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 "bpf-event.h"
  10 #include "debug.h"
  11 #include "symbol.h"
  12 #include "machine.h"
  13 #include "env.h"
  14 #include "session.h"
  15 #include "map.h"
  16 #include "evlist.h"
  17
  18 #define ptr_to_u64(ptr)    ((__u64)(unsigned long)(ptr))
  19
  20 static int snprintf_hex(char *buf, size_t size, unsigned char *data, size_t len)
  21 {
  22         int ret = 0;
  23         size_t i;
  24
  25         for (i = 0; i < len; i++)
  26                 ret += snprintf(buf + ret, size - ret, "%02x", data[i]);
  27         return ret;
  28 }
  29
  30 static int machine__process_bpf_event_load(struct machine *machine,
  31                                            union perf_event *event,
  32                                            struct perf_sample *sample __maybe_unused)
  33 {
  34         struct bpf_prog_info_linear *info_linear;
  35         struct bpf_prog_info_node *info_node;
  36         struct perf_env *env = machine->env;
  37         int id = event->bpf_event.id;
  38         unsigned int i;
  39
  40         /* perf-record, no need to handle bpf-event */
  41         if (env == NULL)
  42                 return 0;
  43
  44         info_node = perf_env__find_bpf_prog_info(env, id);
  45         if (!info_node)
  46                 return 0;
  47         info_linear = info_node->info_linear;
  48
  49         for (i = 0; i < info_linear->info.nr_jited_ksyms; i++) {
  50                 u64 *addrs = (u64 *)(uintptr_t)(info_linear->info.jited_ksyms);
  51                 u64 addr = addrs[i];
  52                 struct map *map;
  53
  54                 map = map_groups__find(&machine->kmaps, addr);
  55
  56                 if (map) {
  57                         map->dso->binary_type = DSO_BINARY_TYPE__BPF_PROG_INFO;
  58                         map->dso->bpf_prog.id = id;
  59                         map->dso->bpf_prog.sub_id = i;
  60                         map->dso->bpf_prog.env = env;
  61                 }
  62         }
  63         return 0;
  64 }
  65
  66 int machine__process_bpf_event(struct machine *machine __maybe_unused,
  67                                union perf_event *event,
  68                                struct perf_sample *sample __maybe_unused)
  69 {
  70         if (dump_trace)
  71                 perf_event__fprintf_bpf_event(event, stdout);
  72
  73         switch (event->bpf_event.type) {
  74         case PERF_BPF_EVENT_PROG_LOAD:
  75                 return machine__process_bpf_event_load(machine, event, sample);
  76
  77         case PERF_BPF_EVENT_PROG_UNLOAD:
  78                 /*
  79                  * Do not free bpf_prog_info and btf of the program here,
  80                  * as annotation still need them. They will be freed at
  81                  * the end of the session.
  82                  */
  83                 break;
  84         default:
  85                 pr_debug("unexpected bpf_event type of %d\n",
  86                          event->bpf_event.type);
  87                 break;
  88         }
  89         return 0;
  90 }
  91
  92 static int perf_env__fetch_btf(struct perf_env *env,
  93                                u32 btf_id,
  94                                struct btf *btf)
  95 {
  96         struct btf_node *node;
  97         u32 data_size;
  98         const void *data;
  99
 100         data = btf__get_raw_data(btf, &data_size);
 101
 102         node = malloc(data_size + sizeof(struct btf_node));
 103         if (!node)
 104                 return -1;
 105
 106         node->id = btf_id;
 107         node->data_size = data_size;
 108         memcpy(node->data, data, data_size);
 109
 110         perf_env__insert_btf(env, node);
 111         return 0;
 112 }
 113
 114 static int synthesize_bpf_prog_name(char *buf, int size,
 115                                     struct bpf_prog_info *info,
 116                                     struct btf *btf,
 117                                     u32 sub_id)
 118 {
 119         u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(uintptr_t)(info->prog_tags);
 120         void *func_infos = (void *)(uintptr_t)(info->func_info);
 121         u32 sub_prog_cnt = info->nr_jited_ksyms;
 122         const struct bpf_func_info *finfo;
 123         const char *short_name = NULL;
 124         const struct btf_type *t;
 125         int name_len;
 126
 127         name_len = snprintf(buf, size, "bpf_prog_");
 128         name_len += snprintf_hex(buf + name_len, size - name_len,
 129                                  prog_tags[sub_id], BPF_TAG_SIZE);
 130         if (btf) {
 131                 finfo = func_infos + sub_id * info->func_info_rec_size;
 132                 t = btf__type_by_id(btf, finfo->type_id);
 133                 short_name = btf__name_by_offset(btf, t->name_off);
 134         } else if (sub_id == 0 && sub_prog_cnt == 1) {
 135                 /* no subprog */
 136                 if (info->name[0])
 137                         short_name = info->name;
 138         } else
 139                 short_name = "F";
 140         if (short_name)
 141                 name_len += snprintf(buf + name_len, size - name_len,
 142                                      "_%s", short_name);
 143         return name_len;
 144 }
 145
 146 /*
 147  * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf
 148  * program. One PERF_RECORD_BPF_EVENT is generated for the program. And
 149  * one PERF_RECORD_KSYMBOL is generated for each sub program.
 150  *
 151  * Returns:
 152  *    0 for success;
 153  *   -1 for failures;
 154  *   -2 for lack of kernel support.
 155  */
 156 static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
 157                                                perf_event__handler_t process,
 158                                                struct machine *machine,
 159                                                int fd,
 160                                                union perf_event *event,
 161                                                struct record_opts *opts)
 162 {
 163         struct ksymbol_event *ksymbol_event = &event->ksymbol_event;
 164         struct bpf_event *bpf_event = &event->bpf_event;
 165         struct bpf_prog_info_linear *info_linear;
 166         struct perf_tool *tool = session->tool;
 167         struct bpf_prog_info_node *info_node;
 168         struct bpf_prog_info *info;
 169         struct btf *btf = NULL;
 170         struct perf_env *env;
 171         u32 sub_prog_cnt, i;
 172         int err = 0;
 173         u64 arrays;
 174
 175         /*
 176          * for perf-record and perf-report use header.env;
 177          * otherwise, use global perf_env.
 178          */
 179         env = session->data ? &session->header.env : &perf_env;
 180
 181         arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
 182         arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
 183         arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
 184         arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
 185         arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
 186         arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
 187         arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;
 188
 189         info_linear = bpf_program__get_prog_info_linear(fd, arrays);
 190         if (IS_ERR_OR_NULL(info_linear)) {
 191                 info_linear = NULL;
 192                 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 193                 return -1;
 194         }
 195
 196         if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
 197                 pr_debug("%s: the kernel is too old, aborting\n", __func__);
 198                 return -2;
 199         }
 200
 201         info = &info_linear->info;
 202
 203         /* number of ksyms, func_lengths, and tags should match */
 204         sub_prog_cnt = info->nr_jited_ksyms;
 205         if (sub_prog_cnt != info->nr_prog_tags ||
 206             sub_prog_cnt != info->nr_jited_func_lens)
 207                 return -1;
 208
 209         /* check BTF func info support */
 210         if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {
 211                 /* btf func info number should be same as sub_prog_cnt */
 212                 if (sub_prog_cnt != info->nr_func_info) {
 213                         pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
 214                         err = -1;
 215                         goto out;
 216                 }
 217                 if (btf__get_from_id(info->btf_id, &btf)) {
 218                         pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
 219                         err = -1;
 220                         btf = NULL;
 221                         goto out;
 222                 }
 223                 perf_env__fetch_btf(env, info->btf_id, btf);
 224         }
 225
 226         /* Synthesize PERF_RECORD_KSYMBOL */
 227         for (i = 0; i < sub_prog_cnt; i++) {
 228                 __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 229                 __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 230                 int name_len;
 231
 232                 *ksymbol_event = (struct ksymbol_event){
 233                         .header = {
 234                                 .type = PERF_RECORD_KSYMBOL,
 235                                 .size = offsetof(struct ksymbol_event, name),
 236                         },
 237                         .addr = prog_addrs[i],
 238                         .len = prog_lens[i],
 239                         .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
 240                         .flags = 0,
 241                 };
 242
 243                 name_len = synthesize_bpf_prog_name(ksymbol_event->name,
 244                                                     KSYM_NAME_LEN, info, btf, i);
 245                 ksymbol_event->header.size += PERF_ALIGN(name_len + 1,
 246                                                          sizeof(u64));
 247
 248                 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
 249                 event->header.size += machine->id_hdr_size;
 250                 err = perf_tool__process_synth_event(tool, event,
 251                                                      machine, process);
 252         }
 253
 254         if (!opts->no_bpf_event) {
 255                 /* Synthesize PERF_RECORD_BPF_EVENT */
 256                 *bpf_event = (struct bpf_event){
 257                         .header = {
 258                                 .type = PERF_RECORD_BPF_EVENT,
 259                                 .size = sizeof(struct bpf_event),
 260                         },
 261                         .type = PERF_BPF_EVENT_PROG_LOAD,
 262                         .flags = 0,
 263                         .id = info->id,
 264                 };
 265                 memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);
 266                 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
 267                 event->header.size += machine->id_hdr_size;
 268
 269                 /* save bpf_prog_info to env */
 270                 info_node = malloc(sizeof(struct bpf_prog_info_node));
 271                 if (!info_node) {
 272                         err = -1;
 273                         goto out;
 274                 }
 275
 276                 info_node->info_linear = info_linear;
 277                 perf_env__insert_bpf_prog_info(env, info_node);
 278                 info_linear = NULL;
 279
 280                 /*
 281                  * process after saving bpf_prog_info to env, so that
 282                  * required information is ready for look up
 283                  */
 284                 err = perf_tool__process_synth_event(tool, event,
 285                                                      machine, process);
 286         }
 287
 288 out:
 289         free(info_linear);
 290         free(btf);
 291         return err ? -1 : 0;
 292 }
 293
 294 int perf_event__synthesize_bpf_events(struct perf_session *session,
 295                                       perf_event__handler_t process,
 296                                       struct machine *machine,
 297                                       struct record_opts *opts)
 298 {
 299         union perf_event *event;
 300         __u32 id = 0;
 301         int err;
 302         int fd;
 303
 304         event = malloc(sizeof(event->bpf_event) + KSYM_NAME_LEN + machine->id_hdr_size);
 305         if (!event)
 306                 return -1;
 307         while (true) {
 308                 err = bpf_prog_get_next_id(id, &id);
 309                 if (err) {
 310                         if (errno == ENOENT) {
 311                                 err = 0;
 312                                 break;
 313                         }
 314                         pr_debug("%s: can't get next program: %s%s\n",
 315                                  __func__, strerror(errno),
 316                                  errno == EINVAL ? " -- kernel too old?" : "");
 317                         /* don't report error on old kernel or EPERM  */
 318                         err = (errno == EINVAL || errno == EPERM) ? 0 : -1;
 319                         break;
 320                 }
 321                 fd = bpf_prog_get_fd_by_id(id);
 322                 if (fd < 0) {
 323                         pr_debug("%s: failed to get fd for prog_id %u\n",
 324                                  __func__, id);
 325                         continue;
 326                 }
 327
 328                 err = perf_event__synthesize_one_bpf_prog(session, process,
 329                                                           machine, fd,
 330                                                           event, opts);
 331                 close(fd);
 332                 if (err) {
 333                         /* do not return error for old kernel */
 334                         if (err == -2)
 335                                 err = 0;
 336                         break;
 337                 }
 338         }
 339         free(event);
 340         return err;
 341 }
 342
 343 static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
 344 {
 345         struct bpf_prog_info_linear *info_linear;
 346         struct bpf_prog_info_node *info_node;
 347         struct btf *btf = NULL;
 348         u64 arrays;
 349         u32 btf_id;
 350         int fd;
 351
 352         fd = bpf_prog_get_fd_by_id(id);
 353         if (fd < 0)
 354                 return;
 355
 356         arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
 357         arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
 358         arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
 359         arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
 360         arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
 361         arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
 362         arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;
 363
 364         info_linear = bpf_program__get_prog_info_linear(fd, arrays);
 365         if (IS_ERR_OR_NULL(info_linear)) {
 366                 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 367                 goto out;
 368         }
 369
 370         btf_id = info_linear->info.btf_id;
 371
 372         info_node = malloc(sizeof(struct bpf_prog_info_node));
 373         if (info_node) {
 374                 info_node->info_linear = info_linear;
 375                 perf_env__insert_bpf_prog_info(env, info_node);
 376         } else
 377                 free(info_linear);
 378
 379         if (btf_id == 0)
 380                 goto out;
 381
 382         if (btf__get_from_id(btf_id, &btf)) {
 383                 pr_debug("%s: failed to get BTF of id %u, aborting\n",
 384                          __func__, btf_id);
 385                 goto out;
 386         }
 387         perf_env__fetch_btf(env, btf_id, btf);
 388
 389 out:
 390         free(btf);
 391         close(fd);
 392 }
 393
 394 static int bpf_event__sb_cb(union perf_event *event, void *data)
 395 {
 396         struct perf_env *env = data;
 397
 398         if (event->header.type != PERF_RECORD_BPF_EVENT)
 399                 return -1;
 400
 401         switch (event->bpf_event.type) {
 402         case PERF_BPF_EVENT_PROG_LOAD:
 403                 perf_env__add_bpf_info(env, event->bpf_event.id);
 404
 405         case PERF_BPF_EVENT_PROG_UNLOAD:
 406                 /*
 407                  * Do not free bpf_prog_info and btf of the program here,
 408                  * as annotation still need them. They will be freed at
 409                  * the end of the session.
 410                  */
 411                 break;
 412         default:
 413                 pr_debug("unexpected bpf_event type of %d\n",
 414                          event->bpf_event.type);
 415                 break;
 416         }
 417
 418         return 0;
 419 }
 420
 421 int bpf_event__add_sb_event(struct perf_evlist **evlist,
 422                             struct perf_env *env)
 423 {
 424         struct perf_event_attr attr = {
 425                 .type             = PERF_TYPE_SOFTWARE,
 426                 .config           = PERF_COUNT_SW_DUMMY,
 427                 .sample_id_all    = 1,
 428                 .watermark        = 1,
 429                 .bpf_event        = 1,
 430                 .size      = sizeof(attr), /* to capture ABI version */
 431         };
 432
 433         /*
 434          * Older gcc versions don't support designated initializers, like above,
 435          * for unnamed union members, such as the following:
 436          */
 437         attr.wakeup_watermark = 1;
 438
 439         return perf_evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
 440 }
 441
 442 void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
 443                                     struct perf_env *env,
 444                                     FILE *fp)
 445 {
 446         __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 447         __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 448         char name[KSYM_NAME_LEN];
 449         struct btf *btf = NULL;
 450         u32 sub_prog_cnt, i;
 451
 452         sub_prog_cnt = info->nr_jited_ksyms;
 453         if (sub_prog_cnt != info->nr_prog_tags ||
 454             sub_prog_cnt != info->nr_jited_func_lens)
 455                 return;
 456
 457         if (info->btf_id) {
 458                 struct btf_node *node;
 459
 460                 node = perf_env__find_btf(env, info->btf_id);
 461                 if (node)
 462                         btf = btf__new((__u8 *)(node->data),
 463                                        node->data_size);
 464         }
 465
 466         if (sub_prog_cnt == 1) {
 467                 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, 0);
 468                 fprintf(fp, "# bpf_prog_info %u: %s addr 0x%llx size %u\n",
 469                         info->id, name, prog_addrs[0], prog_lens[0]);
 470                 return;
 471         }
 472
 473         fprintf(fp, "# bpf_prog_info %u:\n", info->id);
 474         for (i = 0; i < sub_prog_cnt; i++) {
 475                 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, i);
 476
 477                 fprintf(fp, "# \tsub_prog %u: %s addr 0x%llx size %u\n",
 478                         i, name, prog_addrs[i], prog_lens[i]);
 479         }
 480 }