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 } 481