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: buf + ret, size: size - ret, fmt: "%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, prog_id: 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(maps: 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 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 at
86 * 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, btf_node: 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, fmt: "bpf_prog_");
136 name_len += snprintf_hex(buf: buf + name_len, size: size - name_len,
137 data: 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 } else
147 short_name = "F";
148 if (short_name)
149 name_len += snprintf(buf: buf + name_len, size: size - name_len,
150 fmt: "_%s", short_name);
151 return name_len;
152}
153
154/*
155 * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf
156 * program. One PERF_RECORD_BPF_EVENT is generated for the program. And
157 * 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 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(ptr: 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, btf_id: 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(buf: ksymbol_event->name,
259 KSYM_NAME_LEN, info, btf, sub_id: 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 that
297 * required information is ready for look up
298 */
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 struct perf_tool *tool;
314};
315
316static int
317process_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(buf: ksymbol->name, KSYM_NAME_LEN, fmt: "%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 int
347kallsyms_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, addr: 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(ptr: 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 } else
485 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, id: 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 at
518 * 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: &attr, cb: bpf_event__sb_cb, data: 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, btf_id: 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(buf: name, KSYM_NAME_LEN, info, btf, sub_id: 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(buf: name, KSYM_NAME_LEN, info, btf, sub_id: 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

source code of linux/tools/perf/util/bpf-event.c