summaryrefslogtreecommitdiff
path: root/tools/perf/jvmti/jvmti_agent.c
blob: e9651a9d670e90a2b46f5083aaa02e981494baff (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
/*
 * jvmti_agent.c: JVMTI agent interface
 *
 * Adapted from the Oprofile code in opagent.c:
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Copyright 2007 OProfile authors
 * Jens Wilke
 * Daniel Hansel
 * Copyright IBM Corporation 2007
 */
#include <sys/types.h>
#include <sys/stat.h> /* for mkdir() */
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <limits.h>
#include <fcntl.h>
#include <unistd.h>
#include <time.h>
#include <sys/mman.h>
#include <syscall.h> /* for gettid() */
#include <err.h>

#include "jvmti_agent.h"
#include "../util/jitdump.h"

#define JIT_LANG "java"

static char jit_path[PATH_MAX];
static void *marker_addr;

static inline pid_t gettid(void)
{
	return (pid_t)syscall(__NR_gettid);
}

static int get_e_machine(struct jitheader *hdr)
{
	ssize_t sret;
	char id[16];
	int fd, ret = -1;
	struct {
		uint16_t e_type;
		uint16_t e_machine;
	} info;

	fd = open("/proc/self/exe", O_RDONLY);
	if (fd == -1)
		return -1;

	sret = read(fd, id, sizeof(id));
	if (sret != sizeof(id))
		goto error;

	/* check ELF signature */
	if (id[0] != 0x7f || id[1] != 'E' || id[2] != 'L' || id[3] != 'F')
		goto error;

	sret = read(fd, &info, sizeof(info));
	if (sret != sizeof(info))
		goto error;

	hdr->elf_mach = info.e_machine;
	ret = 0;
error:
	close(fd);
	return ret;
}

static int use_arch_timestamp;

static inline uint64_t
get_arch_timestamp(void)
{
#if defined(__i386__) || defined(__x86_64__)
	unsigned int low, high;

	asm volatile("rdtsc" : "=a" (low), "=d" (high));

	return low | ((uint64_t)high) << 32;
#else
	return 0;
#endif
}

#define NSEC_PER_SEC	1000000000
static int perf_clk_id = CLOCK_MONOTONIC;

static inline uint64_t
timespec_to_ns(const struct timespec *ts)
{
        return ((uint64_t) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
}

static inline uint64_t
perf_get_timestamp(void)
{
	struct timespec ts;
	int ret;

	if (use_arch_timestamp)
		return get_arch_timestamp();

	ret = clock_gettime(perf_clk_id, &ts);
	if (ret)
		return 0;

	return timespec_to_ns(&ts);
}

static int
debug_cache_init(void)
{
	char str[32];
	char *base, *p;
	struct tm tm;
	time_t t;
	int ret;

	time(&t);
	localtime_r(&t, &tm);

	base = getenv("JITDUMPDIR");
	if (!base)
		base = getenv("HOME");
	if (!base)
		base = ".";

	strftime(str, sizeof(str), JIT_LANG"-jit-%Y%m%d", &tm);

	snprintf(jit_path, PATH_MAX - 1, "%s/.debug/", base);

	ret = mkdir(jit_path, 0755);
	if (ret == -1) {
		if (errno != EEXIST) {
			warn("jvmti: cannot create jit cache dir %s", jit_path);
			return -1;
		}
	}

	snprintf(jit_path, PATH_MAX - 1, "%s/.debug/jit", base);
	ret = mkdir(jit_path, 0755);
	if (ret == -1) {
		if (errno != EEXIST) {
			warn("cannot create jit cache dir %s", jit_path);
			return -1;
		}
	}

	snprintf(jit_path, PATH_MAX - 1, "%s/.debug/jit/%s.XXXXXXXX", base, str);

	p = mkdtemp(jit_path);
	if (p != jit_path) {
		warn("cannot create jit cache dir %s", jit_path);
		return -1;
	}

	return 0;
}

static int
perf_open_marker_file(int fd)
{
	long pgsz;

	pgsz = sysconf(_SC_PAGESIZE);
	if (pgsz == -1)
		return -1;

	/*
	 * we mmap the jitdump to create an MMAP RECORD in perf.data file.
	 * The mmap is captured either live (perf record running when we mmap)
	 * or  in deferred mode, via /proc/PID/maps
	 * the MMAP record is used as a marker of a jitdump file for more meta
	 * data info about the jitted code. Perf report/annotate detect this
	 * special filename and process the jitdump file.
	 *
	 * mapping must be PROT_EXEC to ensure it is captured by perf record
	 * even when not using -d option
	 */
	marker_addr = mmap(NULL, pgsz, PROT_READ|PROT_EXEC, MAP_PRIVATE, fd, 0);
	return (marker_addr == MAP_FAILED) ? -1 : 0;
}

static void
perf_close_marker_file(void)
{
	long pgsz;

	if (!marker_addr)
		return;

	pgsz = sysconf(_SC_PAGESIZE);
	if (pgsz == -1)
		return;

	munmap(marker_addr, pgsz);
}

static void
init_arch_timestamp(void)
{
	char *str = getenv("JITDUMP_USE_ARCH_TIMESTAMP");

	if (!str || !*str || !strcmp(str, "0"))
		return;

	use_arch_timestamp = 1;
}

void *jvmti_open(void)
{
	char dump_path[PATH_MAX];
	struct jitheader header;
	int fd;
	FILE *fp;

	init_arch_timestamp();

	/*
	 * check if clockid is supported
	 */
	if (!perf_get_timestamp()) {
		if (use_arch_timestamp)
			warnx("jvmti: arch timestamp not supported");
		else
			warnx("jvmti: kernel does not support %d clock id", perf_clk_id);
	}

	memset(&header, 0, sizeof(header));

	debug_cache_init();

	/*
	 * jitdump file name
	 */
	snprintf(dump_path, PATH_MAX, "%s/jit-%i.dump", jit_path, getpid());

	fd = open(dump_path, O_CREAT|O_TRUNC|O_RDWR, 0666);
	if (fd == -1)
		return NULL;

	/*
	 * create perf.data maker for the jitdump file
	 */
	if (perf_open_marker_file(fd)) {
		warnx("jvmti: failed to create marker file");
		return NULL;
	}

	fp = fdopen(fd, "w+");
	if (!fp) {
		warn("jvmti: cannot create %s", dump_path);
		close(fd);
		goto error;
	}

	warnx("jvmti: jitdump in %s", dump_path);

	if (get_e_machine(&header)) {
		warn("get_e_machine failed\n");
		goto error;
	}

	header.magic      = JITHEADER_MAGIC;
	header.version    = JITHEADER_VERSION;
	header.total_size = sizeof(header);
	header.pid        = getpid();

	header.timestamp = perf_get_timestamp();

	if (use_arch_timestamp)
		header.flags |= JITDUMP_FLAGS_ARCH_TIMESTAMP;

	if (!fwrite(&header, sizeof(header), 1, fp)) {
		warn("jvmti: cannot write dumpfile header");
		goto error;
	}
	return fp;
error:
	fclose(fp);
	return NULL;
}

int
jvmti_close(void *agent)
{
	struct jr_code_close rec;
	FILE *fp = agent;

	if (!fp) {
		warnx("jvmti: incalid fd in close_agent");
		return -1;
	}

	rec.p.id = JIT_CODE_CLOSE;
	rec.p.total_size = sizeof(rec);

	rec.p.timestamp = perf_get_timestamp();

	if (!fwrite(&rec, sizeof(rec), 1, fp))
		return -1;

	fclose(fp);

	fp = NULL;

	perf_close_marker_file();

	return 0;
}

int
jvmti_write_code(void *agent, char const *sym,
	uint64_t vma, void const *code, unsigned int const size)
{
	static int code_generation = 1;
	struct jr_code_load rec;
	size_t sym_len;
	FILE *fp = agent;
	int ret = -1;

	/* don't care about 0 length function, no samples */
	if (size == 0)
		return 0;

	if (!fp) {
		warnx("jvmti: invalid fd in write_native_code");
		return -1;
	}

	sym_len = strlen(sym) + 1;

	rec.p.id           = JIT_CODE_LOAD;
	rec.p.total_size   = sizeof(rec) + sym_len;
	rec.p.timestamp    = perf_get_timestamp();

	rec.code_size  = size;
	rec.vma        = vma;
	rec.code_addr  = vma;
	rec.pid	       = getpid();
	rec.tid	       = gettid();

	if (code)
		rec.p.total_size += size;

	/*
	 * If JVM is multi-threaded, nultiple concurrent calls to agent
	 * may be possible, so protect file writes
	 */
	flockfile(fp);

	/*
	 * get code index inside lock to avoid race condition
	 */
	rec.code_index = code_generation++;

	ret = fwrite_unlocked(&rec, sizeof(rec), 1, fp);
	fwrite_unlocked(sym, sym_len, 1, fp);

	if (code)
		fwrite_unlocked(code, size, 1, fp);

	funlockfile(fp);

	ret = 0;

	return ret;
}

int
jvmti_write_debug_info(void *agent, uint64_t code, const char *file,
		       jvmti_line_info_t *li, int nr_lines)
{
	struct jr_code_debug_info rec;
	size_t sret, len, size, flen;
	uint64_t addr;
	const char *fn = file;
	FILE *fp = agent;
	int i;

	/*
	 * no entry to write
	 */
	if (!nr_lines)
		return 0;

	if (!fp) {
		warnx("jvmti: invalid fd in write_debug_info");
		return -1;
	}

	flen = strlen(file) + 1;

	rec.p.id        = JIT_CODE_DEBUG_INFO;
	size            = sizeof(rec);
	rec.p.timestamp = perf_get_timestamp();
	rec.code_addr   = (uint64_t)(uintptr_t)code;
	rec.nr_entry    = nr_lines;

	/*
	 * on disk source line info layout:
	 * uint64_t : addr
	 * int      : line number
	 * int      : column discriminator
	 * file[]   : source file name
	 */
	size += nr_lines * sizeof(struct debug_entry);
	size += flen * nr_lines;
	rec.p.total_size = size;

	/*
	 * If JVM is multi-threaded, nultiple concurrent calls to agent
	 * may be possible, so protect file writes
	 */
	flockfile(fp);

	sret = fwrite_unlocked(&rec, sizeof(rec), 1, fp);
	if (sret != 1)
		goto error;

	for (i = 0; i < nr_lines; i++) {

		addr = (uint64_t)li[i].pc;
		len  = sizeof(addr);
		sret = fwrite_unlocked(&addr, len, 1, fp);
		if (sret != 1)
			goto error;

		len  = sizeof(li[0].line_number);
		sret = fwrite_unlocked(&li[i].line_number, len, 1, fp);
		if (sret != 1)
			goto error;

		len  = sizeof(li[0].discrim);
		sret = fwrite_unlocked(&li[i].discrim, len, 1, fp);
		if (sret != 1)
			goto error;

		sret = fwrite_unlocked(fn, flen, 1, fp);
		if (sret != 1)
			goto error;
	}
	funlockfile(fp);
	return 0;
error:
	funlockfile(fp);
	return -1;
}