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