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/synthetic-events.h"
  30 #include "thread.h"
  31
  32 #include "tests.h"
  33
  34 #include <linux/ctype.h>
  35
  36 #define BUFSZ   1024
  37 #define READLEN 128
  38
  39 struct state {
  40         u64 done[1024];
  41         size_t done_cnt;
  42 };
  43
  44 static unsigned int hex(char c)
  45 {
  46         if (c >= '0' && c <= '9')
  47                 return c - '0';
  48         if (c >= 'a' && c <= 'f')
  49                 return c - 'a' + 10;
  50         return c - 'A' + 10;
  51 }
  52
  53 static size_t read_objdump_chunk(const char **line, unsigned char **buf,
  54                                  size_t *buf_len)
  55 {
  56         size_t bytes_read = 0;
  57         unsigned char *chunk_start = *buf;
  58
  59         /* Read bytes */
  60         while (*buf_len > 0) {
  61                 char c1, c2;
  62
  63                 /* Get 2 hex digits */
  64                 c1 = *(*line)++;
  65                 if (!isxdigit(c1))
  66                         break;
  67                 c2 = *(*line)++;
  68                 if (!isxdigit(c2))
  69                         break;
  70
  71                 /* Store byte and advance buf */
  72                 **buf = (hex(c1) << 4) | hex(c2);
  73                 (*buf)++;
  74                 (*buf_len)--;
  75                 bytes_read++;
  76
  77                 /* End of chunk? */
  78                 if (isspace(**line))
  79                         break;
  80         }
  81
  82         /*
  83          * objdump will display raw insn as LE if code endian
  84          * is LE and bytes_per_chunk > 1. In that case reverse
  85          * the chunk we just read.
  86          *
  87          * see disassemble_bytes() at binutils/objdump.c for details
  88          * how objdump chooses display endian)
  89          */
  90         if (bytes_read > 1 && !bigendian()) {
  91                 unsigned char *chunk_end = chunk_start + bytes_read - 1;
  92                 unsigned char tmp;
  93
  94                 while (chunk_start < chunk_end) {
  95                         tmp = *chunk_start;
  96                         *chunk_start = *chunk_end;
  97                         *chunk_end = tmp;
  98                         chunk_start++;
  99                         chunk_end--;
 100                 }
 101         }
 102
 103         return bytes_read;
 104 }
 105
 106 static size_t read_objdump_line(const char *line, unsigned char *buf,
 107                                 size_t buf_len)
 108 {
 109         const char *p;
 110         size_t ret, bytes_read = 0;
 111
 112         /* Skip to a colon */
 113         p = strchr(line, ':');
 114         if (!p)
 115                 return 0;
 116         p++;
 117
 118         /* Skip initial spaces */
 119         while (*p) {
 120                 if (!isspace(*p))
 121                         break;
 122                 p++;
 123         }
 124
 125         do {
 126                 ret = read_objdump_chunk(&p, &buf, &buf_len);
 127                 bytes_read += ret;
 128                 p++;
 129         } while (ret > 0);
 130
 131         /* return number of successfully read bytes */
 132         return bytes_read;
 133 }
 134
 135 static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
 136 {
 137         char *line = NULL;
 138         size_t line_len, off_last = 0;
 139         ssize_t ret;
 140         int err = 0;
 141         u64 addr, last_addr = start_addr;
 142
 143         while (off_last < *len) {
 144                 size_t off, read_bytes, written_bytes;
 145                 unsigned char tmp[BUFSZ];
 146
 147                 ret = getline(&line, &line_len, f);
 148                 if (feof(f))
 149                         break;
 150                 if (ret < 0) {
 151                         pr_debug("getline failed\n");
 152                         err = -1;
 153                         break;
 154                 }
 155
 156                 /* read objdump data into temporary buffer */
 157                 read_bytes = read_objdump_line(line, tmp, sizeof(tmp));
 158                 if (!read_bytes)
 159                         continue;
 160
 161                 if (sscanf(line, "%"PRIx64, &addr) != 1)
 162                         continue;
 163                 if (addr < last_addr) {
 164                         pr_debug("addr going backwards, read beyond section?\n");
 165                         break;
 166                 }
 167                 last_addr = addr;
 168
 169                 /* copy it from temporary buffer to 'buf' according
 170                  * to address on current objdump line */
 171                 off = addr - start_addr;
 172                 if (off >= *len)
 173                         break;
 174                 written_bytes = MIN(read_bytes, *len - off);
 175                 memcpy(buf + off, tmp, written_bytes);
 176                 off_last = off + written_bytes;
 177         }
 178
 179         /* len returns number of bytes that could not be read */
 180         *len -= off_last;
 181
 182         free(line);
 183
 184         return err;
 185 }
 186
 187 static int read_via_objdump(const char *filename, u64 addr, void *buf,
 188                             size_t len)
 189 {
 190         char cmd[PATH_MAX * 2];
 191         const char *fmt;
 192         FILE *f;
 193         int ret;
 194
 195         fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
 196         ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len,
 197                        filename);
 198         if (ret <= 0 || (size_t)ret >= sizeof(cmd))
 199                 return -1;
 200
 201         pr_debug("Objdump command is: %s\n", cmd);
 202
 203         /* Ignore objdump errors */
 204         strcat(cmd, " 2>/dev/null");
 205
 206         f = popen(cmd, "r");
 207         if (!f) {
 208                 pr_debug("popen failed\n");
 209                 return -1;
 210         }
 211
 212         ret = read_objdump_output(f, buf, &len, addr);
 213         if (len) {
 214                 pr_debug("objdump read too few bytes: %zd\n", len);
 215                 if (!ret)
 216                         ret = len;
 217         }
 218
 219         pclose(f);
 220
 221         return ret;
 222 }
 223
 224 static void dump_buf(unsigned char *buf, size_t len)
 225 {
 226         size_t i;
 227
 228         for (i = 0; i < len; i++) {
 229                 pr_debug("0x%02x ", buf[i]);
 230                 if (i % 16 == 15)
 231                         pr_debug("\n");
 232         }
 233         pr_debug("\n");
 234 }
 235
 236 static int read_object_code(u64 addr, size_t len, u8 cpumode,
 237                             struct thread *thread, struct state *state)
 238 {
 239         struct addr_location al;
 240         unsigned char buf1[BUFSZ];
 241         unsigned char buf2[BUFSZ];
 242         size_t ret_len;
 243         u64 objdump_addr;
 244         const char *objdump_name;
 245         char decomp_name[KMOD_DECOMP_LEN];
 246         bool decomp = false;
 247         int ret;
 248
 249         pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
 250
 251         if (!thread__find_map(thread, cpumode, addr, &al) || !al.map->dso) {
 252                 if (cpumode == PERF_RECORD_MISC_HYPERVISOR) {
 253                         pr_debug("Hypervisor address can not be resolved - skipping\n");
 254                         return 0;
 255                 }
 256
 257                 pr_debug("thread__find_map failed\n");
 258                 return -1;
 259         }
 260
 261         pr_debug("File is: %s\n", al.map->dso->long_name);
 262
 263         if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
 264             !dso__is_kcore(al.map->dso)) {
 265                 pr_debug("Unexpected kernel address - skipping\n");
 266                 return 0;
 267         }
 268
 269         pr_debug("On file address is: %#"PRIx64"\n", al.addr);
 270
 271         if (len > BUFSZ)
 272                 len = BUFSZ;
 273
 274         /* Do not go off the map */
 275         if (addr + len > al.map->end)
 276                 len = al.map->end - addr;
 277
 278         /* Read the object code using perf */
 279         ret_len = dso__data_read_offset(al.map->dso, thread->maps->machine,
 280                                         al.addr, buf1, len);
 281         if (ret_len != len) {
 282                 pr_debug("dso__data_read_offset failed\n");
 283                 return -1;
 284         }
 285
 286         /*
 287          * Converting addresses for use by objdump requires more information.
 288          * map__load() does that.  See map__rip_2objdump() for details.
 289          */
 290         if (map__load(al.map))
 291                 return -1;
 292
 293         /* objdump struggles with kcore - try each map only once */
 294         if (dso__is_kcore(al.map->dso)) {
 295                 size_t d;
 296
 297                 for (d = 0; d < state->done_cnt; d++) {
 298                         if (state->done[d] == al.map->start) {
 299                                 pr_debug("kcore map tested already");
 300                                 pr_debug(" - skipping\n");
 301                                 return 0;
 302                         }
 303                 }
 304                 if (state->done_cnt >= ARRAY_SIZE(state->done)) {
 305                         pr_debug("Too many kcore maps - skipping\n");
 306                         return 0;
 307                 }
 308                 state->done[state->done_cnt++] = al.map->start;
 309         }
 310
 311         objdump_name = al.map->dso->long_name;
 312         if (dso__needs_decompress(al.map->dso)) {
 313                 if (dso__decompress_kmodule_path(al.map->dso, objdump_name,
 314                                                  decomp_name,
 315                                                  sizeof(decomp_name)) < 0) {
 316                         pr_debug("decompression failed\n");
 317                         return -1;
 318                 }
 319
 320                 decomp = true;
 321                 objdump_name = decomp_name;
 322         }
 323
 324         /* Read the object code using objdump */
 325         objdump_addr = map__rip_2objdump(al.map, al.addr);
 326         ret = read_via_objdump(objdump_name, objdump_addr, buf2, len);
 327
 328         if (decomp)
 329                 unlink(objdump_name);
 330
 331         if (ret > 0) {
 332                 /*
 333                  * The kernel maps are inaccurate - assume objdump is right in
 334                  * that case.
 335                  */
 336                 if (cpumode == PERF_RECORD_MISC_KERNEL ||
 337                     cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
 338                         len -= ret;
 339                         if (len) {
 340                                 pr_debug("Reducing len to %zu\n", len);
 341                         } else if (dso__is_kcore(al.map->dso)) {
 342                                 /*
 343                                  * objdump cannot handle very large segments
 344                                  * that may be found in kcore.
 345                                  */
 346                                 pr_debug("objdump failed for kcore");
 347                                 pr_debug(" - skipping\n");
 348                                 return 0;
 349                         } else {
 350                                 return -1;
 351                         }
 352                 }
 353         }
 354         if (ret < 0) {
 355                 pr_debug("read_via_objdump failed\n");
 356                 return -1;
 357         }
 358
 359         /* The results should be identical */
 360         if (memcmp(buf1, buf2, len)) {
 361                 pr_debug("Bytes read differ from those read by objdump\n");
 362                 pr_debug("buf1 (dso):\n");
 363                 dump_buf(buf1, len);
 364                 pr_debug("buf2 (objdump):\n");
 365                 dump_buf(buf2, len);
 366                 return -1;
 367         }
 368         pr_debug("Bytes read match those read by objdump\n");
 369
 370         return 0;
 371 }
 372
 373 static int process_sample_event(struct machine *machine,
 374                                 struct evlist *evlist,
 375                                 union perf_event *event, struct state *state)
 376 {
 377         struct perf_sample sample;
 378         struct thread *thread;
 379         int ret;
 380
 381         if (perf_evlist__parse_sample(evlist, event, &sample)) {
 382                 pr_debug("perf_evlist__parse_sample failed\n");
 383                 return -1;
 384         }
 385
 386         thread = machine__findnew_thread(machine, sample.pid, sample.tid);
 387         if (!thread) {
 388                 pr_debug("machine__findnew_thread failed\n");
 389                 return -1;
 390         }
 391
 392         ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state);
 393         thread__put(thread);
 394         return ret;
 395 }
 396
 397 static int process_event(struct machine *machine, struct evlist *evlist,
 398                          union perf_event *event, struct state *state)
 399 {
 400         if (event->header.type == PERF_RECORD_SAMPLE)
 401                 return process_sample_event(machine, evlist, event, state);
 402
 403         if (event->header.type == PERF_RECORD_THROTTLE ||
 404             event->header.type == PERF_RECORD_UNTHROTTLE)
 405                 return 0;
 406
 407         if (event->header.type < PERF_RECORD_MAX) {
 408                 int ret;
 409
 410                 ret = machine__process_event(machine, event, NULL);
 411                 if (ret < 0)
 412                         pr_debug("machine__process_event failed, event type %u\n",
 413                                  event->header.type);
 414                 return ret;
 415         }
 416
 417         return 0;
 418 }
 419
 420 static int process_events(struct machine *machine, struct evlist *evlist,
 421                           struct state *state)
 422 {
 423         union perf_event *event;
 424         struct mmap *md;
 425         int i, ret;
 426
 427         for (i = 0; i < evlist->core.nr_mmaps; i++) {
 428                 md = &evlist->mmap[i];
 429                 if (perf_mmap__read_init(&md->core) < 0)
 430                         continue;
 431
 432                 while ((event = perf_mmap__read_event(&md->core)) != NULL) {
 433                         ret = process_event(machine, evlist, event, state);
 434                         perf_mmap__consume(&md->core);
 435                         if (ret < 0)
 436                                 return ret;
 437                 }
 438                 perf_mmap__read_done(&md->core);
 439         }
 440         return 0;
 441 }
 442
 443 static int comp(const void *a, const void *b)
 444 {
 445         return *(int *)a - *(int *)b;
 446 }
 447
 448 static void do_sort_something(void)
 449 {
 450         int buf[40960], i;
 451
 452         for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
 453                 buf[i] = ARRAY_SIZE(buf) - i - 1;
 454
 455         qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
 456
 457         for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
 458                 if (buf[i] != i) {
 459                         pr_debug("qsort failed\n");
 460                         break;
 461                 }
 462         }
 463 }
 464
 465 static void sort_something(void)
 466 {
 467         int i;
 468
 469         for (i = 0; i < 10; i++)
 470                 do_sort_something();
 471 }
 472
 473 static void syscall_something(void)
 474 {
 475         int pipefd[2];
 476         int i;
 477
 478         for (i = 0; i < 1000; i++) {
 479                 if (pipe(pipefd) < 0) {
 480                         pr_debug("pipe failed\n");
 481                         break;
 482                 }
 483                 close(pipefd[1]);
 484                 close(pipefd[0]);
 485         }
 486 }
 487
 488 static void fs_something(void)
 489 {
 490         const char *test_file_name = "temp-perf-code-reading-test-file--";
 491         FILE *f;
 492         int i;
 493
 494         for (i = 0; i < 1000; i++) {
 495                 f = fopen(test_file_name, "w+");
 496                 if (f) {
 497                         fclose(f);
 498                         unlink(test_file_name);
 499                 }
 500         }
 501 }
 502
 503 #ifdef __s390x__
 504 #include "header.h" // for get_cpuid()
 505 #endif
 506
 507 static const char *do_determine_event(bool excl_kernel)
 508 {
 509         const char *event = excl_kernel ? "cycles:u" : "cycles";
 510
 511 #ifdef __s390x__
 512         char cpuid[128], model[16], model_c[16], cpum_cf_v[16];
 513         unsigned int family;
 514         int ret, cpum_cf_a;
 515
 516         if (get_cpuid(cpuid, sizeof(cpuid)))
 517                 goto out_clocks;
 518         ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c,
 519                      model, cpum_cf_v, &cpum_cf_a);
 520         if (ret != 5)            /* Not available */
 521                 goto out_clocks;
 522         if (excl_kernel && (cpum_cf_a & 4))
 523                 return event;
 524         if (!excl_kernel && (cpum_cf_a & 2))
 525                 return event;
 526
 527         /* Fall through: missing authorization */
 528 out_clocks:
 529         event = excl_kernel ? "cpu-clock:u" : "cpu-clock";
 530
 531 #endif
 532         return event;
 533 }
 534
 535 static void do_something(void)
 536 {
 537         fs_something();
 538
 539         sort_something();
 540
 541         syscall_something();
 542 }
 543
 544 enum {
 545         TEST_CODE_READING_OK,
 546         TEST_CODE_READING_NO_VMLINUX,
 547         TEST_CODE_READING_NO_KCORE,
 548         TEST_CODE_READING_NO_ACCESS,
 549         TEST_CODE_READING_NO_KERNEL_OBJ,
 550 };
 551
 552 static int do_test_code_reading(bool try_kcore)
 553 {
 554         struct machine *machine;
 555         struct thread *thread;
 556         struct record_opts opts = {
 557                 .mmap_pages          = UINT_MAX,
 558                 .user_freq           = UINT_MAX,
 559                 .user_interval       = ULLONG_MAX,
 560                 .freq                = 500,
 561                 .target              = {
 562                         .uses_mmap   = true,
 563                 },
 564         };
 565         struct state state = {
 566                 .done_cnt = 0,
 567         };
 568         struct perf_thread_map *threads = NULL;
 569         struct perf_cpu_map *cpus = NULL;
 570         struct evlist *evlist = NULL;
 571         struct evsel *evsel = NULL;
 572         int err = -1, ret;
 573         pid_t pid;
 574         struct map *map;
 575         bool have_vmlinux, have_kcore, excl_kernel = false;
 576
 577         pid = getpid();
 578
 579         machine = machine__new_host();
 580         machine->env = &perf_env;
 581
 582         ret = machine__create_kernel_maps(machine);
 583         if (ret < 0) {
 584                 pr_debug("machine__create_kernel_maps failed\n");
 585                 goto out_err;
 586         }
 587
 588         /* Force the use of kallsyms instead of vmlinux to try kcore */
 589         if (try_kcore)
 590                 symbol_conf.kallsyms_name = "/proc/kallsyms";
 591
 592         /* Load kernel map */
 593         map = machine__kernel_map(machine);
 594         ret = map__load(map);
 595         if (ret < 0) {
 596                 pr_debug("map__load failed\n");
 597                 goto out_err;
 598         }
 599         have_vmlinux = dso__is_vmlinux(map->dso);
 600         have_kcore = dso__is_kcore(map->dso);
 601
 602         /* 2nd time through we just try kcore */
 603         if (try_kcore && !have_kcore)
 604                 return TEST_CODE_READING_NO_KCORE;
 605
 606         /* No point getting kernel events if there is no kernel object */
 607         if (!have_vmlinux && !have_kcore)
 608                 excl_kernel = true;
 609
 610         threads = thread_map__new_by_tid(pid);
 611         if (!threads) {
 612                 pr_debug("thread_map__new_by_tid failed\n");
 613                 goto out_err;
 614         }
 615
 616         ret = perf_event__synthesize_thread_map(NULL, threads,
 617                                                 perf_event__process, machine, false);
 618         if (ret < 0) {
 619                 pr_debug("perf_event__synthesize_thread_map failed\n");
 620                 goto out_err;
 621         }
 622
 623         thread = machine__findnew_thread(machine, pid, pid);
 624         if (!thread) {
 625                 pr_debug("machine__findnew_thread failed\n");
 626                 goto out_put;
 627         }
 628
 629         cpus = perf_cpu_map__new(NULL);
 630         if (!cpus) {
 631                 pr_debug("perf_cpu_map__new failed\n");
 632                 goto out_put;
 633         }
 634
 635         while (1) {
 636                 const char *str;
 637
 638                 evlist = evlist__new();
 639                 if (!evlist) {
 640                         pr_debug("perf_evlist__new failed\n");
 641                         goto out_put;
 642                 }
 643
 644                 perf_evlist__set_maps(&evlist->core, cpus, threads);
 645
 646                 str = do_determine_event(excl_kernel);
 647                 pr_debug("Parsing event '%s'\n", str);
 648                 ret = parse_events(evlist, str, NULL);
 649                 if (ret < 0) {
 650                         pr_debug("parse_events failed\n");
 651                         goto out_put;
 652                 }
 653
 654                 perf_evlist__config(evlist, &opts, NULL);
 655
 656                 evsel = evlist__first(evlist);
 657
 658                 evsel->core.attr.comm = 1;
 659                 evsel->core.attr.disabled = 1;
 660                 evsel->core.attr.enable_on_exec = 0;
 661
 662                 ret = evlist__open(evlist);
 663                 if (ret < 0) {
 664                         if (!excl_kernel) {
 665                                 excl_kernel = true;
 666                                 /*
 667                                  * Both cpus and threads are now owned by evlist
 668                                  * and will be freed by following perf_evlist__set_maps
 669                                  * call. Getting refference to keep them alive.
 670                                  */
 671                                 perf_cpu_map__get(cpus);
 672                                 perf_thread_map__get(threads);
 673                                 perf_evlist__set_maps(&evlist->core, NULL, NULL);
 674                                 evlist__delete(evlist);
 675                                 evlist = NULL;
 676                                 continue;
 677                         }
 678
 679                         if (verbose > 0) {
 680                                 char errbuf[512];
 681                                 perf_evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
 682                                 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
 683                         }
 684
 685                         goto out_put;
 686                 }
 687                 break;
 688         }
 689
 690         ret = evlist__mmap(evlist, UINT_MAX);
 691         if (ret < 0) {
 692                 pr_debug("evlist__mmap failed\n");
 693                 goto out_put;
 694         }
 695
 696         evlist__enable(evlist);
 697
 698         do_something();
 699
 700         evlist__disable(evlist);
 701
 702         ret = process_events(machine, evlist, &state);
 703         if (ret < 0)
 704                 goto out_put;
 705
 706         if (!have_vmlinux && !have_kcore && !try_kcore)
 707                 err = TEST_CODE_READING_NO_KERNEL_OBJ;
 708         else if (!have_vmlinux && !try_kcore)
 709                 err = TEST_CODE_READING_NO_VMLINUX;
 710         else if (excl_kernel)
 711                 err = TEST_CODE_READING_NO_ACCESS;
 712         else
 713                 err = TEST_CODE_READING_OK;
 714 out_put:
 715         thread__put(thread);
 716 out_err:
 717
 718         if (evlist) {
 719                 evlist__delete(evlist);
 720         } else {
 721                 perf_cpu_map__put(cpus);
 722                 perf_thread_map__put(threads);
 723         }
 724         machine__delete_threads(machine);
 725         machine__delete(machine);
 726
 727         return err;
 728 }
 729
 730 int test__code_reading(struct test *test __maybe_unused, int subtest __maybe_unused)
 731 {
 732         int ret;
 733
 734         ret = do_test_code_reading(false);
 735         if (!ret)
 736                 ret = do_test_code_reading(true);
 737
 738         switch (ret) {
 739         case TEST_CODE_READING_OK:
 740                 return 0;
 741         case TEST_CODE_READING_NO_VMLINUX:
 742                 pr_debug("no vmlinux\n");
 743                 return 0;
 744         case TEST_CODE_READING_NO_KCORE:
 745                 pr_debug("no kcore\n");
 746                 return 0;
 747         case TEST_CODE_READING_NO_ACCESS:
 748                 pr_debug("no access\n");
 749                 return 0;
 750         case TEST_CODE_READING_NO_KERNEL_OBJ:
 751                 pr_debug("no kernel obj\n");
 752                 return 0;
 753         default:
 754                 return -1;
 755         };
 756 }