590 lines · c
1// SPDX-License-Identifier: GPL-2.02#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 "bpf-utils.h"14#include "debug.h"15#include "dso.h"16#include "symbol.h"17#include "machine.h"18#include "env.h"19#include "session.h"20#include "map.h"21#include "evlist.h"22#include "record.h"23#include "util/synthetic-events.h"24 25static int snprintf_hex(char *buf, size_t size, unsigned char *data, size_t len)26{27 int ret = 0;28 size_t i;29 30 for (i = 0; i < len; i++)31 ret += snprintf(buf + ret, size - ret, "%02x", data[i]);32 return ret;33}34 35static int machine__process_bpf_event_load(struct machine *machine,36 union perf_event *event,37 struct perf_sample *sample __maybe_unused)38{39 struct bpf_prog_info_node *info_node;40 struct perf_env *env = machine->env;41 struct perf_bpil *info_linear;42 int id = event->bpf.id;43 unsigned int i;44 45 /* perf-record, no need to handle bpf-event */46 if (env == NULL)47 return 0;48 49 info_node = perf_env__find_bpf_prog_info(env, id);50 if (!info_node)51 return 0;52 info_linear = info_node->info_linear;53 54 for (i = 0; i < info_linear->info.nr_jited_ksyms; i++) {55 u64 *addrs = (u64 *)(uintptr_t)(info_linear->info.jited_ksyms);56 u64 addr = addrs[i];57 struct map *map = maps__find(machine__kernel_maps(machine), addr);58 59 if (map) {60 struct dso *dso = map__dso(map);61 62 dso__set_binary_type(dso, DSO_BINARY_TYPE__BPF_PROG_INFO);63 dso__bpf_prog(dso)->id = id;64 dso__bpf_prog(dso)->sub_id = i;65 dso__bpf_prog(dso)->env = env;66 map__put(map);67 }68 }69 return 0;70}71 72int machine__process_bpf(struct machine *machine, union perf_event *event,73 struct perf_sample *sample)74{75 if (dump_trace)76 perf_event__fprintf_bpf(event, stdout);77 78 switch (event->bpf.type) {79 case PERF_BPF_EVENT_PROG_LOAD:80 return machine__process_bpf_event_load(machine, event, sample);81 82 case PERF_BPF_EVENT_PROG_UNLOAD:83 /*84 * Do not free bpf_prog_info and btf of the program here,85 * as annotation still need them. They will be freed at86 * the end of the session.87 */88 break;89 default:90 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);91 break;92 }93 return 0;94}95 96static int perf_env__fetch_btf(struct perf_env *env,97 u32 btf_id,98 struct btf *btf)99{100 struct btf_node *node;101 u32 data_size;102 const void *data;103 104 data = btf__raw_data(btf, &data_size);105 106 node = malloc(data_size + sizeof(struct btf_node));107 if (!node)108 return -1;109 110 node->id = btf_id;111 node->data_size = data_size;112 memcpy(node->data, data, data_size);113 114 if (!perf_env__insert_btf(env, node)) {115 /* Insertion failed because of a duplicate. */116 free(node);117 return -1;118 }119 return 0;120}121 122static int synthesize_bpf_prog_name(char *buf, int size,123 struct bpf_prog_info *info,124 struct btf *btf,125 u32 sub_id)126{127 u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(uintptr_t)(info->prog_tags);128 void *func_infos = (void *)(uintptr_t)(info->func_info);129 u32 sub_prog_cnt = info->nr_jited_ksyms;130 const struct bpf_func_info *finfo;131 const char *short_name = NULL;132 const struct btf_type *t;133 int name_len;134 135 name_len = snprintf(buf, size, "bpf_prog_");136 name_len += snprintf_hex(buf + name_len, size - name_len,137 prog_tags[sub_id], BPF_TAG_SIZE);138 if (btf) {139 finfo = func_infos + sub_id * info->func_info_rec_size;140 t = btf__type_by_id(btf, finfo->type_id);141 short_name = btf__name_by_offset(btf, t->name_off);142 } else if (sub_id == 0 && sub_prog_cnt == 1) {143 /* no subprog */144 if (info->name[0])145 short_name = info->name;146 } else147 short_name = "F";148 if (short_name)149 name_len += snprintf(buf + name_len, size - name_len,150 "_%s", short_name);151 return name_len;152}153 154/*155 * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf156 * program. One PERF_RECORD_BPF_EVENT is generated for the program. And157 * one PERF_RECORD_KSYMBOL is generated for each sub program.158 *159 * Returns:160 * 0 for success;161 * -1 for failures;162 * -2 for lack of kernel support.163 */164static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,165 perf_event__handler_t process,166 struct machine *machine,167 int fd,168 union perf_event *event,169 struct record_opts *opts)170{171 struct perf_record_ksymbol *ksymbol_event = &event->ksymbol;172 struct perf_record_bpf_event *bpf_event = &event->bpf;173 const struct perf_tool *tool = session->tool;174 struct bpf_prog_info_node *info_node;175 struct perf_bpil *info_linear;176 struct bpf_prog_info *info;177 struct btf *btf = NULL;178 struct perf_env *env;179 u32 sub_prog_cnt, i;180 int err = 0;181 u64 arrays;182 183 /*184 * for perf-record and perf-report use header.env;185 * otherwise, use global perf_env.186 */187 env = session->data ? &session->header.env : &perf_env;188 189 arrays = 1UL << PERF_BPIL_JITED_KSYMS;190 arrays |= 1UL << PERF_BPIL_JITED_FUNC_LENS;191 arrays |= 1UL << PERF_BPIL_FUNC_INFO;192 arrays |= 1UL << PERF_BPIL_PROG_TAGS;193 arrays |= 1UL << PERF_BPIL_JITED_INSNS;194 arrays |= 1UL << PERF_BPIL_LINE_INFO;195 arrays |= 1UL << PERF_BPIL_JITED_LINE_INFO;196 197 info_linear = get_bpf_prog_info_linear(fd, arrays);198 if (IS_ERR_OR_NULL(info_linear)) {199 info_linear = NULL;200 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);201 return -1;202 }203 204 if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {205 free(info_linear);206 pr_debug("%s: the kernel is too old, aborting\n", __func__);207 return -2;208 }209 210 info = &info_linear->info;211 if (!info->jited_ksyms) {212 free(info_linear);213 return -1;214 }215 216 /* number of ksyms, func_lengths, and tags should match */217 sub_prog_cnt = info->nr_jited_ksyms;218 if (sub_prog_cnt != info->nr_prog_tags ||219 sub_prog_cnt != info->nr_jited_func_lens) {220 free(info_linear);221 return -1;222 }223 224 /* check BTF func info support */225 if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {226 /* btf func info number should be same as sub_prog_cnt */227 if (sub_prog_cnt != info->nr_func_info) {228 pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);229 free(info_linear);230 return -1;231 }232 btf = btf__load_from_kernel_by_id(info->btf_id);233 if (libbpf_get_error(btf)) {234 pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);235 err = -1;236 goto out;237 }238 perf_env__fetch_btf(env, info->btf_id, btf);239 }240 241 /* Synthesize PERF_RECORD_KSYMBOL */242 for (i = 0; i < sub_prog_cnt; i++) {243 __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);244 __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);245 int name_len;246 247 *ksymbol_event = (struct perf_record_ksymbol) {248 .header = {249 .type = PERF_RECORD_KSYMBOL,250 .size = offsetof(struct perf_record_ksymbol, name),251 },252 .addr = prog_addrs[i],253 .len = prog_lens[i],254 .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,255 .flags = 0,256 };257 258 name_len = synthesize_bpf_prog_name(ksymbol_event->name,259 KSYM_NAME_LEN, info, btf, i);260 ksymbol_event->header.size += PERF_ALIGN(name_len + 1,261 sizeof(u64));262 263 memset((void *)event + event->header.size, 0, machine->id_hdr_size);264 event->header.size += machine->id_hdr_size;265 err = perf_tool__process_synth_event(tool, event,266 machine, process);267 }268 269 if (!opts->no_bpf_event) {270 /* Synthesize PERF_RECORD_BPF_EVENT */271 *bpf_event = (struct perf_record_bpf_event) {272 .header = {273 .type = PERF_RECORD_BPF_EVENT,274 .size = sizeof(struct perf_record_bpf_event),275 },276 .type = PERF_BPF_EVENT_PROG_LOAD,277 .flags = 0,278 .id = info->id,279 };280 memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);281 memset((void *)event + event->header.size, 0, machine->id_hdr_size);282 event->header.size += machine->id_hdr_size;283 284 /* save bpf_prog_info to env */285 info_node = malloc(sizeof(struct bpf_prog_info_node));286 if (!info_node) {287 err = -1;288 goto out;289 }290 291 info_node->info_linear = info_linear;292 perf_env__insert_bpf_prog_info(env, info_node);293 info_linear = NULL;294 295 /*296 * process after saving bpf_prog_info to env, so that297 * required information is ready for look up298 */299 err = perf_tool__process_synth_event(tool, event,300 machine, process);301 }302 303out:304 free(info_linear);305 btf__free(btf);306 return err ? -1 : 0;307}308 309struct kallsyms_parse {310 union perf_event *event;311 perf_event__handler_t process;312 struct machine *machine;313 const struct perf_tool *tool;314};315 316static int317process_bpf_image(char *name, u64 addr, struct kallsyms_parse *data)318{319 struct machine *machine = data->machine;320 union perf_event *event = data->event;321 struct perf_record_ksymbol *ksymbol;322 int len;323 324 ksymbol = &event->ksymbol;325 326 *ksymbol = (struct perf_record_ksymbol) {327 .header = {328 .type = PERF_RECORD_KSYMBOL,329 .size = offsetof(struct perf_record_ksymbol, name),330 },331 .addr = addr,332 .len = page_size,333 .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,334 .flags = 0,335 };336 337 len = scnprintf(ksymbol->name, KSYM_NAME_LEN, "%s", name);338 ksymbol->header.size += PERF_ALIGN(len + 1, sizeof(u64));339 memset((void *) event + event->header.size, 0, machine->id_hdr_size);340 event->header.size += machine->id_hdr_size;341 342 return perf_tool__process_synth_event(data->tool, event, machine,343 data->process);344}345 346static int347kallsyms_process_symbol(void *data, const char *_name,348 char type __maybe_unused, u64 start)349{350 char disp[KSYM_NAME_LEN];351 char *module, *name;352 unsigned long id;353 int err = 0;354 355 module = strchr(_name, '\t');356 if (!module)357 return 0;358 359 /* We are going after [bpf] module ... */360 if (strcmp(module + 1, "[bpf]"))361 return 0;362 363 name = memdup(_name, (module - _name) + 1);364 if (!name)365 return -ENOMEM;366 367 name[module - _name] = 0;368 369 /* .. and only for trampolines and dispatchers */370 if ((sscanf(name, "bpf_trampoline_%lu", &id) == 1) ||371 (sscanf(name, "bpf_dispatcher_%s", disp) == 1))372 err = process_bpf_image(name, start, data);373 374 free(name);375 return err;376}377 378int perf_event__synthesize_bpf_events(struct perf_session *session,379 perf_event__handler_t process,380 struct machine *machine,381 struct record_opts *opts)382{383 const char *kallsyms_filename = "/proc/kallsyms";384 struct kallsyms_parse arg;385 union perf_event *event;386 __u32 id = 0;387 int err;388 int fd;389 390 if (opts->no_bpf_event)391 return 0;392 393 event = malloc(sizeof(event->bpf) + KSYM_NAME_LEN + machine->id_hdr_size);394 if (!event)395 return -1;396 397 /* Synthesize all the bpf programs in system. */398 while (true) {399 err = bpf_prog_get_next_id(id, &id);400 if (err) {401 if (errno == ENOENT) {402 err = 0;403 break;404 }405 pr_debug("%s: can't get next program: %s%s\n",406 __func__, strerror(errno),407 errno == EINVAL ? " -- kernel too old?" : "");408 /* don't report error on old kernel or EPERM */409 err = (errno == EINVAL || errno == EPERM) ? 0 : -1;410 break;411 }412 fd = bpf_prog_get_fd_by_id(id);413 if (fd < 0) {414 pr_debug("%s: failed to get fd for prog_id %u\n",415 __func__, id);416 continue;417 }418 419 err = perf_event__synthesize_one_bpf_prog(session, process,420 machine, fd,421 event, opts);422 close(fd);423 if (err) {424 /* do not return error for old kernel */425 if (err == -2)426 err = 0;427 break;428 }429 }430 431 /* Synthesize all the bpf images - trampolines/dispatchers. */432 if (symbol_conf.kallsyms_name != NULL)433 kallsyms_filename = symbol_conf.kallsyms_name;434 435 arg = (struct kallsyms_parse) {436 .event = event,437 .process = process,438 .machine = machine,439 .tool = session->tool,440 };441 442 if (kallsyms__parse(kallsyms_filename, &arg, kallsyms_process_symbol)) {443 pr_err("%s: failed to synthesize bpf images: %s\n",444 __func__, strerror(errno));445 }446 447 free(event);448 return err;449}450 451static void perf_env__add_bpf_info(struct perf_env *env, u32 id)452{453 struct bpf_prog_info_node *info_node;454 struct perf_bpil *info_linear;455 struct btf *btf = NULL;456 u64 arrays;457 u32 btf_id;458 int fd;459 460 fd = bpf_prog_get_fd_by_id(id);461 if (fd < 0)462 return;463 464 arrays = 1UL << PERF_BPIL_JITED_KSYMS;465 arrays |= 1UL << PERF_BPIL_JITED_FUNC_LENS;466 arrays |= 1UL << PERF_BPIL_FUNC_INFO;467 arrays |= 1UL << PERF_BPIL_PROG_TAGS;468 arrays |= 1UL << PERF_BPIL_JITED_INSNS;469 arrays |= 1UL << PERF_BPIL_LINE_INFO;470 arrays |= 1UL << PERF_BPIL_JITED_LINE_INFO;471 472 info_linear = get_bpf_prog_info_linear(fd, arrays);473 if (IS_ERR_OR_NULL(info_linear)) {474 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);475 goto out;476 }477 478 btf_id = info_linear->info.btf_id;479 480 info_node = malloc(sizeof(struct bpf_prog_info_node));481 if (info_node) {482 info_node->info_linear = info_linear;483 perf_env__insert_bpf_prog_info(env, info_node);484 } else485 free(info_linear);486 487 if (btf_id == 0)488 goto out;489 490 btf = btf__load_from_kernel_by_id(btf_id);491 if (libbpf_get_error(btf)) {492 pr_debug("%s: failed to get BTF of id %u, aborting\n",493 __func__, btf_id);494 goto out;495 }496 perf_env__fetch_btf(env, btf_id, btf);497 498out:499 btf__free(btf);500 close(fd);501}502 503static int bpf_event__sb_cb(union perf_event *event, void *data)504{505 struct perf_env *env = data;506 507 if (event->header.type != PERF_RECORD_BPF_EVENT)508 return -1;509 510 switch (event->bpf.type) {511 case PERF_BPF_EVENT_PROG_LOAD:512 perf_env__add_bpf_info(env, event->bpf.id);513 514 case PERF_BPF_EVENT_PROG_UNLOAD:515 /*516 * Do not free bpf_prog_info and btf of the program here,517 * as annotation still need them. They will be freed at518 * the end of the session.519 */520 break;521 default:522 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);523 break;524 }525 526 return 0;527}528 529int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)530{531 struct perf_event_attr attr = {532 .type = PERF_TYPE_SOFTWARE,533 .config = PERF_COUNT_SW_DUMMY,534 .sample_id_all = 1,535 .watermark = 1,536 .bpf_event = 1,537 .size = sizeof(attr), /* to capture ABI version */538 };539 540 /*541 * Older gcc versions don't support designated initializers, like above,542 * for unnamed union members, such as the following:543 */544 attr.wakeup_watermark = 1;545 546 return evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);547}548 549void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,550 struct perf_env *env,551 FILE *fp)552{553 __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);554 __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);555 char name[KSYM_NAME_LEN];556 struct btf *btf = NULL;557 u32 sub_prog_cnt, i;558 559 sub_prog_cnt = info->nr_jited_ksyms;560 if (sub_prog_cnt != info->nr_prog_tags ||561 sub_prog_cnt != info->nr_jited_func_lens)562 return;563 564 if (info->btf_id) {565 struct btf_node *node;566 567 node = __perf_env__find_btf(env, info->btf_id);568 if (node)569 btf = btf__new((__u8 *)(node->data),570 node->data_size);571 }572 573 if (sub_prog_cnt == 1) {574 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, 0);575 fprintf(fp, "# bpf_prog_info %u: %s addr 0x%llx size %u\n",576 info->id, name, prog_addrs[0], prog_lens[0]);577 goto out;578 }579 580 fprintf(fp, "# bpf_prog_info %u:\n", info->id);581 for (i = 0; i < sub_prog_cnt; i++) {582 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, i);583 584 fprintf(fp, "# \tsub_prog %u: %s addr 0x%llx size %u\n",585 i, name, prog_addrs[i], prog_lens[i]);586 }587out:588 btf__free(btf);589}590