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