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 "evlist.h"
  20 #include "evsel.h"
  21 #include "thread_map.h"
  22 #include "machine.h"
  23 #include "map.h"
  24 #include "symbol.h"
  25 #include "event.h"
  26 #include "record.h"
  27 #include "util/mmap.h"
  28 #include "util/string2.h"
  29 #include "util/synthetic-events.h"
  30 #include "util/util.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 && !host_is_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, err = 0;
 240         struct dso *dso;
 241
 242         pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
 243
 244         addr_location__init(&al);
 245         if (!thread__find_map(thread, cpumode, addr, &al) || !map__dso(al.map)) {
 246                 if (cpumode == PERF_RECORD_MISC_HYPERVISOR) {
 247                         pr_debug("Hypervisor address can not be resolved - skipping\n");
 248                         goto out;
 249                 }
 250
 251                 pr_debug("thread__find_map failed\n");
 252                 err = -1;
 253                 goto out;
 254         }
 255         dso = map__dso(al.map);
 256         pr_debug("File is: %s\n", dso->long_name);
 257
 258         if (dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS && !dso__is_kcore(dso)) {
 259                 pr_debug("Unexpected kernel address - skipping\n");
 260                 goto out;
 261         }
 262
 263         pr_debug("On file address is: %#"PRIx64"\n", al.addr);
 264
 265         if (len > BUFSZ)
 266                 len = BUFSZ;
 267
 268         /* Do not go off the map */
 269         if (addr + len > map__end(al.map))
 270                 len = map__end(al.map) - addr;
 271
 272         /* Read the object code using perf */
 273         ret_len = dso__data_read_offset(dso, maps__machine(thread__maps(thread)),
 274                                         al.addr, buf1, len);
 275         if (ret_len != len) {
 276                 pr_debug("dso__data_read_offset failed\n");
 277                 err = -1;
 278                 goto out;
 279         }
 280
 281         /*
 282          * Converting addresses for use by objdump requires more information.
 283          * map__load() does that.  See map__rip_2objdump() for details.
 284          */
 285         if (map__load(al.map)) {
 286                 err = -1;
 287                 goto out;
 288         }
 289
 290         /* objdump struggles with kcore - try each map only once */
 291         if (dso__is_kcore(dso)) {
 292                 size_t d;
 293
 294                 for (d = 0; d < state->done_cnt; d++) {
 295                         if (state->done[d] == map__start(al.map)) {
 296                                 pr_debug("kcore map tested already");
 297                                 pr_debug(" - skipping\n");
 298                                 goto out;
 299                         }
 300                 }
 301                 if (state->done_cnt >= ARRAY_SIZE(state->done)) {
 302                         pr_debug("Too many kcore maps - skipping\n");
 303                         goto out;
 304                 }
 305                 state->done[state->done_cnt++] = map__start(al.map);
 306         }
 307
 308         objdump_name = dso->long_name;
 309         if (dso__needs_decompress(dso)) {
 310                 if (dso__decompress_kmodule_path(dso, objdump_name,
 311                                                  decomp_name,
 312                                                  sizeof(decomp_name)) < 0) {
 313                         pr_debug("decompression failed\n");
 314                         err = -1;
 315                         goto out;
 316                 }
 317
 318                 decomp = true;
 319                 objdump_name = decomp_name;
 320         }
 321
 322         /* Read the object code using objdump */
 323         objdump_addr = map__rip_2objdump(al.map, al.addr);
 324         ret = read_via_objdump(objdump_name, objdump_addr, buf2, len);
 325
 326         if (decomp)
 327                 unlink(objdump_name);
 328
 329         if (ret > 0) {
 330                 /*
 331                  * The kernel maps are inaccurate - assume objdump is right in
 332                  * that case.
 333                  */
 334                 if (cpumode == PERF_RECORD_MISC_KERNEL ||
 335                     cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
 336                         len -= ret;
 337                         if (len) {
 338                                 pr_debug("Reducing len to %zu\n", len);
 339                         } else if (dso__is_kcore(dso)) {
 340                                 /*
 341                                  * objdump cannot handle very large segments
 342                                  * that may be found in kcore.
 343                                  */
 344                                 pr_debug("objdump failed for kcore");
 345                                 pr_debug(" - skipping\n");
 346                         } else {
 347                                 err = -1;
 348                         }
 349                         goto out;
 350                 }
 351         }
 352         if (ret < 0) {
 353                 pr_debug("read_via_objdump failed\n");
 354                 err = -1;
 355                 goto out;
 356         }
 357
 358         /* The results should be identical */
 359         if (memcmp(buf1, buf2, len)) {
 360                 pr_debug("Bytes read differ from those read by objdump\n");
 361                 pr_debug("buf1 (dso):\n");
 362                 dump_buf(buf1, len);
 363                 pr_debug("buf2 (objdump):\n");
 364                 dump_buf(buf2, len);
 365                 err = -1;
 366                 goto out;
 367         }
 368         pr_debug("Bytes read match those read by objdump\n");
 369 out:
 370         addr_location__exit(&al);
 371         return err;
 372 }
 373
 374 static int process_sample_event(struct machine *machine,
 375                                 struct evlist *evlist,
 376                                 union perf_event *event, struct state *state)
 377 {
 378         struct perf_sample sample;
 379         struct thread *thread;
 380         int ret;
 381
 382         if (evlist__parse_sample(evlist, event, &sample)) {
 383                 pr_debug("evlist__parse_sample failed\n");
 384                 return -1;
 385         }
 386
 387         thread = machine__findnew_thread(machine, sample.pid, sample.tid);
 388         if (!thread) {
 389                 pr_debug("machine__findnew_thread failed\n");
 390                 return -1;
 391         }
 392
 393         ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state);
 394         thread__put(thread);
 395         return ret;
 396 }
 397
 398 static int process_event(struct machine *machine, struct evlist *evlist,
 399                          union perf_event *event, struct state *state)
 400 {
 401         if (event->header.type == PERF_RECORD_SAMPLE)
 402                 return process_sample_event(machine, evlist, event, state);
 403
 404         if (event->header.type == PERF_RECORD_THROTTLE ||
 405             event->header.type == PERF_RECORD_UNTHROTTLE)
 406                 return 0;
 407
 408         if (event->header.type < PERF_RECORD_MAX) {
 409                 int ret;
 410
 411                 ret = machine__process_event(machine, event, NULL);
 412                 if (ret < 0)
 413                         pr_debug("machine__process_event failed, event type %u\n",
 414                                  event->header.type);
 415                 return ret;
 416         }
 417
 418         return 0;
 419 }
 420
 421 static int process_events(struct machine *machine, struct evlist *evlist,
 422                           struct state *state)
 423 {
 424         union perf_event *event;
 425         struct mmap *md;
 426         int i, ret;
 427
 428         for (i = 0; i < evlist->core.nr_mmaps; i++) {
 429                 md = &evlist->mmap[i];
 430                 if (perf_mmap__read_init(&md->core) < 0)
 431                         continue;
 432
 433                 while ((event = perf_mmap__read_event(&md->core)) != NULL) {
 434                         ret = process_event(machine, evlist, event, state);
 435                         perf_mmap__consume(&md->core);
 436                         if (ret < 0)
 437                                 return ret;
 438                 }
 439                 perf_mmap__read_done(&md->core);
 440         }
 441         return 0;
 442 }
 443
 444 static int comp(const void *a, const void *b)
 445 {
 446         return *(int *)a - *(int *)b;
 447 }
 448
 449 static void do_sort_something(void)
 450 {
 451         int buf[40960], i;
 452
 453         for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
 454                 buf[i] = ARRAY_SIZE(buf) - i - 1;
 455
 456         qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
 457
 458         for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
 459                 if (buf[i] != i) {
 460                         pr_debug("qsort failed\n");
 461                         break;
 462                 }
 463         }
 464 }
 465
 466 static void sort_something(void)
 467 {
 468         int i;
 469
 470         for (i = 0; i < 10; i++)
 471                 do_sort_something();
 472 }
 473
 474 static void syscall_something(void)
 475 {
 476         int pipefd[2];
 477         int i;
 478
 479         for (i = 0; i < 1000; i++) {
 480                 if (pipe(pipefd) < 0) {
 481                         pr_debug("pipe failed\n");
 482                         break;
 483                 }
 484                 close(pipefd[1]);
 485                 close(pipefd[0]);
 486         }
 487 }
 488
 489 static void fs_something(void)
 490 {
 491         const char *test_file_name = "temp-perf-code-reading-test-file--";
 492         FILE *f;
 493         int i;
 494
 495         for (i = 0; i < 1000; i++) {
 496                 f = fopen(test_file_name, "w+");
 497                 if (f) {
 498                         fclose(f);
 499                         unlink(test_file_name);
 500                 }
 501         }
 502 }
 503
 504 #ifdef __s390x__
 505 #include "header.h" // for get_cpuid()
 506 #endif
 507
 508 static const char *do_determine_event(bool excl_kernel)
 509 {
 510         const char *event = excl_kernel ? "cycles:u" : "cycles";
 511
 512 #ifdef __s390x__
 513         char cpuid[128], model[16], model_c[16], cpum_cf_v[16];
 514         unsigned int family;
 515         int ret, cpum_cf_a;
 516
 517         if (get_cpuid(cpuid, sizeof(cpuid)))
 518                 goto out_clocks;
 519         ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c,
 520                      model, cpum_cf_v, &cpum_cf_a);
 521         if (ret != 5)            /* Not available */
 522                 goto out_clocks;
 523         if (excl_kernel && (cpum_cf_a & 4))
 524                 return event;
 525         if (!excl_kernel && (cpum_cf_a & 2))
 526                 return event;
 527
 528         /* Fall through: missing authorization */
 529 out_clocks:
 530         event = excl_kernel ? "cpu-clock:u" : "cpu-clock";
 531
 532 #endif
 533         return event;
 534 }
 535
 536 static void do_something(void)
 537 {
 538         fs_something();
 539
 540         sort_something();
 541
 542         syscall_something();
 543 }
 544
 545 enum {
 546         TEST_CODE_READING_OK,
 547         TEST_CODE_READING_NO_VMLINUX,
 548         TEST_CODE_READING_NO_KCORE,
 549         TEST_CODE_READING_NO_ACCESS,
 550         TEST_CODE_READING_NO_KERNEL_OBJ,
 551 };
 552
 553 static int do_test_code_reading(bool try_kcore)
 554 {
 555         struct machine *machine;
 556         struct thread *thread;
 557         struct record_opts opts = {
 558                 .mmap_pages          = UINT_MAX,
 559                 .user_freq           = UINT_MAX,
 560                 .user_interval       = ULLONG_MAX,
 561                 .freq                = 500,
 562                 .target              = {
 563                         .uses_mmap   = true,
 564                 },
 565         };
 566         struct state state = {
 567                 .done_cnt = 0,
 568         };
 569         struct perf_thread_map *threads = NULL;
 570         struct perf_cpu_map *cpus = NULL;
 571         struct evlist *evlist = NULL;
 572         struct evsel *evsel = NULL;
 573         int err = -1, ret;
 574         pid_t pid;
 575         struct map *map;
 576         bool have_vmlinux, have_kcore, excl_kernel = false;
 577         struct dso *dso;
 578
 579         pid = getpid();
 580
 581         machine = machine__new_host();
 582         machine->env = &perf_env;
 583
 584         ret = machine__create_kernel_maps(machine);
 585         if (ret < 0) {
 586                 pr_debug("machine__create_kernel_maps failed\n");
 587                 goto out_err;
 588         }
 589
 590         /* Force the use of kallsyms instead of vmlinux to try kcore */
 591         if (try_kcore)
 592                 symbol_conf.kallsyms_name = "/proc/kallsyms";
 593
 594         /* Load kernel map */
 595         map = machine__kernel_map(machine);
 596         ret = map__load(map);
 597         if (ret < 0) {
 598                 pr_debug("map__load failed\n");
 599                 goto out_err;
 600         }
 601         dso = map__dso(map);
 602         have_vmlinux = dso__is_vmlinux(dso);
 603         have_kcore = dso__is_kcore(dso);
 604
 605         /* 2nd time through we just try kcore */
 606         if (try_kcore && !have_kcore)
 607                 return TEST_CODE_READING_NO_KCORE;
 608
 609         /* No point getting kernel events if there is no kernel object */
 610         if (!have_vmlinux && !have_kcore)
 611                 excl_kernel = true;
 612
 613         threads = thread_map__new_by_tid(pid);
 614         if (!threads) {
 615                 pr_debug("thread_map__new_by_tid failed\n");
 616                 goto out_err;
 617         }
 618
 619         ret = perf_event__synthesize_thread_map(NULL, threads,
 620                                                 perf_event__process, machine,
 621                                                 true, false);
 622         if (ret < 0) {
 623                 pr_debug("perf_event__synthesize_thread_map failed\n");
 624                 goto out_err;
 625         }
 626
 627         thread = machine__findnew_thread(machine, pid, pid);
 628         if (!thread) {
 629                 pr_debug("machine__findnew_thread failed\n");
 630                 goto out_put;
 631         }
 632
 633         cpus = perf_cpu_map__new(NULL);
 634         if (!cpus) {
 635                 pr_debug("perf_cpu_map__new failed\n");
 636                 goto out_put;
 637         }
 638
 639         while (1) {
 640                 const char *str;
 641
 642                 evlist = evlist__new();
 643                 if (!evlist) {
 644                         pr_debug("evlist__new failed\n");
 645                         goto out_put;
 646                 }
 647
 648                 perf_evlist__set_maps(&evlist->core, cpus, threads);
 649
 650                 str = do_determine_event(excl_kernel);
 651                 pr_debug("Parsing event '%s'\n", str);
 652                 ret = parse_event(evlist, str);
 653                 if (ret < 0) {
 654                         pr_debug("parse_events failed\n");
 655                         goto out_put;
 656                 }
 657
 658                 evlist__config(evlist, &opts, NULL);
 659
 660                 evsel = evlist__first(evlist);
 661
 662                 evsel->core.attr.comm = 1;
 663                 evsel->core.attr.disabled = 1;
 664                 evsel->core.attr.enable_on_exec = 0;
 665
 666                 ret = evlist__open(evlist);
 667                 if (ret < 0) {
 668                         if (!excl_kernel) {
 669                                 excl_kernel = true;
 670                                 /*
 671                                  * Both cpus and threads are now owned by evlist
 672                                  * and will be freed by following perf_evlist__set_maps
 673                                  * call. Getting reference to keep them alive.
 674                                  */
 675                                 perf_cpu_map__get(cpus);
 676                                 perf_thread_map__get(threads);
 677                                 perf_evlist__set_maps(&evlist->core, NULL, NULL);
 678                                 evlist__delete(evlist);
 679                                 evlist = NULL;
 680                                 continue;
 681                         }
 682
 683                         if (verbose > 0) {
 684                                 char errbuf[512];
 685                                 evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
 686                                 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
 687                         }
 688
 689                         goto out_put;
 690                 }
 691                 break;
 692         }
 693
 694         ret = evlist__mmap(evlist, UINT_MAX);
 695         if (ret < 0) {
 696                 pr_debug("evlist__mmap failed\n");
 697                 goto out_put;
 698         }
 699
 700         evlist__enable(evlist);
 701
 702         do_something();
 703
 704         evlist__disable(evlist);
 705
 706         ret = process_events(machine, evlist, &state);
 707         if (ret < 0)
 708                 goto out_put;
 709
 710         if (!have_vmlinux && !have_kcore && !try_kcore)
 711                 err = TEST_CODE_READING_NO_KERNEL_OBJ;
 712         else if (!have_vmlinux && !try_kcore)
 713                 err = TEST_CODE_READING_NO_VMLINUX;
 714         else if (excl_kernel)
 715                 err = TEST_CODE_READING_NO_ACCESS;
 716         else
 717                 err = TEST_CODE_READING_OK;
 718 out_put:
 719         thread__put(thread);
 720 out_err:
 721         evlist__delete(evlist);
 722         perf_cpu_map__put(cpus);
 723         perf_thread_map__put(threads);
 724         machine__delete(machine);
 725
 726         return err;
 727 }
 728
 729 static int test__code_reading(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
 730 {
 731         int ret;
 732
 733         ret = do_test_code_reading(false);
 734         if (!ret)
 735                 ret = do_test_code_reading(true);
 736
 737         switch (ret) {
 738         case TEST_CODE_READING_OK:
 739                 return 0;
 740         case TEST_CODE_READING_NO_VMLINUX:
 741                 pr_debug("no vmlinux\n");
 742                 return 0;
 743         case TEST_CODE_READING_NO_KCORE:
 744                 pr_debug("no kcore\n");
 745                 return 0;
 746         case TEST_CODE_READING_NO_ACCESS:
 747                 pr_debug("no access\n");
 748                 return 0;
 749         case TEST_CODE_READING_NO_KERNEL_OBJ:
 750                 pr_debug("no kernel obj\n");
 751                 return 0;
 752         default:
 753                 return -1;
 754         };
 755 }
 756
 757 DEFINE_SUITE("Object code reading", code_reading);