tools/perf/tests/code-reading.c

   1 #include <linux/types.h>
   2 #include <stdlib.h>
   3 #include <unistd.h>
   4 #include <stdio.h>
   5 #include <ctype.h>
   6 #include <string.h>
   7
   8 #include "parse-events.h"
   9 #include "evlist.h"
  10 #include "evsel.h"
  11 #include "thread_map.h"
  12 #include "cpumap.h"
  13 #include "machine.h"
  14 #include "event.h"
  15 #include "thread.h"
  16
  17 #include "tests.h"
  18
  19 #define BUFSZ   1024
  20 #define READLEN 128
  21
  22 struct state {
  23         u64 done[1024];
  24         size_t done_cnt;
  25 };
  26
  27 static unsigned int hex(char c)
  28 {
  29         if (c >= '0' && c <= '9')
  30                 return c - '0';
  31         if (c >= 'a' && c <= 'f')
  32                 return c - 'a' + 10;
  33         return c - 'A' + 10;
  34 }
  35
  36 static size_t read_objdump_chunk(const char **line, unsigned char **buf,
  37                                  size_t *buf_len)
  38 {
  39         size_t bytes_read = 0;
  40         unsigned char *chunk_start = *buf;
  41
  42         /* Read bytes */
  43         while (*buf_len > 0) {
  44                 char c1, c2;
  45
  46                 /* Get 2 hex digits */
  47                 c1 = *(*line)++;
  48                 if (!isxdigit(c1))
  49                         break;
  50                 c2 = *(*line)++;
  51                 if (!isxdigit(c2))
  52                         break;
  53
  54                 /* Store byte and advance buf */
  55                 **buf = (hex(c1) << 4) | hex(c2);
  56                 (*buf)++;
  57                 (*buf_len)--;
  58                 bytes_read++;
  59
  60                 /* End of chunk? */
  61                 if (isspace(**line))
  62                         break;
  63         }
  64
  65         /*
  66          * objdump will display raw insn as LE if code endian
  67          * is LE and bytes_per_chunk > 1. In that case reverse
  68          * the chunk we just read.
  69          *
  70          * see disassemble_bytes() at binutils/objdump.c for details
  71          * how objdump chooses display endian)
  72          */
  73         if (bytes_read > 1 && !bigendian()) {
  74                 unsigned char *chunk_end = chunk_start + bytes_read - 1;
  75                 unsigned char tmp;
  76
  77                 while (chunk_start < chunk_end) {
  78                         tmp = *chunk_start;
  79                         *chunk_start = *chunk_end;
  80                         *chunk_end = tmp;
  81                         chunk_start++;
  82                         chunk_end--;
  83                 }
  84         }
  85
  86         return bytes_read;
  87 }
  88
  89 static size_t read_objdump_line(const char *line, unsigned char *buf,
  90                                 size_t buf_len)
  91 {
  92         const char *p;
  93         size_t ret, bytes_read = 0;
  94
  95         /* Skip to a colon */
  96         p = strchr(line, ':');
  97         if (!p)
  98                 return 0;
  99         p++;
 100
 101         /* Skip initial spaces */
 102         while (*p) {
 103                 if (!isspace(*p))
 104                         break;
 105                 p++;
 106         }
 107
 108         do {
 109                 ret = read_objdump_chunk(&p, &buf, &buf_len);
 110                 bytes_read += ret;
 111                 p++;
 112         } while (ret > 0);
 113
 114         /* return number of successfully read bytes */
 115         return bytes_read;
 116 }
 117
 118 static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
 119 {
 120         char *line = NULL;
 121         size_t line_len, off_last = 0;
 122         ssize_t ret;
 123         int err = 0;
 124         u64 addr, last_addr = start_addr;
 125
 126         while (off_last < *len) {
 127                 size_t off, read_bytes, written_bytes;
 128                 unsigned char tmp[BUFSZ];
 129
 130                 ret = getline(&line, &line_len, f);
 131                 if (feof(f))
 132                         break;
 133                 if (ret < 0) {
 134                         pr_debug("getline failed\n");
 135                         err = -1;
 136                         break;
 137                 }
 138
 139                 /* read objdump data into temporary buffer */
 140                 read_bytes = read_objdump_line(line, tmp, sizeof(tmp));
 141                 if (!read_bytes)
 142                         continue;
 143
 144                 if (sscanf(line, "%"PRIx64, &addr) != 1)
 145                         continue;
 146                 if (addr < last_addr) {
 147                         pr_debug("addr going backwards, read beyond section?\n");
 148                         break;
 149                 }
 150                 last_addr = addr;
 151
 152                 /* copy it from temporary buffer to 'buf' according
 153                  * to address on current objdump line */
 154                 off = addr - start_addr;
 155                 if (off >= *len)
 156                         break;
 157                 written_bytes = MIN(read_bytes, *len - off);
 158                 memcpy(buf + off, tmp, written_bytes);
 159                 off_last = off + written_bytes;
 160         }
 161
 162         /* len returns number of bytes that could not be read */
 163         *len -= off_last;
 164
 165         free(line);
 166
 167         return err;
 168 }
 169
 170 static int read_via_objdump(const char *filename, u64 addr, void *buf,
 171                             size_t len)
 172 {
 173         char cmd[PATH_MAX * 2];
 174         const char *fmt;
 175         FILE *f;
 176         int ret;
 177
 178         fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
 179         ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len,
 180                        filename);
 181         if (ret <= 0 || (size_t)ret >= sizeof(cmd))
 182                 return -1;
 183
 184         pr_debug("Objdump command is: %s\n", cmd);
 185
 186         /* Ignore objdump errors */
 187         strcat(cmd, " 2>/dev/null");
 188
 189         f = popen(cmd, "r");
 190         if (!f) {
 191                 pr_debug("popen failed\n");
 192                 return -1;
 193         }
 194
 195         ret = read_objdump_output(f, buf, &len, addr);
 196         if (len) {
 197                 pr_debug("objdump read too few bytes: %zd\n", len);
 198                 if (!ret)
 199                         ret = len;
 200         }
 201
 202         pclose(f);
 203
 204         return ret;
 205 }
 206
 207 static void dump_buf(unsigned char *buf, size_t len)
 208 {
 209         size_t i;
 210
 211         for (i = 0; i < len; i++) {
 212                 pr_debug("0x%02x ", buf[i]);
 213                 if (i % 16 == 15)
 214                         pr_debug("\n");
 215         }
 216         pr_debug("\n");
 217 }
 218
 219 static int read_object_code(u64 addr, size_t len, u8 cpumode,
 220                             struct thread *thread, struct state *state)
 221 {
 222         struct addr_location al;
 223         unsigned char buf1[BUFSZ];
 224         unsigned char buf2[BUFSZ];
 225         size_t ret_len;
 226         u64 objdump_addr;
 227         int ret;
 228
 229         pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
 230
 231         thread__find_addr_map(thread, cpumode, MAP__FUNCTION, addr, &al);
 232         if (!al.map || !al.map->dso) {
 233                 pr_debug("thread__find_addr_map failed\n");
 234                 return -1;
 235         }
 236
 237         pr_debug("File is: %s\n", al.map->dso->long_name);
 238
 239         if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
 240             !dso__is_kcore(al.map->dso)) {
 241                 pr_debug("Unexpected kernel address - skipping\n");
 242                 return 0;
 243         }
 244
 245         pr_debug("On file address is: %#"PRIx64"\n", al.addr);
 246
 247         if (len > BUFSZ)
 248                 len = BUFSZ;
 249
 250         /* Do not go off the map */
 251         if (addr + len > al.map->end)
 252                 len = al.map->end - addr;
 253
 254         /* Read the object code using perf */
 255         ret_len = dso__data_read_offset(al.map->dso, thread->mg->machine,
 256                                         al.addr, buf1, len);
 257         if (ret_len != len) {
 258                 pr_debug("dso__data_read_offset failed\n");
 259                 return -1;
 260         }
 261
 262         /*
 263          * Converting addresses for use by objdump requires more information.
 264          * map__load() does that.  See map__rip_2objdump() for details.
 265          */
 266         if (map__load(al.map, NULL))
 267                 return -1;
 268
 269         /* objdump struggles with kcore - try each map only once */
 270         if (dso__is_kcore(al.map->dso)) {
 271                 size_t d;
 272
 273                 for (d = 0; d < state->done_cnt; d++) {
 274                         if (state->done[d] == al.map->start) {
 275                                 pr_debug("kcore map tested already");
 276                                 pr_debug(" - skipping\n");
 277                                 return 0;
 278                         }
 279                 }
 280                 if (state->done_cnt >= ARRAY_SIZE(state->done)) {
 281                         pr_debug("Too many kcore maps - skipping\n");
 282                         return 0;
 283                 }
 284                 state->done[state->done_cnt++] = al.map->start;
 285         }
 286
 287         /* Read the object code using objdump */
 288         objdump_addr = map__rip_2objdump(al.map, al.addr);
 289         ret = read_via_objdump(al.map->dso->long_name, objdump_addr, buf2, len);
 290         if (ret > 0) {
 291                 /*
 292                  * The kernel maps are inaccurate - assume objdump is right in
 293                  * that case.
 294                  */
 295                 if (cpumode == PERF_RECORD_MISC_KERNEL ||
 296                     cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
 297                         len -= ret;
 298                         if (len) {
 299                                 pr_debug("Reducing len to %zu\n", len);
 300                         } else if (dso__is_kcore(al.map->dso)) {
 301                                 /*
 302                                  * objdump cannot handle very large segments
 303                                  * that may be found in kcore.
 304                                  */
 305                                 pr_debug("objdump failed for kcore");
 306                                 pr_debug(" - skipping\n");
 307                                 return 0;
 308                         } else {
 309                                 return -1;
 310                         }
 311                 }
 312         }
 313         if (ret < 0) {
 314                 pr_debug("read_via_objdump failed\n");
 315                 return -1;
 316         }
 317
 318         /* The results should be identical */
 319         if (memcmp(buf1, buf2, len)) {
 320                 pr_debug("Bytes read differ from those read by objdump\n");
 321                 pr_debug("buf1 (dso):\n");
 322                 dump_buf(buf1, len);
 323                 pr_debug("buf2 (objdump):\n");
 324                 dump_buf(buf2, len);
 325                 return -1;
 326         }
 327         pr_debug("Bytes read match those read by objdump\n");
 328
 329         return 0;
 330 }
 331
 332 static int process_sample_event(struct machine *machine,
 333                                 struct perf_evlist *evlist,
 334                                 union perf_event *event, struct state *state)
 335 {
 336         struct perf_sample sample;
 337         struct thread *thread;
 338         int ret;
 339
 340         if (perf_evlist__parse_sample(evlist, event, &sample)) {
 341                 pr_debug("perf_evlist__parse_sample failed\n");
 342                 return -1;
 343         }
 344
 345         thread = machine__findnew_thread(machine, sample.pid, sample.tid);
 346         if (!thread) {
 347                 pr_debug("machine__findnew_thread failed\n");
 348                 return -1;
 349         }
 350
 351         ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state);
 352         thread__put(thread);
 353         return ret;
 354 }
 355
 356 static int process_event(struct machine *machine, struct perf_evlist *evlist,
 357                          union perf_event *event, struct state *state)
 358 {
 359         if (event->header.type == PERF_RECORD_SAMPLE)
 360                 return process_sample_event(machine, evlist, event, state);
 361
 362         if (event->header.type == PERF_RECORD_THROTTLE ||
 363             event->header.type == PERF_RECORD_UNTHROTTLE)
 364                 return 0;
 365
 366         if (event->header.type < PERF_RECORD_MAX) {
 367                 int ret;
 368
 369                 ret = machine__process_event(machine, event, NULL);
 370                 if (ret < 0)
 371                         pr_debug("machine__process_event failed, event type %u\n",
 372                                  event->header.type);
 373                 return ret;
 374         }
 375
 376         return 0;
 377 }
 378
 379 static int process_events(struct machine *machine, struct perf_evlist *evlist,
 380                           struct state *state)
 381 {
 382         union perf_event *event;
 383         int i, ret;
 384
 385         for (i = 0; i < evlist->nr_mmaps; i++) {
 386                 while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) {
 387                         ret = process_event(machine, evlist, event, state);
 388                         perf_evlist__mmap_consume(evlist, i);
 389                         if (ret < 0)
 390                                 return ret;
 391                 }
 392         }
 393         return 0;
 394 }
 395
 396 static int comp(const void *a, const void *b)
 397 {
 398         return *(int *)a - *(int *)b;
 399 }
 400
 401 static void do_sort_something(void)
 402 {
 403         int buf[40960], i;
 404
 405         for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
 406                 buf[i] = ARRAY_SIZE(buf) - i - 1;
 407
 408         qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
 409
 410         for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
 411                 if (buf[i] != i) {
 412                         pr_debug("qsort failed\n");
 413                         break;
 414                 }
 415         }
 416 }
 417
 418 static void sort_something(void)
 419 {
 420         int i;
 421
 422         for (i = 0; i < 10; i++)
 423                 do_sort_something();
 424 }
 425
 426 static void syscall_something(void)
 427 {
 428         int pipefd[2];
 429         int i;
 430
 431         for (i = 0; i < 1000; i++) {
 432                 if (pipe(pipefd) < 0) {
 433                         pr_debug("pipe failed\n");
 434                         break;
 435                 }
 436                 close(pipefd[1]);
 437                 close(pipefd[0]);
 438         }
 439 }
 440
 441 static void fs_something(void)
 442 {
 443         const char *test_file_name = "temp-perf-code-reading-test-file--";
 444         FILE *f;
 445         int i;
 446
 447         for (i = 0; i < 1000; i++) {
 448                 f = fopen(test_file_name, "w+");
 449                 if (f) {
 450                         fclose(f);
 451                         unlink(test_file_name);
 452                 }
 453         }
 454 }
 455
 456 static void do_something(void)
 457 {
 458         fs_something();
 459
 460         sort_something();
 461
 462         syscall_something();
 463 }
 464
 465 enum {
 466         TEST_CODE_READING_OK,
 467         TEST_CODE_READING_NO_VMLINUX,
 468         TEST_CODE_READING_NO_KCORE,
 469         TEST_CODE_READING_NO_ACCESS,
 470         TEST_CODE_READING_NO_KERNEL_OBJ,
 471 };
 472
 473 static int do_test_code_reading(bool try_kcore)
 474 {
 475         struct machine *machine;
 476         struct thread *thread;
 477         struct record_opts opts = {
 478                 .mmap_pages          = UINT_MAX,
 479                 .user_freq           = UINT_MAX,
 480                 .user_interval       = ULLONG_MAX,
 481                 .freq                = 500,
 482                 .target              = {
 483                         .uses_mmap   = true,
 484                 },
 485         };
 486         struct state state = {
 487                 .done_cnt = 0,
 488         };
 489         struct thread_map *threads = NULL;
 490         struct cpu_map *cpus = NULL;
 491         struct perf_evlist *evlist = NULL;
 492         struct perf_evsel *evsel = NULL;
 493         int err = -1, ret;
 494         pid_t pid;
 495         struct map *map;
 496         bool have_vmlinux, have_kcore, excl_kernel = false;
 497
 498         pid = getpid();
 499
 500         machine = machine__new_host();
 501
 502         ret = machine__create_kernel_maps(machine);
 503         if (ret < 0) {
 504                 pr_debug("machine__create_kernel_maps failed\n");
 505                 goto out_err;
 506         }
 507
 508         /* Force the use of kallsyms instead of vmlinux to try kcore */
 509         if (try_kcore)
 510                 symbol_conf.kallsyms_name = "/proc/kallsyms";
 511
 512         /* Load kernel map */
 513         map = machine__kernel_map(machine);
 514         ret = map__load(map, NULL);
 515         if (ret < 0) {
 516                 pr_debug("map__load failed\n");
 517                 goto out_err;
 518         }
 519         have_vmlinux = dso__is_vmlinux(map->dso);
 520         have_kcore = dso__is_kcore(map->dso);
 521
 522         /* 2nd time through we just try kcore */
 523         if (try_kcore && !have_kcore)
 524                 return TEST_CODE_READING_NO_KCORE;
 525
 526         /* No point getting kernel events if there is no kernel object */
 527         if (!have_vmlinux && !have_kcore)
 528                 excl_kernel = true;
 529
 530         threads = thread_map__new_by_tid(pid);
 531         if (!threads) {
 532                 pr_debug("thread_map__new_by_tid failed\n");
 533                 goto out_err;
 534         }
 535
 536         ret = perf_event__synthesize_thread_map(NULL, threads,
 537                                                 perf_event__process, machine, false, 500);
 538         if (ret < 0) {
 539                 pr_debug("perf_event__synthesize_thread_map failed\n");
 540                 goto out_err;
 541         }
 542
 543         thread = machine__findnew_thread(machine, pid, pid);
 544         if (!thread) {
 545                 pr_debug("machine__findnew_thread failed\n");
 546                 goto out_put;
 547         }
 548
 549         cpus = cpu_map__new(NULL);
 550         if (!cpus) {
 551                 pr_debug("cpu_map__new failed\n");
 552                 goto out_put;
 553         }
 554
 555         while (1) {
 556                 const char *str;
 557
 558                 evlist = perf_evlist__new();
 559                 if (!evlist) {
 560                         pr_debug("perf_evlist__new failed\n");
 561                         goto out_put;
 562                 }
 563
 564                 perf_evlist__set_maps(evlist, cpus, threads);
 565
 566                 if (excl_kernel)
 567                         str = "cycles:u";
 568                 else
 569                         str = "cycles";
 570                 pr_debug("Parsing event '%s'\n", str);
 571                 ret = parse_events(evlist, str, NULL);
 572                 if (ret < 0) {
 573                         pr_debug("parse_events failed\n");
 574                         goto out_put;
 575                 }
 576
 577                 perf_evlist__config(evlist, &opts, NULL);
 578
 579                 evsel = perf_evlist__first(evlist);
 580
 581                 evsel->attr.comm = 1;
 582                 evsel->attr.disabled = 1;
 583                 evsel->attr.enable_on_exec = 0;
 584
 585                 ret = perf_evlist__open(evlist);
 586                 if (ret < 0) {
 587                         if (!excl_kernel) {
 588                                 excl_kernel = true;
 589                                 /*
 590                                  * Both cpus and threads are now owned by evlist
 591                                  * and will be freed by following perf_evlist__set_maps
 592                                  * call. Getting refference to keep them alive.
 593                                  */
 594                                 cpu_map__get(cpus);
 595                                 thread_map__get(threads);
 596                                 perf_evlist__set_maps(evlist, NULL, NULL);
 597                                 perf_evlist__delete(evlist);
 598                                 evlist = NULL;
 599                                 continue;
 600                         }
 601
 602                         if (verbose) {
 603                                 char errbuf[512];
 604                                 perf_evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
 605                                 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
 606                         }
 607
 608                         goto out_put;
 609                 }
 610                 break;
 611         }
 612
 613         ret = perf_evlist__mmap(evlist, UINT_MAX, false);
 614         if (ret < 0) {
 615                 pr_debug("perf_evlist__mmap failed\n");
 616                 goto out_put;
 617         }
 618
 619         perf_evlist__enable(evlist);
 620
 621         do_something();
 622
 623         perf_evlist__disable(evlist);
 624
 625         ret = process_events(machine, evlist, &state);
 626         if (ret < 0)
 627                 goto out_put;
 628
 629         if (!have_vmlinux && !have_kcore && !try_kcore)
 630                 err = TEST_CODE_READING_NO_KERNEL_OBJ;
 631         else if (!have_vmlinux && !try_kcore)
 632                 err = TEST_CODE_READING_NO_VMLINUX;
 633         else if (excl_kernel)
 634                 err = TEST_CODE_READING_NO_ACCESS;
 635         else
 636                 err = TEST_CODE_READING_OK;
 637 out_put:
 638         thread__put(thread);
 639 out_err:
 640
 641         if (evlist) {
 642                 perf_evlist__delete(evlist);
 643         } else {
 644                 cpu_map__put(cpus);
 645                 thread_map__put(threads);
 646         }
 647         machine__delete_threads(machine);
 648         machine__delete(machine);
 649
 650         return err;
 651 }
 652
 653 int test__code_reading(int subtest __maybe_unused)
 654 {
 655         int ret;
 656
 657         ret = do_test_code_reading(false);
 658         if (!ret)
 659                 ret = do_test_code_reading(true);
 660
 661         switch (ret) {
 662         case TEST_CODE_READING_OK:
 663                 return 0;
 664         case TEST_CODE_READING_NO_VMLINUX:
 665                 pr_debug("no vmlinux\n");
 666                 return 0;
 667         case TEST_CODE_READING_NO_KCORE:
 668                 pr_debug("no kcore\n");
 669                 return 0;
 670         case TEST_CODE_READING_NO_ACCESS:
 671                 pr_debug("no access\n");
 672                 return 0;
 673         case TEST_CODE_READING_NO_KERNEL_OBJ:
 674                 pr_debug("no kernel obj\n");
 675                 return 0;
 676         default:
 677                 return -1;
 678         };
 679 }