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