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