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