summaryrefslogtreecommitdiffstats
path: root/kernel/trace/trace_events.c
blob: 97e2c4d2e9ebdfeed72e8518a34e0e25f6b045d4 (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
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
/*
 * event tracer
 *
 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
 *
 *  - Added format output of fields of the trace point.
 *    This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
 *
 */

#include <linux/workqueue.h>
#include <linux/spinlock.h>
#include <linux/kthread.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/delay.h>

#include <asm/setup.h>

#include "trace_output.h"

#define TRACE_SYSTEM "TRACE_SYSTEM"

DEFINE_MUTEX(event_mutex);

LIST_HEAD(ftrace_events);

int trace_define_field(struct ftrace_event_call *call, const char *type,
		       const char *name, int offset, int size, int is_signed,
		       int filter_type)
{
	struct ftrace_event_field *field;

	field = kzalloc(sizeof(*field), GFP_KERNEL);
	if (!field)
		goto err;

	field->name = kstrdup(name, GFP_KERNEL);
	if (!field->name)
		goto err;

	field->type = kstrdup(type, GFP_KERNEL);
	if (!field->type)
		goto err;

	if (filter_type == FILTER_OTHER)
		field->filter_type = filter_assign_type(type);
	else
		field->filter_type = filter_type;

	field->offset = offset;
	field->size = size;
	field->is_signed = is_signed;

	list_add(&field->link, &call->fields);

	return 0;

err:
	if (field) {
		kfree(field->name);
		kfree(field->type);
	}
	kfree(field);

	return -ENOMEM;
}
EXPORT_SYMBOL_GPL(trace_define_field);

#define __common_field(type, item)					\
	ret = trace_define_field(call, #type, "common_" #item,		\
				 offsetof(typeof(ent), item),		\
				 sizeof(ent.item),			\
				 is_signed_type(type), FILTER_OTHER);	\
	if (ret)							\
		return ret;

int trace_define_common_fields(struct ftrace_event_call *call)
{
	int ret;
	struct trace_entry ent;

	__common_field(unsigned short, type);
	__common_field(unsigned char, flags);
	__common_field(unsigned char, preempt_count);
	__common_field(int, pid);
	__common_field(int, tgid);

	return ret;
}
EXPORT_SYMBOL_GPL(trace_define_common_fields);

#ifdef CONFIG_MODULES

static void trace_destroy_fields(struct ftrace_event_call *call)
{
	struct ftrace_event_field *field, *next;

	list_for_each_entry_safe(field, next, &call->fields, link) {
		list_del(&field->link);
		kfree(field->type);
		kfree(field->name);
		kfree(field);
	}
}

#endif /* CONFIG_MODULES */

static void ftrace_event_enable_disable(struct ftrace_event_call *call,
					int enable)
{
	switch (enable) {
	case 0:
		if (call->enabled) {
			call->enabled = 0;
			tracing_stop_cmdline_record();
			call->unregfunc(call->data);
		}
		break;
	case 1:
		if (!call->enabled) {
			call->enabled = 1;
			tracing_start_cmdline_record();
			call->regfunc(call->data);
		}
		break;
	}
}

static void ftrace_clear_events(void)
{
	struct ftrace_event_call *call;

	mutex_lock(&event_mutex);
	list_for_each_entry(call, &ftrace_events, list) {
		ftrace_event_enable_disable(call, 0);
	}
	mutex_unlock(&event_mutex);
}

/*
 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
 */
static int __ftrace_set_clr_event(const char *match, const char *sub,
				  const char *event, int set)
{
	struct ftrace_event_call *call;
	int ret = -EINVAL;

	mutex_lock(&event_mutex);
	list_for_each_entry(call, &ftrace_events, list) {

		if (!call->name || !call->regfunc)
			continue;

		if (match &&
		    strcmp(match, call->name) != 0 &&
		    strcmp(match, call->system) != 0)
			continue;

		if (sub && strcmp(sub, call->system) != 0)
			continue;

		if (event && strcmp(event, call->name) != 0)
			continue;

		ftrace_event_enable_disable(call, set);

		ret = 0;
	}
	mutex_unlock(&event_mutex);

	return ret;
}

static int ftrace_set_clr_event(char *buf, int set)
{
	char *event = NULL, *sub = NULL, *match;

	/*
	 * The buf format can be <subsystem>:<event-name>
	 *  *:<event-name> means any event by that name.
	 *  :<event-name> is the same.
	 *
	 *  <subsystem>:* means all events in that subsystem
	 *  <subsystem>: means the same.
	 *
	 *  <name> (no ':') means all events in a subsystem with
	 *  the name <name> or any event that matches <name>
	 */

	match = strsep(&buf, ":");
	if (buf) {
		sub = match;
		event = buf;
		match = NULL;

		if (!strlen(sub) || strcmp(sub, "*") == 0)
			sub = NULL;
		if (!strlen(event) || strcmp(event, "*") == 0)
			event = NULL;
	}

	return __ftrace_set_clr_event(match, sub, event, set);
}

/**
 * trace_set_clr_event - enable or disable an event
 * @system: system name to match (NULL for any system)
 * @event: event name to match (NULL for all events, within system)
 * @set: 1 to enable, 0 to disable
 *
 * This is a way for other parts of the kernel to enable or disable
 * event recording.
 *
 * Returns 0 on success, -EINVAL if the parameters do not match any
 * registered events.
 */
int trace_set_clr_event(const char *system, const char *event, int set)
{
	return __ftrace_set_clr_event(NULL, system, event, set);
}

/* 128 should be much more than enough */
#define EVENT_BUF_SIZE		127

static ssize_t
ftrace_event_write(struct file *file, const char __user *ubuf,
		   size_t cnt, loff_t *ppos)
{
	size_t read = 0;
	int i, set = 1;
	ssize_t ret;
	char *buf;
	char ch;

	if (!cnt || cnt < 0)
		return 0;

	ret = tracing_update_buffers();
	if (ret < 0)
		return ret;

	ret = get_user(ch, ubuf++);
	if (ret)
		return ret;
	read++;
	cnt--;

	/* skip white space */
	while (cnt && isspace(ch)) {
		ret = get_user(ch, ubuf++);
		if (ret)
			return ret;
		read++;
		cnt--;
	}

	/* Only white space found? */
	if (isspace(ch)) {
		file->f_pos += read;
		ret = read;
		return ret;
	}

	buf = kmalloc(EVENT_BUF_SIZE+1, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	if (cnt > EVENT_BUF_SIZE)
		cnt = EVENT_BUF_SIZE;

	i = 0;
	while (cnt && !isspace(ch)) {
		if (!i && ch == '!')
			set = 0;
		else
			buf[i++] = ch;

		ret = get_user(ch, ubuf++);
		if (ret)
			goto out_free;
		read++;
		cnt--;
	}
	buf[i] = 0;

	file->f_pos += read;

	ret = ftrace_set_clr_event(buf, set);
	if (ret)
		goto out_free;

	ret = read;

 out_free:
	kfree(buf);

	return ret;
}

static void *
t_next(struct seq_file *m, void *v, loff_t *pos)
{
	struct list_head *list = m->private;
	struct ftrace_event_call *call;

	(*pos)++;

	for (;;) {
		if (list == &ftrace_events)
			return NULL;

		call = list_entry(list, struct ftrace_event_call, list);

		/*
		 * The ftrace subsystem is for showing formats only.
		 * They can not be enabled or disabled via the event files.
		 */
		if (call->regfunc)
			break;

		list = list->next;
	}

	m->private = list->next;

	return call;
}

static void *t_start(struct seq_file *m, loff_t *pos)
{
	struct ftrace_event_call *call = NULL;
	loff_t l;

	mutex_lock(&event_mutex);

	m->private = ftrace_events.next;
	for (l = 0; l <= *pos; ) {
		call = t_next(m, NULL, &l);
		if (!call)
			break;
	}
	return call;
}

static void *
s_next(struct seq_file *m, void *v, loff_t *pos)
{
	struct list_head *list = m->private;
	struct ftrace_event_call *call;

	(*pos)++;

 retry:
	if (list == &ftrace_events)
		return NULL;

	call = list_entry(list, struct ftrace_event_call, list);

	if (!call->enabled) {
		list = list->next;
		goto retry;
	}

	m->private = list->next;

	return call;
}

static void *s_start(struct seq_file *m, loff_t *pos)
{
	struct ftrace_event_call *call = NULL;
	loff_t l;

	mutex_lock(&event_mutex);

	m->private = ftrace_events.next;
	for (l = 0; l <= *pos; ) {
		call = s_next(m, NULL, &l);
		if (!call)
			break;
	}
	return call;
}

static int t_show(struct seq_file *m, void *v)
{
	struct ftrace_event_call *call = v;

	if (strcmp(call->system, TRACE_SYSTEM) != 0)
		seq_printf(m, "%s:", call->system);
	seq_printf(m, "%s\n", call->name);

	return 0;
}

static void t_stop(struct seq_file *m, void *p)
{
	mutex_unlock(&event_mutex);
}

static int
ftrace_event_seq_open(struct inode *inode, struct file *file)
{
	const struct seq_operations *seq_ops;

	if ((file->f_mode & FMODE_WRITE) &&
	    (file->f_flags & O_TRUNC))
		ftrace_clear_events();

	seq_ops = inode->i_private;
	return seq_open(file, seq_ops);
}

static ssize_t
event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
		  loff_t *ppos)
{
	struct ftrace_event_call *call = filp->private_data;
	char *buf;

	if (call->enabled)
		buf = "1\n";
	else
		buf = "0\n";

	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
}

static ssize_t
event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
		   loff_t *ppos)
{
	struct ftrace_event_call *call = filp->private_data;
	char buf[64];
	unsigned long val;
	int ret;

	if (cnt >= sizeof(buf))
		return -EINVAL;

	if (copy_from_user(&buf, ubuf, cnt))
		return -EFAULT;

	buf[cnt] = 0;

	ret = strict_strtoul(buf, 10, &val);
	if (ret < 0)
		return ret;

	ret = tracing_update_buffers();
	if (ret < 0)
		return ret;

	switch (val) {
	case 0:
	case 1:
		mutex_lock(&event_mutex);
		ftrace_event_enable_disable(call, val);
		mutex_unlock(&event_mutex);
		break;

	default:
		return -EINVAL;
	}

	*ppos += cnt;

	return cnt;
}

static ssize_t
system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
		   loff_t *ppos)
{
	const char set_to_char[4] = { '?', '0', '1', 'X' };
	const char *system = filp->private_data;
	struct ftrace_event_call *call;
	char buf[2];
	int set = 0;
	int ret;

	mutex_lock(&event_mutex);
	list_for_each_entry(call, &ftrace_events, list) {
		if (!call->name || !call->regfunc)
			continue;

		if (system && strcmp(call->system, system) != 0)
			continue;

		/*
		 * We need to find out if all the events are set
		 * or if all events or cleared, or if we have
		 * a mixture.
		 */
		set |= (1 << !!call->enabled);

		/*
		 * If we have a mixture, no need to look further.
		 */
		if (set == 3)
			break;
	}
	mutex_unlock(&event_mutex);

	buf[0] = set_to_char[set];
	buf[1] = '\n';

	ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);

	return ret;
}

static ssize_t
system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
		    loff_t *ppos)
{
	const char *system = filp->private_data;
	unsigned long val;
	char buf[64];
	ssize_t ret;

	if (cnt >= sizeof(buf))
		return -EINVAL;

	if (copy_from_user(&buf, ubuf, cnt))
		return -EFAULT;

	buf[cnt] = 0;

	ret = strict_strtoul(buf, 10, &val);
	if (ret < 0)
		return ret;

	ret = tracing_update_buffers();
	if (ret < 0)
		return ret;

	if (val != 0 && val != 1)
		return -EINVAL;

	ret = __ftrace_set_clr_event(NULL, system, NULL, val);
	if (ret)
		goto out;

	ret = cnt;

out:
	*ppos += cnt;

	return ret;
}

extern char *__bad_type_size(void);

#undef FIELD
#define FIELD(type, name)						\
	sizeof(type) != sizeof(field.name) ? __bad_type_size() :	\
	#type, "common_" #name, offsetof(typeof(field), name),		\
		sizeof(field.name)

static int trace_write_header(struct trace_seq *s)
{
	struct trace_entry field;

	/* struct trace_entry */
	return trace_seq_printf(s,
				"\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
				"\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
				"\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
				"\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
				"\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
				"\n",
				FIELD(unsigned short, type),
				FIELD(unsigned char, flags),
				FIELD(unsigned char, preempt_count),
				FIELD(int, pid),
				FIELD(int, tgid));
}

static ssize_t
event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
		  loff_t *ppos)
{
	struct ftrace_event_call *call = filp->private_data;
	struct trace_seq *s;
	char *buf;
	int r;

	if (*ppos)
		return 0;

	s = kmalloc(sizeof(*s), GFP_KERNEL);
	if (!s)
		return -ENOMEM;

	trace_seq_init(s);

	/* If any of the first writes fail, so will the show_format. */

	trace_seq_printf(s, "name: %s\n", call->name);
	trace_seq_printf(s, "ID: %d\n", call->id);
	trace_seq_printf(s, "format:\n");
	trace_write_header(s);

	r = call->show_format(call, s);
	if (!r) {
		/*
		 * ug!  The format output is bigger than a PAGE!!
		 */
		buf = "FORMAT TOO BIG\n";
		r = simple_read_from_buffer(ubuf, cnt, ppos,
					      buf, strlen(buf));
		goto out;
	}

	r = simple_read_from_buffer(ubuf, cnt, ppos,
				    s->buffer, s->len);
 out:
	kfree(s);
	return r;
}

static ssize_t
event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
{
	struct ftrace_event_call *call = filp->private_data;
	struct trace_seq *s;
	int r;

	if (*ppos)
		return 0;

	s = kmalloc(sizeof(*s), GFP_KERNEL);
	if (!s)
		return -ENOMEM;

	trace_seq_init(s);
	trace_seq_printf(s, "%d\n", call->id);

	r = simple_read_from_buffer(ubuf, cnt, ppos,
				    s->buffer, s->len);
	kfree(s);
	return r;
}

static ssize_t
event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
		  loff_t *ppos)
{
	struct ftrace_event_call *call = filp->private_data;
	struct trace_seq *s;
	int r;

	if (*ppos)
		return 0;

	s = kmalloc(sizeof(*s), GFP_KERNEL);
	if (!s)
		return -ENOMEM;

	trace_seq_init(s);

	print_event_filter(call, s);
	r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);

	kfree(s);

	return r;
}

static ssize_t
event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
		   loff_t *ppos)
{
	struct ftrace_event_call *call = filp->private_data;
	char *buf;
	int err;

	if (cnt >= PAGE_SIZE)
		return -EINVAL;

	buf = (char *)__get_free_page(GFP_TEMPORARY);
	if (!buf)
		return -ENOMEM;

	if (copy_from_user(buf, ubuf, cnt)) {
		free_page((unsigned long) buf);
		return -EFAULT;
	}
	buf[cnt] = '\0';

	err = apply_event_filter(call, buf);
	free_page((unsigned long) buf);
	if (err < 0)
		return err;

	*ppos += cnt;

	return cnt;
}

static ssize_t
subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
		      loff_t *ppos)
{
	struct event_subsystem *system = filp->private_data;
	struct trace_seq *s;
	int r;

	if (*ppos)
		return 0;

	s = kmalloc(sizeof(*s), GFP_KERNEL);
	if (!s)
		return -ENOMEM;

	trace_seq_init(s);

	print_subsystem_event_filter(system, s);
	r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);

	kfree(s);

	return r;
}

static ssize_t
subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
		       loff_t *ppos)
{
	struct event_subsystem *system = filp->private_data;
	char *buf;
	int err;

	if (cnt >= PAGE_SIZE)
		return -EINVAL;

	buf = (char *)__get_free_page(GFP_TEMPORARY);
	if (!buf)
		return -ENOMEM;

	if (copy_from_user(buf, ubuf, cnt)) {
		free_page((unsigned long) buf);
		return -EFAULT;
	}
	buf[cnt] = '\0';

	err = apply_subsystem_event_filter(system, buf);
	free_page((unsigned long) buf);
	if (err < 0)
		return err;

	*ppos += cnt;

	return cnt;
}

static ssize_t
show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
{
	int (*func)(struct trace_seq *s) = filp->private_data;
	struct trace_seq *s;
	int r;

	if (*ppos)
		return 0;

	s = kmalloc(sizeof(*s), GFP_KERNEL);
	if (!s)
		return -ENOMEM;

	trace_seq_init(s);

	func(s);
	r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);

	kfree(s);

	return r;
}

static const struct seq_operations show_event_seq_ops = {
	.start = t_start,
	.next = t_next,
	.show = t_show,
	.stop = t_stop,
};

static const struct seq_operations show_set_event_seq_ops = {
	.start = s_start,
	.next = s_next,
	.show = t_show,
	.stop = t_stop,
};

static const struct file_operations ftrace_avail_fops = {
	.open = ftrace_event_seq_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = seq_release,
};

static const struct file_operations ftrace_set_event_fops = {
	.open = ftrace_event_seq_open,
	.read = seq_read,
	.write = ftrace_event_write,
	.llseek = seq_lseek,
	.release = seq_release,
};

static const struct file_operations ftrace_enable_fops = {
	.open = tracing_open_generic,
	.read = event_enable_read,
	.write = event_enable_write,
};

static const struct file_operations ftrace_event_format_fops = {
	.open = tracing_open_generic,
	.read = event_format_read,
};

static const struct file_operations ftrace_event_id_fops = {
	.open = tracing_open_generic,
	.read = event_id_read,
};

static const struct file_operations ftrace_event_filter_fops = {
	.open = tracing_open_generic,
	.read = event_filter_read,
	.write = event_filter_write,
};

static const struct file_operations ftrace_subsystem_filter_fops = {
	.open = tracing_open_generic,
	.read = subsystem_filter_read,
	.write = subsystem_filter_write,
};

static const struct file_operations ftrace_system_enable_fops = {
	.open = tracing_open_generic,
	.read = system_enable_read,
	.write = system_enable_write,
};

static const struct file_operations ftrace_show_header_fops = {
	.open = tracing_open_generic,
	.read = show_header,
};

static struct dentry *event_trace_events_dir(void)
{
	static struct dentry *d_tracer;
	static struct dentry *d_events;

	if (d_events)
		return d_events;

	d_tracer = tracing_init_dentry();
	if (!d_tracer)
		return NULL;

	d_events = debugfs_create_dir("events", d_tracer);
	if (!d_events)
		pr_warning("Could not create debugfs "
			   "'events' directory\n");

	return d_events;
}

static LIST_HEAD(event_subsystems);

static struct dentry *
event_subsystem_dir(const char *name, struct dentry *d_events)
{
	struct event_subsystem *system;
	struct dentry *entry;

	/* First see if we did not already create this dir */
	list_for_each_entry(system, &event_subsystems, list) {
		if (strcmp(system->name, name) == 0) {
			system->nr_events++;
			return system->entry;
		}
	}

	/* need to create new entry */
	system = kmalloc(sizeof(*system), GFP_KERNEL);
	if (!system) {
		pr_warning("No memory to create event subsystem %s\n",
			   name);
		return d_events;
	}

	system->entry = debugfs_create_dir(name, d_events);
	if (!system->entry) {
		pr_warning("Could not create event subsystem %s\n",
			   name);
		kfree(system);
		return d_events;
	}

	system->nr_events = 1;
	system->name = kstrdup(name, GFP_KERNEL);
	if (!system->name) {
		debugfs_remove(system->entry);
		kfree(system);
		return d_events;
	}

	list_add(&system->list, &event_subsystems);

	system->filter = NULL;

	system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
	if (!system->filter) {
		pr_warning("Could not allocate filter for subsystem "
			   "'%s'\n", name);
		return system->entry;
	}

	entry = debugfs_create_file("filter", 0644, system->entry, system,
				    &ftrace_subsystem_filter_fops);
	if (!entry) {
		kfree(system->filter);
		system->filter = NULL;
		pr_warning("Could not create debugfs "
			   "'%s/filter' entry\n", name);
	}

	entry = trace_create_file("enable", 0644, system->entry,
				  (void *)system->name,
				  &ftrace_system_enable_fops);

	return system->entry;
}

static int
event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
		 const struct file_operations *id,
		 const struct file_operations *enable,
		 const struct file_operations *filter,
		 const struct file_operations *format)
{
	struct dentry *entry;
	int ret;

	/*
	 * If the trace point header did not define TRACE_SYSTEM
	 * then the system would be called "TRACE_SYSTEM".
	 */
	if (strcmp(call->system, TRACE_SYSTEM) != 0)
		d_events = event_subsystem_dir(call->system, d_events);

	call->dir = debugfs_create_dir(call->name, d_events);
	if (!call->dir) {
		pr_warning("Could not create debugfs "
			   "'%s' directory\n", call->name);
		return -1;
	}

	if (call->regfunc)
		entry = trace_create_file("enable", 0644, call->dir, call,
					  enable);

	if (call->id && call->profile_enable)
		entry = trace_create_file("id", 0444, call->dir, call,
					  id);

	if (call->define_fields) {
		ret = call->define_fields(call);
		if (ret < 0) {
			pr_warning("Could not initialize trace point"
				   " events/%s\n", call->name);
			return ret;
		}
		entry = trace_create_file("filter", 0644, call->dir, call,
					  filter);
	}

	/* A trace may not want to export its format */
	if (!call->show_format)
		return 0;

	entry = trace_create_file("format", 0444, call->dir, call,
				  format);

	return 0;
}

#define for_each_event(event, start, end)			\
	for (event = start;					\
	     (unsigned long)event < (unsigned long)end;		\
	     event++)

#ifdef CONFIG_MODULES

static LIST_HEAD(ftrace_module_file_list);

/*
 * Modules must own their file_operations to keep up with
 * reference counting.
 */
struct ftrace_module_file_ops {
	struct list_head		list;
	struct module			*mod;
	struct file_operations		id;
	struct file_operations		enable;
	struct file_operations		format;
	struct file_operations		filter;
};

static void remove_subsystem_dir(const char *name)
{
	struct event_subsystem *system;

	if (strcmp(name, TRACE_SYSTEM) == 0)
		return;

	list_for_each_entry(system, &event_subsystems, list) {
		if (strcmp(system->name, name) == 0) {
			if (!--system->nr_events) {
				struct event_filter *filter = system->filter;

				debugfs_remove_recursive(system->entry);
				list_del(&system->list);
				if (filter) {
					kfree(filter->filter_string);
					kfree(filter);
				}
				kfree(system->name);
				kfree(system);
			}
			break;
		}
	}
}

static struct ftrace_module_file_ops *
trace_create_file_ops(struct module *mod)
{
	struct ftrace_module_file_ops *file_ops;

	/*
	 * This is a bit of a PITA. To allow for correct reference
	 * counting, modules must "own" their file_operations.
	 * To do this, we allocate the file operations that will be
	 * used in the event directory.
	 */

	file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
	if (!file_ops)
		return NULL;

	file_ops->mod = mod;

	file_ops->id = ftrace_event_id_fops;
	file_ops->id.owner = mod;

	file_ops->enable = ftrace_enable_fops;
	file_ops->enable.owner = mod;

	file_ops->filter = ftrace_event_filter_fops;
	file_ops->filter.owner = mod;

	file_ops->format = ftrace_event_format_fops;
	file_ops->format.owner = mod;

	list_add(&file_ops->list, &ftrace_module_file_list);

	return file_ops;
}

static void trace_module_add_events(struct module *mod)
{
	struct ftrace_module_file_ops *file_ops = NULL;
	struct ftrace_event_call *call, *start, *end;
	struct dentry *d_events;
	int ret;

	start = mod->trace_events;
	end = mod->trace_events + mod->num_trace_events;

	if (start == end)
		return;

	d_events = event_trace_events_dir();
	if (!d_events)
		return;

	for_each_event(call, start, end) {
		/* The linker may leave blanks */
		if (!call->name)
			continue;
		if (call->raw_init) {
			ret = call->raw_init();
			if (ret < 0) {
				if (ret != -ENOSYS)
					pr_warning("Could not initialize trace "
					"point events/%s\n", call->name);
				continue;
			}
		}
		/*
		 * This module has events, create file ops for this module
		 * if not already done.
		 */
		if (!file_ops) {
			file_ops = trace_create_file_ops(mod);
			if (!file_ops)
				return;
		}
		call->mod = mod;
		list_add(&call->list, &ftrace_events);
		event_create_dir(call, d_events,
				 &file_ops->id, &file_ops->enable,
				 &file_ops->filter, &file_ops->format);
	}
}

static void trace_module_remove_events(struct module *mod)
{
	struct ftrace_module_file_ops *file_ops;
	struct ftrace_event_call *call, *p;
	bool found = false;

	down_write(&trace_event_mutex);
	list_for_each_entry_safe(call, p, &ftrace_events, list) {
		if (call->mod == mod) {
			found = true;
			ftrace_event_enable_disable(call, 0);
			if (call->event)
				__unregister_ftrace_event(call->event);
			debugfs_remove_recursive(call->dir);
			list_del(&call->list);
			trace_destroy_fields(call);
			destroy_preds(call);
			remove_subsystem_dir(call->system);
		}
	}

	/* Now free the file_operations */
	list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
		if (file_ops->mod == mod)
			break;
	}
	if (&file_ops->list != &ftrace_module_file_list) {
		list_del(&file_ops->list);
		kfree(file_ops);
	}

	/*
	 * It is safest to reset the ring buffer if the module being unloaded
	 * registered any events.
	 */
	if (found)
		tracing_reset_current_online_cpus();
	up_write(&trace_event_mutex);
}

static int trace_module_notify(struct notifier_block *self,
			       unsigned long val, void *data)
{
	struct module *mod = data;

	mutex_lock(&event_mutex);
	switch (val) {
	case MODULE_STATE_COMING:
		trace_module_add_events(mod);
		break;
	case MODULE_STATE_GOING:
		trace_module_remove_events(mod);
		break;
	}
	mutex_unlock(&event_mutex);

	return 0;
}
#else
static int trace_module_notify(struct notifier_block *self,
			       unsigned long val, void *data)
{
	return 0;
}
#endif /* CONFIG_MODULES */

struct notifier_block trace_module_nb = {
	.notifier_call = trace_module_notify,
	.priority = 0,
};

extern struct ftrace_event_call __start_ftrace_events[];
extern struct ftrace_event_call __stop_ftrace_events[];

static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;

static __init int setup_trace_event(char *str)
{
	strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
	ring_buffer_expanded = 1;
	tracing_selftest_disabled = 1;

	return 1;
}
__setup("trace_event=", setup_trace_event);

static __init int event_trace_init(void)
{
	struct ftrace_event_call *call;
	struct dentry *d_tracer;
	struct dentry *entry;
	struct dentry *d_events;
	int ret;
	char *buf = bootup_event_buf;
	char *token;

	d_tracer = tracing_init_dentry();
	if (!d_tracer)
		return 0;

	entry = debugfs_create_file("available_events", 0444, d_tracer,
				    (void *)&show_event_seq_ops,
				    &ftrace_avail_fops);
	if (!entry)
		pr_warning("Could not create debugfs "
			   "'available_events' entry\n");

	entry = debugfs_create_file("set_event", 0644, d_tracer,
				    (void *)&show_set_event_seq_ops,
				    &ftrace_set_event_fops);
	if (!entry)
		pr_warning("Could not create debugfs "
			   "'set_event' entry\n");

	d_events = event_trace_events_dir();
	if (!d_events)
		return 0;

	/* ring buffer internal formats */
	trace_create_file("header_page", 0444, d_events,
			  ring_buffer_print_page_header,
			  &ftrace_show_header_fops);

	trace_create_file("header_event", 0444, d_events,
			  ring_buffer_print_entry_header,
			  &ftrace_show_header_fops);

	trace_create_file("enable", 0644, d_events,
			  NULL, &ftrace_system_enable_fops);

	for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
		/* The linker may leave blanks */
		if (!call->name)
			continue;
		if (call->raw_init) {
			ret = call->raw_init();
			if (ret < 0) {
				if (ret != -ENOSYS)
					pr_warning("Could not initialize trace "
					"point events/%s\n", call->name);
				continue;
			}
		}
		list_add(&call->list, &ftrace_events);
		event_create_dir(call, d_events, &ftrace_event_id_fops,
				 &ftrace_enable_fops, &ftrace_event_filter_fops,
				 &ftrace_event_format_fops);
	}

	while (true) {
		token = strsep(&buf, ",");

		if (!token)
			break;
		if (!*token)
			continue;

		ret = ftrace_set_clr_event(token, 1);
		if (ret)
			pr_warning("Failed to enable trace event: %s\n", token);
	}

	ret = register_module_notifier(&trace_module_nb);
	if (ret)
		pr_warning("Failed to register trace events module notifier\n");

	return 0;
}
fs_initcall(event_trace_init);

#ifdef CONFIG_FTRACE_STARTUP_TEST

static DEFINE_SPINLOCK(test_spinlock);
static DEFINE_SPINLOCK(test_spinlock_irq);
static DEFINE_MUTEX(test_mutex);

static __init void test_work(struct work_struct *dummy)
{
	spin_lock(&test_spinlock);
	spin_lock_irq(&test_spinlock_irq);
	udelay(1);
	spin_unlock_irq(&test_spinlock_irq);
	spin_unlock(&test_spinlock);

	mutex_lock(&test_mutex);
	msleep(1);
	mutex_unlock(&test_mutex);
}

static __init int event_test_thread(void *unused)
{
	void *test_malloc;

	test_malloc = kmalloc(1234, GFP_KERNEL);
	if (!test_malloc)
		pr_info("failed to kmalloc\n");

	schedule_on_each_cpu(test_work);

	kfree(test_malloc);

	set_current_state(TASK_INTERRUPTIBLE);
	while (!kthread_should_stop())
		schedule();

	return 0;
}

/*
 * Do various things that may trigger events.
 */
static __init void event_test_stuff(void)
{
	struct task_struct *test_thread;

	test_thread = kthread_run(event_test_thread, NULL, "test-events");
	msleep(1);
	kthread_stop(test_thread);
}

/*
 * For every trace event defined, we will test each trace point separately,
 * and then by groups, and finally all trace points.
 */
static __init void event_trace_self_tests(void)
{
	struct ftrace_event_call *call;
	struct event_subsystem *system;
	int ret;

	pr_info("Running tests on trace events:\n");

	list_for_each_entry(call, &ftrace_events, list) {

		/* Only test those that have a regfunc */
		if (!call->regfunc)
			continue;

		pr_info("Testing event %s: ", call->name);

		/*
		 * If an event is already enabled, someone is using
		 * it and the self test should not be on.
		 */
		if (call->enabled) {
			pr_warning("Enabled event during self test!\n");
			WARN_ON_ONCE(1);
			continue;
		}

		ftrace_event_enable_disable(call, 1);
		event_test_stuff();
		ftrace_event_enable_disable(call, 0);

		pr_cont("OK\n");
	}

	/* Now test at the sub system level */

	pr_info("Running tests on trace event systems:\n");

	list_for_each_entry(system, &event_subsystems, list) {

		/* the ftrace system is special, skip it */
		if (strcmp(system->name, "ftrace") == 0)
			continue;

		pr_info("Testing event system %s: ", system->name);

		ret = __ftrace_set_clr_event(NULL, system->name, NULL, 1);
		if (WARN_ON_ONCE(ret)) {
			pr_warning("error enabling system %s\n",
				   system->name);
			continue;
		}

		event_test_stuff();

		ret = __ftrace_set_clr_event(NULL, system->name, NULL, 0);
		if (WARN_ON_ONCE(ret))
			pr_warning("error disabling system %s\n",
				   system->name);

		pr_cont("OK\n");
	}

	/* Test with all events enabled */

	pr_info("Running tests on all trace events:\n");
	pr_info("Testing all events: ");

	ret = __ftrace_set_clr_event(NULL, NULL, NULL, 1);
	if (WARN_ON_ONCE(ret)) {
		pr_warning("error enabling all events\n");
		return;
	}

	event_test_stuff();

	/* reset sysname */
	ret = __ftrace_set_clr_event(NULL, NULL, NULL, 0);
	if (WARN_ON_ONCE(ret)) {
		pr_warning("error disabling all events\n");
		return;
	}

	pr_cont("OK\n");
}

#ifdef CONFIG_FUNCTION_TRACER

static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);

static void
function_test_events_call(unsigned long ip, unsigned long parent_ip)
{
	struct ring_buffer_event *event;
	struct ring_buffer *buffer;
	struct ftrace_entry *entry;
	unsigned long flags;
	long disabled;
	int resched;
	int cpu;
	int pc;

	pc = preempt_count();
	resched = ftrace_preempt_disable();
	cpu = raw_smp_processor_id();
	disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));

	if (disabled != 1)
		goto out;

	local_save_flags(flags);

	event = trace_current_buffer_lock_reserve(&buffer,
						  TRACE_FN, sizeof(*entry),
						  flags, pc);
	if (!event)
		goto out;
	entry	= ring_buffer_event_data(event);
	entry->ip			= ip;
	entry->parent_ip		= parent_ip;

	trace_nowake_buffer_unlock_commit(buffer, event, flags, pc);

 out:
	atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
	ftrace_preempt_enable(resched);
}

static struct ftrace_ops trace_ops __initdata  =
{
	.func = function_test_events_call,
};

static __init void event_trace_self_test_with_function(void)
{
	register_ftrace_function(&trace_ops);
	pr_info("Running tests again, along with the function tracer\n");
	event_trace_self_tests();
	unregister_ftrace_function(&trace_ops);
}
#else
static __init void event_trace_self_test_with_function(void)
{
}
#endif

static __init int event_trace_self_tests_init(void)
{
	if (!tracing_selftest_disabled) {
		event_trace_self_tests();
		event_trace_self_test_with_function();
	}

	return 0;
}

late_initcall(event_trace_self_tests_init);

#endif
OpenPOWER on IntegriCloud