xref: /linux/tools/perf/util/jitdump.c (revision 63307d015b91e626c97bb82e88054af3d0b74643)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <sys/sysmacros.h>
3 #include <sys/types.h>
4 #include <errno.h>
5 #include <libgen.h>
6 #include <stdio.h>
7 #include <stdlib.h>
8 #include <string.h>
9 #include <fcntl.h>
10 #include <unistd.h>
11 #include <inttypes.h>
12 #include <byteswap.h>
13 #include <sys/stat.h>
14 #include <sys/mman.h>
15 #include <linux/stringify.h>
16 
17 #include "util.h"
18 #include "event.h"
19 #include "debug.h"
20 #include "evlist.h"
21 #include "symbol.h"
22 #include <elf.h>
23 
24 #include "tsc.h"
25 #include "session.h"
26 #include "jit.h"
27 #include "jitdump.h"
28 #include "genelf.h"
29 #include "../builtin.h"
30 
31 #include "sane_ctype.h"
32 
33 struct jit_buf_desc {
34 	struct perf_data *output;
35 	struct perf_session *session;
36 	struct machine *machine;
37 	union jr_entry   *entry;
38 	void             *buf;
39 	uint64_t	 sample_type;
40 	size_t           bufsize;
41 	FILE             *in;
42 	bool		 needs_bswap; /* handles cross-endianness */
43 	bool		 use_arch_timestamp;
44 	void		 *debug_data;
45 	void		 *unwinding_data;
46 	uint64_t	 unwinding_size;
47 	uint64_t	 unwinding_mapped_size;
48 	uint64_t         eh_frame_hdr_size;
49 	size_t		 nr_debug_entries;
50 	uint32_t         code_load_count;
51 	u64		 bytes_written;
52 	struct rb_root   code_root;
53 	char		 dir[PATH_MAX];
54 };
55 
56 struct debug_line_info {
57 	unsigned long vma;
58 	unsigned int lineno;
59 	/* The filename format is unspecified, absolute path, relative etc. */
60 	char const filename[0];
61 };
62 
63 struct jit_tool {
64 	struct perf_tool tool;
65 	struct perf_data	output;
66 	struct perf_data	input;
67 	u64 bytes_written;
68 };
69 
70 #define hmax(a, b) ((a) > (b) ? (a) : (b))
71 #define get_jit_tool(t) (container_of(tool, struct jit_tool, tool))
72 
73 static int
74 jit_emit_elf(char *filename,
75 	     const char *sym,
76 	     uint64_t code_addr,
77 	     const void *code,
78 	     int csize,
79 	     void *debug,
80 	     int nr_debug_entries,
81 	     void *unwinding,
82 	     uint32_t unwinding_header_size,
83 	     uint32_t unwinding_size)
84 {
85 	int ret, fd;
86 
87 	if (verbose > 0)
88 		fprintf(stderr, "write ELF image %s\n", filename);
89 
90 	fd = open(filename, O_CREAT|O_TRUNC|O_WRONLY, 0644);
91 	if (fd == -1) {
92 		pr_warning("cannot create jit ELF %s: %s\n", filename, strerror(errno));
93 		return -1;
94 	}
95 
96 	ret = jit_write_elf(fd, code_addr, sym, (const void *)code, csize, debug, nr_debug_entries,
97 			    unwinding, unwinding_header_size, unwinding_size);
98 
99         close(fd);
100 
101         if (ret)
102                 unlink(filename);
103 
104 	return ret;
105 }
106 
107 static void
108 jit_close(struct jit_buf_desc *jd)
109 {
110 	if (!(jd && jd->in))
111 		return;
112 	funlockfile(jd->in);
113 	fclose(jd->in);
114 	jd->in = NULL;
115 }
116 
117 static int
118 jit_validate_events(struct perf_session *session)
119 {
120 	struct perf_evsel *evsel;
121 
122 	/*
123 	 * check that all events use CLOCK_MONOTONIC
124 	 */
125 	evlist__for_each_entry(session->evlist, evsel) {
126 		if (evsel->attr.use_clockid == 0 || evsel->attr.clockid != CLOCK_MONOTONIC)
127 			return -1;
128 	}
129 	return 0;
130 }
131 
132 static int
133 jit_open(struct jit_buf_desc *jd, const char *name)
134 {
135 	struct jitheader header;
136 	struct jr_prefix *prefix;
137 	ssize_t bs, bsz = 0;
138 	void *n, *buf = NULL;
139 	int ret, retval = -1;
140 
141 	jd->in = fopen(name, "r");
142 	if (!jd->in)
143 		return -1;
144 
145 	bsz = hmax(sizeof(header), sizeof(*prefix));
146 
147 	buf = malloc(bsz);
148 	if (!buf)
149 		goto error;
150 
151 	/*
152 	 * protect from writer modifying the file while we are reading it
153 	 */
154 	flockfile(jd->in);
155 
156 	ret = fread(buf, sizeof(header), 1, jd->in);
157 	if (ret != 1)
158 		goto error;
159 
160 	memcpy(&header, buf, sizeof(header));
161 
162 	if (header.magic != JITHEADER_MAGIC) {
163 		if (header.magic != JITHEADER_MAGIC_SW)
164 			goto error;
165 		jd->needs_bswap = true;
166 	}
167 
168 	if (jd->needs_bswap) {
169 		header.version    = bswap_32(header.version);
170 		header.total_size = bswap_32(header.total_size);
171 		header.pid	  = bswap_32(header.pid);
172 		header.elf_mach   = bswap_32(header.elf_mach);
173 		header.timestamp  = bswap_64(header.timestamp);
174 		header.flags      = bswap_64(header.flags);
175 	}
176 
177 	jd->use_arch_timestamp = header.flags & JITDUMP_FLAGS_ARCH_TIMESTAMP;
178 
179 	if (verbose > 2)
180 		pr_debug("version=%u\nhdr.size=%u\nts=0x%llx\npid=%d\nelf_mach=%d\nuse_arch_timestamp=%d\n",
181 			header.version,
182 			header.total_size,
183 			(unsigned long long)header.timestamp,
184 			header.pid,
185 			header.elf_mach,
186 			jd->use_arch_timestamp);
187 
188 	if (header.version > JITHEADER_VERSION) {
189 		pr_err("wrong jitdump version %u, expected " __stringify(JITHEADER_VERSION),
190 			header.version);
191 		goto error;
192 	}
193 
194 	if (header.flags & JITDUMP_FLAGS_RESERVED) {
195 		pr_err("jitdump file contains invalid or unsupported flags 0x%llx\n",
196 		       (unsigned long long)header.flags & JITDUMP_FLAGS_RESERVED);
197 		goto error;
198 	}
199 
200 	if (jd->use_arch_timestamp && !jd->session->time_conv.time_mult) {
201 		pr_err("jitdump file uses arch timestamps but there is no timestamp conversion\n");
202 		goto error;
203 	}
204 
205 	/*
206 	 * validate event is using the correct clockid
207 	 */
208 	if (!jd->use_arch_timestamp && jit_validate_events(jd->session)) {
209 		pr_err("error, jitted code must be sampled with perf record -k 1\n");
210 		goto error;
211 	}
212 
213 	bs = header.total_size - sizeof(header);
214 
215 	if (bs > bsz) {
216 		n = realloc(buf, bs);
217 		if (!n)
218 			goto error;
219 		bsz = bs;
220 		buf = n;
221 		/* read extra we do not know about */
222 		ret = fread(buf, bs - bsz, 1, jd->in);
223 		if (ret != 1)
224 			goto error;
225 	}
226 	/*
227 	 * keep dirname for generating files and mmap records
228 	 */
229 	strcpy(jd->dir, name);
230 	dirname(jd->dir);
231 
232 	return 0;
233 error:
234 	funlockfile(jd->in);
235 	fclose(jd->in);
236 	return retval;
237 }
238 
239 static union jr_entry *
240 jit_get_next_entry(struct jit_buf_desc *jd)
241 {
242 	struct jr_prefix *prefix;
243 	union jr_entry *jr;
244 	void *addr;
245 	size_t bs, size;
246 	int id, ret;
247 
248 	if (!(jd && jd->in))
249 		return NULL;
250 
251 	if (jd->buf == NULL) {
252 		size_t sz = getpagesize();
253 		if (sz < sizeof(*prefix))
254 			sz = sizeof(*prefix);
255 
256 		jd->buf = malloc(sz);
257 		if (jd->buf == NULL)
258 			return NULL;
259 
260 		jd->bufsize = sz;
261 	}
262 
263 	prefix = jd->buf;
264 
265 	/*
266 	 * file is still locked at this point
267 	 */
268 	ret = fread(prefix, sizeof(*prefix), 1, jd->in);
269 	if (ret  != 1)
270 		return NULL;
271 
272 	if (jd->needs_bswap) {
273 		prefix->id   	   = bswap_32(prefix->id);
274 		prefix->total_size = bswap_32(prefix->total_size);
275 		prefix->timestamp  = bswap_64(prefix->timestamp);
276 	}
277 	id   = prefix->id;
278 	size = prefix->total_size;
279 
280 	bs = (size_t)size;
281 	if (bs < sizeof(*prefix))
282 		return NULL;
283 
284 	if (id >= JIT_CODE_MAX) {
285 		pr_warning("next_entry: unknown record type %d, skipping\n", id);
286 	}
287 	if (bs > jd->bufsize) {
288 		void *n;
289 		n = realloc(jd->buf, bs);
290 		if (!n)
291 			return NULL;
292 		jd->buf = n;
293 		jd->bufsize = bs;
294 	}
295 
296 	addr = ((void *)jd->buf) + sizeof(*prefix);
297 
298 	ret = fread(addr, bs - sizeof(*prefix), 1, jd->in);
299 	if (ret != 1)
300 		return NULL;
301 
302 	jr = (union jr_entry *)jd->buf;
303 
304 	switch(id) {
305 	case JIT_CODE_DEBUG_INFO:
306 		if (jd->needs_bswap) {
307 			uint64_t n;
308 			jr->info.code_addr = bswap_64(jr->info.code_addr);
309 			jr->info.nr_entry  = bswap_64(jr->info.nr_entry);
310 			for (n = 0 ; n < jr->info.nr_entry; n++) {
311 				jr->info.entries[n].addr    = bswap_64(jr->info.entries[n].addr);
312 				jr->info.entries[n].lineno  = bswap_32(jr->info.entries[n].lineno);
313 				jr->info.entries[n].discrim = bswap_32(jr->info.entries[n].discrim);
314 			}
315 		}
316 		break;
317 	case JIT_CODE_UNWINDING_INFO:
318 		if (jd->needs_bswap) {
319 			jr->unwinding.unwinding_size = bswap_64(jr->unwinding.unwinding_size);
320 			jr->unwinding.eh_frame_hdr_size = bswap_64(jr->unwinding.eh_frame_hdr_size);
321 			jr->unwinding.mapped_size = bswap_64(jr->unwinding.mapped_size);
322 		}
323 		break;
324 	case JIT_CODE_CLOSE:
325 		break;
326 	case JIT_CODE_LOAD:
327 		if (jd->needs_bswap) {
328 			jr->load.pid       = bswap_32(jr->load.pid);
329 			jr->load.tid       = bswap_32(jr->load.tid);
330 			jr->load.vma       = bswap_64(jr->load.vma);
331 			jr->load.code_addr = bswap_64(jr->load.code_addr);
332 			jr->load.code_size = bswap_64(jr->load.code_size);
333 			jr->load.code_index= bswap_64(jr->load.code_index);
334 		}
335 		jd->code_load_count++;
336 		break;
337 	case JIT_CODE_MOVE:
338 		if (jd->needs_bswap) {
339 			jr->move.pid           = bswap_32(jr->move.pid);
340 			jr->move.tid           = bswap_32(jr->move.tid);
341 			jr->move.vma           = bswap_64(jr->move.vma);
342 			jr->move.old_code_addr = bswap_64(jr->move.old_code_addr);
343 			jr->move.new_code_addr = bswap_64(jr->move.new_code_addr);
344 			jr->move.code_size     = bswap_64(jr->move.code_size);
345 			jr->move.code_index    = bswap_64(jr->move.code_index);
346 		}
347 		break;
348 	case JIT_CODE_MAX:
349 	default:
350 		/* skip unknown record (we have read them) */
351 		break;
352 	}
353 	return jr;
354 }
355 
356 static int
357 jit_inject_event(struct jit_buf_desc *jd, union perf_event *event)
358 {
359 	ssize_t size;
360 
361 	size = perf_data__write(jd->output, event, event->header.size);
362 	if (size < 0)
363 		return -1;
364 
365 	jd->bytes_written += size;
366 	return 0;
367 }
368 
369 static uint64_t convert_timestamp(struct jit_buf_desc *jd, uint64_t timestamp)
370 {
371 	struct perf_tsc_conversion tc;
372 
373 	if (!jd->use_arch_timestamp)
374 		return timestamp;
375 
376 	tc.time_shift = jd->session->time_conv.time_shift;
377 	tc.time_mult  = jd->session->time_conv.time_mult;
378 	tc.time_zero  = jd->session->time_conv.time_zero;
379 
380 	if (!tc.time_mult)
381 		return 0;
382 
383 	return tsc_to_perf_time(timestamp, &tc);
384 }
385 
386 static int jit_repipe_code_load(struct jit_buf_desc *jd, union jr_entry *jr)
387 {
388 	struct perf_sample sample;
389 	union perf_event *event;
390 	struct perf_tool *tool = jd->session->tool;
391 	uint64_t code, addr;
392 	uintptr_t uaddr;
393 	char *filename;
394 	struct stat st;
395 	size_t size;
396 	u16 idr_size;
397 	const char *sym;
398 	uint32_t count;
399 	int ret, csize, usize;
400 	pid_t pid, tid;
401 	struct {
402 		u32 pid, tid;
403 		u64 time;
404 	} *id;
405 
406 	pid   = jr->load.pid;
407 	tid   = jr->load.tid;
408 	csize = jr->load.code_size;
409 	usize = jd->unwinding_mapped_size;
410 	addr  = jr->load.code_addr;
411 	sym   = (void *)((unsigned long)jr + sizeof(jr->load));
412 	code  = (unsigned long)jr + jr->load.p.total_size - csize;
413 	count = jr->load.code_index;
414 	idr_size = jd->machine->id_hdr_size;
415 
416 	event = calloc(1, sizeof(*event) + idr_size);
417 	if (!event)
418 		return -1;
419 
420 	filename = event->mmap2.filename;
421 	size = snprintf(filename, PATH_MAX, "%s/jitted-%d-%u.so",
422 			jd->dir,
423 			pid,
424 			count);
425 
426 	size++; /* for \0 */
427 
428 	size = PERF_ALIGN(size, sizeof(u64));
429 	uaddr = (uintptr_t)code;
430 	ret = jit_emit_elf(filename, sym, addr, (const void *)uaddr, csize, jd->debug_data, jd->nr_debug_entries,
431 			   jd->unwinding_data, jd->eh_frame_hdr_size, jd->unwinding_size);
432 
433 	if (jd->debug_data && jd->nr_debug_entries) {
434 		free(jd->debug_data);
435 		jd->debug_data = NULL;
436 		jd->nr_debug_entries = 0;
437 	}
438 
439 	if (jd->unwinding_data && jd->eh_frame_hdr_size) {
440 		free(jd->unwinding_data);
441 		jd->unwinding_data = NULL;
442 		jd->eh_frame_hdr_size = 0;
443 		jd->unwinding_mapped_size = 0;
444 		jd->unwinding_size = 0;
445 	}
446 
447 	if (ret) {
448 		free(event);
449 		return -1;
450 	}
451 	if (stat(filename, &st))
452 		memset(&st, 0, sizeof(st));
453 
454 	event->mmap2.header.type = PERF_RECORD_MMAP2;
455 	event->mmap2.header.misc = PERF_RECORD_MISC_USER;
456 	event->mmap2.header.size = (sizeof(event->mmap2) -
457 			(sizeof(event->mmap2.filename) - size) + idr_size);
458 
459 	event->mmap2.pgoff = GEN_ELF_TEXT_OFFSET;
460 	event->mmap2.start = addr;
461 	event->mmap2.len   = usize ? ALIGN_8(csize) + usize : csize;
462 	event->mmap2.pid   = pid;
463 	event->mmap2.tid   = tid;
464 	event->mmap2.ino   = st.st_ino;
465 	event->mmap2.maj   = major(st.st_dev);
466 	event->mmap2.min   = minor(st.st_dev);
467 	event->mmap2.prot  = st.st_mode;
468 	event->mmap2.flags = MAP_SHARED;
469 	event->mmap2.ino_generation = 1;
470 
471 	id = (void *)((unsigned long)event + event->mmap.header.size - idr_size);
472 	if (jd->sample_type & PERF_SAMPLE_TID) {
473 		id->pid  = pid;
474 		id->tid  = tid;
475 	}
476 	if (jd->sample_type & PERF_SAMPLE_TIME)
477 		id->time = convert_timestamp(jd, jr->load.p.timestamp);
478 
479 	/*
480 	 * create pseudo sample to induce dso hit increment
481 	 * use first address as sample address
482 	 */
483 	memset(&sample, 0, sizeof(sample));
484 	sample.cpumode = PERF_RECORD_MISC_USER;
485 	sample.pid  = pid;
486 	sample.tid  = tid;
487 	sample.time = id->time;
488 	sample.ip   = addr;
489 
490 	ret = perf_event__process_mmap2(tool, event, &sample, jd->machine);
491 	if (ret)
492 		return ret;
493 
494 	ret = jit_inject_event(jd, event);
495 	/*
496 	 * mark dso as use to generate buildid in the header
497 	 */
498 	if (!ret)
499 		build_id__mark_dso_hit(tool, event, &sample, NULL, jd->machine);
500 
501 	return ret;
502 }
503 
504 static int jit_repipe_code_move(struct jit_buf_desc *jd, union jr_entry *jr)
505 {
506 	struct perf_sample sample;
507 	union perf_event *event;
508 	struct perf_tool *tool = jd->session->tool;
509 	char *filename;
510 	size_t size;
511 	struct stat st;
512 	int usize;
513 	u16 idr_size;
514 	int ret;
515 	pid_t pid, tid;
516 	struct {
517 		u32 pid, tid;
518 		u64 time;
519 	} *id;
520 
521 	pid = jr->move.pid;
522 	tid =  jr->move.tid;
523 	usize = jd->unwinding_mapped_size;
524 	idr_size = jd->machine->id_hdr_size;
525 
526 	/*
527 	 * +16 to account for sample_id_all (hack)
528 	 */
529 	event = calloc(1, sizeof(*event) + 16);
530 	if (!event)
531 		return -1;
532 
533 	filename = event->mmap2.filename;
534 	size = snprintf(filename, PATH_MAX, "%s/jitted-%d-%"PRIu64,
535 	         jd->dir,
536 	         pid,
537 		 jr->move.code_index);
538 
539 	size++; /* for \0 */
540 
541 	if (stat(filename, &st))
542 		memset(&st, 0, sizeof(st));
543 
544 	size = PERF_ALIGN(size, sizeof(u64));
545 
546 	event->mmap2.header.type = PERF_RECORD_MMAP2;
547 	event->mmap2.header.misc = PERF_RECORD_MISC_USER;
548 	event->mmap2.header.size = (sizeof(event->mmap2) -
549 			(sizeof(event->mmap2.filename) - size) + idr_size);
550 	event->mmap2.pgoff = GEN_ELF_TEXT_OFFSET;
551 	event->mmap2.start = jr->move.new_code_addr;
552 	event->mmap2.len   = usize ? ALIGN_8(jr->move.code_size) + usize
553 				   : jr->move.code_size;
554 	event->mmap2.pid   = pid;
555 	event->mmap2.tid   = tid;
556 	event->mmap2.ino   = st.st_ino;
557 	event->mmap2.maj   = major(st.st_dev);
558 	event->mmap2.min   = minor(st.st_dev);
559 	event->mmap2.prot  = st.st_mode;
560 	event->mmap2.flags = MAP_SHARED;
561 	event->mmap2.ino_generation = 1;
562 
563 	id = (void *)((unsigned long)event + event->mmap.header.size - idr_size);
564 	if (jd->sample_type & PERF_SAMPLE_TID) {
565 		id->pid  = pid;
566 		id->tid  = tid;
567 	}
568 	if (jd->sample_type & PERF_SAMPLE_TIME)
569 		id->time = convert_timestamp(jd, jr->load.p.timestamp);
570 
571 	/*
572 	 * create pseudo sample to induce dso hit increment
573 	 * use first address as sample address
574 	 */
575 	memset(&sample, 0, sizeof(sample));
576 	sample.cpumode = PERF_RECORD_MISC_USER;
577 	sample.pid  = pid;
578 	sample.tid  = tid;
579 	sample.time = id->time;
580 	sample.ip   = jr->move.new_code_addr;
581 
582 	ret = perf_event__process_mmap2(tool, event, &sample, jd->machine);
583 	if (ret)
584 		return ret;
585 
586 	ret = jit_inject_event(jd, event);
587 	if (!ret)
588 		build_id__mark_dso_hit(tool, event, &sample, NULL, jd->machine);
589 
590 	return ret;
591 }
592 
593 static int jit_repipe_debug_info(struct jit_buf_desc *jd, union jr_entry *jr)
594 {
595 	void *data;
596 	size_t sz;
597 
598 	if (!(jd && jr))
599 		return -1;
600 
601 	sz  = jr->prefix.total_size - sizeof(jr->info);
602 	data = malloc(sz);
603 	if (!data)
604 		return -1;
605 
606 	memcpy(data, &jr->info.entries, sz);
607 
608 	jd->debug_data       = data;
609 
610 	/*
611 	 * we must use nr_entry instead of size here because
612 	 * we cannot distinguish actual entry from padding otherwise
613 	 */
614 	jd->nr_debug_entries = jr->info.nr_entry;
615 
616 	return 0;
617 }
618 
619 static int
620 jit_repipe_unwinding_info(struct jit_buf_desc *jd, union jr_entry *jr)
621 {
622 	void *unwinding_data;
623 	uint32_t unwinding_data_size;
624 
625 	if (!(jd && jr))
626 		return -1;
627 
628 	unwinding_data_size  = jr->prefix.total_size - sizeof(jr->unwinding);
629 	unwinding_data = malloc(unwinding_data_size);
630 	if (!unwinding_data)
631 		return -1;
632 
633 	memcpy(unwinding_data, &jr->unwinding.unwinding_data,
634 	       unwinding_data_size);
635 
636 	jd->eh_frame_hdr_size = jr->unwinding.eh_frame_hdr_size;
637 	jd->unwinding_size = jr->unwinding.unwinding_size;
638 	jd->unwinding_mapped_size = jr->unwinding.mapped_size;
639 	jd->unwinding_data = unwinding_data;
640 
641 	return 0;
642 }
643 
644 static int
645 jit_process_dump(struct jit_buf_desc *jd)
646 {
647 	union jr_entry *jr;
648 	int ret = 0;
649 
650 	while ((jr = jit_get_next_entry(jd))) {
651 		switch(jr->prefix.id) {
652 		case JIT_CODE_LOAD:
653 			ret = jit_repipe_code_load(jd, jr);
654 			break;
655 		case JIT_CODE_MOVE:
656 			ret = jit_repipe_code_move(jd, jr);
657 			break;
658 		case JIT_CODE_DEBUG_INFO:
659 			ret = jit_repipe_debug_info(jd, jr);
660 			break;
661 		case JIT_CODE_UNWINDING_INFO:
662 			ret = jit_repipe_unwinding_info(jd, jr);
663 			break;
664 		default:
665 			ret = 0;
666 			continue;
667 		}
668 	}
669 	return ret;
670 }
671 
672 static int
673 jit_inject(struct jit_buf_desc *jd, char *path)
674 {
675 	int ret;
676 
677 	if (verbose > 0)
678 		fprintf(stderr, "injecting: %s\n", path);
679 
680 	ret = jit_open(jd, path);
681 	if (ret)
682 		return -1;
683 
684 	ret = jit_process_dump(jd);
685 
686 	jit_close(jd);
687 
688 	if (verbose > 0)
689 		fprintf(stderr, "injected: %s (%d)\n", path, ret);
690 
691 	return 0;
692 }
693 
694 /*
695  * File must be with pattern .../jit-XXXX.dump
696  * where XXXX is the PID of the process which did the mmap()
697  * as captured in the RECORD_MMAP record
698  */
699 static int
700 jit_detect(char *mmap_name, pid_t pid)
701  {
702 	char *p;
703 	char *end = NULL;
704 	pid_t pid2;
705 
706 	if (verbose > 2)
707 		fprintf(stderr, "jit marker trying : %s\n", mmap_name);
708 	/*
709 	 * get file name
710 	 */
711 	p = strrchr(mmap_name, '/');
712 	if (!p)
713 		return -1;
714 
715 	/*
716 	 * match prefix
717 	 */
718 	if (strncmp(p, "/jit-", 5))
719 		return -1;
720 
721 	/*
722 	 * skip prefix
723 	 */
724 	p += 5;
725 
726 	/*
727 	 * must be followed by a pid
728 	 */
729 	if (!isdigit(*p))
730 		return -1;
731 
732 	pid2 = (int)strtol(p, &end, 10);
733 	if (!end)
734 		return -1;
735 
736 	/*
737 	 * pid does not match mmap pid
738 	 * pid==0 in system-wide mode (synthesized)
739 	 */
740 	if (pid && pid2 != pid)
741 		return -1;
742 	/*
743 	 * validate suffix
744 	 */
745 	if (strcmp(end, ".dump"))
746 		return -1;
747 
748 	if (verbose > 0)
749 		fprintf(stderr, "jit marker found: %s\n", mmap_name);
750 
751 	return 0;
752 }
753 
754 int
755 jit_process(struct perf_session *session,
756 	    struct perf_data *output,
757 	    struct machine *machine,
758 	    char *filename,
759 	    pid_t pid,
760 	    u64 *nbytes)
761 {
762 	struct perf_evsel *first;
763 	struct jit_buf_desc jd;
764 	int ret;
765 
766 	/*
767 	 * first, detect marker mmap (i.e., the jitdump mmap)
768 	 */
769 	if (jit_detect(filename, pid))
770 		return 0;
771 
772 	memset(&jd, 0, sizeof(jd));
773 
774 	jd.session = session;
775 	jd.output  = output;
776 	jd.machine = machine;
777 
778 	/*
779 	 * track sample_type to compute id_all layout
780 	 * perf sets the same sample type to all events as of now
781 	 */
782 	first = perf_evlist__first(session->evlist);
783 	jd.sample_type = first->attr.sample_type;
784 
785 	*nbytes = 0;
786 
787 	ret = jit_inject(&jd, filename);
788 	if (!ret) {
789 		*nbytes = jd.bytes_written;
790 		ret = 1;
791 	}
792 
793 	return ret;
794 }
795