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