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