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_line(const char *line, size_t line_len, void *buf,
  37                               size_t len)
  38 {
  39         const char *p;
  40         size_t i, j = 0;
  41
  42         /* Skip to a colon */
  43         p = strchr(line, ':');
  44         if (!p)
  45                 return 0;
  46         i = p + 1 - line;
  47
  48         /* Read bytes */
  49         while (j < len) {
  50                 char c1, c2;
  51
  52                 /* Skip spaces */
  53                 for (; i < line_len; i++) {
  54                         if (!isspace(line[i]))
  55                                 break;
  56                 }
  57                 /* Get 2 hex digits */
  58                 if (i >= line_len || !isxdigit(line[i]))
  59                         break;
  60                 c1 = line[i++];
  61                 if (i >= line_len || !isxdigit(line[i]))
  62                         break;
  63                 c2 = line[i++];
  64                 /* Followed by a space */
  65                 if (i < line_len && line[i] && !isspace(line[i]))
  66                         break;
  67                 /* Store byte */
  68                 *(unsigned char *)buf = (hex(c1) << 4) | hex(c2);
  69                 buf += 1;
  70                 j++;
  71         }
  72         /* return number of successfully read bytes */
  73         return j;
  74 }
  75
  76 static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
  77 {
  78         char *line = NULL;
  79         size_t line_len, off_last = 0;
  80         ssize_t ret;
  81         int err = 0;
  82         u64 addr, last_addr = start_addr;
  83
  84         while (off_last < *len) {
  85                 size_t off, read_bytes, written_bytes;
  86                 unsigned char tmp[BUFSZ];
  87
  88                 ret = getline(&line, &line_len, f);
  89                 if (feof(f))
  90                         break;
  91                 if (ret < 0) {
  92                         pr_debug("getline failed\n");
  93                         err = -1;
  94                         break;
  95                 }
  96
  97                 /* read objdump data into temporary buffer */
  98                 read_bytes = read_objdump_line(line, ret, tmp, sizeof(tmp));
  99                 if (!read_bytes)
 100                         continue;
 101
 102                 if (sscanf(line, "%"PRIx64, &addr) != 1)
 103                         continue;
 104                 if (addr < last_addr) {
 105                         pr_debug("addr going backwards, read beyond section?\n");
 106                         break;
 107                 }
 108                 last_addr = addr;
 109
 110                 /* copy it from temporary buffer to 'buf' according
 111                  * to address on current objdump line */
 112                 off = addr - start_addr;
 113                 if (off >= *len)
 114                         break;
 115                 written_bytes = MIN(read_bytes, *len - off);
 116                 memcpy(buf + off, tmp, written_bytes);
 117                 off_last = off + written_bytes;
 118         }
 119
 120         /* len returns number of bytes that could not be read */
 121         *len -= off_last;
 122
 123         free(line);
 124
 125         return err;
 126 }
 127
 128 static int read_via_objdump(const char *filename, u64 addr, void *buf,
 129                             size_t len)
 130 {
 131         char cmd[PATH_MAX * 2];
 132         const char *fmt;
 133         FILE *f;
 134         int ret;
 135
 136         fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
 137         ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len,
 138                        filename);
 139         if (ret <= 0 || (size_t)ret >= sizeof(cmd))
 140                 return -1;
 141
 142         pr_debug("Objdump command is: %s\n", cmd);
 143
 144         /* Ignore objdump errors */
 145         strcat(cmd, " 2>/dev/null");
 146
 147         f = popen(cmd, "r");
 148         if (!f) {
 149                 pr_debug("popen failed\n");
 150                 return -1;
 151         }
 152
 153         ret = read_objdump_output(f, buf, &len, addr);
 154         if (len) {
 155                 pr_debug("objdump read too few bytes\n");
 156                 if (!ret)
 157                         ret = len;
 158         }
 159
 160         pclose(f);
 161
 162         return ret;
 163 }
 164
 165 static void dump_buf(unsigned char *buf, size_t len)
 166 {
 167         size_t i;
 168
 169         for (i = 0; i < len; i++) {
 170                 pr_debug("0x%02x ", buf[i]);
 171                 if (i % 16 == 15)
 172                         pr_debug("\n");
 173         }
 174         pr_debug("\n");
 175 }
 176
 177 static int read_object_code(u64 addr, size_t len, u8 cpumode,
 178                             struct thread *thread, struct state *state)
 179 {
 180         struct addr_location al;
 181         unsigned char buf1[BUFSZ];
 182         unsigned char buf2[BUFSZ];
 183         size_t ret_len;
 184         u64 objdump_addr;
 185         int ret;
 186
 187         pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
 188
 189         thread__find_addr_map(thread, cpumode, MAP__FUNCTION, addr, &al);
 190         if (!al.map || !al.map->dso) {
 191                 pr_debug("thread__find_addr_map failed\n");
 192                 return -1;
 193         }
 194
 195         pr_debug("File is: %s\n", al.map->dso->long_name);
 196
 197         if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
 198             !dso__is_kcore(al.map->dso)) {
 199                 pr_debug("Unexpected kernel address - skipping\n");
 200                 return 0;
 201         }
 202
 203         pr_debug("On file address is: %#"PRIx64"\n", al.addr);
 204
 205         if (len > BUFSZ)
 206                 len = BUFSZ;
 207
 208         /* Do not go off the map */
 209         if (addr + len > al.map->end)
 210                 len = al.map->end - addr;
 211
 212         /* Read the object code using perf */
 213         ret_len = dso__data_read_offset(al.map->dso, thread->mg->machine,
 214                                         al.addr, buf1, len);
 215         if (ret_len != len) {
 216                 pr_debug("dso__data_read_offset failed\n");
 217                 return -1;
 218         }
 219
 220         /*
 221          * Converting addresses for use by objdump requires more information.
 222          * map__load() does that.  See map__rip_2objdump() for details.
 223          */
 224         if (map__load(al.map, NULL))
 225                 return -1;
 226
 227         /* objdump struggles with kcore - try each map only once */
 228         if (dso__is_kcore(al.map->dso)) {
 229                 size_t d;
 230
 231                 for (d = 0; d < state->done_cnt; d++) {
 232                         if (state->done[d] == al.map->start) {
 233                                 pr_debug("kcore map tested already");
 234                                 pr_debug(" - skipping\n");
 235                                 return 0;
 236                         }
 237                 }
 238                 if (state->done_cnt >= ARRAY_SIZE(state->done)) {
 239                         pr_debug("Too many kcore maps - skipping\n");
 240                         return 0;
 241                 }
 242                 state->done[state->done_cnt++] = al.map->start;
 243         }
 244
 245         /* Read the object code using objdump */
 246         objdump_addr = map__rip_2objdump(al.map, al.addr);
 247         ret = read_via_objdump(al.map->dso->long_name, objdump_addr, buf2, len);
 248         if (ret > 0) {
 249                 /*
 250                  * The kernel maps are inaccurate - assume objdump is right in
 251                  * that case.
 252                  */
 253                 if (cpumode == PERF_RECORD_MISC_KERNEL ||
 254                     cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
 255                         len -= ret;
 256                         if (len) {
 257                                 pr_debug("Reducing len to %zu\n", len);
 258                         } else if (dso__is_kcore(al.map->dso)) {
 259                                 /*
 260                                  * objdump cannot handle very large segments
 261                                  * that may be found in kcore.
 262                                  */
 263                                 pr_debug("objdump failed for kcore");
 264                                 pr_debug(" - skipping\n");
 265                                 return 0;
 266                         } else {
 267                                 return -1;
 268                         }
 269                 }
 270         }
 271         if (ret < 0) {
 272                 pr_debug("read_via_objdump failed\n");
 273                 return -1;
 274         }
 275
 276         /* The results should be identical */
 277         if (memcmp(buf1, buf2, len)) {
 278                 pr_debug("Bytes read differ from those read by objdump\n");
 279                 pr_debug("buf1 (dso):\n");
 280                 dump_buf(buf1, len);
 281                 pr_debug("buf2 (objdump):\n");
 282                 dump_buf(buf2, len);
 283                 return -1;
 284         }
 285         pr_debug("Bytes read match those read by objdump\n");
 286
 287         return 0;
 288 }
 289
 290 static int process_sample_event(struct machine *machine,
 291                                 struct perf_evlist *evlist,
 292                                 union perf_event *event, struct state *state)
 293 {
 294         struct perf_sample sample;
 295         struct thread *thread;
 296         u8 cpumode;
 297         int ret;
 298
 299         if (perf_evlist__parse_sample(evlist, event, &sample)) {
 300                 pr_debug("perf_evlist__parse_sample failed\n");
 301                 return -1;
 302         }
 303
 304         thread = machine__findnew_thread(machine, sample.pid, sample.tid);
 305         if (!thread) {
 306                 pr_debug("machine__findnew_thread failed\n");
 307                 return -1;
 308         }
 309
 310         cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
 311
 312         ret = read_object_code(sample.ip, READLEN, cpumode, thread, state);
 313         thread__put(thread);
 314         return ret;
 315 }
 316
 317 static int process_event(struct machine *machine, struct perf_evlist *evlist,
 318                          union perf_event *event, struct state *state)
 319 {
 320         if (event->header.type == PERF_RECORD_SAMPLE)
 321                 return process_sample_event(machine, evlist, event, state);
 322
 323         if (event->header.type == PERF_RECORD_THROTTLE ||
 324             event->header.type == PERF_RECORD_UNTHROTTLE)
 325                 return 0;
 326
 327         if (event->header.type < PERF_RECORD_MAX) {
 328                 int ret;
 329
 330                 ret = machine__process_event(machine, event, NULL);
 331                 if (ret < 0)
 332                         pr_debug("machine__process_event failed, event type %u\n",
 333                                  event->header.type);
 334                 return ret;
 335         }
 336
 337         return 0;
 338 }
 339
 340 static int process_events(struct machine *machine, struct perf_evlist *evlist,
 341                           struct state *state)
 342 {
 343         union perf_event *event;
 344         int i, ret;
 345
 346         for (i = 0; i < evlist->nr_mmaps; i++) {
 347                 while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) {
 348                         ret = process_event(machine, evlist, event, state);
 349                         perf_evlist__mmap_consume(evlist, i);
 350                         if (ret < 0)
 351                                 return ret;
 352                 }
 353         }
 354         return 0;
 355 }
 356
 357 static int comp(const void *a, const void *b)
 358 {
 359         return *(int *)a - *(int *)b;
 360 }
 361
 362 static void do_sort_something(void)
 363 {
 364         int buf[40960], i;
 365
 366         for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
 367                 buf[i] = ARRAY_SIZE(buf) - i - 1;
 368
 369         qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
 370
 371         for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
 372                 if (buf[i] != i) {
 373                         pr_debug("qsort failed\n");
 374                         break;
 375                 }
 376         }
 377 }
 378
 379 static void sort_something(void)
 380 {
 381         int i;
 382
 383         for (i = 0; i < 10; i++)
 384                 do_sort_something();
 385 }
 386
 387 static void syscall_something(void)
 388 {
 389         int pipefd[2];
 390         int i;
 391
 392         for (i = 0; i < 1000; i++) {
 393                 if (pipe(pipefd) < 0) {
 394                         pr_debug("pipe failed\n");
 395                         break;
 396                 }
 397                 close(pipefd[1]);
 398                 close(pipefd[0]);
 399         }
 400 }
 401
 402 static void fs_something(void)
 403 {
 404         const char *test_file_name = "temp-perf-code-reading-test-file--";
 405         FILE *f;
 406         int i;
 407
 408         for (i = 0; i < 1000; i++) {
 409                 f = fopen(test_file_name, "w+");
 410                 if (f) {
 411                         fclose(f);
 412                         unlink(test_file_name);
 413                 }
 414         }
 415 }
 416
 417 static void do_something(void)
 418 {
 419         fs_something();
 420
 421         sort_something();
 422
 423         syscall_something();
 424 }
 425
 426 enum {
 427         TEST_CODE_READING_OK,
 428         TEST_CODE_READING_NO_VMLINUX,
 429         TEST_CODE_READING_NO_KCORE,
 430         TEST_CODE_READING_NO_ACCESS,
 431         TEST_CODE_READING_NO_KERNEL_OBJ,
 432 };
 433
 434 static int do_test_code_reading(bool try_kcore)
 435 {
 436         struct machine *machine;
 437         struct thread *thread;
 438         struct record_opts opts = {
 439                 .mmap_pages          = UINT_MAX,
 440                 .user_freq           = UINT_MAX,
 441                 .user_interval       = ULLONG_MAX,
 442                 .freq                = 4000,
 443                 .target              = {
 444                         .uses_mmap   = true,
 445                 },
 446         };
 447         struct state state = {
 448                 .done_cnt = 0,
 449         };
 450         struct thread_map *threads = NULL;
 451         struct cpu_map *cpus = NULL;
 452         struct perf_evlist *evlist = NULL;
 453         struct perf_evsel *evsel = NULL;
 454         int err = -1, ret;
 455         pid_t pid;
 456         struct map *map;
 457         bool have_vmlinux, have_kcore, excl_kernel = false;
 458
 459         pid = getpid();
 460
 461         machine = machine__new_host();
 462
 463         ret = machine__create_kernel_maps(machine);
 464         if (ret < 0) {
 465                 pr_debug("machine__create_kernel_maps failed\n");
 466                 goto out_err;
 467         }
 468
 469         /* Force the use of kallsyms instead of vmlinux to try kcore */
 470         if (try_kcore)
 471                 symbol_conf.kallsyms_name = "/proc/kallsyms";
 472
 473         /* Load kernel map */
 474         map = machine__kernel_map(machine);
 475         ret = map__load(map, NULL);
 476         if (ret < 0) {
 477                 pr_debug("map__load failed\n");
 478                 goto out_err;
 479         }
 480         have_vmlinux = dso__is_vmlinux(map->dso);
 481         have_kcore = dso__is_kcore(map->dso);
 482
 483         /* 2nd time through we just try kcore */
 484         if (try_kcore && !have_kcore)
 485                 return TEST_CODE_READING_NO_KCORE;
 486
 487         /* No point getting kernel events if there is no kernel object */
 488         if (!have_vmlinux && !have_kcore)
 489                 excl_kernel = true;
 490
 491         threads = thread_map__new_by_tid(pid);
 492         if (!threads) {
 493                 pr_debug("thread_map__new_by_tid failed\n");
 494                 goto out_err;
 495         }
 496
 497         ret = perf_event__synthesize_thread_map(NULL, threads,
 498                                                 perf_event__process, machine, false, 500);
 499         if (ret < 0) {
 500                 pr_debug("perf_event__synthesize_thread_map failed\n");
 501                 goto out_err;
 502         }
 503
 504         thread = machine__findnew_thread(machine, pid, pid);
 505         if (!thread) {
 506                 pr_debug("machine__findnew_thread failed\n");
 507                 goto out_put;
 508         }
 509
 510         cpus = cpu_map__new(NULL);
 511         if (!cpus) {
 512                 pr_debug("cpu_map__new failed\n");
 513                 goto out_put;
 514         }
 515
 516         while (1) {
 517                 const char *str;
 518
 519                 evlist = perf_evlist__new();
 520                 if (!evlist) {
 521                         pr_debug("perf_evlist__new failed\n");
 522                         goto out_put;
 523                 }
 524
 525                 perf_evlist__set_maps(evlist, cpus, threads);
 526
 527                 if (excl_kernel)
 528                         str = "cycles:u";
 529                 else
 530                         str = "cycles";
 531                 pr_debug("Parsing event '%s'\n", str);
 532                 ret = parse_events(evlist, str, NULL);
 533                 if (ret < 0) {
 534                         pr_debug("parse_events failed\n");
 535                         goto out_put;
 536                 }
 537
 538                 perf_evlist__config(evlist, &opts);
 539
 540                 evsel = perf_evlist__first(evlist);
 541
 542                 evsel->attr.comm = 1;
 543                 evsel->attr.disabled = 1;
 544                 evsel->attr.enable_on_exec = 0;
 545
 546                 ret = perf_evlist__open(evlist);
 547                 if (ret < 0) {
 548                         if (!excl_kernel) {
 549                                 excl_kernel = true;
 550                                 /*
 551                                  * Both cpus and threads are now owned by evlist
 552                                  * and will be freed by following perf_evlist__set_maps
 553                                  * call. Getting refference to keep them alive.
 554                                  */
 555                                 cpu_map__get(cpus);
 556                                 thread_map__get(threads);
 557                                 perf_evlist__set_maps(evlist, NULL, NULL);
 558                                 perf_evlist__delete(evlist);
 559                                 evlist = NULL;
 560                                 continue;
 561                         }
 562                         pr_debug("perf_evlist__open failed\n");
 563                         goto out_put;
 564                 }
 565                 break;
 566         }
 567
 568         ret = perf_evlist__mmap(evlist, UINT_MAX, false);
 569         if (ret < 0) {
 570                 pr_debug("perf_evlist__mmap failed\n");
 571                 goto out_put;
 572         }
 573
 574         perf_evlist__enable(evlist);
 575
 576         do_something();
 577
 578         perf_evlist__disable(evlist);
 579
 580         ret = process_events(machine, evlist, &state);
 581         if (ret < 0)
 582                 goto out_put;
 583
 584         if (!have_vmlinux && !have_kcore && !try_kcore)
 585                 err = TEST_CODE_READING_NO_KERNEL_OBJ;
 586         else if (!have_vmlinux && !try_kcore)
 587                 err = TEST_CODE_READING_NO_VMLINUX;
 588         else if (excl_kernel)
 589                 err = TEST_CODE_READING_NO_ACCESS;
 590         else
 591                 err = TEST_CODE_READING_OK;
 592 out_put:
 593         thread__put(thread);
 594 out_err:
 595
 596         if (evlist) {
 597                 perf_evlist__delete(evlist);
 598         } else {
 599                 cpu_map__put(cpus);
 600                 thread_map__put(threads);
 601         }
 602         machine__delete_threads(machine);
 603         machine__delete(machine);
 604
 605         return err;
 606 }
 607
 608 int test__code_reading(int subtest __maybe_unused)
 609 {
 610         int ret;
 611
 612         ret = do_test_code_reading(false);
 613         if (!ret)
 614                 ret = do_test_code_reading(true);
 615
 616         switch (ret) {
 617         case TEST_CODE_READING_OK:
 618                 return 0;
 619         case TEST_CODE_READING_NO_VMLINUX:
 620                 pr_debug("no vmlinux\n");
 621                 return 0;
 622         case TEST_CODE_READING_NO_KCORE:
 623                 pr_debug("no kcore\n");
 624                 return 0;
 625         case TEST_CODE_READING_NO_ACCESS:
 626                 pr_debug("no access\n");
 627                 return 0;
 628         case TEST_CODE_READING_NO_KERNEL_OBJ:
 629                 pr_debug("no kernel obj\n");
 630                 return 0;
 631         default:
 632                 return -1;
 633         };
 634 }