tools/perf/util/bpf-event.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <errno.h>
   3 #include <stdlib.h>
   4 #include <bpf/bpf.h>
   5 #include <bpf/btf.h>
   6 #include <bpf/libbpf.h>
   7 #include <linux/btf.h>
   8 #include <linux/err.h>
   9 #include <linux/string.h>
  10 #include <internal/lib.h>
  11 #include <symbol/kallsyms.h>
  12 #include "bpf-event.h"
  13 #include "debug.h"
  14 #include "dso.h"
  15 #include "symbol.h"
  16 #include "machine.h"
  17 #include "env.h"
  18 #include "session.h"
  19 #include "map.h"
  20 #include "evlist.h"
  21 #include "record.h"
  22 #include "util/synthetic-events.h"
  23
  24 struct btf * __weak btf__load_from_kernel_by_id(__u32 id)
  25 {
  26        struct btf *btf;
  27 #pragma GCC diagnostic push
  28 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
  29        int err = btf__get_from_id(id, &btf);
  30 #pragma GCC diagnostic pop
  31
  32        return err ? ERR_PTR(err) : btf;
  33 }
  34
  35 #define ptr_to_u64(ptr)    ((__u64)(unsigned long)(ptr))
  36
  37 static int snprintf_hex(char *buf, size_t size, unsigned char *data, size_t len)
  38 {
  39         int ret = 0;
  40         size_t i;
  41
  42         for (i = 0; i < len; i++)
  43                 ret += snprintf(buf + ret, size - ret, "%02x", data[i]);
  44         return ret;
  45 }
  46
  47 static int machine__process_bpf_event_load(struct machine *machine,
  48                                            union perf_event *event,
  49                                            struct perf_sample *sample __maybe_unused)
  50 {
  51         struct bpf_prog_info_linear *info_linear;
  52         struct bpf_prog_info_node *info_node;
  53         struct perf_env *env = machine->env;
  54         int id = event->bpf.id;
  55         unsigned int i;
  56
  57         /* perf-record, no need to handle bpf-event */
  58         if (env == NULL)
  59                 return 0;
  60
  61         info_node = perf_env__find_bpf_prog_info(env, id);
  62         if (!info_node)
  63                 return 0;
  64         info_linear = info_node->info_linear;
  65
  66         for (i = 0; i < info_linear->info.nr_jited_ksyms; i++) {
  67                 u64 *addrs = (u64 *)(uintptr_t)(info_linear->info.jited_ksyms);
  68                 u64 addr = addrs[i];
  69                 struct map *map = maps__find(&machine->kmaps, addr);
  70
  71                 if (map) {
  72                         map->dso->binary_type = DSO_BINARY_TYPE__BPF_PROG_INFO;
  73                         map->dso->bpf_prog.id = id;
  74                         map->dso->bpf_prog.sub_id = i;
  75                         map->dso->bpf_prog.env = env;
  76                 }
  77         }
  78         return 0;
  79 }
  80
  81 int machine__process_bpf(struct machine *machine, union perf_event *event,
  82                          struct perf_sample *sample)
  83 {
  84         if (dump_trace)
  85                 perf_event__fprintf_bpf(event, stdout);
  86
  87         switch (event->bpf.type) {
  88         case PERF_BPF_EVENT_PROG_LOAD:
  89                 return machine__process_bpf_event_load(machine, event, sample);
  90
  91         case PERF_BPF_EVENT_PROG_UNLOAD:
  92                 /*
  93                  * Do not free bpf_prog_info and btf of the program here,
  94                  * as annotation still need them. They will be freed at
  95                  * the end of the session.
  96                  */
  97                 break;
  98         default:
  99                 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
 100                 break;
 101         }
 102         return 0;
 103 }
 104
 105 static int perf_env__fetch_btf(struct perf_env *env,
 106                                u32 btf_id,
 107                                struct btf *btf)
 108 {
 109         struct btf_node *node;
 110         u32 data_size;
 111         const void *data;
 112
 113         data = btf__get_raw_data(btf, &data_size);
 114
 115         node = malloc(data_size + sizeof(struct btf_node));
 116         if (!node)
 117                 return -1;
 118
 119         node->id = btf_id;
 120         node->data_size = data_size;
 121         memcpy(node->data, data, data_size);
 122
 123         perf_env__insert_btf(env, node);
 124         return 0;
 125 }
 126
 127 static int synthesize_bpf_prog_name(char *buf, int size,
 128                                     struct bpf_prog_info *info,
 129                                     struct btf *btf,
 130                                     u32 sub_id)
 131 {
 132         u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(uintptr_t)(info->prog_tags);
 133         void *func_infos = (void *)(uintptr_t)(info->func_info);
 134         u32 sub_prog_cnt = info->nr_jited_ksyms;
 135         const struct bpf_func_info *finfo;
 136         const char *short_name = NULL;
 137         const struct btf_type *t;
 138         int name_len;
 139
 140         name_len = snprintf(buf, size, "bpf_prog_");
 141         name_len += snprintf_hex(buf + name_len, size - name_len,
 142                                  prog_tags[sub_id], BPF_TAG_SIZE);
 143         if (btf) {
 144                 finfo = func_infos + sub_id * info->func_info_rec_size;
 145                 t = btf__type_by_id(btf, finfo->type_id);
 146                 short_name = btf__name_by_offset(btf, t->name_off);
 147         } else if (sub_id == 0 && sub_prog_cnt == 1) {
 148                 /* no subprog */
 149                 if (info->name[0])
 150                         short_name = info->name;
 151         } else
 152                 short_name = "F";
 153         if (short_name)
 154                 name_len += snprintf(buf + name_len, size - name_len,
 155                                      "_%s", short_name);
 156         return name_len;
 157 }
 158
 159 /*
 160  * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf
 161  * program. One PERF_RECORD_BPF_EVENT is generated for the program. And
 162  * one PERF_RECORD_KSYMBOL is generated for each sub program.
 163  *
 164  * Returns:
 165  *    0 for success;
 166  *   -1 for failures;
 167  *   -2 for lack of kernel support.
 168  */
 169 static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
 170                                                perf_event__handler_t process,
 171                                                struct machine *machine,
 172                                                int fd,
 173                                                union perf_event *event,
 174                                                struct record_opts *opts)
 175 {
 176         struct perf_record_ksymbol *ksymbol_event = &event->ksymbol;
 177         struct perf_record_bpf_event *bpf_event = &event->bpf;
 178         struct bpf_prog_info_linear *info_linear;
 179         struct perf_tool *tool = session->tool;
 180         struct bpf_prog_info_node *info_node;
 181         struct bpf_prog_info *info;
 182         struct btf *btf = NULL;
 183         struct perf_env *env;
 184         u32 sub_prog_cnt, i;
 185         int err = 0;
 186         u64 arrays;
 187
 188         /*
 189          * for perf-record and perf-report use header.env;
 190          * otherwise, use global perf_env.
 191          */
 192         env = session->data ? &session->header.env : &perf_env;
 193
 194         arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
 195         arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
 196         arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
 197         arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
 198         arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
 199         arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
 200         arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;
 201
 202         info_linear = bpf_program__get_prog_info_linear(fd, arrays);
 203         if (IS_ERR_OR_NULL(info_linear)) {
 204                 info_linear = NULL;
 205                 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 206                 return -1;
 207         }
 208
 209         if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
 210                 free(info_linear);
 211                 pr_debug("%s: the kernel is too old, aborting\n", __func__);
 212                 return -2;
 213         }
 214
 215         info = &info_linear->info;
 216         if (!info->jited_ksyms) {
 217                 free(info_linear);
 218                 return -1;
 219         }
 220
 221         /* number of ksyms, func_lengths, and tags should match */
 222         sub_prog_cnt = info->nr_jited_ksyms;
 223         if (sub_prog_cnt != info->nr_prog_tags ||
 224             sub_prog_cnt != info->nr_jited_func_lens) {
 225                 free(info_linear);
 226                 return -1;
 227         }
 228
 229         /* check BTF func info support */
 230         if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {
 231                 /* btf func info number should be same as sub_prog_cnt */
 232                 if (sub_prog_cnt != info->nr_func_info) {
 233                         pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
 234                         free(info_linear);
 235                         return -1;
 236                 }
 237                 btf = btf__load_from_kernel_by_id(info->btf_id);
 238                 if (libbpf_get_error(btf)) {
 239                         pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
 240                         err = -1;
 241                         goto out;
 242                 }
 243                 perf_env__fetch_btf(env, info->btf_id, btf);
 244         }
 245
 246         /* Synthesize PERF_RECORD_KSYMBOL */
 247         for (i = 0; i < sub_prog_cnt; i++) {
 248                 __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 249                 __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 250                 int name_len;
 251
 252                 *ksymbol_event = (struct perf_record_ksymbol) {
 253                         .header = {
 254                                 .type = PERF_RECORD_KSYMBOL,
 255                                 .size = offsetof(struct perf_record_ksymbol, name),
 256                         },
 257                         .addr = prog_addrs[i],
 258                         .len = prog_lens[i],
 259                         .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
 260                         .flags = 0,
 261                 };
 262
 263                 name_len = synthesize_bpf_prog_name(ksymbol_event->name,
 264                                                     KSYM_NAME_LEN, info, btf, i);
 265                 ksymbol_event->header.size += PERF_ALIGN(name_len + 1,
 266                                                          sizeof(u64));
 267
 268                 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
 269                 event->header.size += machine->id_hdr_size;
 270                 err = perf_tool__process_synth_event(tool, event,
 271                                                      machine, process);
 272         }
 273
 274         if (!opts->no_bpf_event) {
 275                 /* Synthesize PERF_RECORD_BPF_EVENT */
 276                 *bpf_event = (struct perf_record_bpf_event) {
 277                         .header = {
 278                                 .type = PERF_RECORD_BPF_EVENT,
 279                                 .size = sizeof(struct perf_record_bpf_event),
 280                         },
 281                         .type = PERF_BPF_EVENT_PROG_LOAD,
 282                         .flags = 0,
 283                         .id = info->id,
 284                 };
 285                 memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);
 286                 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
 287                 event->header.size += machine->id_hdr_size;
 288
 289                 /* save bpf_prog_info to env */
 290                 info_node = malloc(sizeof(struct bpf_prog_info_node));
 291                 if (!info_node) {
 292                         err = -1;
 293                         goto out;
 294                 }
 295
 296                 info_node->info_linear = info_linear;
 297                 perf_env__insert_bpf_prog_info(env, info_node);
 298                 info_linear = NULL;
 299
 300                 /*
 301                  * process after saving bpf_prog_info to env, so that
 302                  * required information is ready for look up
 303                  */
 304                 err = perf_tool__process_synth_event(tool, event,
 305                                                      machine, process);
 306         }
 307
 308 out:
 309         free(info_linear);
 310         btf__free(btf);
 311         return err ? -1 : 0;
 312 }
 313
 314 struct kallsyms_parse {
 315         union perf_event        *event;
 316         perf_event__handler_t    process;
 317         struct machine          *machine;
 318         struct perf_tool        *tool;
 319 };
 320
 321 static int
 322 process_bpf_image(char *name, u64 addr, struct kallsyms_parse *data)
 323 {
 324         struct machine *machine = data->machine;
 325         union perf_event *event = data->event;
 326         struct perf_record_ksymbol *ksymbol;
 327         int len;
 328
 329         ksymbol = &event->ksymbol;
 330
 331         *ksymbol = (struct perf_record_ksymbol) {
 332                 .header = {
 333                         .type = PERF_RECORD_KSYMBOL,
 334                         .size = offsetof(struct perf_record_ksymbol, name),
 335                 },
 336                 .addr      = addr,
 337                 .len       = page_size,
 338                 .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
 339                 .flags     = 0,
 340         };
 341
 342         len = scnprintf(ksymbol->name, KSYM_NAME_LEN, "%s", name);
 343         ksymbol->header.size += PERF_ALIGN(len + 1, sizeof(u64));
 344         memset((void *) event + event->header.size, 0, machine->id_hdr_size);
 345         event->header.size += machine->id_hdr_size;
 346
 347         return perf_tool__process_synth_event(data->tool, event, machine,
 348                                               data->process);
 349 }
 350
 351 static int
 352 kallsyms_process_symbol(void *data, const char *_name,
 353                         char type __maybe_unused, u64 start)
 354 {
 355         char disp[KSYM_NAME_LEN];
 356         char *module, *name;
 357         unsigned long id;
 358         int err = 0;
 359
 360         module = strchr(_name, '\t');
 361         if (!module)
 362                 return 0;
 363
 364         /* We are going after [bpf] module ... */
 365         if (strcmp(module + 1, "[bpf]"))
 366                 return 0;
 367
 368         name = memdup(_name, (module - _name) + 1);
 369         if (!name)
 370                 return -ENOMEM;
 371
 372         name[module - _name] = 0;
 373
 374         /* .. and only for trampolines and dispatchers */
 375         if ((sscanf(name, "bpf_trampoline_%lu", &id) == 1) ||
 376             (sscanf(name, "bpf_dispatcher_%s", disp) == 1))
 377                 err = process_bpf_image(name, start, data);
 378
 379         free(name);
 380         return err;
 381 }
 382
 383 int perf_event__synthesize_bpf_events(struct perf_session *session,
 384                                       perf_event__handler_t process,
 385                                       struct machine *machine,
 386                                       struct record_opts *opts)
 387 {
 388         const char *kallsyms_filename = "/proc/kallsyms";
 389         struct kallsyms_parse arg;
 390         union perf_event *event;
 391         __u32 id = 0;
 392         int err;
 393         int fd;
 394
 395         event = malloc(sizeof(event->bpf) + KSYM_NAME_LEN + machine->id_hdr_size);
 396         if (!event)
 397                 return -1;
 398
 399         /* Synthesize all the bpf programs in system. */
 400         while (true) {
 401                 err = bpf_prog_get_next_id(id, &id);
 402                 if (err) {
 403                         if (errno == ENOENT) {
 404                                 err = 0;
 405                                 break;
 406                         }
 407                         pr_debug("%s: can't get next program: %s%s\n",
 408                                  __func__, strerror(errno),
 409                                  errno == EINVAL ? " -- kernel too old?" : "");
 410                         /* don't report error on old kernel or EPERM  */
 411                         err = (errno == EINVAL || errno == EPERM) ? 0 : -1;
 412                         break;
 413                 }
 414                 fd = bpf_prog_get_fd_by_id(id);
 415                 if (fd < 0) {
 416                         pr_debug("%s: failed to get fd for prog_id %u\n",
 417                                  __func__, id);
 418                         continue;
 419                 }
 420
 421                 err = perf_event__synthesize_one_bpf_prog(session, process,
 422                                                           machine, fd,
 423                                                           event, opts);
 424                 close(fd);
 425                 if (err) {
 426                         /* do not return error for old kernel */
 427                         if (err == -2)
 428                                 err = 0;
 429                         break;
 430                 }
 431         }
 432
 433         /* Synthesize all the bpf images - trampolines/dispatchers. */
 434         if (symbol_conf.kallsyms_name != NULL)
 435                 kallsyms_filename = symbol_conf.kallsyms_name;
 436
 437         arg = (struct kallsyms_parse) {
 438                 .event   = event,
 439                 .process = process,
 440                 .machine = machine,
 441                 .tool    = session->tool,
 442         };
 443
 444         if (kallsyms__parse(kallsyms_filename, &arg, kallsyms_process_symbol)) {
 445                 pr_err("%s: failed to synthesize bpf images: %s\n",
 446                        __func__, strerror(errno));
 447         }
 448
 449         free(event);
 450         return err;
 451 }
 452
 453 static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
 454 {
 455         struct bpf_prog_info_linear *info_linear;
 456         struct bpf_prog_info_node *info_node;
 457         struct btf *btf = NULL;
 458         u64 arrays;
 459         u32 btf_id;
 460         int fd;
 461
 462         fd = bpf_prog_get_fd_by_id(id);
 463         if (fd < 0)
 464                 return;
 465
 466         arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
 467         arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
 468         arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
 469         arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
 470         arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
 471         arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
 472         arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;
 473
 474         info_linear = bpf_program__get_prog_info_linear(fd, arrays);
 475         if (IS_ERR_OR_NULL(info_linear)) {
 476                 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 477                 goto out;
 478         }
 479
 480         btf_id = info_linear->info.btf_id;
 481
 482         info_node = malloc(sizeof(struct bpf_prog_info_node));
 483         if (info_node) {
 484                 info_node->info_linear = info_linear;
 485                 perf_env__insert_bpf_prog_info(env, info_node);
 486         } else
 487                 free(info_linear);
 488
 489         if (btf_id == 0)
 490                 goto out;
 491
 492         btf = btf__load_from_kernel_by_id(btf_id);
 493         if (libbpf_get_error(btf)) {
 494                 pr_debug("%s: failed to get BTF of id %u, aborting\n",
 495                          __func__, btf_id);
 496                 goto out;
 497         }
 498         perf_env__fetch_btf(env, btf_id, btf);
 499
 500 out:
 501         btf__free(btf);
 502         close(fd);
 503 }
 504
 505 static int bpf_event__sb_cb(union perf_event *event, void *data)
 506 {
 507         struct perf_env *env = data;
 508
 509         if (event->header.type != PERF_RECORD_BPF_EVENT)
 510                 return -1;
 511
 512         switch (event->bpf.type) {
 513         case PERF_BPF_EVENT_PROG_LOAD:
 514                 perf_env__add_bpf_info(env, event->bpf.id);
 515
 516         case PERF_BPF_EVENT_PROG_UNLOAD:
 517                 /*
 518                  * Do not free bpf_prog_info and btf of the program here,
 519                  * as annotation still need them. They will be freed at
 520                  * the end of the session.
 521                  */
 522                 break;
 523         default:
 524                 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
 525                 break;
 526         }
 527
 528         return 0;
 529 }
 530
 531 int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
 532 {
 533         struct perf_event_attr attr = {
 534                 .type             = PERF_TYPE_SOFTWARE,
 535                 .config           = PERF_COUNT_SW_DUMMY,
 536                 .sample_id_all    = 1,
 537                 .watermark        = 1,
 538                 .bpf_event        = 1,
 539                 .size      = sizeof(attr), /* to capture ABI version */
 540         };
 541
 542         /*
 543          * Older gcc versions don't support designated initializers, like above,
 544          * for unnamed union members, such as the following:
 545          */
 546         attr.wakeup_watermark = 1;
 547
 548         return evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
 549 }
 550
 551 void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
 552                                     struct perf_env *env,
 553                                     FILE *fp)
 554 {
 555         __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 556         __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 557         char name[KSYM_NAME_LEN];
 558         struct btf *btf = NULL;
 559         u32 sub_prog_cnt, i;
 560
 561         sub_prog_cnt = info->nr_jited_ksyms;
 562         if (sub_prog_cnt != info->nr_prog_tags ||
 563             sub_prog_cnt != info->nr_jited_func_lens)
 564                 return;
 565
 566         if (info->btf_id) {
 567                 struct btf_node *node;
 568
 569                 node = perf_env__find_btf(env, info->btf_id);
 570                 if (node)
 571                         btf = btf__new((__u8 *)(node->data),
 572                                        node->data_size);
 573         }
 574
 575         if (sub_prog_cnt == 1) {
 576                 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, 0);
 577                 fprintf(fp, "# bpf_prog_info %u: %s addr 0x%llx size %u\n",
 578                         info->id, name, prog_addrs[0], prog_lens[0]);
 579                 return;
 580         }
 581
 582         fprintf(fp, "# bpf_prog_info %u:\n", info->id);
 583         for (i = 0; i < sub_prog_cnt; i++) {
 584                 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, i);
 585
 586                 fprintf(fp, "# \tsub_prog %u: %s addr 0x%llx size %u\n",
 587                         i, name, prog_addrs[i], prog_lens[i]);
 588         }
 589 }