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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 "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->binary_type = DSO_BINARY_TYPE__BPF_PROG_INFO;
63 dso->bpf_prog.id = id;
64 dso->bpf_prog.sub_id = i;
65 dso->bpf_prog.env = env;
66 }
67 }
68 return 0;
69}
70
71int machine__process_bpf(struct machine *machine, union perf_event *event,
72 struct perf_sample *sample)
73{
74 if (dump_trace)
75 perf_event__fprintf_bpf(event, stdout);
76
77 switch (event->bpf.type) {
78 case PERF_BPF_EVENT_PROG_LOAD:
79 return machine__process_bpf_event_load(machine, event, sample);
80
81 case PERF_BPF_EVENT_PROG_UNLOAD:
82 /*
83 * Do not free bpf_prog_info and btf of the program here,
84 * as annotation still need them. They will be freed at
85 * the end of the session.
86 */
87 break;
88 default:
89 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
90 break;
91 }
92 return 0;
93}
94
95static int perf_env__fetch_btf(struct perf_env *env,
96 u32 btf_id,
97 struct btf *btf)
98{
99 struct btf_node *node;
100 u32 data_size;
101 const void *data;
102
103 data = btf__raw_data(btf, &data_size);
104
105 node = malloc(data_size + sizeof(struct btf_node));
106 if (!node)
107 return -1;
108
109 node->id = btf_id;
110 node->data_size = data_size;
111 memcpy(node->data, data, data_size);
112
113 if (!perf_env__insert_btf(env, node)) {
114 /* Insertion failed because of a duplicate. */
115 free(node);
116 return -1;
117 }
118 return 0;
119}
120
121static int synthesize_bpf_prog_name(char *buf, int size,
122 struct bpf_prog_info *info,
123 struct btf *btf,
124 u32 sub_id)
125{
126 u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(uintptr_t)(info->prog_tags);
127 void *func_infos = (void *)(uintptr_t)(info->func_info);
128 u32 sub_prog_cnt = info->nr_jited_ksyms;
129 const struct bpf_func_info *finfo;
130 const char *short_name = NULL;
131 const struct btf_type *t;
132 int name_len;
133
134 name_len = snprintf(buf, size, "bpf_prog_");
135 name_len += snprintf_hex(buf + name_len, size - name_len,
136 prog_tags[sub_id], BPF_TAG_SIZE);
137 if (btf) {
138 finfo = func_infos + sub_id * info->func_info_rec_size;
139 t = btf__type_by_id(btf, finfo->type_id);
140 short_name = btf__name_by_offset(btf, t->name_off);
141 } else if (sub_id == 0 && sub_prog_cnt == 1) {
142 /* no subprog */
143 if (info->name[0])
144 short_name = info->name;
145 } else
146 short_name = "F";
147 if (short_name)
148 name_len += snprintf(buf + name_len, size - name_len,
149 "_%s", short_name);
150 return name_len;
151}
152
153/*
154 * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf
155 * program. One PERF_RECORD_BPF_EVENT is generated for the program. And
156 * one PERF_RECORD_KSYMBOL is generated for each sub program.
157 *
158 * Returns:
159 * 0 for success;
160 * -1 for failures;
161 * -2 for lack of kernel support.
162 */
163static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
164 perf_event__handler_t process,
165 struct machine *machine,
166 int fd,
167 union perf_event *event,
168 struct record_opts *opts)
169{
170 struct perf_record_ksymbol *ksymbol_event = &event->ksymbol;
171 struct perf_record_bpf_event *bpf_event = &event->bpf;
172 struct perf_tool *tool = session->tool;
173 struct bpf_prog_info_node *info_node;
174 struct perf_bpil *info_linear;
175 struct bpf_prog_info *info;
176 struct btf *btf = NULL;
177 struct perf_env *env;
178 u32 sub_prog_cnt, i;
179 int err = 0;
180 u64 arrays;
181
182 /*
183 * for perf-record and perf-report use header.env;
184 * otherwise, use global perf_env.
185 */
186 env = session->data ? &session->header.env : &perf_env;
187
188 arrays = 1UL << PERF_BPIL_JITED_KSYMS;
189 arrays |= 1UL << PERF_BPIL_JITED_FUNC_LENS;
190 arrays |= 1UL << PERF_BPIL_FUNC_INFO;
191 arrays |= 1UL << PERF_BPIL_PROG_TAGS;
192 arrays |= 1UL << PERF_BPIL_JITED_INSNS;
193 arrays |= 1UL << PERF_BPIL_LINE_INFO;
194 arrays |= 1UL << PERF_BPIL_JITED_LINE_INFO;
195
196 info_linear = get_bpf_prog_info_linear(fd, arrays);
197 if (IS_ERR_OR_NULL(info_linear)) {
198 info_linear = NULL;
199 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
200 return -1;
201 }
202
203 if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
204 free(info_linear);
205 pr_debug("%s: the kernel is too old, aborting\n", __func__);
206 return -2;
207 }
208
209 info = &info_linear->info;
210 if (!info->jited_ksyms) {
211 free(info_linear);
212 return -1;
213 }
214
215 /* number of ksyms, func_lengths, and tags should match */
216 sub_prog_cnt = info->nr_jited_ksyms;
217 if (sub_prog_cnt != info->nr_prog_tags ||
218 sub_prog_cnt != info->nr_jited_func_lens) {
219 free(info_linear);
220 return -1;
221 }
222
223 /* check BTF func info support */
224 if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {
225 /* btf func info number should be same as sub_prog_cnt */
226 if (sub_prog_cnt != info->nr_func_info) {
227 pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
228 free(info_linear);
229 return -1;
230 }
231 btf = btf__load_from_kernel_by_id(info->btf_id);
232 if (libbpf_get_error(btf)) {
233 pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
234 err = -1;
235 goto out;
236 }
237 perf_env__fetch_btf(env, info->btf_id, btf);
238 }
239
240 /* Synthesize PERF_RECORD_KSYMBOL */
241 for (i = 0; i < sub_prog_cnt; i++) {
242 __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
243 __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
244 int name_len;
245
246 *ksymbol_event = (struct perf_record_ksymbol) {
247 .header = {
248 .type = PERF_RECORD_KSYMBOL,
249 .size = offsetof(struct perf_record_ksymbol, name),
250 },
251 .addr = prog_addrs[i],
252 .len = prog_lens[i],
253 .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
254 .flags = 0,
255 };
256
257 name_len = synthesize_bpf_prog_name(ksymbol_event->name,
258 KSYM_NAME_LEN, info, btf, i);
259 ksymbol_event->header.size += PERF_ALIGN(name_len + 1,
260 sizeof(u64));
261
262 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
263 event->header.size += machine->id_hdr_size;
264 err = perf_tool__process_synth_event(tool, event,
265 machine, process);
266 }
267
268 if (!opts->no_bpf_event) {
269 /* Synthesize PERF_RECORD_BPF_EVENT */
270 *bpf_event = (struct perf_record_bpf_event) {
271 .header = {
272 .type = PERF_RECORD_BPF_EVENT,
273 .size = sizeof(struct perf_record_bpf_event),
274 },
275 .type = PERF_BPF_EVENT_PROG_LOAD,
276 .flags = 0,
277 .id = info->id,
278 };
279 memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);
280 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
281 event->header.size += machine->id_hdr_size;
282
283 /* save bpf_prog_info to env */
284 info_node = malloc(sizeof(struct bpf_prog_info_node));
285 if (!info_node) {
286 err = -1;
287 goto out;
288 }
289
290 info_node->info_linear = info_linear;
291 perf_env__insert_bpf_prog_info(env, info_node);
292 info_linear = NULL;
293
294 /*
295 * process after saving bpf_prog_info to env, so that
296 * required information is ready for look up
297 */
298 err = perf_tool__process_synth_event(tool, event,
299 machine, process);
300 }
301
302out:
303 free(info_linear);
304 btf__free(btf);
305 return err ? -1 : 0;
306}
307
308struct kallsyms_parse {
309 union perf_event *event;
310 perf_event__handler_t process;
311 struct machine *machine;
312 struct perf_tool *tool;
313};
314
315static int
316process_bpf_image(char *name, u64 addr, struct kallsyms_parse *data)
317{
318 struct machine *machine = data->machine;
319 union perf_event *event = data->event;
320 struct perf_record_ksymbol *ksymbol;
321 int len;
322
323 ksymbol = &event->ksymbol;
324
325 *ksymbol = (struct perf_record_ksymbol) {
326 .header = {
327 .type = PERF_RECORD_KSYMBOL,
328 .size = offsetof(struct perf_record_ksymbol, name),
329 },
330 .addr = addr,
331 .len = page_size,
332 .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
333 .flags = 0,
334 };
335
336 len = scnprintf(ksymbol->name, KSYM_NAME_LEN, "%s", name);
337 ksymbol->header.size += PERF_ALIGN(len + 1, sizeof(u64));
338 memset((void *) event + event->header.size, 0, machine->id_hdr_size);
339 event->header.size += machine->id_hdr_size;
340
341 return perf_tool__process_synth_event(data->tool, event, machine,
342 data->process);
343}
344
345static int
346kallsyms_process_symbol(void *data, const char *_name,
347 char type __maybe_unused, u64 start)
348{
349 char disp[KSYM_NAME_LEN];
350 char *module, *name;
351 unsigned long id;
352 int err = 0;
353
354 module = strchr(_name, '\t');
355 if (!module)
356 return 0;
357
358 /* We are going after [bpf] module ... */
359 if (strcmp(module + 1, "[bpf]"))
360 return 0;
361
362 name = memdup(_name, (module - _name) + 1);
363 if (!name)
364 return -ENOMEM;
365
366 name[module - _name] = 0;
367
368 /* .. and only for trampolines and dispatchers */
369 if ((sscanf(name, "bpf_trampoline_%lu", &id) == 1) ||
370 (sscanf(name, "bpf_dispatcher_%s", disp) == 1))
371 err = process_bpf_image(name, start, data);
372
373 free(name);
374 return err;
375}
376
377int perf_event__synthesize_bpf_events(struct perf_session *session,
378 perf_event__handler_t process,
379 struct machine *machine,
380 struct record_opts *opts)
381{
382 const char *kallsyms_filename = "/proc/kallsyms";
383 struct kallsyms_parse arg;
384 union perf_event *event;
385 __u32 id = 0;
386 int err;
387 int fd;
388
389 if (opts->no_bpf_event)
390 return 0;
391
392 event = malloc(sizeof(event->bpf) + KSYM_NAME_LEN + machine->id_hdr_size);
393 if (!event)
394 return -1;
395
396 /* Synthesize all the bpf programs in system. */
397 while (true) {
398 err = bpf_prog_get_next_id(id, &id);
399 if (err) {
400 if (errno == ENOENT) {
401 err = 0;
402 break;
403 }
404 pr_debug("%s: can't get next program: %s%s\n",
405 __func__, strerror(errno),
406 errno == EINVAL ? " -- kernel too old?" : "");
407 /* don't report error on old kernel or EPERM */
408 err = (errno == EINVAL || errno == EPERM) ? 0 : -1;
409 break;
410 }
411 fd = bpf_prog_get_fd_by_id(id);
412 if (fd < 0) {
413 pr_debug("%s: failed to get fd for prog_id %u\n",
414 __func__, id);
415 continue;
416 }
417
418 err = perf_event__synthesize_one_bpf_prog(session, process,
419 machine, fd,
420 event, opts);
421 close(fd);
422 if (err) {
423 /* do not return error for old kernel */
424 if (err == -2)
425 err = 0;
426 break;
427 }
428 }
429
430 /* Synthesize all the bpf images - trampolines/dispatchers. */
431 if (symbol_conf.kallsyms_name != NULL)
432 kallsyms_filename = symbol_conf.kallsyms_name;
433
434 arg = (struct kallsyms_parse) {
435 .event = event,
436 .process = process,
437 .machine = machine,
438 .tool = session->tool,
439 };
440
441 if (kallsyms__parse(kallsyms_filename, &arg, kallsyms_process_symbol)) {
442 pr_err("%s: failed to synthesize bpf images: %s\n",
443 __func__, strerror(errno));
444 }
445
446 free(event);
447 return err;
448}
449
450static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
451{
452 struct bpf_prog_info_node *info_node;
453 struct perf_bpil *info_linear;
454 struct btf *btf = NULL;
455 u64 arrays;
456 u32 btf_id;
457 int fd;
458
459 fd = bpf_prog_get_fd_by_id(id);
460 if (fd < 0)
461 return;
462
463 arrays = 1UL << PERF_BPIL_JITED_KSYMS;
464 arrays |= 1UL << PERF_BPIL_JITED_FUNC_LENS;
465 arrays |= 1UL << PERF_BPIL_FUNC_INFO;
466 arrays |= 1UL << PERF_BPIL_PROG_TAGS;
467 arrays |= 1UL << PERF_BPIL_JITED_INSNS;
468 arrays |= 1UL << PERF_BPIL_LINE_INFO;
469 arrays |= 1UL << PERF_BPIL_JITED_LINE_INFO;
470
471 info_linear = get_bpf_prog_info_linear(fd, arrays);
472 if (IS_ERR_OR_NULL(info_linear)) {
473 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
474 goto out;
475 }
476
477 btf_id = info_linear->info.btf_id;
478
479 info_node = malloc(sizeof(struct bpf_prog_info_node));
480 if (info_node) {
481 info_node->info_linear = info_linear;
482 perf_env__insert_bpf_prog_info(env, info_node);
483 } else
484 free(info_linear);
485
486 if (btf_id == 0)
487 goto out;
488
489 btf = btf__load_from_kernel_by_id(btf_id);
490 if (libbpf_get_error(btf)) {
491 pr_debug("%s: failed to get BTF of id %u, aborting\n",
492 __func__, btf_id);
493 goto out;
494 }
495 perf_env__fetch_btf(env, btf_id, btf);
496
497out:
498 btf__free(btf);
499 close(fd);
500}
501
502static int bpf_event__sb_cb(union perf_event *event, void *data)
503{
504 struct perf_env *env = data;
505
506 if (event->header.type != PERF_RECORD_BPF_EVENT)
507 return -1;
508
509 switch (event->bpf.type) {
510 case PERF_BPF_EVENT_PROG_LOAD:
511 perf_env__add_bpf_info(env, event->bpf.id);
512
513 case PERF_BPF_EVENT_PROG_UNLOAD:
514 /*
515 * Do not free bpf_prog_info and btf of the program here,
516 * as annotation still need them. They will be freed at
517 * the end of the session.
518 */
519 break;
520 default:
521 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
522 break;
523 }
524
525 return 0;
526}
527
528int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
529{
530 struct perf_event_attr attr = {
531 .type = PERF_TYPE_SOFTWARE,
532 .config = PERF_COUNT_SW_DUMMY,
533 .sample_id_all = 1,
534 .watermark = 1,
535 .bpf_event = 1,
536 .size = sizeof(attr), /* to capture ABI version */
537 };
538
539 /*
540 * Older gcc versions don't support designated initializers, like above,
541 * for unnamed union members, such as the following:
542 */
543 attr.wakeup_watermark = 1;
544
545 return evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
546}
547
548void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
549 struct perf_env *env,
550 FILE *fp)
551{
552 __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
553 __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
554 char name[KSYM_NAME_LEN];
555 struct btf *btf = NULL;
556 u32 sub_prog_cnt, i;
557
558 sub_prog_cnt = info->nr_jited_ksyms;
559 if (sub_prog_cnt != info->nr_prog_tags ||
560 sub_prog_cnt != info->nr_jited_func_lens)
561 return;
562
563 if (info->btf_id) {
564 struct btf_node *node;
565
566 node = __perf_env__find_btf(env, info->btf_id);
567 if (node)
568 btf = btf__new((__u8 *)(node->data),
569 node->data_size);
570 }
571
572 if (sub_prog_cnt == 1) {
573 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, 0);
574 fprintf(fp, "# bpf_prog_info %u: %s addr 0x%llx size %u\n",
575 info->id, name, prog_addrs[0], prog_lens[0]);
576 goto out;
577 }
578
579 fprintf(fp, "# bpf_prog_info %u:\n", info->id);
580 for (i = 0; i < sub_prog_cnt; i++) {
581 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, i);
582
583 fprintf(fp, "# \tsub_prog %u: %s addr 0x%llx size %u\n",
584 i, name, prog_addrs[i], prog_lens[i]);
585 }
586out:
587 btf__free(btf);
588}