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 "bpf-utils.h"
  14 #include "debug.h"
  15 #include "dso.h"
  16 #include "symbol.h"
  17 #include "machine.h"
  18 #include "env.h"
  19 #include "session.h"
  20 #include "map.h"
  21 #include "evlist.h"
  22 #include "record.h"
  23 #include "util/synthetic-events.h"
  24
  25 #ifndef HAVE_LIBBPF_BTF__LOAD_FROM_KERNEL_BY_ID
  26 struct btf *btf__load_from_kernel_by_id(__u32 id)
  27 {
  28        struct btf *btf;
  29 #pragma GCC diagnostic push
  30 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
  31        int err = btf__get_from_id(id, &btf);
  32 #pragma GCC diagnostic pop
  33
  34        return err ? ERR_PTR(err) : btf;
  35 }
  36 #endif
  37
  38 #ifndef HAVE_LIBBPF_BPF_PROG_LOAD
  39 int bpf_prog_load(enum bpf_prog_type prog_type,
  40                   const char *prog_name __maybe_unused,
  41                   const char *license,
  42                   const struct bpf_insn *insns, size_t insn_cnt,
  43                   const struct bpf_prog_load_opts *opts)
  44 {
  45 #pragma GCC diagnostic push
  46 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
  47         return bpf_load_program(prog_type, insns, insn_cnt, license,
  48                                 opts->kern_version, opts->log_buf, opts->log_size);
  49 #pragma GCC diagnostic pop
  50 }
  51 #endif
  52
  53 #ifndef HAVE_LIBBPF_BPF_OBJECT__NEXT_PROGRAM
  54 struct bpf_program *
  55 bpf_object__next_program(const struct bpf_object *obj, struct bpf_program *prev)
  56 {
  57 #pragma GCC diagnostic push
  58 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
  59         return bpf_program__next(prev, obj);
  60 #pragma GCC diagnostic pop
  61 }
  62 #endif
  63
  64 struct bpf_map * __weak
  65 bpf_object__next_map(const struct bpf_object *obj, const struct bpf_map *prev)
  66 {
  67 #pragma GCC diagnostic push
  68 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
  69         return bpf_map__next(prev, obj);
  70 #pragma GCC diagnostic pop
  71 }
  72
  73 const void * __weak
  74 btf__raw_data(const struct btf *btf_ro, __u32 *size)
  75 {
  76 #pragma GCC diagnostic push
  77 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
  78         return btf__get_raw_data(btf_ro, size);
  79 #pragma GCC diagnostic pop
  80 }
  81
  82 static int snprintf_hex(char *buf, size_t size, unsigned char *data, size_t len)
  83 {
  84         int ret = 0;
  85         size_t i;
  86
  87         for (i = 0; i < len; i++)
  88                 ret += snprintf(buf + ret, size - ret, "%02x", data[i]);
  89         return ret;
  90 }
  91
  92 static int machine__process_bpf_event_load(struct machine *machine,
  93                                            union perf_event *event,
  94                                            struct perf_sample *sample __maybe_unused)
  95 {
  96         struct bpf_prog_info_node *info_node;
  97         struct perf_env *env = machine->env;
  98         struct perf_bpil *info_linear;
  99         int id = event->bpf.id;
 100         unsigned int i;
 101
 102         /* perf-record, no need to handle bpf-event */
 103         if (env == NULL)
 104                 return 0;
 105
 106         info_node = perf_env__find_bpf_prog_info(env, id);
 107         if (!info_node)
 108                 return 0;
 109         info_linear = info_node->info_linear;
 110
 111         for (i = 0; i < info_linear->info.nr_jited_ksyms; i++) {
 112                 u64 *addrs = (u64 *)(uintptr_t)(info_linear->info.jited_ksyms);
 113                 u64 addr = addrs[i];
 114                 struct map *map = maps__find(machine__kernel_maps(machine), addr);
 115
 116                 if (map) {
 117                         map->dso->binary_type = DSO_BINARY_TYPE__BPF_PROG_INFO;
 118                         map->dso->bpf_prog.id = id;
 119                         map->dso->bpf_prog.sub_id = i;
 120                         map->dso->bpf_prog.env = env;
 121                 }
 122         }
 123         return 0;
 124 }
 125
 126 int machine__process_bpf(struct machine *machine, union perf_event *event,
 127                          struct perf_sample *sample)
 128 {
 129         if (dump_trace)
 130                 perf_event__fprintf_bpf(event, stdout);
 131
 132         switch (event->bpf.type) {
 133         case PERF_BPF_EVENT_PROG_LOAD:
 134                 return machine__process_bpf_event_load(machine, event, sample);
 135
 136         case PERF_BPF_EVENT_PROG_UNLOAD:
 137                 /*
 138                  * Do not free bpf_prog_info and btf of the program here,
 139                  * as annotation still need them. They will be freed at
 140                  * the end of the session.
 141                  */
 142                 break;
 143         default:
 144                 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
 145                 break;
 146         }
 147         return 0;
 148 }
 149
 150 static int perf_env__fetch_btf(struct perf_env *env,
 151                                u32 btf_id,
 152                                struct btf *btf)
 153 {
 154         struct btf_node *node;
 155         u32 data_size;
 156         const void *data;
 157
 158         data = btf__raw_data(btf, &data_size);
 159
 160         node = malloc(data_size + sizeof(struct btf_node));
 161         if (!node)
 162                 return -1;
 163
 164         node->id = btf_id;
 165         node->data_size = data_size;
 166         memcpy(node->data, data, data_size);
 167
 168         if (!perf_env__insert_btf(env, node)) {
 169                 /* Insertion failed because of a duplicate. */
 170                 free(node);
 171                 return -1;
 172         }
 173         return 0;
 174 }
 175
 176 static int synthesize_bpf_prog_name(char *buf, int size,
 177                                     struct bpf_prog_info *info,
 178                                     struct btf *btf,
 179                                     u32 sub_id)
 180 {
 181         u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(uintptr_t)(info->prog_tags);
 182         void *func_infos = (void *)(uintptr_t)(info->func_info);
 183         u32 sub_prog_cnt = info->nr_jited_ksyms;
 184         const struct bpf_func_info *finfo;
 185         const char *short_name = NULL;
 186         const struct btf_type *t;
 187         int name_len;
 188
 189         name_len = snprintf(buf, size, "bpf_prog_");
 190         name_len += snprintf_hex(buf + name_len, size - name_len,
 191                                  prog_tags[sub_id], BPF_TAG_SIZE);
 192         if (btf) {
 193                 finfo = func_infos + sub_id * info->func_info_rec_size;
 194                 t = btf__type_by_id(btf, finfo->type_id);
 195                 short_name = btf__name_by_offset(btf, t->name_off);
 196         } else if (sub_id == 0 && sub_prog_cnt == 1) {
 197                 /* no subprog */
 198                 if (info->name[0])
 199                         short_name = info->name;
 200         } else
 201                 short_name = "F";
 202         if (short_name)
 203                 name_len += snprintf(buf + name_len, size - name_len,
 204                                      "_%s", short_name);
 205         return name_len;
 206 }
 207
 208 /*
 209  * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf
 210  * program. One PERF_RECORD_BPF_EVENT is generated for the program. And
 211  * one PERF_RECORD_KSYMBOL is generated for each sub program.
 212  *
 213  * Returns:
 214  *    0 for success;
 215  *   -1 for failures;
 216  *   -2 for lack of kernel support.
 217  */
 218 static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
 219                                                perf_event__handler_t process,
 220                                                struct machine *machine,
 221                                                int fd,
 222                                                union perf_event *event,
 223                                                struct record_opts *opts)
 224 {
 225         struct perf_record_ksymbol *ksymbol_event = &event->ksymbol;
 226         struct perf_record_bpf_event *bpf_event = &event->bpf;
 227         struct perf_tool *tool = session->tool;
 228         struct bpf_prog_info_node *info_node;
 229         struct perf_bpil *info_linear;
 230         struct bpf_prog_info *info;
 231         struct btf *btf = NULL;
 232         struct perf_env *env;
 233         u32 sub_prog_cnt, i;
 234         int err = 0;
 235         u64 arrays;
 236
 237         /*
 238          * for perf-record and perf-report use header.env;
 239          * otherwise, use global perf_env.
 240          */
 241         env = session->data ? &session->header.env : &perf_env;
 242
 243         arrays = 1UL << PERF_BPIL_JITED_KSYMS;
 244         arrays |= 1UL << PERF_BPIL_JITED_FUNC_LENS;
 245         arrays |= 1UL << PERF_BPIL_FUNC_INFO;
 246         arrays |= 1UL << PERF_BPIL_PROG_TAGS;
 247         arrays |= 1UL << PERF_BPIL_JITED_INSNS;
 248         arrays |= 1UL << PERF_BPIL_LINE_INFO;
 249         arrays |= 1UL << PERF_BPIL_JITED_LINE_INFO;
 250
 251         info_linear = get_bpf_prog_info_linear(fd, arrays);
 252         if (IS_ERR_OR_NULL(info_linear)) {
 253                 info_linear = NULL;
 254                 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 255                 return -1;
 256         }
 257
 258         if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
 259                 free(info_linear);
 260                 pr_debug("%s: the kernel is too old, aborting\n", __func__);
 261                 return -2;
 262         }
 263
 264         info = &info_linear->info;
 265         if (!info->jited_ksyms) {
 266                 free(info_linear);
 267                 return -1;
 268         }
 269
 270         /* number of ksyms, func_lengths, and tags should match */
 271         sub_prog_cnt = info->nr_jited_ksyms;
 272         if (sub_prog_cnt != info->nr_prog_tags ||
 273             sub_prog_cnt != info->nr_jited_func_lens) {
 274                 free(info_linear);
 275                 return -1;
 276         }
 277
 278         /* check BTF func info support */
 279         if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {
 280                 /* btf func info number should be same as sub_prog_cnt */
 281                 if (sub_prog_cnt != info->nr_func_info) {
 282                         pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
 283                         free(info_linear);
 284                         return -1;
 285                 }
 286                 btf = btf__load_from_kernel_by_id(info->btf_id);
 287                 if (libbpf_get_error(btf)) {
 288                         pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
 289                         err = -1;
 290                         goto out;
 291                 }
 292                 perf_env__fetch_btf(env, info->btf_id, btf);
 293         }
 294
 295         /* Synthesize PERF_RECORD_KSYMBOL */
 296         for (i = 0; i < sub_prog_cnt; i++) {
 297                 __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 298                 __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 299                 int name_len;
 300
 301                 *ksymbol_event = (struct perf_record_ksymbol) {
 302                         .header = {
 303                                 .type = PERF_RECORD_KSYMBOL,
 304                                 .size = offsetof(struct perf_record_ksymbol, name),
 305                         },
 306                         .addr = prog_addrs[i],
 307                         .len = prog_lens[i],
 308                         .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
 309                         .flags = 0,
 310                 };
 311
 312                 name_len = synthesize_bpf_prog_name(ksymbol_event->name,
 313                                                     KSYM_NAME_LEN, info, btf, i);
 314                 ksymbol_event->header.size += PERF_ALIGN(name_len + 1,
 315                                                          sizeof(u64));
 316
 317                 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
 318                 event->header.size += machine->id_hdr_size;
 319                 err = perf_tool__process_synth_event(tool, event,
 320                                                      machine, process);
 321         }
 322
 323         if (!opts->no_bpf_event) {
 324                 /* Synthesize PERF_RECORD_BPF_EVENT */
 325                 *bpf_event = (struct perf_record_bpf_event) {
 326                         .header = {
 327                                 .type = PERF_RECORD_BPF_EVENT,
 328                                 .size = sizeof(struct perf_record_bpf_event),
 329                         },
 330                         .type = PERF_BPF_EVENT_PROG_LOAD,
 331                         .flags = 0,
 332                         .id = info->id,
 333                 };
 334                 memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);
 335                 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
 336                 event->header.size += machine->id_hdr_size;
 337
 338                 /* save bpf_prog_info to env */
 339                 info_node = malloc(sizeof(struct bpf_prog_info_node));
 340                 if (!info_node) {
 341                         err = -1;
 342                         goto out;
 343                 }
 344
 345                 info_node->info_linear = info_linear;
 346                 perf_env__insert_bpf_prog_info(env, info_node);
 347                 info_linear = NULL;
 348
 349                 /*
 350                  * process after saving bpf_prog_info to env, so that
 351                  * required information is ready for look up
 352                  */
 353                 err = perf_tool__process_synth_event(tool, event,
 354                                                      machine, process);
 355         }
 356
 357 out:
 358         free(info_linear);
 359         btf__free(btf);
 360         return err ? -1 : 0;
 361 }
 362
 363 struct kallsyms_parse {
 364         union perf_event        *event;
 365         perf_event__handler_t    process;
 366         struct machine          *machine;
 367         struct perf_tool        *tool;
 368 };
 369
 370 static int
 371 process_bpf_image(char *name, u64 addr, struct kallsyms_parse *data)
 372 {
 373         struct machine *machine = data->machine;
 374         union perf_event *event = data->event;
 375         struct perf_record_ksymbol *ksymbol;
 376         int len;
 377
 378         ksymbol = &event->ksymbol;
 379
 380         *ksymbol = (struct perf_record_ksymbol) {
 381                 .header = {
 382                         .type = PERF_RECORD_KSYMBOL,
 383                         .size = offsetof(struct perf_record_ksymbol, name),
 384                 },
 385                 .addr      = addr,
 386                 .len       = page_size,
 387                 .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
 388                 .flags     = 0,
 389         };
 390
 391         len = scnprintf(ksymbol->name, KSYM_NAME_LEN, "%s", name);
 392         ksymbol->header.size += PERF_ALIGN(len + 1, sizeof(u64));
 393         memset((void *) event + event->header.size, 0, machine->id_hdr_size);
 394         event->header.size += machine->id_hdr_size;
 395
 396         return perf_tool__process_synth_event(data->tool, event, machine,
 397                                               data->process);
 398 }
 399
 400 static int
 401 kallsyms_process_symbol(void *data, const char *_name,
 402                         char type __maybe_unused, u64 start)
 403 {
 404         char disp[KSYM_NAME_LEN];
 405         char *module, *name;
 406         unsigned long id;
 407         int err = 0;
 408
 409         module = strchr(_name, '\t');
 410         if (!module)
 411                 return 0;
 412
 413         /* We are going after [bpf] module ... */
 414         if (strcmp(module + 1, "[bpf]"))
 415                 return 0;
 416
 417         name = memdup(_name, (module - _name) + 1);
 418         if (!name)
 419                 return -ENOMEM;
 420
 421         name[module - _name] = 0;
 422
 423         /* .. and only for trampolines and dispatchers */
 424         if ((sscanf(name, "bpf_trampoline_%lu", &id) == 1) ||
 425             (sscanf(name, "bpf_dispatcher_%s", disp) == 1))
 426                 err = process_bpf_image(name, start, data);
 427
 428         free(name);
 429         return err;
 430 }
 431
 432 int perf_event__synthesize_bpf_events(struct perf_session *session,
 433                                       perf_event__handler_t process,
 434                                       struct machine *machine,
 435                                       struct record_opts *opts)
 436 {
 437         const char *kallsyms_filename = "/proc/kallsyms";
 438         struct kallsyms_parse arg;
 439         union perf_event *event;
 440         __u32 id = 0;
 441         int err;
 442         int fd;
 443
 444         event = malloc(sizeof(event->bpf) + KSYM_NAME_LEN + machine->id_hdr_size);
 445         if (!event)
 446                 return -1;
 447
 448         /* Synthesize all the bpf programs in system. */
 449         while (true) {
 450                 err = bpf_prog_get_next_id(id, &id);
 451                 if (err) {
 452                         if (errno == ENOENT) {
 453                                 err = 0;
 454                                 break;
 455                         }
 456                         pr_debug("%s: can't get next program: %s%s\n",
 457                                  __func__, strerror(errno),
 458                                  errno == EINVAL ? " -- kernel too old?" : "");
 459                         /* don't report error on old kernel or EPERM  */
 460                         err = (errno == EINVAL || errno == EPERM) ? 0 : -1;
 461                         break;
 462                 }
 463                 fd = bpf_prog_get_fd_by_id(id);
 464                 if (fd < 0) {
 465                         pr_debug("%s: failed to get fd for prog_id %u\n",
 466                                  __func__, id);
 467                         continue;
 468                 }
 469
 470                 err = perf_event__synthesize_one_bpf_prog(session, process,
 471                                                           machine, fd,
 472                                                           event, opts);
 473                 close(fd);
 474                 if (err) {
 475                         /* do not return error for old kernel */
 476                         if (err == -2)
 477                                 err = 0;
 478                         break;
 479                 }
 480         }
 481
 482         /* Synthesize all the bpf images - trampolines/dispatchers. */
 483         if (symbol_conf.kallsyms_name != NULL)
 484                 kallsyms_filename = symbol_conf.kallsyms_name;
 485
 486         arg = (struct kallsyms_parse) {
 487                 .event   = event,
 488                 .process = process,
 489                 .machine = machine,
 490                 .tool    = session->tool,
 491         };
 492
 493         if (kallsyms__parse(kallsyms_filename, &arg, kallsyms_process_symbol)) {
 494                 pr_err("%s: failed to synthesize bpf images: %s\n",
 495                        __func__, strerror(errno));
 496         }
 497
 498         free(event);
 499         return err;
 500 }
 501
 502 static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
 503 {
 504         struct bpf_prog_info_node *info_node;
 505         struct perf_bpil *info_linear;
 506         struct btf *btf = NULL;
 507         u64 arrays;
 508         u32 btf_id;
 509         int fd;
 510
 511         fd = bpf_prog_get_fd_by_id(id);
 512         if (fd < 0)
 513                 return;
 514
 515         arrays = 1UL << PERF_BPIL_JITED_KSYMS;
 516         arrays |= 1UL << PERF_BPIL_JITED_FUNC_LENS;
 517         arrays |= 1UL << PERF_BPIL_FUNC_INFO;
 518         arrays |= 1UL << PERF_BPIL_PROG_TAGS;
 519         arrays |= 1UL << PERF_BPIL_JITED_INSNS;
 520         arrays |= 1UL << PERF_BPIL_LINE_INFO;
 521         arrays |= 1UL << PERF_BPIL_JITED_LINE_INFO;
 522
 523         info_linear = get_bpf_prog_info_linear(fd, arrays);
 524         if (IS_ERR_OR_NULL(info_linear)) {
 525                 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 526                 goto out;
 527         }
 528
 529         btf_id = info_linear->info.btf_id;
 530
 531         info_node = malloc(sizeof(struct bpf_prog_info_node));
 532         if (info_node) {
 533                 info_node->info_linear = info_linear;
 534                 perf_env__insert_bpf_prog_info(env, info_node);
 535         } else
 536                 free(info_linear);
 537
 538         if (btf_id == 0)
 539                 goto out;
 540
 541         btf = btf__load_from_kernel_by_id(btf_id);
 542         if (libbpf_get_error(btf)) {
 543                 pr_debug("%s: failed to get BTF of id %u, aborting\n",
 544                          __func__, btf_id);
 545                 goto out;
 546         }
 547         perf_env__fetch_btf(env, btf_id, btf);
 548
 549 out:
 550         btf__free(btf);
 551         close(fd);
 552 }
 553
 554 static int bpf_event__sb_cb(union perf_event *event, void *data)
 555 {
 556         struct perf_env *env = data;
 557
 558         if (event->header.type != PERF_RECORD_BPF_EVENT)
 559                 return -1;
 560
 561         switch (event->bpf.type) {
 562         case PERF_BPF_EVENT_PROG_LOAD:
 563                 perf_env__add_bpf_info(env, event->bpf.id);
 564
 565         case PERF_BPF_EVENT_PROG_UNLOAD:
 566                 /*
 567                  * Do not free bpf_prog_info and btf of the program here,
 568                  * as annotation still need them. They will be freed at
 569                  * the end of the session.
 570                  */
 571                 break;
 572         default:
 573                 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
 574                 break;
 575         }
 576
 577         return 0;
 578 }
 579
 580 int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
 581 {
 582         struct perf_event_attr attr = {
 583                 .type             = PERF_TYPE_SOFTWARE,
 584                 .config           = PERF_COUNT_SW_DUMMY,
 585                 .sample_id_all    = 1,
 586                 .watermark        = 1,
 587                 .bpf_event        = 1,
 588                 .size      = sizeof(attr), /* to capture ABI version */
 589         };
 590
 591         /*
 592          * Older gcc versions don't support designated initializers, like above,
 593          * for unnamed union members, such as the following:
 594          */
 595         attr.wakeup_watermark = 1;
 596
 597         return evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
 598 }
 599
 600 void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
 601                                     struct perf_env *env,
 602                                     FILE *fp)
 603 {
 604         __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 605         __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 606         char name[KSYM_NAME_LEN];
 607         struct btf *btf = NULL;
 608         u32 sub_prog_cnt, i;
 609
 610         sub_prog_cnt = info->nr_jited_ksyms;
 611         if (sub_prog_cnt != info->nr_prog_tags ||
 612             sub_prog_cnt != info->nr_jited_func_lens)
 613                 return;
 614
 615         if (info->btf_id) {
 616                 struct btf_node *node;
 617
 618                 node = perf_env__find_btf(env, info->btf_id);
 619                 if (node)
 620                         btf = btf__new((__u8 *)(node->data),
 621                                        node->data_size);
 622         }
 623
 624         if (sub_prog_cnt == 1) {
 625                 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, 0);
 626                 fprintf(fp, "# bpf_prog_info %u: %s addr 0x%llx size %u\n",
 627                         info->id, name, prog_addrs[0], prog_lens[0]);
 628                 goto out;
 629         }
 630
 631         fprintf(fp, "# bpf_prog_info %u:\n", info->id);
 632         for (i = 0; i < sub_prog_cnt; i++) {
 633                 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, i);
 634
 635                 fprintf(fp, "# \tsub_prog %u: %s addr 0x%llx size %u\n",
 636                         i, name, prog_addrs[i], prog_lens[i]);
 637         }
 638 out:
 639         btf__free(btf);
 640 }