tools/perf/util/bpf-event.c

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

DEFINITIONS
