tools/perf/tests/code-reading.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <errno.h>
   3 #include <linux/kernel.h>
   4 #include <linux/types.h>
   5 #include <inttypes.h>
   6 #include <stdlib.h>
   7 #include <unistd.h>
   8 #include <stdio.h>
   9 #include <string.h>
  10 #include <sys/param.h>
  11 #include <perf/cpumap.h>
  12 #include <perf/evlist.h>
  13 #include <perf/mmap.h>
  14
  15 #include "debug.h"
  16 #include "dso.h"
  17 #include "env.h"
  18 #include "parse-events.h"
  19 #include "trace-event.h"
  20 #include "evlist.h"
  21 #include "evsel.h"
  22 #include "thread_map.h"
  23 #include "machine.h"
  24 #include "map.h"
  25 #include "symbol.h"
  26 #include "event.h"
  27 #include "record.h"
  28 #include "util/mmap.h"
  29 #include "util/string2.h"
  30 #include "util/synthetic-events.h"
  31 #include "thread.h"
  32
  33 #include "tests.h"
  34
  35 #include <linux/ctype.h>
  36
  37 #define BUFSZ   1024
  38 #define READLEN 128
  39
  40 struct state {
  41         u64 done[1024];
  42         size_t done_cnt;
  43 };
  44
  45 static size_t read_objdump_chunk(const char **line, unsigned char **buf,
  46                                  size_t *buf_len)
  47 {
  48         size_t bytes_read = 0;
  49         unsigned char *chunk_start = *buf;
  50
  51         /* Read bytes */
  52         while (*buf_len > 0) {
  53                 char c1, c2;
  54
  55                 /* Get 2 hex digits */
  56                 c1 = *(*line)++;
  57                 if (!isxdigit(c1))
  58                         break;
  59                 c2 = *(*line)++;
  60                 if (!isxdigit(c2))
  61                         break;
  62
  63                 /* Store byte and advance buf */
  64                 **buf = (hex(c1) << 4) | hex(c2);
  65                 (*buf)++;
  66                 (*buf_len)--;
  67                 bytes_read++;
  68
  69                 /* End of chunk? */
  70                 if (isspace(**line))
  71                         break;
  72         }
  73
  74         /*
  75          * objdump will display raw insn as LE if code endian
  76          * is LE and bytes_per_chunk > 1. In that case reverse
  77          * the chunk we just read.
  78          *
  79          * see disassemble_bytes() at binutils/objdump.c for details
  80          * how objdump chooses display endian)
  81          */
  82         if (bytes_read > 1 && !bigendian()) {
  83                 unsigned char *chunk_end = chunk_start + bytes_read - 1;
  84                 unsigned char tmp;
  85
  86                 while (chunk_start < chunk_end) {
  87                         tmp = *chunk_start;
  88                         *chunk_start = *chunk_end;
  89                         *chunk_end = tmp;
  90                         chunk_start++;
  91                         chunk_end--;
  92                 }
  93         }
  94
  95         return bytes_read;
  96 }
  97
  98 static size_t read_objdump_line(const char *line, unsigned char *buf,
  99                                 size_t buf_len)
 100 {
 101         const char *p;
 102         size_t ret, bytes_read = 0;
 103
 104         /* Skip to a colon */
 105         p = strchr(line, ':');
 106         if (!p)
 107                 return 0;
 108         p++;
 109
 110         /* Skip initial spaces */
 111         while (*p) {
 112                 if (!isspace(*p))
 113                         break;
 114                 p++;
 115         }
 116
 117         do {
 118                 ret = read_objdump_chunk(&p, &buf, &buf_len);
 119                 bytes_read += ret;
 120                 p++;
 121         } while (ret > 0);
 122
 123         /* return number of successfully read bytes */
 124         return bytes_read;
 125 }
 126
 127 static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
 128 {
 129         char *line = NULL;
 130         size_t line_len, off_last = 0;
 131         ssize_t ret;
 132         int err = 0;
 133         u64 addr, last_addr = start_addr;
 134
 135         while (off_last < *len) {
 136                 size_t off, read_bytes, written_bytes;
 137                 unsigned char tmp[BUFSZ];
 138
 139                 ret = getline(&line, &line_len, f);
 140                 if (feof(f))
 141                         break;
 142                 if (ret < 0) {
 143                         pr_debug("getline failed\n");
 144                         err = -1;
 145                         break;
 146                 }
 147
 148                 /* read objdump data into temporary buffer */
 149                 read_bytes = read_objdump_line(line, tmp, sizeof(tmp));
 150                 if (!read_bytes)
 151                         continue;
 152
 153                 if (sscanf(line, "%"PRIx64, &addr) != 1)
 154                         continue;
 155                 if (addr < last_addr) {
 156                         pr_debug("addr going backwards, read beyond section?\n");
 157                         break;
 158                 }
 159                 last_addr = addr;
 160
 161                 /* copy it from temporary buffer to 'buf' according
 162                  * to address on current objdump line */
 163                 off = addr - start_addr;
 164                 if (off >= *len)
 165                         break;
 166                 written_bytes = MIN(read_bytes, *len - off);
 167                 memcpy(buf + off, tmp, written_bytes);
 168                 off_last = off + written_bytes;
 169         }
 170
 171         /* len returns number of bytes that could not be read */
 172         *len -= off_last;
 173
 174         free(line);
 175
 176         return err;
 177 }
 178
 179 static int read_via_objdump(const char *filename, u64 addr, void *buf,
 180                             size_t len)
 181 {
 182         char cmd[PATH_MAX * 2];
 183         const char *fmt;
 184         FILE *f;
 185         int ret;
 186
 187         fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
 188         ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len,
 189                        filename);
 190         if (ret <= 0 || (size_t)ret >= sizeof(cmd))
 191                 return -1;
 192
 193         pr_debug("Objdump command is: %s\n", cmd);
 194
 195         /* Ignore objdump errors */
 196         strcat(cmd, " 2>/dev/null");
 197
 198         f = popen(cmd, "r");
 199         if (!f) {
 200                 pr_debug("popen failed\n");
 201                 return -1;
 202         }
 203
 204         ret = read_objdump_output(f, buf, &len, addr);
 205         if (len) {
 206                 pr_debug("objdump read too few bytes: %zd\n", len);
 207                 if (!ret)
 208                         ret = len;
 209         }
 210
 211         pclose(f);
 212
 213         return ret;
 214 }
 215
 216 static void dump_buf(unsigned char *buf, size_t len)
 217 {
 218         size_t i;
 219
 220         for (i = 0; i < len; i++) {
 221                 pr_debug("0x%02x ", buf[i]);
 222                 if (i % 16 == 15)
 223                         pr_debug("\n");
 224         }
 225         pr_debug("\n");
 226 }
 227
 228 static int read_object_code(u64 addr, size_t len, u8 cpumode,
 229                             struct thread *thread, struct state *state)
 230 {
 231         struct addr_location al;
 232         unsigned char buf1[BUFSZ] = {0};
 233         unsigned char buf2[BUFSZ] = {0};
 234         size_t ret_len;
 235         u64 objdump_addr;
 236         const char *objdump_name;
 237         char decomp_name[KMOD_DECOMP_LEN];
 238         bool decomp = false;
 239         int ret;
 240
 241         pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
 242
 243         if (!thread__find_map(thread, cpumode, addr, &al) || !al.map->dso) {
 244                 if (cpumode == PERF_RECORD_MISC_HYPERVISOR) {
 245                         pr_debug("Hypervisor address can not be resolved - skipping\n");
 246                         return 0;
 247                 }
 248
 249                 pr_debug("thread__find_map failed\n");
 250                 return -1;
 251         }
 252
 253         pr_debug("File is: %s\n", al.map->dso->long_name);
 254
 255         if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
 256             !dso__is_kcore(al.map->dso)) {
 257                 pr_debug("Unexpected kernel address - skipping\n");
 258                 return 0;
 259         }
 260
 261         pr_debug("On file address is: %#"PRIx64"\n", al.addr);
 262
 263         if (len > BUFSZ)
 264                 len = BUFSZ;
 265
 266         /* Do not go off the map */
 267         if (addr + len > al.map->end)
 268                 len = al.map->end - addr;
 269
 270         /* Read the object code using perf */
 271         ret_len = dso__data_read_offset(al.map->dso, thread->maps->machine,
 272                                         al.addr, buf1, len);
 273         if (ret_len != len) {
 274                 pr_debug("dso__data_read_offset failed\n");
 275                 return -1;
 276         }
 277
 278         /*
 279          * Converting addresses for use by objdump requires more information.
 280          * map__load() does that.  See map__rip_2objdump() for details.
 281          */
 282         if (map__load(al.map))
 283                 return -1;
 284
 285         /* objdump struggles with kcore - try each map only once */
 286         if (dso__is_kcore(al.map->dso)) {
 287                 size_t d;
 288
 289                 for (d = 0; d < state->done_cnt; d++) {
 290                         if (state->done[d] == al.map->start) {
 291                                 pr_debug("kcore map tested already");
 292                                 pr_debug(" - skipping\n");
 293                                 return 0;
 294                         }
 295                 }
 296                 if (state->done_cnt >= ARRAY_SIZE(state->done)) {
 297                         pr_debug("Too many kcore maps - skipping\n");
 298                         return 0;
 299                 }
 300                 state->done[state->done_cnt++] = al.map->start;
 301         }
 302
 303         objdump_name = al.map->dso->long_name;
 304         if (dso__needs_decompress(al.map->dso)) {
 305                 if (dso__decompress_kmodule_path(al.map->dso, objdump_name,
 306                                                  decomp_name,
 307                                                  sizeof(decomp_name)) < 0) {
 308                         pr_debug("decompression failed\n");
 309                         return -1;
 310                 }
 311
 312                 decomp = true;
 313                 objdump_name = decomp_name;
 314         }
 315
 316         /* Read the object code using objdump */
 317         objdump_addr = map__rip_2objdump(al.map, al.addr);
 318         ret = read_via_objdump(objdump_name, objdump_addr, buf2, len);
 319
 320         if (decomp)
 321                 unlink(objdump_name);
 322
 323         if (ret > 0) {
 324                 /*
 325                  * The kernel maps are inaccurate - assume objdump is right in
 326                  * that case.
 327                  */
 328                 if (cpumode == PERF_RECORD_MISC_KERNEL ||
 329                     cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
 330                         len -= ret;
 331                         if (len) {
 332                                 pr_debug("Reducing len to %zu\n", len);
 333                         } else if (dso__is_kcore(al.map->dso)) {
 334                                 /*
 335                                  * objdump cannot handle very large segments
 336                                  * that may be found in kcore.
 337                                  */
 338                                 pr_debug("objdump failed for kcore");
 339                                 pr_debug(" - skipping\n");
 340                                 return 0;
 341                         } else {
 342                                 return -1;
 343                         }
 344                 }
 345         }
 346         if (ret < 0) {
 347                 pr_debug("read_via_objdump failed\n");
 348                 return -1;
 349         }
 350
 351         /* The results should be identical */
 352         if (memcmp(buf1, buf2, len)) {
 353                 pr_debug("Bytes read differ from those read by objdump\n");
 354                 pr_debug("buf1 (dso):\n");
 355                 dump_buf(buf1, len);
 356                 pr_debug("buf2 (objdump):\n");
 357                 dump_buf(buf2, len);
 358                 return -1;
 359         }
 360         pr_debug("Bytes read match those read by objdump\n");
 361
 362         return 0;
 363 }
 364
 365 static int process_sample_event(struct machine *machine,
 366                                 struct evlist *evlist,
 367                                 union perf_event *event, struct state *state)
 368 {
 369         struct perf_sample sample;
 370         struct thread *thread;
 371         int ret;
 372
 373         if (evlist__parse_sample(evlist, event, &sample)) {
 374                 pr_debug("evlist__parse_sample failed\n");
 375                 return -1;
 376         }
 377
 378         thread = machine__findnew_thread(machine, sample.pid, sample.tid);
 379         if (!thread) {
 380                 pr_debug("machine__findnew_thread failed\n");
 381                 return -1;
 382         }
 383
 384         ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state);
 385         thread__put(thread);
 386         return ret;
 387 }
 388
 389 static int process_event(struct machine *machine, struct evlist *evlist,
 390                          union perf_event *event, struct state *state)
 391 {
 392         if (event->header.type == PERF_RECORD_SAMPLE)
 393                 return process_sample_event(machine, evlist, event, state);
 394
 395         if (event->header.type == PERF_RECORD_THROTTLE ||
 396             event->header.type == PERF_RECORD_UNTHROTTLE)
 397                 return 0;
 398
 399         if (event->header.type < PERF_RECORD_MAX) {
 400                 int ret;
 401
 402                 ret = machine__process_event(machine, event, NULL);
 403                 if (ret < 0)
 404                         pr_debug("machine__process_event failed, event type %u\n",
 405                                  event->header.type);
 406                 return ret;
 407         }
 408
 409         return 0;
 410 }
 411
 412 static int process_events(struct machine *machine, struct evlist *evlist,
 413                           struct state *state)
 414 {
 415         union perf_event *event;
 416         struct mmap *md;
 417         int i, ret;
 418
 419         for (i = 0; i < evlist->core.nr_mmaps; i++) {
 420                 md = &evlist->mmap[i];
 421                 if (perf_mmap__read_init(&md->core) < 0)
 422                         continue;
 423
 424                 while ((event = perf_mmap__read_event(&md->core)) != NULL) {
 425                         ret = process_event(machine, evlist, event, state);
 426                         perf_mmap__consume(&md->core);
 427                         if (ret < 0)
 428                                 return ret;
 429                 }
 430                 perf_mmap__read_done(&md->core);
 431         }
 432         return 0;
 433 }
 434
 435 static int comp(const void *a, const void *b)
 436 {
 437         return *(int *)a - *(int *)b;
 438 }
 439
 440 static void do_sort_something(void)
 441 {
 442         int buf[40960], i;
 443
 444         for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
 445                 buf[i] = ARRAY_SIZE(buf) - i - 1;
 446
 447         qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
 448
 449         for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
 450                 if (buf[i] != i) {
 451                         pr_debug("qsort failed\n");
 452                         break;
 453                 }
 454         }
 455 }
 456
 457 static void sort_something(void)
 458 {
 459         int i;
 460
 461         for (i = 0; i < 10; i++)
 462                 do_sort_something();
 463 }
 464
 465 static void syscall_something(void)
 466 {
 467         int pipefd[2];
 468         int i;
 469
 470         for (i = 0; i < 1000; i++) {
 471                 if (pipe(pipefd) < 0) {
 472                         pr_debug("pipe failed\n");
 473                         break;
 474                 }
 475                 close(pipefd[1]);
 476                 close(pipefd[0]);
 477         }
 478 }
 479
 480 static void fs_something(void)
 481 {
 482         const char *test_file_name = "temp-perf-code-reading-test-file--";
 483         FILE *f;
 484         int i;
 485
 486         for (i = 0; i < 1000; i++) {
 487                 f = fopen(test_file_name, "w+");
 488                 if (f) {
 489                         fclose(f);
 490                         unlink(test_file_name);
 491                 }
 492         }
 493 }
 494
 495 #ifdef __s390x__
 496 #include "header.h" // for get_cpuid()
 497 #endif
 498
 499 static const char *do_determine_event(bool excl_kernel)
 500 {
 501         const char *event = excl_kernel ? "cycles:u" : "cycles";
 502
 503 #ifdef __s390x__
 504         char cpuid[128], model[16], model_c[16], cpum_cf_v[16];
 505         unsigned int family;
 506         int ret, cpum_cf_a;
 507
 508         if (get_cpuid(cpuid, sizeof(cpuid)))
 509                 goto out_clocks;
 510         ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c,
 511                      model, cpum_cf_v, &cpum_cf_a);
 512         if (ret != 5)            /* Not available */
 513                 goto out_clocks;
 514         if (excl_kernel && (cpum_cf_a & 4))
 515                 return event;
 516         if (!excl_kernel && (cpum_cf_a & 2))
 517                 return event;
 518
 519         /* Fall through: missing authorization */
 520 out_clocks:
 521         event = excl_kernel ? "cpu-clock:u" : "cpu-clock";
 522
 523 #endif
 524         return event;
 525 }
 526
 527 static void do_something(void)
 528 {
 529         fs_something();
 530
 531         sort_something();
 532
 533         syscall_something();
 534 }
 535
 536 enum {
 537         TEST_CODE_READING_OK,
 538         TEST_CODE_READING_NO_VMLINUX,
 539         TEST_CODE_READING_NO_KCORE,
 540         TEST_CODE_READING_NO_ACCESS,
 541         TEST_CODE_READING_NO_KERNEL_OBJ,
 542 };
 543
 544 static int do_test_code_reading(bool try_kcore)
 545 {
 546         struct machine *machine;
 547         struct thread *thread;
 548         struct record_opts opts = {
 549                 .mmap_pages          = UINT_MAX,
 550                 .user_freq           = UINT_MAX,
 551                 .user_interval       = ULLONG_MAX,
 552                 .freq                = 500,
 553                 .target              = {
 554                         .uses_mmap   = true,
 555                 },
 556         };
 557         struct state state = {
 558                 .done_cnt = 0,
 559         };
 560         struct perf_thread_map *threads = NULL;
 561         struct perf_cpu_map *cpus = NULL;
 562         struct evlist *evlist = NULL;
 563         struct evsel *evsel = NULL;
 564         int err = -1, ret;
 565         pid_t pid;
 566         struct map *map;
 567         bool have_vmlinux, have_kcore, excl_kernel = false;
 568
 569         pid = getpid();
 570
 571         machine = machine__new_host();
 572         machine->env = &perf_env;
 573
 574         ret = machine__create_kernel_maps(machine);
 575         if (ret < 0) {
 576                 pr_debug("machine__create_kernel_maps failed\n");
 577                 goto out_err;
 578         }
 579
 580         /* Force the use of kallsyms instead of vmlinux to try kcore */
 581         if (try_kcore)
 582                 symbol_conf.kallsyms_name = "/proc/kallsyms";
 583
 584         /* Load kernel map */
 585         map = machine__kernel_map(machine);
 586         ret = map__load(map);
 587         if (ret < 0) {
 588                 pr_debug("map__load failed\n");
 589                 goto out_err;
 590         }
 591         have_vmlinux = dso__is_vmlinux(map->dso);
 592         have_kcore = dso__is_kcore(map->dso);
 593
 594         /* 2nd time through we just try kcore */
 595         if (try_kcore && !have_kcore)
 596                 return TEST_CODE_READING_NO_KCORE;
 597
 598         /* No point getting kernel events if there is no kernel object */
 599         if (!have_vmlinux && !have_kcore)
 600                 excl_kernel = true;
 601
 602         threads = thread_map__new_by_tid(pid);
 603         if (!threads) {
 604                 pr_debug("thread_map__new_by_tid failed\n");
 605                 goto out_err;
 606         }
 607
 608         ret = perf_event__synthesize_thread_map(NULL, threads,
 609                                                 perf_event__process, machine,
 610                                                 true, false);
 611         if (ret < 0) {
 612                 pr_debug("perf_event__synthesize_thread_map failed\n");
 613                 goto out_err;
 614         }
 615
 616         thread = machine__findnew_thread(machine, pid, pid);
 617         if (!thread) {
 618                 pr_debug("machine__findnew_thread failed\n");
 619                 goto out_put;
 620         }
 621
 622         cpus = perf_cpu_map__new(NULL);
 623         if (!cpus) {
 624                 pr_debug("perf_cpu_map__new failed\n");
 625                 goto out_put;
 626         }
 627
 628         while (1) {
 629                 const char *str;
 630
 631                 evlist = evlist__new();
 632                 if (!evlist) {
 633                         pr_debug("evlist__new failed\n");
 634                         goto out_put;
 635                 }
 636
 637                 perf_evlist__set_maps(&evlist->core, cpus, threads);
 638
 639                 str = do_determine_event(excl_kernel);
 640                 pr_debug("Parsing event '%s'\n", str);
 641                 ret = parse_event(evlist, str);
 642                 if (ret < 0) {
 643                         pr_debug("parse_events failed\n");
 644                         goto out_put;
 645                 }
 646
 647                 evlist__config(evlist, &opts, NULL);
 648
 649                 evsel = evlist__first(evlist);
 650
 651                 evsel->core.attr.comm = 1;
 652                 evsel->core.attr.disabled = 1;
 653                 evsel->core.attr.enable_on_exec = 0;
 654
 655                 ret = evlist__open(evlist);
 656                 if (ret < 0) {
 657                         if (!excl_kernel) {
 658                                 excl_kernel = true;
 659                                 /*
 660                                  * Both cpus and threads are now owned by evlist
 661                                  * and will be freed by following perf_evlist__set_maps
 662                                  * call. Getting reference to keep them alive.
 663                                  */
 664                                 perf_cpu_map__get(cpus);
 665                                 perf_thread_map__get(threads);
 666                                 perf_evlist__set_maps(&evlist->core, NULL, NULL);
 667                                 evlist__delete(evlist);
 668                                 evlist = NULL;
 669                                 continue;
 670                         }
 671
 672                         if (verbose > 0) {
 673                                 char errbuf[512];
 674                                 evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
 675                                 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
 676                         }
 677
 678                         goto out_put;
 679                 }
 680                 break;
 681         }
 682
 683         ret = evlist__mmap(evlist, UINT_MAX);
 684         if (ret < 0) {
 685                 pr_debug("evlist__mmap failed\n");
 686                 goto out_put;
 687         }
 688
 689         evlist__enable(evlist);
 690
 691         do_something();
 692
 693         evlist__disable(evlist);
 694
 695         ret = process_events(machine, evlist, &state);
 696         if (ret < 0)
 697                 goto out_put;
 698
 699         if (!have_vmlinux && !have_kcore && !try_kcore)
 700                 err = TEST_CODE_READING_NO_KERNEL_OBJ;
 701         else if (!have_vmlinux && !try_kcore)
 702                 err = TEST_CODE_READING_NO_VMLINUX;
 703         else if (excl_kernel)
 704                 err = TEST_CODE_READING_NO_ACCESS;
 705         else
 706                 err = TEST_CODE_READING_OK;
 707 out_put:
 708         thread__put(thread);
 709 out_err:
 710         evlist__delete(evlist);
 711         perf_cpu_map__put(cpus);
 712         perf_thread_map__put(threads);
 713         machine__delete_threads(machine);
 714         machine__delete(machine);
 715
 716         return err;
 717 }
 718
 719 static int test__code_reading(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
 720 {
 721         int ret;
 722
 723         ret = do_test_code_reading(false);
 724         if (!ret)
 725                 ret = do_test_code_reading(true);
 726
 727         switch (ret) {
 728         case TEST_CODE_READING_OK:
 729                 return 0;
 730         case TEST_CODE_READING_NO_VMLINUX:
 731                 pr_debug("no vmlinux\n");
 732                 return 0;
 733         case TEST_CODE_READING_NO_KCORE:
 734                 pr_debug("no kcore\n");
 735                 return 0;
 736         case TEST_CODE_READING_NO_ACCESS:
 737                 pr_debug("no access\n");
 738                 return 0;
 739         case TEST_CODE_READING_NO_KERNEL_OBJ:
 740                 pr_debug("no kernel obj\n");
 741                 return 0;
 742         default:
 743                 return -1;
 744         };
 745 }
 746
 747 DEFINE_SUITE("Object code reading", code_reading);