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                 pr_debug("%s: the kernel is too old, aborting\n", __func__);
 200                 return -2;
 201         }
 202
 203         info = &info_linear->info;
 204
 205         /* number of ksyms, func_lengths, and tags should match */
 206         sub_prog_cnt = info->nr_jited_ksyms;
 207         if (sub_prog_cnt != info->nr_prog_tags ||
 208             sub_prog_cnt != info->nr_jited_func_lens)
 209                 return -1;
 210
 211         /* check BTF func info support */
 212         if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {
 213                 /* btf func info number should be same as sub_prog_cnt */
 214                 if (sub_prog_cnt != info->nr_func_info) {
 215                         pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
 216                         err = -1;
 217                         goto out;
 218                 }
 219                 if (btf__get_from_id(info->btf_id, &btf)) {
 220                         pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
 221                         err = -1;
 222                         btf = NULL;
 223                         goto out;
 224                 }
 225                 perf_env__fetch_btf(env, info->btf_id, btf);
 226         }
 227
 228         /* Synthesize PERF_RECORD_KSYMBOL */
 229         for (i = 0; i < sub_prog_cnt; i++) {
 230                 __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 231                 __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 232                 int name_len;
 233
 234                 *ksymbol_event = (struct perf_record_ksymbol) {
 235                         .header = {
 236                                 .type = PERF_RECORD_KSYMBOL,
 237                                 .size = offsetof(struct perf_record_ksymbol, name),
 238                         },
 239                         .addr = prog_addrs[i],
 240                         .len = prog_lens[i],
 241                         .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
 242                         .flags = 0,
 243                 };
 244
 245                 name_len = synthesize_bpf_prog_name(ksymbol_event->name,
 246                                                     KSYM_NAME_LEN, info, btf, i);
 247                 ksymbol_event->header.size += PERF_ALIGN(name_len + 1,
 248                                                          sizeof(u64));
 249
 250                 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
 251                 event->header.size += machine->id_hdr_size;
 252                 err = perf_tool__process_synth_event(tool, event,
 253                                                      machine, process);
 254         }
 255
 256         if (!opts->no_bpf_event) {
 257                 /* Synthesize PERF_RECORD_BPF_EVENT */
 258                 *bpf_event = (struct perf_record_bpf_event) {
 259                         .header = {
 260                                 .type = PERF_RECORD_BPF_EVENT,
 261                                 .size = sizeof(struct perf_record_bpf_event),
 262                         },
 263                         .type = PERF_BPF_EVENT_PROG_LOAD,
 264                         .flags = 0,
 265                         .id = info->id,
 266                 };
 267                 memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);
 268                 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
 269                 event->header.size += machine->id_hdr_size;
 270
 271                 /* save bpf_prog_info to env */
 272                 info_node = malloc(sizeof(struct bpf_prog_info_node));
 273                 if (!info_node) {
 274                         err = -1;
 275                         goto out;
 276                 }
 277
 278                 info_node->info_linear = info_linear;
 279                 perf_env__insert_bpf_prog_info(env, info_node);
 280                 info_linear = NULL;
 281
 282                 /*
 283                  * process after saving bpf_prog_info to env, so that
 284                  * required information is ready for look up
 285                  */
 286                 err = perf_tool__process_synth_event(tool, event,
 287                                                      machine, process);
 288         }
 289
 290 out:
 291         free(info_linear);
 292         free(btf);
 293         return err ? -1 : 0;
 294 }
 295
 296 struct kallsyms_parse {
 297         union perf_event        *event;
 298         perf_event__handler_t    process;
 299         struct machine          *machine;
 300         struct perf_tool        *tool;
 301 };
 302
 303 static int
 304 process_bpf_image(char *name, u64 addr, struct kallsyms_parse *data)
 305 {
 306         struct machine *machine = data->machine;
 307         union perf_event *event = data->event;
 308         struct perf_record_ksymbol *ksymbol;
 309         int len;
 310
 311         ksymbol = &event->ksymbol;
 312
 313         *ksymbol = (struct perf_record_ksymbol) {
 314                 .header = {
 315                         .type = PERF_RECORD_KSYMBOL,
 316                         .size = offsetof(struct perf_record_ksymbol, name),
 317                 },
 318                 .addr      = addr,
 319                 .len       = page_size,
 320                 .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
 321                 .flags     = 0,
 322         };
 323
 324         len = scnprintf(ksymbol->name, KSYM_NAME_LEN, "%s", name);
 325         ksymbol->header.size += PERF_ALIGN(len + 1, sizeof(u64));
 326         memset((void *) event + event->header.size, 0, machine->id_hdr_size);
 327         event->header.size += machine->id_hdr_size;
 328
 329         return perf_tool__process_synth_event(data->tool, event, machine,
 330                                               data->process);
 331 }
 332
 333 static int
 334 kallsyms_process_symbol(void *data, const char *_name,
 335                         char type __maybe_unused, u64 start)
 336 {
 337         char disp[KSYM_NAME_LEN];
 338         char *module, *name;
 339         unsigned long id;
 340         int err = 0;
 341
 342         module = strchr(_name, '\t');
 343         if (!module)
 344                 return 0;
 345
 346         /* We are going after [bpf] module ... */
 347         if (strcmp(module + 1, "[bpf]"))
 348                 return 0;
 349
 350         name = memdup(_name, (module - _name) + 1);
 351         if (!name)
 352                 return -ENOMEM;
 353
 354         name[module - _name] = 0;
 355
 356         /* .. and only for trampolines and dispatchers */
 357         if ((sscanf(name, "bpf_trampoline_%lu", &id) == 1) ||
 358             (sscanf(name, "bpf_dispatcher_%s", disp) == 1))
 359                 err = process_bpf_image(name, start, data);
 360
 361         free(name);
 362         return err;
 363 }
 364
 365 int perf_event__synthesize_bpf_events(struct perf_session *session,
 366                                       perf_event__handler_t process,
 367                                       struct machine *machine,
 368                                       struct record_opts *opts)
 369 {
 370         const char *kallsyms_filename = "/proc/kallsyms";
 371         struct kallsyms_parse arg;
 372         union perf_event *event;
 373         __u32 id = 0;
 374         int err;
 375         int fd;
 376
 377         event = malloc(sizeof(event->bpf) + KSYM_NAME_LEN + machine->id_hdr_size);
 378         if (!event)
 379                 return -1;
 380
 381         /* Synthesize all the bpf programs in system. */
 382         while (true) {
 383                 err = bpf_prog_get_next_id(id, &id);
 384                 if (err) {
 385                         if (errno == ENOENT) {
 386                                 err = 0;
 387                                 break;
 388                         }
 389                         pr_debug("%s: can't get next program: %s%s\n",
 390                                  __func__, strerror(errno),
 391                                  errno == EINVAL ? " -- kernel too old?" : "");
 392                         /* don't report error on old kernel or EPERM  */
 393                         err = (errno == EINVAL || errno == EPERM) ? 0 : -1;
 394                         break;
 395                 }
 396                 fd = bpf_prog_get_fd_by_id(id);
 397                 if (fd < 0) {
 398                         pr_debug("%s: failed to get fd for prog_id %u\n",
 399                                  __func__, id);
 400                         continue;
 401                 }
 402
 403                 err = perf_event__synthesize_one_bpf_prog(session, process,
 404                                                           machine, fd,
 405                                                           event, opts);
 406                 close(fd);
 407                 if (err) {
 408                         /* do not return error for old kernel */
 409                         if (err == -2)
 410                                 err = 0;
 411                         break;
 412                 }
 413         }
 414
 415         /* Synthesize all the bpf images - trampolines/dispatchers. */
 416         if (symbol_conf.kallsyms_name != NULL)
 417                 kallsyms_filename = symbol_conf.kallsyms_name;
 418
 419         arg = (struct kallsyms_parse) {
 420                 .event   = event,
 421                 .process = process,
 422                 .machine = machine,
 423                 .tool    = session->tool,
 424         };
 425
 426         if (kallsyms__parse(kallsyms_filename, &arg, kallsyms_process_symbol)) {
 427                 pr_err("%s: failed to synthesize bpf images: %s\n",
 428                        __func__, strerror(errno));
 429         }
 430
 431         free(event);
 432         return err;
 433 }
 434
 435 static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
 436 {
 437         struct bpf_prog_info_linear *info_linear;
 438         struct bpf_prog_info_node *info_node;
 439         struct btf *btf = NULL;
 440         u64 arrays;
 441         u32 btf_id;
 442         int fd;
 443
 444         fd = bpf_prog_get_fd_by_id(id);
 445         if (fd < 0)
 446                 return;
 447
 448         arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
 449         arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
 450         arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
 451         arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
 452         arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
 453         arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
 454         arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;
 455
 456         info_linear = bpf_program__get_prog_info_linear(fd, arrays);
 457         if (IS_ERR_OR_NULL(info_linear)) {
 458                 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 459                 goto out;
 460         }
 461
 462         btf_id = info_linear->info.btf_id;
 463
 464         info_node = malloc(sizeof(struct bpf_prog_info_node));
 465         if (info_node) {
 466                 info_node->info_linear = info_linear;
 467                 perf_env__insert_bpf_prog_info(env, info_node);
 468         } else
 469                 free(info_linear);
 470
 471         if (btf_id == 0)
 472                 goto out;
 473
 474         if (btf__get_from_id(btf_id, &btf)) {
 475                 pr_debug("%s: failed to get BTF of id %u, aborting\n",
 476                          __func__, btf_id);
 477                 goto out;
 478         }
 479         perf_env__fetch_btf(env, btf_id, btf);
 480
 481 out:
 482         free(btf);
 483         close(fd);
 484 }
 485
 486 static int bpf_event__sb_cb(union perf_event *event, void *data)
 487 {
 488         struct perf_env *env = data;
 489
 490         if (event->header.type != PERF_RECORD_BPF_EVENT)
 491                 return -1;
 492
 493         switch (event->bpf.type) {
 494         case PERF_BPF_EVENT_PROG_LOAD:
 495                 perf_env__add_bpf_info(env, event->bpf.id);
 496
 497         case PERF_BPF_EVENT_PROG_UNLOAD:
 498                 /*
 499                  * Do not free bpf_prog_info and btf of the program here,
 500                  * as annotation still need them. They will be freed at
 501                  * the end of the session.
 502                  */
 503                 break;
 504         default:
 505                 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
 506                 break;
 507         }
 508
 509         return 0;
 510 }
 511
 512 int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
 513 {
 514         struct perf_event_attr attr = {
 515                 .type             = PERF_TYPE_SOFTWARE,
 516                 .config           = PERF_COUNT_SW_DUMMY,
 517                 .sample_id_all    = 1,
 518                 .watermark        = 1,
 519                 .bpf_event        = 1,
 520                 .size      = sizeof(attr), /* to capture ABI version */
 521         };
 522
 523         /*
 524          * Older gcc versions don't support designated initializers, like above,
 525          * for unnamed union members, such as the following:
 526          */
 527         attr.wakeup_watermark = 1;
 528
 529         return perf_evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
 530 }
 531
 532 void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
 533                                     struct perf_env *env,
 534                                     FILE *fp)
 535 {
 536         __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 537         __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 538         char name[KSYM_NAME_LEN];
 539         struct btf *btf = NULL;
 540         u32 sub_prog_cnt, i;
 541
 542         sub_prog_cnt = info->nr_jited_ksyms;
 543         if (sub_prog_cnt != info->nr_prog_tags ||
 544             sub_prog_cnt != info->nr_jited_func_lens)
 545                 return;
 546
 547         if (info->btf_id) {
 548                 struct btf_node *node;
 549
 550                 node = perf_env__find_btf(env, info->btf_id);
 551                 if (node)
 552                         btf = btf__new((__u8 *)(node->data),
 553                                        node->data_size);
 554         }
 555
 556         if (sub_prog_cnt == 1) {
 557                 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, 0);
 558                 fprintf(fp, "# bpf_prog_info %u: %s addr 0x%llx size %u\n",
 559                         info->id, name, prog_addrs[0], prog_lens[0]);
 560                 return;
 561         }
 562
 563         fprintf(fp, "# bpf_prog_info %u:\n", info->id);
 564         for (i = 0; i < sub_prog_cnt; i++) {
 565                 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, i);
 566
 567                 fprintf(fp, "# \tsub_prog %u: %s addr 0x%llx size %u\n",
 568                         i, name, prog_addrs[i], prog_lens[i]);
 569         }
 570 }