tools/perf/tests/code-reading.c

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