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