\n"); 301 return 0; 302 } 303 } 304 if (state->done_cnt >= ARRAY_SIZE(state->done)) { 305 pr_debug("Too many kcore maps - skipping\n"); 306 return 0; 307 } 308 state->done[state->done_cnt++] = al.map->start; 309 } 310 311 objdump_name = al.map->dso->long_name; 312 if (dso__needs_decompress(al.map->dso)) { 313 if (dso__decompress_kmodule_path(al.map->dso, objdump_name, 314 decomp_name, 315 sizeof(decomp_name)) < 0) { 316 pr_debug("decompression failed\n"); 317 return -1; 318 } 319 320 decomp = true; 321 objdump_name = decomp_name; 322 } 323 324 /* Read the object code using objdump */ 325 objdump_addr = map__rip_2objdump(al.map, al.addr); 326 ret = read_via_objdump(objdump_name, objdump_addr, buf2, len); 327 328 if (decomp) 329 unlink(objdump_name); 330 331 if (ret > 0) { 332 /* 333 * The kernel maps are inaccurate - assume objdump is right in 334 * that case. 335 */ 336 if (cpumode == PERF_RECORD_MISC_KERNEL || 337 cpumode == PERF_RECORD_MISC_GUEST_KERNEL) { 338 len -= ret; 339 if (len) { 340 pr_debug("Reducing len to %zu\n", len); 341 } else if (dso__is_kcore(al.map->dso)) { 342 /* 343 * objdump cannot handle very large segments 344 * that may be found in kcore. 345 */ 346 pr_debug("objdump failed for kcore"); 347 pr_debug(" - skipping\n"); 348 return 0; 349 } else { 350 return -1; 351 } 352 } 353 } 354 if (ret < 0) { 355 pr_debug("read_via_objdump failed\n"); 356 return -1; 357 } 358 359 /* The results should be identical */ 360 if (memcmp(buf1, buf2, len)) { 361 pr_debug("Bytes read differ from those read by objdump\n"); 362 pr_debug("buf1 (dso):\n"); 363 dump_buf(buf1, len); 364 pr_debug("buf2 (objdump):\n"); 365 dump_buf(buf2, len); 366 return -1; 367 } 368 pr_debug("Bytes read match those read by objdump\n"); 369 370 return 0; 371 } 372 373 static int process_sample_event(struct machine *machine, 374 struct evlist *evlist, 375 union perf_event *event, struct state *state) 376 { 377 struct perf_sample sample; 378 struct thread *thread; 379 int ret; 380 381 if (perf_evlist__parse_sample(evlist, event, &sample)) { 382 pr_debug("perf_evlist__parse_sample failed\n"); 383 return -1; 384 } 385 386 thread = machine__findnew_thread(machine, sample.pid, sample.tid); 387 if (!thread) { 388 pr_debug("machine__findnew_thread failed\n"); 389 return -1; 390 } 391 392 ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state); 393 thread__put(thread); 394 return ret; 395 } 396 397 static int process_event(struct machine *machine, struct evlist *evlist, 398 union perf_event *event, struct state *state) 399 { 400 if (event->header.type == PERF_RECORD_SAMPLE) 401 return process_sample_event(machine, evlist, event, state); 402 403 if (event->header.type == PERF_RECORD_THROTTLE || 404 event->header.type == PERF_RECORD_UNTHROTTLE) 405 return 0; 406 407 if (event->header.type < PERF_RECORD_MAX) { 408 int ret; 409 410 ret = machine__process_event(machine, event, NULL); 411 if (ret < 0) 412 pr_debug("machine__process_event failed, event type %u\n", 413 event->header.type); 414 return ret; 415 } 416 417 return 0; 418 } 419 420 static int process_events(struct machine *machine, struct evlist *evlist, 421 struct state *state) 422 { 423 union perf_event *event; 424 struct mmap *md; 425 int i, ret; 426 427 for (i = 0; i < evlist->core.nr_mmaps; i++) { 428 md = &evlist->mmap[i]; 429 if (perf_mmap__read_init(&md->core) < 0) 430 continue; 431 432 while ((event = perf_mmap__read_event(&md->core)) != NULL) { 433 ret = process_event(machine, evlist, event, state); 434 perf_mmap__consume(&md->core); 435 if (ret < 0) 436 return ret; 437 } 438 perf_mmap__read_done(&md->core); 439 } 440 return 0; 441 } 442 443 static int comp(const void *a, const void *b) 444 { 445 return *(int *)a - *(int *)b; 446 } 447 448 static void do_sort_something(void) 449 { 450 int buf[40960], i; 451 452 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) 453 buf[i] = ARRAY_SIZE(buf) - i - 1; 454 455 qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp); 456 457 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) { 458 if (buf[i] != i) { 459 pr_debug("qsort failed\n"); 460 break; 461 } 462 } 463 } 464 465 static void sort_something(void) 466 { 467 int i; 468 469 for (i = 0; i < 10; i++) 470 do_sort_something(); 471 } 472 473 static void syscall_something(void) 474 { 475 int pipefd[2]; 476 int i; 477 478 for (i = 0; i < 1000; i++) { 479 if (pipe(pipefd) < 0) { 480 pr_debug("pipe failed\n"); 481 break; 482 } 483 close(pipefd[1]); 484 close(pipefd[0]); 485 } 486 } 487 488 static void fs_something(void) 489 { 490 const char *test_file_name = "temp-perf-code-reading-test-file--"; 491 FILE *f; 492 int i; 493 494 for (i = 0; i < 1000; i++) { 495 f = fopen(test_file_name, "w+"); 496 if (f) { 497 fclose(f); 498 unlink(test_file_name); 499 } 500 } 501 } 502 503 #ifdef __s390x__ 504 #include "header.h" // for get_cpuid() 505 #endif 506 507 static const char *do_determine_event(bool excl_kernel) 508 { 509 const char *event = excl_kernel ? "cycles:u" : "cycles"; 510 511 #ifdef __s390x__ 512 char cpuid[128], model[16], model_c[16], cpum_cf_v[16]; 513 unsigned int family; 514 int ret, cpum_cf_a; 515 516 if (get_cpuid(cpuid, sizeof(cpuid))) 517 goto out_clocks; 518 ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c, 519 model, cpum_cf_v, &cpum_cf_a); 520 if (ret != 5) /* Not available */ 521 goto out_clocks; 522 if (excl_kernel && (cpum_cf_a & 4)) 523 return event; 524 if (!excl_kernel && (cpum_cf_a & 2)) 525 return event; 526 527 /* Fall through: missing authorization */ 528 out_clocks: 529 event = excl_kernel ? "cpu-clock:u" : "cpu-clock"; 530 531 #endif 532 return event; 533 } 534 535 static void do_something(void) 536 { 537 fs_something(); 538 539 sort_something(); 540 541 syscall_something(); 542 } 543 544 enum { 545 TEST_CODE_READING_OK, 546 TEST_CODE_READING_NO_VMLINUX, 547 TEST_CODE_READING_NO_KCORE, 548 TEST_CODE_READING_NO_ACCESS, 549 TEST_CODE_READING_NO_KERNEL_OBJ, 550 }; 551 552 static int do_test_code_reading(bool try_kcore) 553 { 554 struct machine *machine; 555 struct thread *thread; 556 struct record_opts opts = { 557 .mmap_pages = UINT_MAX, 558 .user_freq = UINT_MAX, 559 .user_interval = ULLONG_MAX, 560 .freq = 500, 561 .target = { 562 .uses_mmap = true, 563 }, 564 }; 565 struct state state = { 566 .done_cnt = 0, 567 }; 568 struct perf_thread_map *threads = NULL; 569 struct perf_cpu_map *cpus = NULL; 570 struct evlist *evlist = NULL; 571 struct evsel *evsel = NULL; 572 int err = -1, ret; 573 pid_t pid; 574 struct map *map; 575 bool have_vmlinux, have_kcore, excl_kernel = false; 576 577 pid = getpid(); 578 579 machine = machine__new_host(); 580 machine->env = &perf_env; 581 582 ret = machine__create_kernel_maps(machine); 583 if (ret < 0) { 584 pr_debug("machine__create_kernel_maps failed\n"); 585 goto out_err; 586 } 587 588 /* Force the use of kallsyms instead of vmlinux to try kcore */ 589 if (try_kcore) 590 symbol_conf.kallsyms_name = "/proc/kallsyms"; 591 592 /* Load kernel map */ 593 map = machine__kernel_map(machine); 594 ret = map__load(map); 595 if (ret < 0) { 596 pr_debug("map__load failed\n"); 597 goto out_err; 598 } 599 have_vmlinux = dso__is_vmlinux(map->dso); 600 have_kcore = dso__is_kcore(map->dso); 601 602 /* 2nd time through we just try kcore */ 603 if (try_kcore && !have_kcore) 604 return TEST_CODE_READING_NO_KCORE; 605 606 /* No point getting kernel events if there is no kernel object */ 607 if (!have_vmlinux && !have_kcore) 608 excl_kernel = true; 609 610 threads = thread_map__new_by_tid(pid); 611 if (!threads) { 612 pr_debug("thread_map__new_by_tid failed\n"); 613 goto out_err; 614 } 615 616 ret = perf_event__synthesize_thread_map(NULL, threads, 617 perf_event__process, machine, false); 618 if (ret < 0) { 619 pr_debug("perf_event__synthesize_thread_map failed\n"); 620 goto out_err; 621 } 622 623 thread = machine__findnew_thread(machine, pid, pid); 624 if (!thread) { 625 pr_debug("machine__findnew_thread failed\n"); 626 goto out_put; 627 } 628 629 cpus = perf_cpu_map__new(NULL); 630 if (!cpus) { 631 pr_debug("perf_cpu_map__new failed\n"); 632 goto out_put; 633 } 634 635 while (1) { 636 const char *str; 637 638 evlist = evlist__new(); 639 if (!evlist) { 640 pr_debug("perf_evlist__new failed\n"); 641 goto out_put; 642 } 643 644 perf_evlist__set_maps(&evlist->core, cpus, threads); 645 646 str = do_determine_event(excl_kernel); 647 pr_debug("Parsing event '%s'\n", str); 648 ret = parse_events(evlist, str, NULL); 649 if (ret < 0) { 650 pr_debug("parse_events failed\n"); 651 goto out_put; 652 } 653 654 perf_evlist__config(evlist, &opts, NULL); 655 656 evsel = evlist__first(evlist); 657 658 evsel->core.attr.comm = 1; 659 evsel->core.attr.disabled = 1; 660 evsel->core.attr.enable_on_exec = 0; 661 662 ret = evlist__open(evlist); 663 if (ret < 0) { 664 if (!excl_kernel) { 665 excl_kernel = true; 666 /* 667 * Both cpus and threads are now owned by evlist 668 * and will be freed by following perf_evlist__set_maps 669 * call. Getting refference to keep them alive. 670 */ 671 perf_cpu_map__get(cpus); 672 perf_thread_map__get(threads); 673 perf_evlist__set_maps(&evlist->core, NULL, NULL); 674 evlist__delete(evlist); 675 evlist = NULL; 676 continue; 677 } 678 679 if (verbose > 0) { 680 char errbuf[512]; 681 evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf)); 682 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf); 683 } 684 685 goto out_put; 686 } 687 break; 688 } 689 690 ret = evlist__mmap(evlist, UINT_MAX); 691 if (ret < 0) { 692 pr_debug("evlist__mmap failed\n"); 693 goto out_put; 694 } 695 696 evlist__enable(evlist); 697 698 do_something(); 699 700 evlist__disable(evlist); 701 702 ret = process_events(machine, evlist, &state); 703 if (ret < 0) 704 goto out_put; 705 706 if (!have_vmlinux && !have_kcore && !try_kcore) 707 err = TEST_CODE_READING_NO_KERNEL_OBJ; 708 else if (!have_vmlinux && !try_kcore) 709 err = TEST_CODE_READING_NO_VMLINUX; 710 else if (excl_kernel) 711 err = TEST_CODE_READING_NO_ACCESS; 712 else 713 err = TEST_CODE_READING_OK; 714 out_put: 715 thread__put(thread); 716 out_err: 717 718 if (evlist) { 719 evlist__delete(evlist); 720 } else { 721 perf_cpu_map__put(cpus); 722 perf_thread_map__put(threads); 723 } 724 machine__delete_threads(machine); 725 machine__delete(machine); 726 727 return err; 728 } 729 730 int test__code_reading(struct test *test __maybe_unused, int subtest __maybe_unused) 731 { 732 int ret; 733 734 ret = do_test_code_reading(false); 735 if (!ret) 736 ret = do_test_code_reading(true); 737 738 switch (ret) { 739 case TEST_CODE_READING_OK: 740 return 0; 741 case TEST_CODE_READING_NO_VMLINUX: 742 pr_debug("no vmlinux\n"); 743 return 0; 744 case TEST_CODE_READING_NO_KCORE: 745 pr_debug("no kcore\n"); 746 return 0; 747 case TEST_CODE_READING_NO_ACCESS: 748 pr_debug("no access\n"); 749 return 0; 750 case TEST_CODE_READING_NO_KERNEL_OBJ: 751 pr_debug("no kernel obj\n"); 752 return 0; 753 default: 754 return -1; 755 }; 756 } 757