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 #define ptr_to_u64(ptr)    ((__u64)(unsigned long)(ptr))
  25
  26 static int snprintf_hex(char *buf, size_t size, unsigned char *data, size_t len)
  27 {
  28         int ret = 0;
  29         size_t i;
  30
  31         for (i = 0; i < len; i++)
  32                 ret += snprintf(buf + ret, size - ret, "%02x", data[i]);
  33         return ret;
  34 }
  35
  36 static int machine__process_bpf_event_load(struct machine *machine,
  37                                            union perf_event *event,
  38                                            struct perf_sample *sample __maybe_unused)
  39 {
  40         struct bpf_prog_info_linear *info_linear;
  41         struct bpf_prog_info_node *info_node;
  42         struct perf_env *env = machine->env;
  43         int id = event->bpf.id;
  44         unsigned int i;
  45
  46         /* perf-record, no need to handle bpf-event */
  47         if (env == NULL)
  48                 return 0;
  49
  50         info_node = perf_env__find_bpf_prog_info(env, id);
  51         if (!info_node)
  52                 return 0;
  53         info_linear = info_node->info_linear;
  54
  55         for (i = 0; i < info_linear->info.nr_jited_ksyms; i++) {
  56                 u64 *addrs = (u64 *)(uintptr_t)(info_linear->info.jited_ksyms);
  57                 u64 addr = addrs[i];
  58                 struct map *map = maps__find(&machine->kmaps, addr);
  59
  60                 if (map) {
  61                         map->dso->binary_type = DSO_BINARY_TYPE__BPF_PROG_INFO;
  62                         map->dso->bpf_prog.id = id;
  63                         map->dso->bpf_prog.sub_id = i;
  64                         map->dso->bpf_prog.env = env;
  65                 }
  66         }
  67         return 0;
  68 }
  69
  70 int machine__process_bpf(struct machine *machine, union perf_event *event,
  71                          struct perf_sample *sample)
  72 {
  73         if (dump_trace)
  74                 perf_event__fprintf_bpf(event, stdout);
  75
  76         switch (event->bpf.type) {
  77         case PERF_BPF_EVENT_PROG_LOAD:
  78                 return machine__process_bpf_event_load(machine, event, sample);
  79
  80         case PERF_BPF_EVENT_PROG_UNLOAD:
  81                 /*
  82                  * Do not free bpf_prog_info and btf of the program here,
  83                  * as annotation still need them. They will be freed at
  84                  * the end of the session.
  85                  */
  86                 break;
  87         default:
  88                 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
  89                 break;
  90         }
  91         return 0;
  92 }
  93
  94 static int perf_env__fetch_btf(struct perf_env *env,
  95                                u32 btf_id,
  96                                struct btf *btf)
  97 {
  98         struct btf_node *node;
  99         u32 data_size;
 100         const void *data;
 101
 102         data = btf__get_raw_data(btf, &data_size);
 103
 104         node = malloc(data_size + sizeof(struct btf_node));
 105         if (!node)
 106                 return -1;
 107
 108         node->id = btf_id;
 109         node->data_size = data_size;
 110         memcpy(node->data, data, data_size);
 111
 112         perf_env__insert_btf(env, node);
 113         return 0;
 114 }
 115
 116 static int synthesize_bpf_prog_name(char *buf, int size,
 117                                     struct bpf_prog_info *info,
 118                                     struct btf *btf,
 119                                     u32 sub_id)
 120 {
 121         u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(uintptr_t)(info->prog_tags);
 122         void *func_infos = (void *)(uintptr_t)(info->func_info);
 123         u32 sub_prog_cnt = info->nr_jited_ksyms;
 124         const struct bpf_func_info *finfo;
 125         const char *short_name = NULL;
 126         const struct btf_type *t;
 127         int name_len;
 128
 129         name_len = snprintf(buf, size, "bpf_prog_");
 130         name_len += snprintf_hex(buf + name_len, size - name_len,
 131                                  prog_tags[sub_id], BPF_TAG_SIZE);
 132         if (btf) {
 133                 finfo = func_infos + sub_id * info->func_info_rec_size;
 134                 t = btf__type_by_id(btf, finfo->type_id);
 135                 short_name = btf__name_by_offset(btf, t->name_off);
 136         } else if (sub_id == 0 && sub_prog_cnt == 1) {
 137                 /* no subprog */
 138                 if (info->name[0])
 139                         short_name = info->name;
 140         } else
 141                 short_name = "F";
 142         if (short_name)
 143                 name_len += snprintf(buf + name_len, size - name_len,
 144                                      "_%s", short_name);
 145         return name_len;
 146 }
 147
 148 /*
 149  * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf
 150  * program. One PERF_RECORD_BPF_EVENT is generated for the program. And
 151  * one PERF_RECORD_KSYMBOL is generated for each sub program.
 152  *
 153  * Returns:
 154  *    0 for success;
 155  *   -1 for failures;
 156  *   -2 for lack of kernel support.
 157  */
 158 static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
 159                                                perf_event__handler_t process,
 160                                                struct machine *machine,
 161                                                int fd,
 162                                                union perf_event *event,
 163                                                struct record_opts *opts)
 164 {
 165         struct perf_record_ksymbol *ksymbol_event = &event->ksymbol;
 166         struct perf_record_bpf_event *bpf_event = &event->bpf;
 167         struct bpf_prog_info_linear *info_linear;
 168         struct perf_tool *tool = session->tool;
 169         struct bpf_prog_info_node *info_node;
 170         struct bpf_prog_info *info;
 171         struct btf *btf = NULL;
 172         struct perf_env *env;
 173         u32 sub_prog_cnt, i;
 174         int err = 0;
 175         u64 arrays;
 176
 177         /*
 178          * for perf-record and perf-report use header.env;
 179          * otherwise, use global perf_env.
 180          */
 181         env = session->data ? &session->header.env : &perf_env;
 182
 183         arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
 184         arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
 185         arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
 186         arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
 187         arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
 188         arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
 189         arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;
 190
 191         info_linear = bpf_program__get_prog_info_linear(fd, arrays);
 192         if (IS_ERR_OR_NULL(info_linear)) {
 193                 info_linear = NULL;
 194                 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 195                 return -1;
 196         }
 197
 198         if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
 199                 free(info_linear);
 200                 pr_debug("%s: the kernel is too old, aborting\n", __func__);
 201                 return -2;
 202         }
 203
 204         info = &info_linear->info;
 205         if (!info->jited_ksyms) {
 206                 free(info_linear);
 207                 return -1;
 208         }
 209
 210         /* number of ksyms, func_lengths, and tags should match */
 211         sub_prog_cnt = info->nr_jited_ksyms;
 212         if (sub_prog_cnt != info->nr_prog_tags ||
 213             sub_prog_cnt != info->nr_jited_func_lens) {
 214                 free(info_linear);
 215                 return -1;
 216         }
 217
 218         /* check BTF func info support */
 219         if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {
 220                 /* btf func info number should be same as sub_prog_cnt */
 221                 if (sub_prog_cnt != info->nr_func_info) {
 222                         pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
 223                         free(info_linear);
 224                         return -1;
 225                 }
 226                 btf = btf__load_from_kernel_by_id(info->btf_id);
 227                 if (libbpf_get_error(btf)) {
 228                         pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
 229                         err = -1;
 230                         goto out;
 231                 }
 232                 perf_env__fetch_btf(env, info->btf_id, btf);
 233         }
 234
 235         /* Synthesize PERF_RECORD_KSYMBOL */
 236         for (i = 0; i < sub_prog_cnt; i++) {
 237                 __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 238                 __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 239                 int name_len;
 240
 241                 *ksymbol_event = (struct perf_record_ksymbol) {
 242                         .header = {
 243                                 .type = PERF_RECORD_KSYMBOL,
 244                                 .size = offsetof(struct perf_record_ksymbol, name),
 245                         },
 246                         .addr = prog_addrs[i],
 247                         .len = prog_lens[i],
 248                         .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
 249                         .flags = 0,
 250                 };
 251
 252                 name_len = synthesize_bpf_prog_name(ksymbol_event->name,
 253                                                     KSYM_NAME_LEN, info, btf, i);
 254                 ksymbol_event->header.size += PERF_ALIGN(name_len + 1,
 255                                                          sizeof(u64));
 256
 257                 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
 258                 event->header.size += machine->id_hdr_size;
 259                 err = perf_tool__process_synth_event(tool, event,
 260                                                      machine, process);
 261         }
 262
 263         if (!opts->no_bpf_event) {
 264                 /* Synthesize PERF_RECORD_BPF_EVENT */
 265                 *bpf_event = (struct perf_record_bpf_event) {
 266                         .header = {
 267                                 .type = PERF_RECORD_BPF_EVENT,
 268                                 .size = sizeof(struct perf_record_bpf_event),
 269                         },
 270                         .type = PERF_BPF_EVENT_PROG_LOAD,
 271                         .flags = 0,
 272                         .id = info->id,
 273                 };
 274                 memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);
 275                 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
 276                 event->header.size += machine->id_hdr_size;
 277
 278                 /* save bpf_prog_info to env */
 279                 info_node = malloc(sizeof(struct bpf_prog_info_node));
 280                 if (!info_node) {
 281                         err = -1;
 282                         goto out;
 283                 }
 284
 285                 info_node->info_linear = info_linear;
 286                 perf_env__insert_bpf_prog_info(env, info_node);
 287                 info_linear = NULL;
 288
 289                 /*
 290                  * process after saving bpf_prog_info to env, so that
 291                  * required information is ready for look up
 292                  */
 293                 err = perf_tool__process_synth_event(tool, event,
 294                                                      machine, process);
 295         }
 296
 297 out:
 298         free(info_linear);
 299         btf__free(btf);
 300         return err ? -1 : 0;
 301 }
 302
 303 struct kallsyms_parse {
 304         union perf_event        *event;
 305         perf_event__handler_t    process;
 306         struct machine          *machine;
 307         struct perf_tool        *tool;
 308 };
 309
 310 static int
 311 process_bpf_image(char *name, u64 addr, struct kallsyms_parse *data)
 312 {
 313         struct machine *machine = data->machine;
 314         union perf_event *event = data->event;
 315         struct perf_record_ksymbol *ksymbol;
 316         int len;
 317
 318         ksymbol = &event->ksymbol;
 319
 320         *ksymbol = (struct perf_record_ksymbol) {
 321                 .header = {
 322                         .type = PERF_RECORD_KSYMBOL,
 323                         .size = offsetof(struct perf_record_ksymbol, name),
 324                 },
 325                 .addr      = addr,
 326                 .len       = page_size,
 327                 .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
 328                 .flags     = 0,
 329         };
 330
 331         len = scnprintf(ksymbol->name, KSYM_NAME_LEN, "%s", name);
 332         ksymbol->header.size += PERF_ALIGN(len + 1, sizeof(u64));
 333         memset((void *) event + event->header.size, 0, machine->id_hdr_size);
 334         event->header.size += machine->id_hdr_size;
 335
 336         return perf_tool__process_synth_event(data->tool, event, machine,
 337                                               data->process);
 338 }
 339
 340 static int
 341 kallsyms_process_symbol(void *data, const char *_name,
 342                         char type __maybe_unused, u64 start)
 343 {
 344         char disp[KSYM_NAME_LEN];
 345         char *module, *name;
 346         unsigned long id;
 347         int err = 0;
 348
 349         module = strchr(_name, '\t');
 350         if (!module)
 351                 return 0;
 352
 353         /* We are going after [bpf] module ... */
 354         if (strcmp(module + 1, "[bpf]"))
 355                 return 0;
 356
 357         name = memdup(_name, (module - _name) + 1);
 358         if (!name)
 359                 return -ENOMEM;
 360
 361         name[module - _name] = 0;
 362
 363         /* .. and only for trampolines and dispatchers */
 364         if ((sscanf(name, "bpf_trampoline_%lu", &id) == 1) ||
 365             (sscanf(name, "bpf_dispatcher_%s", disp) == 1))
 366                 err = process_bpf_image(name, start, data);
 367
 368         free(name);
 369         return err;
 370 }
 371
 372 int perf_event__synthesize_bpf_events(struct perf_session *session,
 373                                       perf_event__handler_t process,
 374                                       struct machine *machine,
 375                                       struct record_opts *opts)
 376 {
 377         const char *kallsyms_filename = "/proc/kallsyms";
 378         struct kallsyms_parse arg;
 379         union perf_event *event;
 380         __u32 id = 0;
 381         int err;
 382         int fd;
 383
 384         event = malloc(sizeof(event->bpf) + KSYM_NAME_LEN + machine->id_hdr_size);
 385         if (!event)
 386                 return -1;
 387
 388         /* Synthesize all the bpf programs in system. */
 389         while (true) {
 390                 err = bpf_prog_get_next_id(id, &id);
 391                 if (err) {
 392                         if (errno == ENOENT) {
 393                                 err = 0;
 394                                 break;
 395                         }
 396                         pr_debug("%s: can't get next program: %s%s\n",
 397                                  __func__, strerror(errno),
 398                                  errno == EINVAL ? " -- kernel too old?" : "");
 399                         /* don't report error on old kernel or EPERM  */
 400                         err = (errno == EINVAL || errno == EPERM) ? 0 : -1;
 401                         break;
 402                 }
 403                 fd = bpf_prog_get_fd_by_id(id);
 404                 if (fd < 0) {
 405                         pr_debug("%s: failed to get fd for prog_id %u\n",
 406                                  __func__, id);
 407                         continue;
 408                 }
 409
 410                 err = perf_event__synthesize_one_bpf_prog(session, process,
 411                                                           machine, fd,
 412                                                           event, opts);
 413                 close(fd);
 414                 if (err) {
 415                         /* do not return error for old kernel */
 416                         if (err == -2)
 417                                 err = 0;
 418                         break;
 419                 }
 420         }
 421
 422         /* Synthesize all the bpf images - trampolines/dispatchers. */
 423         if (symbol_conf.kallsyms_name != NULL)
 424                 kallsyms_filename = symbol_conf.kallsyms_name;
 425
 426         arg = (struct kallsyms_parse) {
 427                 .event   = event,
 428                 .process = process,
 429                 .machine = machine,
 430                 .tool    = session->tool,
 431         };
 432
 433         if (kallsyms__parse(kallsyms_filename, &arg, kallsyms_process_symbol)) {
 434                 pr_err("%s: failed to synthesize bpf images: %s\n",
 435                        __func__, strerror(errno));
 436         }
 437
 438         free(event);
 439         return err;
 440 }
 441
 442 static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
 443 {
 444         struct bpf_prog_info_linear *info_linear;
 445         struct bpf_prog_info_node *info_node;
 446         struct btf *btf = NULL;
 447         u64 arrays;
 448         u32 btf_id;
 449         int fd;
 450
 451         fd = bpf_prog_get_fd_by_id(id);
 452         if (fd < 0)
 453                 return;
 454
 455         arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
 456         arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
 457         arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
 458         arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
 459         arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
 460         arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
 461         arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;
 462
 463         info_linear = bpf_program__get_prog_info_linear(fd, arrays);
 464         if (IS_ERR_OR_NULL(info_linear)) {
 465                 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 466                 goto out;
 467         }
 468
 469         btf_id = info_linear->info.btf_id;
 470
 471         info_node = malloc(sizeof(struct bpf_prog_info_node));
 472         if (info_node) {
 473                 info_node->info_linear = info_linear;
 474                 perf_env__insert_bpf_prog_info(env, info_node);
 475         } else
 476                 free(info_linear);
 477
 478         if (btf_id == 0)
 479                 goto out;
 480
 481         btf = btf__load_from_kernel_by_id(btf_id);
 482         if (libbpf_get_error(btf)) {
 483                 pr_debug("%s: failed to get BTF of id %u, aborting\n",
 484                          __func__, btf_id);
 485                 goto out;
 486         }
 487         perf_env__fetch_btf(env, btf_id, btf);
 488
 489 out:
 490         btf__free(btf);
 491         close(fd);
 492 }
 493
 494 static int bpf_event__sb_cb(union perf_event *event, void *data)
 495 {
 496         struct perf_env *env = data;
 497
 498         if (event->header.type != PERF_RECORD_BPF_EVENT)
 499                 return -1;
 500
 501         switch (event->bpf.type) {
 502         case PERF_BPF_EVENT_PROG_LOAD:
 503                 perf_env__add_bpf_info(env, event->bpf.id);
 504
 505         case PERF_BPF_EVENT_PROG_UNLOAD:
 506                 /*
 507                  * Do not free bpf_prog_info and btf of the program here,
 508                  * as annotation still need them. They will be freed at
 509                  * the end of the session.
 510                  */
 511                 break;
 512         default:
 513                 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
 514                 break;
 515         }
 516
 517         return 0;
 518 }
 519
 520 int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
 521 {
 522         struct perf_event_attr attr = {
 523                 .type             = PERF_TYPE_SOFTWARE,
 524                 .config           = PERF_COUNT_SW_DUMMY,
 525                 .sample_id_all    = 1,
 526                 .watermark        = 1,
 527                 .bpf_event        = 1,
 528                 .size      = sizeof(attr), /* to capture ABI version */
 529         };
 530
 531         /*
 532          * Older gcc versions don't support designated initializers, like above,
 533          * for unnamed union members, such as the following:
 534          */
 535         attr.wakeup_watermark = 1;
 536
 537         return evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
 538 }
 539
 540 void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
 541                                     struct perf_env *env,
 542                                     FILE *fp)
 543 {
 544         __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 545         __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 546         char name[KSYM_NAME_LEN];
 547         struct btf *btf = NULL;
 548         u32 sub_prog_cnt, i;
 549
 550         sub_prog_cnt = info->nr_jited_ksyms;
 551         if (sub_prog_cnt != info->nr_prog_tags ||
 552             sub_prog_cnt != info->nr_jited_func_lens)
 553                 return;
 554
 555         if (info->btf_id) {
 556                 struct btf_node *node;
 557
 558                 node = perf_env__find_btf(env, info->btf_id);
 559                 if (node)
 560                         btf = btf__new((__u8 *)(node->data),
 561                                        node->data_size);
 562         }
 563
 564         if (sub_prog_cnt == 1) {
 565                 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, 0);
 566                 fprintf(fp, "# bpf_prog_info %u: %s addr 0x%llx size %u\n",
 567                         info->id, name, prog_addrs[0], prog_lens[0]);
 568                 return;
 569         }
 570
 571         fprintf(fp, "# bpf_prog_info %u:\n", info->id);
 572         for (i = 0; i < sub_prog_cnt; i++) {
 573                 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, i);
 574
 575                 fprintf(fp, "# \tsub_prog %u: %s addr 0x%llx size %u\n",
 576                         i, name, prog_addrs[i], prog_lens[i]);
 577         }
 578 }