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