summaryrefslogtreecommitdiff
path: root/tools/perf/util/bpf-event.c
blob: 7a3d4b12532369fc537bbd7c02e1fb15a3d12511 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <stdlib.h>
#include <bpf/bpf.h>
#include <bpf/btf.h>
#include <bpf/libbpf.h>
#include <linux/btf.h>
#include <linux/err.h>
#include "bpf-event.h"
#include "debug.h"
#include "dso.h"
#include "symbol.h"
#include "machine.h"
#include "env.h"
#include "session.h"
#include "map.h"
#include "evlist.h"
#include "record.h"

#define ptr_to_u64(ptr)    ((__u64)(unsigned long)(ptr))

static int snprintf_hex(char *buf, size_t size, unsigned char *data, size_t len)
{
	int ret = 0;
	size_t i;

	for (i = 0; i < len; i++)
		ret += snprintf(buf + ret, size - ret, "%02x", data[i]);
	return ret;
}

static int machine__process_bpf_event_load(struct machine *machine,
					   union perf_event *event,
					   struct perf_sample *sample __maybe_unused)
{
	struct bpf_prog_info_linear *info_linear;
	struct bpf_prog_info_node *info_node;
	struct perf_env *env = machine->env;
	int id = event->bpf.id;
	unsigned int i;

	/* perf-record, no need to handle bpf-event */
	if (env == NULL)
		return 0;

	info_node = perf_env__find_bpf_prog_info(env, id);
	if (!info_node)
		return 0;
	info_linear = info_node->info_linear;

	for (i = 0; i < info_linear->info.nr_jited_ksyms; i++) {
		u64 *addrs = (u64 *)(uintptr_t)(info_linear->info.jited_ksyms);
		u64 addr = addrs[i];
		struct map *map;

		map = map_groups__find(&machine->kmaps, addr);

		if (map) {
			map->dso->binary_type = DSO_BINARY_TYPE__BPF_PROG_INFO;
			map->dso->bpf_prog.id = id;
			map->dso->bpf_prog.sub_id = i;
			map->dso->bpf_prog.env = env;
		}
	}
	return 0;
}

int machine__process_bpf(struct machine *machine, union perf_event *event,
			 struct perf_sample *sample)
{
	if (dump_trace)
		perf_event__fprintf_bpf(event, stdout);

	switch (event->bpf.type) {
	case PERF_BPF_EVENT_PROG_LOAD:
		return machine__process_bpf_event_load(machine, event, sample);

	case PERF_BPF_EVENT_PROG_UNLOAD:
		/*
		 * Do not free bpf_prog_info and btf of the program here,
		 * as annotation still need them. They will be freed at
		 * the end of the session.
		 */
		break;
	default:
		pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
		break;
	}
	return 0;
}

static int perf_env__fetch_btf(struct perf_env *env,
			       u32 btf_id,
			       struct btf *btf)
{
	struct btf_node *node;
	u32 data_size;
	const void *data;

	data = btf__get_raw_data(btf, &data_size);

	node = malloc(data_size + sizeof(struct btf_node));
	if (!node)
		return -1;

	node->id = btf_id;
	node->data_size = data_size;
	memcpy(node->data, data, data_size);

	perf_env__insert_btf(env, node);
	return 0;
}

static int synthesize_bpf_prog_name(char *buf, int size,
				    struct bpf_prog_info *info,
				    struct btf *btf,
				    u32 sub_id)
{
	u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(uintptr_t)(info->prog_tags);
	void *func_infos = (void *)(uintptr_t)(info->func_info);
	u32 sub_prog_cnt = info->nr_jited_ksyms;
	const struct bpf_func_info *finfo;
	const char *short_name = NULL;
	const struct btf_type *t;
	int name_len;

	name_len = snprintf(buf, size, "bpf_prog_");
	name_len += snprintf_hex(buf + name_len, size - name_len,
				 prog_tags[sub_id], BPF_TAG_SIZE);
	if (btf) {
		finfo = func_infos + sub_id * info->func_info_rec_size;
		t = btf__type_by_id(btf, finfo->type_id);
		short_name = btf__name_by_offset(btf, t->name_off);
	} else if (sub_id == 0 && sub_prog_cnt == 1) {
		/* no subprog */
		if (info->name[0])
			short_name = info->name;
	} else
		short_name = "F";
	if (short_name)
		name_len += snprintf(buf + name_len, size - name_len,
				     "_%s", short_name);
	return name_len;
}

/*
 * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf
 * program. One PERF_RECORD_BPF_EVENT is generated for the program. And
 * one PERF_RECORD_KSYMBOL is generated for each sub program.
 *
 * Returns:
 *    0 for success;
 *   -1 for failures;
 *   -2 for lack of kernel support.
 */
static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
					       perf_event__handler_t process,
					       struct machine *machine,
					       int fd,
					       union perf_event *event,
					       struct record_opts *opts)
{
	struct perf_record_ksymbol *ksymbol_event = &event->ksymbol;
	struct perf_record_bpf_event *bpf_event = &event->bpf;
	struct bpf_prog_info_linear *info_linear;
	struct perf_tool *tool = session->tool;
	struct bpf_prog_info_node *info_node;
	struct bpf_prog_info *info;
	struct btf *btf = NULL;
	struct perf_env *env;
	u32 sub_prog_cnt, i;
	int err = 0;
	u64 arrays;

	/*
	 * for perf-record and perf-report use header.env;
	 * otherwise, use global perf_env.
	 */
	env = session->data ? &session->header.env : &perf_env;

	arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
	arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
	arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
	arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
	arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
	arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
	arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;

	info_linear = bpf_program__get_prog_info_linear(fd, arrays);
	if (IS_ERR_OR_NULL(info_linear)) {
		info_linear = NULL;
		pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
		return -1;
	}

	if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
		pr_debug("%s: the kernel is too old, aborting\n", __func__);
		return -2;
	}

	info = &info_linear->info;

	/* number of ksyms, func_lengths, and tags should match */
	sub_prog_cnt = info->nr_jited_ksyms;
	if (sub_prog_cnt != info->nr_prog_tags ||
	    sub_prog_cnt != info->nr_jited_func_lens)
		return -1;

	/* check BTF func info support */
	if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {
		/* btf func info number should be same as sub_prog_cnt */
		if (sub_prog_cnt != info->nr_func_info) {
			pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
			err = -1;
			goto out;
		}
		if (btf__get_from_id(info->btf_id, &btf)) {
			pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
			err = -1;
			btf = NULL;
			goto out;
		}
		perf_env__fetch_btf(env, info->btf_id, btf);
	}

	/* Synthesize PERF_RECORD_KSYMBOL */
	for (i = 0; i < sub_prog_cnt; i++) {
		__u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
		__u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
		int name_len;

		*ksymbol_event = (struct perf_record_ksymbol) {
			.header = {
				.type = PERF_RECORD_KSYMBOL,
				.size = offsetof(struct perf_record_ksymbol, name),
			},
			.addr = prog_addrs[i],
			.len = prog_lens[i],
			.ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
			.flags = 0,
		};

		name_len = synthesize_bpf_prog_name(ksymbol_event->name,
						    KSYM_NAME_LEN, info, btf, i);
		ksymbol_event->header.size += PERF_ALIGN(name_len + 1,
							 sizeof(u64));

		memset((void *)event + event->header.size, 0, machine->id_hdr_size);
		event->header.size += machine->id_hdr_size;
		err = perf_tool__process_synth_event(tool, event,
						     machine, process);
	}

	if (!opts->no_bpf_event) {
		/* Synthesize PERF_RECORD_BPF_EVENT */
		*bpf_event = (struct perf_record_bpf_event) {
			.header = {
				.type = PERF_RECORD_BPF_EVENT,
				.size = sizeof(struct perf_record_bpf_event),
			},
			.type = PERF_BPF_EVENT_PROG_LOAD,
			.flags = 0,
			.id = info->id,
		};
		memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);
		memset((void *)event + event->header.size, 0, machine->id_hdr_size);
		event->header.size += machine->id_hdr_size;

		/* save bpf_prog_info to env */
		info_node = malloc(sizeof(struct bpf_prog_info_node));
		if (!info_node) {
			err = -1;
			goto out;
		}

		info_node->info_linear = info_linear;
		perf_env__insert_bpf_prog_info(env, info_node);
		info_linear = NULL;

		/*
		 * process after saving bpf_prog_info to env, so that
		 * required information is ready for look up
		 */
		err = perf_tool__process_synth_event(tool, event,
						     machine, process);
	}

out:
	free(info_linear);
	free(btf);
	return err ? -1 : 0;
}

int perf_event__synthesize_bpf_events(struct perf_session *session,
				      perf_event__handler_t process,
				      struct machine *machine,
				      struct record_opts *opts)
{
	union perf_event *event;
	__u32 id = 0;
	int err;
	int fd;

	event = malloc(sizeof(event->bpf) + KSYM_NAME_LEN + machine->id_hdr_size);
	if (!event)
		return -1;
	while (true) {
		err = bpf_prog_get_next_id(id, &id);
		if (err) {
			if (errno == ENOENT) {
				err = 0;
				break;
			}
			pr_debug("%s: can't get next program: %s%s\n",
				 __func__, strerror(errno),
				 errno == EINVAL ? " -- kernel too old?" : "");
			/* don't report error on old kernel or EPERM  */
			err = (errno == EINVAL || errno == EPERM) ? 0 : -1;
			break;
		}
		fd = bpf_prog_get_fd_by_id(id);
		if (fd < 0) {
			pr_debug("%s: failed to get fd for prog_id %u\n",
				 __func__, id);
			continue;
		}

		err = perf_event__synthesize_one_bpf_prog(session, process,
							  machine, fd,
							  event, opts);
		close(fd);
		if (err) {
			/* do not return error for old kernel */
			if (err == -2)
				err = 0;
			break;
		}
	}
	free(event);
	return err;
}

static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
{
	struct bpf_prog_info_linear *info_linear;
	struct bpf_prog_info_node *info_node;
	struct btf *btf = NULL;
	u64 arrays;
	u32 btf_id;
	int fd;

	fd = bpf_prog_get_fd_by_id(id);
	if (fd < 0)
		return;

	arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
	arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
	arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
	arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
	arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
	arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
	arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;

	info_linear = bpf_program__get_prog_info_linear(fd, arrays);
	if (IS_ERR_OR_NULL(info_linear)) {
		pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
		goto out;
	}

	btf_id = info_linear->info.btf_id;

	info_node = malloc(sizeof(struct bpf_prog_info_node));
	if (info_node) {
		info_node->info_linear = info_linear;
		perf_env__insert_bpf_prog_info(env, info_node);
	} else
		free(info_linear);

	if (btf_id == 0)
		goto out;

	if (btf__get_from_id(btf_id, &btf)) {
		pr_debug("%s: failed to get BTF of id %u, aborting\n",
			 __func__, btf_id);
		goto out;
	}
	perf_env__fetch_btf(env, btf_id, btf);

out:
	free(btf);
	close(fd);
}

static int bpf_event__sb_cb(union perf_event *event, void *data)
{
	struct perf_env *env = data;

	if (event->header.type != PERF_RECORD_BPF_EVENT)
		return -1;

	switch (event->bpf.type) {
	case PERF_BPF_EVENT_PROG_LOAD:
		perf_env__add_bpf_info(env, event->bpf.id);

	case PERF_BPF_EVENT_PROG_UNLOAD:
		/*
		 * Do not free bpf_prog_info and btf of the program here,
		 * as annotation still need them. They will be freed at
		 * the end of the session.
		 */
		break;
	default:
		pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
		break;
	}

	return 0;
}

int bpf_event__add_sb_event(struct evlist **evlist,
			    struct perf_env *env)
{
	struct perf_event_attr attr = {
		.type	          = PERF_TYPE_SOFTWARE,
		.config           = PERF_COUNT_SW_DUMMY,
		.sample_id_all    = 1,
		.watermark        = 1,
		.bpf_event        = 1,
		.size	   = sizeof(attr), /* to capture ABI version */
	};

	/*
	 * Older gcc versions don't support designated initializers, like above,
	 * for unnamed union members, such as the following:
	 */
	attr.wakeup_watermark = 1;

	return perf_evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
}

void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
				    struct perf_env *env,
				    FILE *fp)
{
	__u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
	__u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
	char name[KSYM_NAME_LEN];
	struct btf *btf = NULL;
	u32 sub_prog_cnt, i;

	sub_prog_cnt = info->nr_jited_ksyms;
	if (sub_prog_cnt != info->nr_prog_tags ||
	    sub_prog_cnt != info->nr_jited_func_lens)
		return;

	if (info->btf_id) {
		struct btf_node *node;

		node = perf_env__find_btf(env, info->btf_id);
		if (node)
			btf = btf__new((__u8 *)(node->data),
				       node->data_size);
	}

	if (sub_prog_cnt == 1) {
		synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, 0);
		fprintf(fp, "# bpf_prog_info %u: %s addr 0x%llx size %u\n",
			info->id, name, prog_addrs[0], prog_lens[0]);
		return;
	}

	fprintf(fp, "# bpf_prog_info %u:\n", info->id);
	for (i = 0; i < sub_prog_cnt; i++) {
		synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, i);

		fprintf(fp, "# \tsub_prog %u: %s addr 0x%llx size %u\n",
			i, name, prog_addrs[i], prog_lens[i]);
	}
}