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         int ret;
 233
 234         pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
 235
 236         thread__find_addr_map(thread, cpumode, MAP__FUNCTION, addr, &al);
 237         if (!al.map || !al.map->dso) {
 238                 pr_debug("thread__find_addr_map failed\n");
 239                 return -1;
 240         }
 241
 242         pr_debug("File is: %s\n", al.map->dso->long_name);
 243
 244         if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
 245             !dso__is_kcore(al.map->dso)) {
 246                 pr_debug("Unexpected kernel address - skipping\n");
 247                 return 0;
 248         }
 249
 250         pr_debug("On file address is: %#"PRIx64"\n", al.addr);
 251
 252         if (len > BUFSZ)
 253                 len = BUFSZ;
 254
 255         /* Do not go off the map */
 256         if (addr + len > al.map->end)
 257                 len = al.map->end - addr;
 258
 259         /* Read the object code using perf */
 260         ret_len = dso__data_read_offset(al.map->dso, thread->mg->machine,
 261                                         al.addr, buf1, len);
 262         if (ret_len != len) {
 263                 pr_debug("dso__data_read_offset failed\n");
 264                 return -1;
 265         }
 266
 267         /*
 268          * Converting addresses for use by objdump requires more information.
 269          * map__load() does that.  See map__rip_2objdump() for details.
 270          */
 271         if (map__load(al.map))
 272                 return -1;
 273
 274         /* objdump struggles with kcore - try each map only once */
 275         if (dso__is_kcore(al.map->dso)) {
 276                 size_t d;
 277
 278                 for (d = 0; d < state->done_cnt; d++) {
 279                         if (state->done[d] == al.map->start) {
 280                                 pr_debug("kcore map tested already");
 281                                 pr_debug(" - skipping\n");
 282                                 return 0;
 283                         }
 284                 }
 285                 if (state->done_cnt >= ARRAY_SIZE(state->done)) {
 286                         pr_debug("Too many kcore maps - skipping\n");
 287                         return 0;
 288                 }
 289                 state->done[state->done_cnt++] = al.map->start;
 290         }
 291
 292         /* Read the object code using objdump */
 293         objdump_addr = map__rip_2objdump(al.map, al.addr);
 294         ret = read_via_objdump(al.map->dso->long_name, objdump_addr, buf2, len);
 295         if (ret > 0) {
 296                 /*
 297                  * The kernel maps are inaccurate - assume objdump is right in
 298                  * that case.
 299                  */
 300                 if (cpumode == PERF_RECORD_MISC_KERNEL ||
 301                     cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
 302                         len -= ret;
 303                         if (len) {
 304                                 pr_debug("Reducing len to %zu\n", len);
 305                         } else if (dso__is_kcore(al.map->dso)) {
 306                                 /*
 307                                  * objdump cannot handle very large segments
 308                                  * that may be found in kcore.
 309                                  */
 310                                 pr_debug("objdump failed for kcore");
 311                                 pr_debug(" - skipping\n");
 312                                 return 0;
 313                         } else {
 314                                 return -1;
 315                         }
 316                 }
 317         }
 318         if (ret < 0) {
 319                 pr_debug("read_via_objdump failed\n");
 320                 return -1;
 321         }
 322
 323         /* The results should be identical */
 324         if (memcmp(buf1, buf2, len)) {
 325                 pr_debug("Bytes read differ from those read by objdump\n");
 326                 pr_debug("buf1 (dso):\n");
 327                 dump_buf(buf1, len);
 328                 pr_debug("buf2 (objdump):\n");
 329                 dump_buf(buf2, len);
 330                 return -1;
 331         }
 332         pr_debug("Bytes read match those read by objdump\n");
 333
 334         return 0;
 335 }
 336
 337 static int process_sample_event(struct machine *machine,
 338                                 struct perf_evlist *evlist,
 339                                 union perf_event *event, struct state *state)
 340 {
 341         struct perf_sample sample;
 342         struct thread *thread;
 343         int ret;
 344
 345         if (perf_evlist__parse_sample(evlist, event, &sample)) {
 346                 pr_debug("perf_evlist__parse_sample failed\n");
 347                 return -1;
 348         }
 349
 350         thread = machine__findnew_thread(machine, sample.pid, sample.tid);
 351         if (!thread) {
 352                 pr_debug("machine__findnew_thread failed\n");
 353                 return -1;
 354         }
 355
 356         ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state);
 357         thread__put(thread);
 358         return ret;
 359 }
 360
 361 static int process_event(struct machine *machine, struct perf_evlist *evlist,
 362                          union perf_event *event, struct state *state)
 363 {
 364         if (event->header.type == PERF_RECORD_SAMPLE)
 365                 return process_sample_event(machine, evlist, event, state);
 366
 367         if (event->header.type == PERF_RECORD_THROTTLE ||
 368             event->header.type == PERF_RECORD_UNTHROTTLE)
 369                 return 0;
 370
 371         if (event->header.type < PERF_RECORD_MAX) {
 372                 int ret;
 373
 374                 ret = machine__process_event(machine, event, NULL);
 375                 if (ret < 0)
 376                         pr_debug("machine__process_event failed, event type %u\n",
 377                                  event->header.type);
 378                 return ret;
 379         }
 380
 381         return 0;
 382 }
 383
 384 static int process_events(struct machine *machine, struct perf_evlist *evlist,
 385                           struct state *state)
 386 {
 387         union perf_event *event;
 388         int i, ret;
 389
 390         for (i = 0; i < evlist->nr_mmaps; i++) {
 391                 while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) {
 392                         ret = process_event(machine, evlist, event, state);
 393                         perf_evlist__mmap_consume(evlist, i);
 394                         if (ret < 0)
 395                                 return ret;
 396                 }
 397         }
 398         return 0;
 399 }
 400
 401 static int comp(const void *a, const void *b)
 402 {
 403         return *(int *)a - *(int *)b;
 404 }
 405
 406 static void do_sort_something(void)
 407 {
 408         int buf[40960], i;
 409
 410         for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
 411                 buf[i] = ARRAY_SIZE(buf) - i - 1;
 412
 413         qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
 414
 415         for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
 416                 if (buf[i] != i) {
 417                         pr_debug("qsort failed\n");
 418                         break;
 419                 }
 420         }
 421 }
 422
 423 static void sort_something(void)
 424 {
 425         int i;
 426
 427         for (i = 0; i < 10; i++)
 428                 do_sort_something();
 429 }
 430
 431 static void syscall_something(void)
 432 {
 433         int pipefd[2];
 434         int i;
 435
 436         for (i = 0; i < 1000; i++) {
 437                 if (pipe(pipefd) < 0) {
 438                         pr_debug("pipe failed\n");
 439                         break;
 440                 }
 441                 close(pipefd[1]);
 442                 close(pipefd[0]);
 443         }
 444 }
 445
 446 static void fs_something(void)
 447 {
 448         const char *test_file_name = "temp-perf-code-reading-test-file--";
 449         FILE *f;
 450         int i;
 451
 452         for (i = 0; i < 1000; i++) {
 453                 f = fopen(test_file_name, "w+");
 454                 if (f) {
 455                         fclose(f);
 456                         unlink(test_file_name);
 457                 }
 458         }
 459 }
 460
 461 static void do_something(void)
 462 {
 463         fs_something();
 464
 465         sort_something();
 466
 467         syscall_something();
 468 }
 469
 470 enum {
 471         TEST_CODE_READING_OK,
 472         TEST_CODE_READING_NO_VMLINUX,
 473         TEST_CODE_READING_NO_KCORE,
 474         TEST_CODE_READING_NO_ACCESS,
 475         TEST_CODE_READING_NO_KERNEL_OBJ,
 476 };
 477
 478 static int do_test_code_reading(bool try_kcore)
 479 {
 480         struct machine *machine;
 481         struct thread *thread;
 482         struct record_opts opts = {
 483                 .mmap_pages          = UINT_MAX,
 484                 .user_freq           = UINT_MAX,
 485                 .user_interval       = ULLONG_MAX,
 486                 .freq                = 500,
 487                 .target              = {
 488                         .uses_mmap   = true,
 489                 },
 490         };
 491         struct state state = {
 492                 .done_cnt = 0,
 493         };
 494         struct thread_map *threads = NULL;
 495         struct cpu_map *cpus = NULL;
 496         struct perf_evlist *evlist = NULL;
 497         struct perf_evsel *evsel = NULL;
 498         int err = -1, ret;
 499         pid_t pid;
 500         struct map *map;
 501         bool have_vmlinux, have_kcore, excl_kernel = false;
 502
 503         pid = getpid();
 504
 505         machine = machine__new_host();
 506
 507         ret = machine__create_kernel_maps(machine);
 508         if (ret < 0) {
 509                 pr_debug("machine__create_kernel_maps failed\n");
 510                 goto out_err;
 511         }
 512
 513         /* Force the use of kallsyms instead of vmlinux to try kcore */
 514         if (try_kcore)
 515                 symbol_conf.kallsyms_name = "/proc/kallsyms";
 516
 517         /* Load kernel map */
 518         map = machine__kernel_map(machine);
 519         ret = map__load(map);
 520         if (ret < 0) {
 521                 pr_debug("map__load failed\n");
 522                 goto out_err;
 523         }
 524         have_vmlinux = dso__is_vmlinux(map->dso);
 525         have_kcore = dso__is_kcore(map->dso);
 526
 527         /* 2nd time through we just try kcore */
 528         if (try_kcore && !have_kcore)
 529                 return TEST_CODE_READING_NO_KCORE;
 530
 531         /* No point getting kernel events if there is no kernel object */
 532         if (!have_vmlinux && !have_kcore)
 533                 excl_kernel = true;
 534
 535         threads = thread_map__new_by_tid(pid);
 536         if (!threads) {
 537                 pr_debug("thread_map__new_by_tid failed\n");
 538                 goto out_err;
 539         }
 540
 541         ret = perf_event__synthesize_thread_map(NULL, threads,
 542                                                 perf_event__process, machine, false, 500);
 543         if (ret < 0) {
 544                 pr_debug("perf_event__synthesize_thread_map failed\n");
 545                 goto out_err;
 546         }
 547
 548         thread = machine__findnew_thread(machine, pid, pid);
 549         if (!thread) {
 550                 pr_debug("machine__findnew_thread failed\n");
 551                 goto out_put;
 552         }
 553
 554         cpus = cpu_map__new(NULL);
 555         if (!cpus) {
 556                 pr_debug("cpu_map__new failed\n");
 557                 goto out_put;
 558         }
 559
 560         while (1) {
 561                 const char *str;
 562
 563                 evlist = perf_evlist__new();
 564                 if (!evlist) {
 565                         pr_debug("perf_evlist__new failed\n");
 566                         goto out_put;
 567                 }
 568
 569                 perf_evlist__set_maps(evlist, cpus, threads);
 570
 571                 if (excl_kernel)
 572                         str = "cycles:u";
 573                 else
 574                         str = "cycles";
 575                 pr_debug("Parsing event '%s'\n", str);
 576                 ret = parse_events(evlist, str, NULL);
 577                 if (ret < 0) {
 578                         pr_debug("parse_events failed\n");
 579                         goto out_put;
 580                 }
 581
 582                 perf_evlist__config(evlist, &opts, NULL);
 583
 584                 evsel = perf_evlist__first(evlist);
 585
 586                 evsel->attr.comm = 1;
 587                 evsel->attr.disabled = 1;
 588                 evsel->attr.enable_on_exec = 0;
 589
 590                 ret = perf_evlist__open(evlist);
 591                 if (ret < 0) {
 592                         if (!excl_kernel) {
 593                                 excl_kernel = true;
 594                                 /*
 595                                  * Both cpus and threads are now owned by evlist
 596                                  * and will be freed by following perf_evlist__set_maps
 597                                  * call. Getting refference to keep them alive.
 598                                  */
 599                                 cpu_map__get(cpus);
 600                                 thread_map__get(threads);
 601                                 perf_evlist__set_maps(evlist, NULL, NULL);
 602                                 perf_evlist__delete(evlist);
 603                                 evlist = NULL;
 604                                 continue;
 605                         }
 606
 607                         if (verbose > 0) {
 608                                 char errbuf[512];
 609                                 perf_evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
 610                                 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
 611                         }
 612
 613                         goto out_put;
 614                 }
 615                 break;
 616         }
 617
 618         ret = perf_evlist__mmap(evlist, UINT_MAX, false);
 619         if (ret < 0) {
 620                 pr_debug("perf_evlist__mmap failed\n");
 621                 goto out_put;
 622         }
 623
 624         perf_evlist__enable(evlist);
 625
 626         do_something();
 627
 628         perf_evlist__disable(evlist);
 629
 630         ret = process_events(machine, evlist, &state);
 631         if (ret < 0)
 632                 goto out_put;
 633
 634         if (!have_vmlinux && !have_kcore && !try_kcore)
 635                 err = TEST_CODE_READING_NO_KERNEL_OBJ;
 636         else if (!have_vmlinux && !try_kcore)
 637                 err = TEST_CODE_READING_NO_VMLINUX;
 638         else if (excl_kernel)
 639                 err = TEST_CODE_READING_NO_ACCESS;
 640         else
 641                 err = TEST_CODE_READING_OK;
 642 out_put:
 643         thread__put(thread);
 644 out_err:
 645
 646         if (evlist) {
 647                 perf_evlist__delete(evlist);
 648         } else {
 649                 cpu_map__put(cpus);
 650                 thread_map__put(threads);
 651         }
 652         machine__delete_threads(machine);
 653         machine__delete(machine);
 654
 655         return err;
 656 }
 657
 658 int test__code_reading(int subtest __maybe_unused)
 659 {
 660         int ret;
 661
 662         ret = do_test_code_reading(false);
 663         if (!ret)
 664                 ret = do_test_code_reading(true);
 665
 666         switch (ret) {
 667         case TEST_CODE_READING_OK:
 668                 return 0;
 669         case TEST_CODE_READING_NO_VMLINUX:
 670                 pr_debug("no vmlinux\n");
 671                 return 0;
 672         case TEST_CODE_READING_NO_KCORE:
 673                 pr_debug("no kcore\n");
 674                 return 0;
 675         case TEST_CODE_READING_NO_ACCESS:
 676                 pr_debug("no access\n");
 677                 return 0;
 678         case TEST_CODE_READING_NO_KERNEL_OBJ:
 679                 pr_debug("no kernel obj\n");
 680                 return 0;
 681         default:
 682                 return -1;
 683         };
 684 }