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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 "debug.h"
14#include "dso.h"
15#include "symbol.h"
16#include "machine.h"
17#include "env.h"
18#include "session.h"
19#include "map.h"
20#include "evlist.h"
21#include "record.h"
22#include "util/synthetic-events.h"
23
24#define ptr_to_u64(ptr) ((__u64)(unsigned long)(ptr))
25
26static int snprintf_hex(char *buf, size_t size, unsigned char *data, size_t len)
27{
28 int ret = 0;
29 size_t i;
30
31 for (i = 0; i < len; i++)
32 ret += snprintf(buf + ret, size - ret, "%02x", data[i]);
33 return ret;
34}
35
36static int machine__process_bpf_event_load(struct machine *machine,
37 union perf_event *event,
38 struct perf_sample *sample __maybe_unused)
39{
40 struct bpf_prog_info_linear *info_linear;
41 struct bpf_prog_info_node *info_node;
42 struct perf_env *env = machine->env;
43 int id = event->bpf.id;
44 unsigned int i;
45
46 /* perf-record, no need to handle bpf-event */
47 if (env == NULL)
48 return 0;
49
50 info_node = perf_env__find_bpf_prog_info(env, id);
51 if (!info_node)
52 return 0;
53 info_linear = info_node->info_linear;
54
55 for (i = 0; i < info_linear->info.nr_jited_ksyms; i++) {
56 u64 *addrs = (u64 *)(uintptr_t)(info_linear->info.jited_ksyms);
57 u64 addr = addrs[i];
58 struct map *map = maps__find(&machine->kmaps, addr);
59
60 if (map) {
61 map->dso->binary_type = DSO_BINARY_TYPE__BPF_PROG_INFO;
62 map->dso->bpf_prog.id = id;
63 map->dso->bpf_prog.sub_id = i;
64 map->dso->bpf_prog.env = env;
65 }
66 }
67 return 0;
68}
69
70int machine__process_bpf(struct machine *machine, union perf_event *event,
71 struct perf_sample *sample)
72{
73 if (dump_trace)
74 perf_event__fprintf_bpf(event, stdout);
75
76 switch (event->bpf.type) {
77 case PERF_BPF_EVENT_PROG_LOAD:
78 return machine__process_bpf_event_load(machine, event, sample);
79
80 case PERF_BPF_EVENT_PROG_UNLOAD:
81 /*
82 * Do not free bpf_prog_info and btf of the program here,
83 * as annotation still need them. They will be freed at
84 * the end of the session.
85 */
86 break;
87 default:
88 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
89 break;
90 }
91 return 0;
92}
93
94static int perf_env__fetch_btf(struct perf_env *env,
95 u32 btf_id,
96 struct btf *btf)
97{
98 struct btf_node *node;
99 u32 data_size;
100 const void *data;
101
102 data = btf__get_raw_data(btf, &data_size);
103
104 node = malloc(data_size + sizeof(struct btf_node));
105 if (!node)
106 return -1;
107
108 node->id = btf_id;
109 node->data_size = data_size;
110 memcpy(node->data, data, data_size);
111
112 perf_env__insert_btf(env, node);
113 return 0;
114}
115
116static int synthesize_bpf_prog_name(char *buf, int size,
117 struct bpf_prog_info *info,
118 struct btf *btf,
119 u32 sub_id)
120{
121 u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(uintptr_t)(info->prog_tags);
122 void *func_infos = (void *)(uintptr_t)(info->func_info);
123 u32 sub_prog_cnt = info->nr_jited_ksyms;
124 const struct bpf_func_info *finfo;
125 const char *short_name = NULL;
126 const struct btf_type *t;
127 int name_len;
128
129 name_len = snprintf(buf, size, "bpf_prog_");
130 name_len += snprintf_hex(buf + name_len, size - name_len,
131 prog_tags[sub_id], BPF_TAG_SIZE);
132 if (btf) {
133 finfo = func_infos + sub_id * info->func_info_rec_size;
134 t = btf__type_by_id(btf, finfo->type_id);
135 short_name = btf__name_by_offset(btf, t->name_off);
136 } else if (sub_id == 0 && sub_prog_cnt == 1) {
137 /* no subprog */
138 if (info->name[0])
139 short_name = info->name;
140 } else
141 short_name = "F";
142 if (short_name)
143 name_len += snprintf(buf + name_len, size - name_len,
144 "_%s", short_name);
145 return name_len;
146}
147
148/*
149 * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf
150 * program. One PERF_RECORD_BPF_EVENT is generated for the program. And
151 * one PERF_RECORD_KSYMBOL is generated for each sub program.
152 *
153 * Returns:
154 * 0 for success;
155 * -1 for failures;
156 * -2 for lack of kernel support.
157 */
158static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
159 perf_event__handler_t process,
160 struct machine *machine,
161 int fd,
162 union perf_event *event,
163 struct record_opts *opts)
164{
165 struct perf_record_ksymbol *ksymbol_event = &event->ksymbol;
166 struct perf_record_bpf_event *bpf_event = &event->bpf;
167 struct bpf_prog_info_linear *info_linear;
168 struct perf_tool *tool = session->tool;
169 struct bpf_prog_info_node *info_node;
170 struct bpf_prog_info *info;
171 struct btf *btf = NULL;
172 struct perf_env *env;
173 u32 sub_prog_cnt, i;
174 int err = 0;
175 u64 arrays;
176
177 /*
178 * for perf-record and perf-report use header.env;
179 * otherwise, use global perf_env.
180 */
181 env = session->data ? &session->header.env : &perf_env;
182
183 arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
184 arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
185 arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
186 arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
187 arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
188 arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
189 arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;
190
191 info_linear = bpf_program__get_prog_info_linear(fd, arrays);
192 if (IS_ERR_OR_NULL(info_linear)) {
193 info_linear = NULL;
194 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
195 return -1;
196 }
197
198 if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
199 pr_debug("%s: the kernel is too old, aborting\n", __func__);
200 return -2;
201 }
202
203 info = &info_linear->info;
204
205 /* number of ksyms, func_lengths, and tags should match */
206 sub_prog_cnt = info->nr_jited_ksyms;
207 if (sub_prog_cnt != info->nr_prog_tags ||
208 sub_prog_cnt != info->nr_jited_func_lens)
209 return -1;
210
211 /* check BTF func info support */
212 if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {
213 /* btf func info number should be same as sub_prog_cnt */
214 if (sub_prog_cnt != info->nr_func_info) {
215 pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
216 err = -1;
217 goto out;
218 }
219 if (btf__get_from_id(info->btf_id, &btf)) {
220 pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
221 err = -1;
222 btf = NULL;
223 goto out;
224 }
225 perf_env__fetch_btf(env, info->btf_id, btf);
226 }
227
228 /* Synthesize PERF_RECORD_KSYMBOL */
229 for (i = 0; i < sub_prog_cnt; i++) {
230 __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
231 __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
232 int name_len;
233
234 *ksymbol_event = (struct perf_record_ksymbol) {
235 .header = {
236 .type = PERF_RECORD_KSYMBOL,
237 .size = offsetof(struct perf_record_ksymbol, name),
238 },
239 .addr = prog_addrs[i],
240 .len = prog_lens[i],
241 .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
242 .flags = 0,
243 };
244
245 name_len = synthesize_bpf_prog_name(ksymbol_event->name,
246 KSYM_NAME_LEN, info, btf, i);
247 ksymbol_event->header.size += PERF_ALIGN(name_len + 1,
248 sizeof(u64));
249
250 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
251 event->header.size += machine->id_hdr_size;
252 err = perf_tool__process_synth_event(tool, event,
253 machine, process);
254 }
255
256 if (!opts->no_bpf_event) {
257 /* Synthesize PERF_RECORD_BPF_EVENT */
258 *bpf_event = (struct perf_record_bpf_event) {
259 .header = {
260 .type = PERF_RECORD_BPF_EVENT,
261 .size = sizeof(struct perf_record_bpf_event),
262 },
263 .type = PERF_BPF_EVENT_PROG_LOAD,
264 .flags = 0,
265 .id = info->id,
266 };
267 memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);
268 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
269 event->header.size += machine->id_hdr_size;
270
271 /* save bpf_prog_info to env */
272 info_node = malloc(sizeof(struct bpf_prog_info_node));
273 if (!info_node) {
274 err = -1;
275 goto out;
276 }
277
278 info_node->info_linear = info_linear;
279 perf_env__insert_bpf_prog_info(env, info_node);
280 info_linear = NULL;
281
282 /*
283 * process after saving bpf_prog_info to env, so that
284 * required information is ready for look up
285 */
286 err = perf_tool__process_synth_event(tool, event,
287 machine, process);
288 }
289
290out:
291 free(info_linear);
292 free(btf);
293 return err ? -1 : 0;
294}
295
296struct kallsyms_parse {
297 union perf_event *event;
298 perf_event__handler_t process;
299 struct machine *machine;
300 struct perf_tool *tool;
301};
302
303static int
304process_bpf_image(char *name, u64 addr, struct kallsyms_parse *data)
305{
306 struct machine *machine = data->machine;
307 union perf_event *event = data->event;
308 struct perf_record_ksymbol *ksymbol;
309 int len;
310
311 ksymbol = &event->ksymbol;
312
313 *ksymbol = (struct perf_record_ksymbol) {
314 .header = {
315 .type = PERF_RECORD_KSYMBOL,
316 .size = offsetof(struct perf_record_ksymbol, name),
317 },
318 .addr = addr,
319 .len = page_size,
320 .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
321 .flags = 0,
322 };
323
324 len = scnprintf(ksymbol->name, KSYM_NAME_LEN, "%s", name);
325 ksymbol->header.size += PERF_ALIGN(len + 1, sizeof(u64));
326 memset((void *) event + event->header.size, 0, machine->id_hdr_size);
327 event->header.size += machine->id_hdr_size;
328
329 return perf_tool__process_synth_event(data->tool, event, machine,
330 data->process);
331}
332
333static int
334kallsyms_process_symbol(void *data, const char *_name,
335 char type __maybe_unused, u64 start)
336{
337 char disp[KSYM_NAME_LEN];
338 char *module, *name;
339 unsigned long id;
340 int err = 0;
341
342 module = strchr(_name, '\t');
343 if (!module)
344 return 0;
345
346 /* We are going after [bpf] module ... */
347 if (strcmp(module + 1, "[bpf]"))
348 return 0;
349
350 name = memdup(_name, (module - _name) + 1);
351 if (!name)
352 return -ENOMEM;
353
354 name[module - _name] = 0;
355
356 /* .. and only for trampolines and dispatchers */
357 if ((sscanf(name, "bpf_trampoline_%lu", &id) == 1) ||
358 (sscanf(name, "bpf_dispatcher_%s", disp) == 1))
359 err = process_bpf_image(name, start, data);
360
361 free(name);
362 return err;
363}
364
365int perf_event__synthesize_bpf_events(struct perf_session *session,
366 perf_event__handler_t process,
367 struct machine *machine,
368 struct record_opts *opts)
369{
370 const char *kallsyms_filename = "/proc/kallsyms";
371 struct kallsyms_parse arg;
372 union perf_event *event;
373 __u32 id = 0;
374 int err;
375 int fd;
376
377 event = malloc(sizeof(event->bpf) + KSYM_NAME_LEN + machine->id_hdr_size);
378 if (!event)
379 return -1;
380
381 /* Synthesize all the bpf programs in system. */
382 while (true) {
383 err = bpf_prog_get_next_id(id, &id);
384 if (err) {
385 if (errno == ENOENT) {
386 err = 0;
387 break;
388 }
389 pr_debug("%s: can't get next program: %s%s\n",
390 __func__, strerror(errno),
391 errno == EINVAL ? " -- kernel too old?" : "");
392 /* don't report error on old kernel or EPERM */
393 err = (errno == EINVAL || errno == EPERM) ? 0 : -1;
394 break;
395 }
396 fd = bpf_prog_get_fd_by_id(id);
397 if (fd < 0) {
398 pr_debug("%s: failed to get fd for prog_id %u\n",
399 __func__, id);
400 continue;
401 }
402
403 err = perf_event__synthesize_one_bpf_prog(session, process,
404 machine, fd,
405 event, opts);
406 close(fd);
407 if (err) {
408 /* do not return error for old kernel */
409 if (err == -2)
410 err = 0;
411 break;
412 }
413 }
414
415 /* Synthesize all the bpf images - trampolines/dispatchers. */
416 if (symbol_conf.kallsyms_name != NULL)
417 kallsyms_filename = symbol_conf.kallsyms_name;
418
419 arg = (struct kallsyms_parse) {
420 .event = event,
421 .process = process,
422 .machine = machine,
423 .tool = session->tool,
424 };
425
426 if (kallsyms__parse(kallsyms_filename, &arg, kallsyms_process_symbol)) {
427 pr_err("%s: failed to synthesize bpf images: %s\n",
428 __func__, strerror(errno));
429 }
430
431 free(event);
432 return err;
433}
434
435static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
436{
437 struct bpf_prog_info_linear *info_linear;
438 struct bpf_prog_info_node *info_node;
439 struct btf *btf = NULL;
440 u64 arrays;
441 u32 btf_id;
442 int fd;
443
444 fd = bpf_prog_get_fd_by_id(id);
445 if (fd < 0)
446 return;
447
448 arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
449 arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
450 arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
451 arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
452 arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
453 arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
454 arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;
455
456 info_linear = bpf_program__get_prog_info_linear(fd, arrays);
457 if (IS_ERR_OR_NULL(info_linear)) {
458 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
459 goto out;
460 }
461
462 btf_id = info_linear->info.btf_id;
463
464 info_node = malloc(sizeof(struct bpf_prog_info_node));
465 if (info_node) {
466 info_node->info_linear = info_linear;
467 perf_env__insert_bpf_prog_info(env, info_node);
468 } else
469 free(info_linear);
470
471 if (btf_id == 0)
472 goto out;
473
474 if (btf__get_from_id(btf_id, &btf)) {
475 pr_debug("%s: failed to get BTF of id %u, aborting\n",
476 __func__, btf_id);
477 goto out;
478 }
479 perf_env__fetch_btf(env, btf_id, btf);
480
481out:
482 free(btf);
483 close(fd);
484}
485
486static int bpf_event__sb_cb(union perf_event *event, void *data)
487{
488 struct perf_env *env = data;
489
490 if (event->header.type != PERF_RECORD_BPF_EVENT)
491 return -1;
492
493 switch (event->bpf.type) {
494 case PERF_BPF_EVENT_PROG_LOAD:
495 perf_env__add_bpf_info(env, event->bpf.id);
496
497 case PERF_BPF_EVENT_PROG_UNLOAD:
498 /*
499 * Do not free bpf_prog_info and btf of the program here,
500 * as annotation still need them. They will be freed at
501 * the end of the session.
502 */
503 break;
504 default:
505 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
506 break;
507 }
508
509 return 0;
510}
511
512int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
513{
514 struct perf_event_attr attr = {
515 .type = PERF_TYPE_SOFTWARE,
516 .config = PERF_COUNT_SW_DUMMY,
517 .sample_id_all = 1,
518 .watermark = 1,
519 .bpf_event = 1,
520 .size = sizeof(attr), /* to capture ABI version */
521 };
522
523 /*
524 * Older gcc versions don't support designated initializers, like above,
525 * for unnamed union members, such as the following:
526 */
527 attr.wakeup_watermark = 1;
528
529 return perf_evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
530}
531
532void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
533 struct perf_env *env,
534 FILE *fp)
535{
536 __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
537 __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
538 char name[KSYM_NAME_LEN];
539 struct btf *btf = NULL;
540 u32 sub_prog_cnt, i;
541
542 sub_prog_cnt = info->nr_jited_ksyms;
543 if (sub_prog_cnt != info->nr_prog_tags ||
544 sub_prog_cnt != info->nr_jited_func_lens)
545 return;
546
547 if (info->btf_id) {
548 struct btf_node *node;
549
550 node = perf_env__find_btf(env, info->btf_id);
551 if (node)
552 btf = btf__new((__u8 *)(node->data),
553 node->data_size);
554 }
555
556 if (sub_prog_cnt == 1) {
557 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, 0);
558 fprintf(fp, "# bpf_prog_info %u: %s addr 0x%llx size %u\n",
559 info->id, name, prog_addrs[0], prog_lens[0]);
560 return;
561 }
562
563 fprintf(fp, "# bpf_prog_info %u:\n", info->id);
564 for (i = 0; i < sub_prog_cnt; i++) {
565 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, i);
566
567 fprintf(fp, "# \tsub_prog %u: %s addr 0x%llx size %u\n",
568 i, name, prog_addrs[i], prog_lens[i]);
569 }
570}