summaryrefslogtreecommitdiff
path: root/lib/dynamic_debug.c
blob: c78f335fa98137664745e6593c98b707a528bf34 (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
/*
 * lib/dynamic_debug.c
 *
 * make pr_debug()/dev_dbg() calls runtime configurable based upon their
 * source module.
 *
 * Copyright (C) 2008 Jason Baron <jbaron@redhat.com>
 * By Greg Banks <gnb@melbourne.sgi.com>
 * Copyright (c) 2008 Silicon Graphics Inc.  All Rights Reserved.
 * Copyright (C) 2011 Bart Van Assche.  All Rights Reserved.
 * Copyright (C) 2013 Du, Changbin <changbin.du@gmail.com>
 */

#define pr_fmt(fmt) "dyndbg: " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kallsyms.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/list.h>
#include <linux/sysctl.h>
#include <linux/ctype.h>
#include <linux/string.h>
#include <linux/parser.h>
#include <linux/string_helpers.h>
#include <linux/uaccess.h>
#include <linux/dynamic_debug.h>
#include <linux/debugfs.h>
#include <linux/slab.h>
#include <linux/jump_label.h>
#include <linux/hardirq.h>
#include <linux/sched.h>
#include <linux/device.h>
#include <linux/netdevice.h>

#include <rdma/ib_verbs.h>

extern struct _ddebug __start___dyndbg[];
extern struct _ddebug __stop___dyndbg[];
extern struct ddebug_class_map __start___dyndbg_classes[];
extern struct ddebug_class_map __stop___dyndbg_classes[];

struct ddebug_table {
	struct list_head link, maps;
	const char *mod_name;
	unsigned int num_ddebugs;
	struct _ddebug *ddebugs;
};

struct ddebug_query {
	const char *filename;
	const char *module;
	const char *function;
	const char *format;
	const char *class_string;
	unsigned int first_lineno, last_lineno;
};

struct ddebug_iter {
	struct ddebug_table *table;
	int idx;
};

struct flag_settings {
	unsigned int flags;
	unsigned int mask;
};

static DEFINE_MUTEX(ddebug_lock);
static LIST_HEAD(ddebug_tables);
static int verbose;
module_param(verbose, int, 0644);
MODULE_PARM_DESC(verbose, " dynamic_debug/control processing "
		 "( 0 = off (default), 1 = module add/rm, 2 = >control summary, 3 = parsing, 4 = per-site changes)");

/* Return the path relative to source root */
static inline const char *trim_prefix(const char *path)
{
	int skip = strlen(__FILE__) - strlen("lib/dynamic_debug.c");

	if (strncmp(path, __FILE__, skip))
		skip = 0; /* prefix mismatch, don't skip */

	return path + skip;
}

static const struct { unsigned flag:8; char opt_char; } opt_array[] = {
	{ _DPRINTK_FLAGS_PRINT, 'p' },
	{ _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
	{ _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
	{ _DPRINTK_FLAGS_INCL_SOURCENAME, 's' },
	{ _DPRINTK_FLAGS_INCL_LINENO, 'l' },
	{ _DPRINTK_FLAGS_INCL_TID, 't' },
	{ _DPRINTK_FLAGS_NONE, '_' },
};

struct flagsbuf { char buf[ARRAY_SIZE(opt_array)+1]; };

/* format a string into buf[] which describes the _ddebug's flags */
static char *ddebug_describe_flags(unsigned int flags, struct flagsbuf *fb)
{
	char *p = fb->buf;
	int i;

	for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
		if (flags & opt_array[i].flag)
			*p++ = opt_array[i].opt_char;
	if (p == fb->buf)
		*p++ = '_';
	*p = '\0';

	return fb->buf;
}

#define vnpr_info(lvl, fmt, ...)				\
do {								\
	if (verbose >= lvl)					\
		pr_info(fmt, ##__VA_ARGS__);			\
} while (0)

#define vpr_info(fmt, ...)	vnpr_info(1, fmt, ##__VA_ARGS__)
#define v2pr_info(fmt, ...)	vnpr_info(2, fmt, ##__VA_ARGS__)
#define v3pr_info(fmt, ...)	vnpr_info(3, fmt, ##__VA_ARGS__)
#define v4pr_info(fmt, ...)	vnpr_info(4, fmt, ##__VA_ARGS__)

static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
{
	/* trim any trailing newlines */
	int fmtlen = 0;

	if (query->format) {
		fmtlen = strlen(query->format);
		while (fmtlen && query->format[fmtlen - 1] == '\n')
			fmtlen--;
	}

	v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u class=%s\n",
		  msg,
		  query->function ?: "",
		  query->filename ?: "",
		  query->module ?: "",
		  fmtlen, query->format ?: "",
		  query->first_lineno, query->last_lineno, query->class_string);
}

static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt,
							  const char *class_string, int *class_id)
{
	struct ddebug_class_map *map;
	int idx;

	list_for_each_entry(map, &dt->maps, link) {
		idx = match_string(map->class_names, map->length, class_string);
		if (idx >= 0) {
			*class_id = idx + map->base;
			return map;
		}
	}
	*class_id = -ENOENT;
	return NULL;
}

#define __outvar /* filled by callee */
/*
 * Search the tables for _ddebug's which match the given `query' and
 * apply the `flags' and `mask' to them.  Returns number of matching
 * callsites, normally the same as number of changes.  If verbose,
 * logs the changes.  Takes ddebug_lock.
 */
static int ddebug_change(const struct ddebug_query *query,
			 struct flag_settings *modifiers)
{
	int i;
	struct ddebug_table *dt;
	unsigned int newflags;
	unsigned int nfound = 0;
	struct flagsbuf fbuf, nbuf;
	struct ddebug_class_map *map = NULL;
	int __outvar valid_class;

	/* search for matching ddebugs */
	mutex_lock(&ddebug_lock);
	list_for_each_entry(dt, &ddebug_tables, link) {

		/* match against the module name */
		if (query->module &&
		    !match_wildcard(query->module, dt->mod_name))
			continue;

		if (query->class_string) {
			map = ddebug_find_valid_class(dt, query->class_string, &valid_class);
			if (!map)
				continue;
		} else {
			/* constrain query, do not touch class'd callsites */
			valid_class = _DPRINTK_CLASS_DFLT;
		}

		for (i = 0; i < dt->num_ddebugs; i++) {
			struct _ddebug *dp = &dt->ddebugs[i];

			/* match site against query-class */
			if (dp->class_id != valid_class)
				continue;

			/* match against the source filename */
			if (query->filename &&
			    !match_wildcard(query->filename, dp->filename) &&
			    !match_wildcard(query->filename,
					   kbasename(dp->filename)) &&
			    !match_wildcard(query->filename,
					   trim_prefix(dp->filename)))
				continue;

			/* match against the function */
			if (query->function &&
			    !match_wildcard(query->function, dp->function))
				continue;

			/* match against the format */
			if (query->format) {
				if (*query->format == '^') {
					char *p;
					/* anchored search. match must be at beginning */
					p = strstr(dp->format, query->format+1);
					if (p != dp->format)
						continue;
				} else if (!strstr(dp->format, query->format))
					continue;
			}

			/* match against the line number range */
			if (query->first_lineno &&
			    dp->lineno < query->first_lineno)
				continue;
			if (query->last_lineno &&
			    dp->lineno > query->last_lineno)
				continue;

			nfound++;

			newflags = (dp->flags & modifiers->mask) | modifiers->flags;
			if (newflags == dp->flags)
				continue;
#ifdef CONFIG_JUMP_LABEL
			if (dp->flags & _DPRINTK_FLAGS_PRINT) {
				if (!(newflags & _DPRINTK_FLAGS_PRINT))
					static_branch_disable(&dp->key.dd_key_true);
			} else if (newflags & _DPRINTK_FLAGS_PRINT) {
				static_branch_enable(&dp->key.dd_key_true);
			}
#endif
			v4pr_info("changed %s:%d [%s]%s %s => %s\n",
				  trim_prefix(dp->filename), dp->lineno,
				  dt->mod_name, dp->function,
				  ddebug_describe_flags(dp->flags, &fbuf),
				  ddebug_describe_flags(newflags, &nbuf));
			dp->flags = newflags;
		}
	}
	mutex_unlock(&ddebug_lock);

	if (!nfound && verbose)
		pr_info("no matches for query\n");

	return nfound;
}

/*
 * Split the buffer `buf' into space-separated words.
 * Handles simple " and ' quoting, i.e. without nested,
 * embedded or escaped \".  Return the number of words
 * or <0 on error.
 */
static int ddebug_tokenize(char *buf, char *words[], int maxwords)
{
	int nwords = 0;

	while (*buf) {
		char *end;

		/* Skip leading whitespace */
		buf = skip_spaces(buf);
		if (!*buf)
			break;	/* oh, it was trailing whitespace */
		if (*buf == '#')
			break;	/* token starts comment, skip rest of line */

		/* find `end' of word, whitespace separated or quoted */
		if (*buf == '"' || *buf == '\'') {
			int quote = *buf++;
			for (end = buf; *end && *end != quote; end++)
				;
			if (!*end) {
				pr_err("unclosed quote: %s\n", buf);
				return -EINVAL;	/* unclosed quote */
			}
		} else {
			for (end = buf; *end && !isspace(*end); end++)
				;
			BUG_ON(end == buf);
		}

		/* `buf' is start of word, `end' is one past its end */
		if (nwords == maxwords) {
			pr_err("too many words, legal max <=%d\n", maxwords);
			return -EINVAL;	/* ran out of words[] before bytes */
		}
		if (*end)
			*end++ = '\0';	/* terminate the word */
		words[nwords++] = buf;
		buf = end;
	}

	if (verbose >= 3) {
		int i;
		pr_info("split into words:");
		for (i = 0; i < nwords; i++)
			pr_cont(" \"%s\"", words[i]);
		pr_cont("\n");
	}

	return nwords;
}

/*
 * Parse a single line number.  Note that the empty string ""
 * is treated as a special case and converted to zero, which
 * is later treated as a "don't care" value.
 */
static inline int parse_lineno(const char *str, unsigned int *val)
{
	BUG_ON(str == NULL);
	if (*str == '\0') {
		*val = 0;
		return 0;
	}
	if (kstrtouint(str, 10, val) < 0) {
		pr_err("bad line-number: %s\n", str);
		return -EINVAL;
	}
	return 0;
}

static int parse_linerange(struct ddebug_query *query, const char *first)
{
	char *last = strchr(first, '-');

	if (query->first_lineno || query->last_lineno) {
		pr_err("match-spec: line used 2x\n");
		return -EINVAL;
	}
	if (last)
		*last++ = '\0';
	if (parse_lineno(first, &query->first_lineno) < 0)
		return -EINVAL;
	if (last) {
		/* range <first>-<last> */
		if (parse_lineno(last, &query->last_lineno) < 0)
			return -EINVAL;

		/* special case for last lineno not specified */
		if (query->last_lineno == 0)
			query->last_lineno = UINT_MAX;

		if (query->last_lineno < query->first_lineno) {
			pr_err("last-line:%d < 1st-line:%d\n",
			       query->last_lineno,
			       query->first_lineno);
			return -EINVAL;
		}
	} else {
		query->last_lineno = query->first_lineno;
	}
	v3pr_info("parsed line %d-%d\n", query->first_lineno,
		 query->last_lineno);
	return 0;
}

static int check_set(const char **dest, char *src, char *name)
{
	int rc = 0;

	if (*dest) {
		rc = -EINVAL;
		pr_err("match-spec:%s val:%s overridden by %s\n",
		       name, *dest, src);
	}
	*dest = src;
	return rc;
}

/*
 * Parse words[] as a ddebug query specification, which is a series
 * of (keyword, value) pairs chosen from these possibilities:
 *
 * func <function-name>
 * file <full-pathname>
 * file <base-filename>
 * module <module-name>
 * format <escaped-string-to-find-in-format>
 * line <lineno>
 * line <first-lineno>-<last-lineno> // where either may be empty
 *
 * Only 1 of each type is allowed.
 * Returns 0 on success, <0 on error.
 */
static int ddebug_parse_query(char *words[], int nwords,
			struct ddebug_query *query, const char *modname)
{
	unsigned int i;
	int rc = 0;
	char *fline;

	/* check we have an even number of words */
	if (nwords % 2 != 0) {
		pr_err("expecting pairs of match-spec <value>\n");
		return -EINVAL;
	}

	for (i = 0; i < nwords; i += 2) {
		char *keyword = words[i];
		char *arg = words[i+1];

		if (!strcmp(keyword, "func")) {
			rc = check_set(&query->function, arg, "func");
		} else if (!strcmp(keyword, "file")) {
			if (check_set(&query->filename, arg, "file"))
				return -EINVAL;

			/* tail :$info is function or line-range */
			fline = strchr(query->filename, ':');
			if (!fline)
				continue;
			*fline++ = '\0';
			if (isalpha(*fline) || *fline == '*' || *fline == '?') {
				/* take as function name */
				if (check_set(&query->function, fline, "func"))
					return -EINVAL;
			} else {
				if (parse_linerange(query, fline))
					return -EINVAL;
			}
		} else if (!strcmp(keyword, "module")) {
			rc = check_set(&query->module, arg, "module");
		} else if (!strcmp(keyword, "format")) {
			string_unescape_inplace(arg, UNESCAPE_SPACE |
							    UNESCAPE_OCTAL |
							    UNESCAPE_SPECIAL);
			rc = check_set(&query->format, arg, "format");
		} else if (!strcmp(keyword, "line")) {
			if (parse_linerange(query, arg))
				return -EINVAL;
		} else if (!strcmp(keyword, "class")) {
			rc = check_set(&query->class_string, arg, "class");
		} else {
			pr_err("unknown keyword \"%s\"\n", keyword);
			return -EINVAL;
		}
		if (rc)
			return rc;
	}
	if (!query->module && modname)
		/*
		 * support $modname.dyndbg=<multiple queries>, when
		 * not given in the query itself
		 */
		query->module = modname;

	vpr_info_dq(query, "parsed");
	return 0;
}

/*
 * Parse `str' as a flags specification, format [-+=][p]+.
 * Sets up *maskp and *flagsp to be used when changing the
 * flags fields of matched _ddebug's.  Returns 0 on success
 * or <0 on error.
 */
static int ddebug_parse_flags(const char *str, struct flag_settings *modifiers)
{
	int op, i;

	switch (*str) {
	case '+':
	case '-':
	case '=':
		op = *str++;
		break;
	default:
		pr_err("bad flag-op %c, at start of %s\n", *str, str);
		return -EINVAL;
	}
	v3pr_info("op='%c'\n", op);

	for (; *str ; ++str) {
		for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
			if (*str == opt_array[i].opt_char) {
				modifiers->flags |= opt_array[i].flag;
				break;
			}
		}
		if (i < 0) {
			pr_err("unknown flag '%c'\n", *str);
			return -EINVAL;
		}
	}
	v3pr_info("flags=0x%x\n", modifiers->flags);

	/* calculate final flags, mask based upon op */
	switch (op) {
	case '=':
		/* modifiers->flags already set */
		modifiers->mask = 0;
		break;
	case '+':
		modifiers->mask = ~0U;
		break;
	case '-':
		modifiers->mask = ~modifiers->flags;
		modifiers->flags = 0;
		break;
	}
	v3pr_info("*flagsp=0x%x *maskp=0x%x\n", modifiers->flags, modifiers->mask);

	return 0;
}

static int ddebug_exec_query(char *query_string, const char *modname)
{
	struct flag_settings modifiers = {};
	struct ddebug_query query = {};
#define MAXWORDS 9
	int nwords, nfound;
	char *words[MAXWORDS];

	nwords = ddebug_tokenize(query_string, words, MAXWORDS);
	if (nwords <= 0) {
		pr_err("tokenize failed\n");
		return -EINVAL;
	}
	/* check flags 1st (last arg) so query is pairs of spec,val */
	if (ddebug_parse_flags(words[nwords-1], &modifiers)) {
		pr_err("flags parse failed\n");
		return -EINVAL;
	}
	if (ddebug_parse_query(words, nwords-1, &query, modname)) {
		pr_err("query parse failed\n");
		return -EINVAL;
	}
	/* actually go and implement the change */
	nfound = ddebug_change(&query, &modifiers);
	vpr_info_dq(&query, nfound ? "applied" : "no-match");

	return nfound;
}

/* handle multiple queries in query string, continue on error, return
   last error or number of matching callsites.  Module name is either
   in param (for boot arg) or perhaps in query string.
*/
static int ddebug_exec_queries(char *query, const char *modname)
{
	char *split;
	int i, errs = 0, exitcode = 0, rc, nfound = 0;

	for (i = 0; query; query = split) {
		split = strpbrk(query, ";\n");
		if (split)
			*split++ = '\0';

		query = skip_spaces(query);
		if (!query || !*query || *query == '#')
			continue;

		vpr_info("query %d: \"%s\" mod:%s\n", i, query, modname ?: "*");

		rc = ddebug_exec_query(query, modname);
		if (rc < 0) {
			errs++;
			exitcode = rc;
		} else {
			nfound += rc;
		}
		i++;
	}
	if (i)
		v2pr_info("processed %d queries, with %d matches, %d errs\n",
			 i, nfound, errs);

	if (exitcode)
		return exitcode;
	return nfound;
}

/* apply a new bitmap to the sys-knob's current bit-state */
static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
				     unsigned long *new_bits, unsigned long *old_bits)
{
#define QUERY_SIZE 128
	char query[QUERY_SIZE];
	const struct ddebug_class_map *map = dcp->map;
	int matches = 0;
	int bi, ct;

	v2pr_info("apply: 0x%lx to: 0x%lx\n", *new_bits, *old_bits);

	for (bi = 0; bi < map->length; bi++) {
		if (test_bit(bi, new_bits) == test_bit(bi, old_bits))
			continue;

		snprintf(query, QUERY_SIZE, "class %s %c%s", map->class_names[bi],
			 test_bit(bi, new_bits) ? '+' : '-', dcp->flags);

		ct = ddebug_exec_queries(query, NULL);
		matches += ct;

		v2pr_info("bit_%d: %d matches on class: %s -> 0x%lx\n", bi,
			  ct, map->class_names[bi], *new_bits);
	}
	return matches;
}

/* stub to later conditionally add "$module." prefix where not already done */
#define KP_NAME(kp)	kp->name

#define CLASSMAP_BITMASK(width) ((1UL << (width)) - 1)

/* accept comma-separated-list of [+-] classnames */
static int param_set_dyndbg_classnames(const char *instr, const struct kernel_param *kp)
{
	const struct ddebug_class_param *dcp = kp->arg;
	const struct ddebug_class_map *map = dcp->map;
	unsigned long curr_bits, old_bits;
	char *cl_str, *p, *tmp;
	int cls_id, totct = 0;
	bool wanted;

	cl_str = tmp = kstrdup_and_replace(instr, '\n', '\0', GFP_KERNEL);
	if (!tmp)
		return -ENOMEM;

	/* start with previously set state-bits, then modify */
	curr_bits = old_bits = *dcp->bits;
	vpr_info("\"%s\" > %s:0x%lx\n", cl_str, KP_NAME(kp), curr_bits);

	for (; cl_str; cl_str = p) {
		p = strchr(cl_str, ',');
		if (p)
			*p++ = '\0';

		if (*cl_str == '-') {
			wanted = false;
			cl_str++;
		} else {
			wanted = true;
			if (*cl_str == '+')
				cl_str++;
		}
		cls_id = match_string(map->class_names, map->length, cl_str);
		if (cls_id < 0) {
			pr_err("%s unknown to %s\n", cl_str, KP_NAME(kp));
			continue;
		}

		/* have one or more valid class_ids of one *_NAMES type */
		switch (map->map_type) {
		case DD_CLASS_TYPE_DISJOINT_NAMES:
			/* the +/- pertains to a single bit */
			if (test_bit(cls_id, &curr_bits) == wanted) {
				v3pr_info("no change on %s\n", cl_str);
				continue;
			}
			curr_bits ^= BIT(cls_id);
			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, dcp->bits);
			*dcp->bits = curr_bits;
			v2pr_info("%s: changed bit %d:%s\n", KP_NAME(kp), cls_id,
				  map->class_names[cls_id]);
			break;
		case DD_CLASS_TYPE_LEVEL_NAMES:
			/* cls_id = N in 0..max. wanted +/- determines N or N-1 */
			old_bits = CLASSMAP_BITMASK(*dcp->lvl);
			curr_bits = CLASSMAP_BITMASK(cls_id + (wanted ? 1 : 0 ));

			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, &old_bits);
			*dcp->lvl = (cls_id + (wanted ? 1 : 0));
			v2pr_info("%s: changed bit-%d: \"%s\" %lx->%lx\n", KP_NAME(kp), cls_id,
				  map->class_names[cls_id], old_bits, curr_bits);
			break;
		default:
			pr_err("illegal map-type value %d\n", map->map_type);
		}
	}
	kfree(tmp);
	vpr_info("total matches: %d\n", totct);
	return 0;
}

/**
 * param_set_dyndbg_classes - class FOO >control
 * @instr: string echo>d to sysfs, input depends on map_type
 * @kp:    kp->arg has state: bits/lvl, map, map_type
 *
 * Enable/disable prdbgs by their class, as given in the arguments to
 * DECLARE_DYNDBG_CLASSMAP.  For LEVEL map-types, enforce relative
 * levels by bitpos.
 *
 * Returns: 0 or <0 if error.
 */
int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
{
	const struct ddebug_class_param *dcp = kp->arg;
	const struct ddebug_class_map *map = dcp->map;
	unsigned long inrep, new_bits, old_bits;
	int rc, totct = 0;

	switch (map->map_type) {

	case DD_CLASS_TYPE_DISJOINT_NAMES:
	case DD_CLASS_TYPE_LEVEL_NAMES:
		/* handle [+-]classnames list separately, we are done here */
		return param_set_dyndbg_classnames(instr, kp);

	case DD_CLASS_TYPE_DISJOINT_BITS:
	case DD_CLASS_TYPE_LEVEL_NUM:
		/* numeric input, accept and fall-thru */
		rc = kstrtoul(instr, 0, &inrep);
		if (rc) {
			pr_err("expecting numeric input: %s > %s\n", instr, KP_NAME(kp));
			return -EINVAL;
		}
		break;
	default:
		pr_err("%s: bad map type: %d\n", KP_NAME(kp), map->map_type);
		return -EINVAL;
	}

	/* only _BITS,_NUM (numeric) map-types get here */
	switch (map->map_type) {
	case DD_CLASS_TYPE_DISJOINT_BITS:
		/* expect bits. mask and warn if too many */
		if (inrep & ~CLASSMAP_BITMASK(map->length)) {
			pr_warn("%s: input: 0x%lx exceeds mask: 0x%lx, masking\n",
				KP_NAME(kp), inrep, CLASSMAP_BITMASK(map->length));
			inrep &= CLASSMAP_BITMASK(map->length);
		}
		v2pr_info("bits:%lx > %s\n", inrep, KP_NAME(kp));
		totct += ddebug_apply_class_bitmap(dcp, &inrep, dcp->bits);
		*dcp->bits = inrep;
		break;
	case DD_CLASS_TYPE_LEVEL_NUM:
		/* input is bitpos, of highest verbosity to be enabled */
		if (inrep > map->length) {
			pr_warn("%s: level:%ld exceeds max:%d, clamping\n",
				KP_NAME(kp), inrep, map->length);
			inrep = map->length;
		}
		old_bits = CLASSMAP_BITMASK(*dcp->lvl);
		new_bits = CLASSMAP_BITMASK(inrep);
		v2pr_info("lvl:%ld bits:0x%lx > %s\n", inrep, new_bits, KP_NAME(kp));
		totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits);
		*dcp->lvl = inrep;
		break;
	default:
		pr_warn("%s: bad map type: %d\n", KP_NAME(kp), map->map_type);
	}
	vpr_info("%s: total matches: %d\n", KP_NAME(kp), totct);
	return 0;
}
EXPORT_SYMBOL(param_set_dyndbg_classes);

/**
 * param_get_dyndbg_classes - classes reader
 * @buffer: string description of controlled bits -> classes
 * @kp:     kp->arg has state: bits, map
 *
 * Reads last written state, underlying prdbg state may have been
 * altered by direct >control.  Displays 0x for DISJOINT, 0-N for
 * LEVEL Returns: #chars written or <0 on error
 */
int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp)
{
	const struct ddebug_class_param *dcp = kp->arg;
	const struct ddebug_class_map *map = dcp->map;

	switch (map->map_type) {

	case DD_CLASS_TYPE_DISJOINT_NAMES:
	case DD_CLASS_TYPE_DISJOINT_BITS:
		return scnprintf(buffer, PAGE_SIZE, "0x%lx\n", *dcp->bits);

	case DD_CLASS_TYPE_LEVEL_NAMES:
	case DD_CLASS_TYPE_LEVEL_NUM:
		return scnprintf(buffer, PAGE_SIZE, "%d\n", *dcp->lvl);
	default:
		return -1;
	}
}
EXPORT_SYMBOL(param_get_dyndbg_classes);

const struct kernel_param_ops param_ops_dyndbg_classes = {
	.set = param_set_dyndbg_classes,
	.get = param_get_dyndbg_classes,
};
EXPORT_SYMBOL(param_ops_dyndbg_classes);

#define PREFIX_SIZE 128

static int remaining(int wrote)
{
	if (PREFIX_SIZE - wrote > 0)
		return PREFIX_SIZE - wrote;
	return 0;
}

static char *__dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
{
	int pos_after_tid;
	int pos = 0;

	if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
		if (in_interrupt())
			pos += snprintf(buf + pos, remaining(pos), "<intr> ");
		else
			pos += snprintf(buf + pos, remaining(pos), "[%d] ",
					task_pid_vnr(current));
	}
	pos_after_tid = pos;
	if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
		pos += snprintf(buf + pos, remaining(pos), "%s:",
				desc->modname);
	if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
		pos += snprintf(buf + pos, remaining(pos), "%s:",
				desc->function);
	if (desc->flags & _DPRINTK_FLAGS_INCL_SOURCENAME)
		pos += snprintf(buf + pos, remaining(pos), "%s:",
				trim_prefix(desc->filename));
	if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
		pos += snprintf(buf + pos, remaining(pos), "%d:",
				desc->lineno);
	if (pos - pos_after_tid)
		pos += snprintf(buf + pos, remaining(pos), " ");
	if (pos >= PREFIX_SIZE)
		buf[PREFIX_SIZE - 1] = '\0';

	return buf;
}

static inline char *dynamic_emit_prefix(struct _ddebug *desc, char *buf)
{
	if (unlikely(desc->flags & _DPRINTK_FLAGS_INCL_ANY))
		return __dynamic_emit_prefix(desc, buf);
	return buf;
}

void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
{
	va_list args;
	struct va_format vaf;
	char buf[PREFIX_SIZE] = "";

	BUG_ON(!descriptor);
	BUG_ON(!fmt);

	va_start(args, fmt);

	vaf.fmt = fmt;
	vaf.va = &args;

	printk(KERN_DEBUG "%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);

	va_end(args);
}
EXPORT_SYMBOL(__dynamic_pr_debug);

void __dynamic_dev_dbg(struct _ddebug *descriptor,
		      const struct device *dev, const char *fmt, ...)
{
	struct va_format vaf;
	va_list args;

	BUG_ON(!descriptor);
	BUG_ON(!fmt);

	va_start(args, fmt);

	vaf.fmt = fmt;
	vaf.va = &args;

	if (!dev) {
		printk(KERN_DEBUG "(NULL device *): %pV", &vaf);
	} else {
		char buf[PREFIX_SIZE] = "";

		dev_printk_emit(LOGLEVEL_DEBUG, dev, "%s%s %s: %pV",
				dynamic_emit_prefix(descriptor, buf),
				dev_driver_string(dev), dev_name(dev),
				&vaf);
	}

	va_end(args);
}
EXPORT_SYMBOL(__dynamic_dev_dbg);

#ifdef CONFIG_NET

void __dynamic_netdev_dbg(struct _ddebug *descriptor,
			  const struct net_device *dev, const char *fmt, ...)
{
	struct va_format vaf;
	va_list args;

	BUG_ON(!descriptor);
	BUG_ON(!fmt);

	va_start(args, fmt);

	vaf.fmt = fmt;
	vaf.va = &args;

	if (dev && dev->dev.parent) {
		char buf[PREFIX_SIZE] = "";

		dev_printk_emit(LOGLEVEL_DEBUG, dev->dev.parent,
				"%s%s %s %s%s: %pV",
				dynamic_emit_prefix(descriptor, buf),
				dev_driver_string(dev->dev.parent),
				dev_name(dev->dev.parent),
				netdev_name(dev), netdev_reg_state(dev),
				&vaf);
	} else if (dev) {
		printk(KERN_DEBUG "%s%s: %pV", netdev_name(dev),
		       netdev_reg_state(dev), &vaf);
	} else {
		printk(KERN_DEBUG "(NULL net_device): %pV", &vaf);
	}

	va_end(args);
}
EXPORT_SYMBOL(__dynamic_netdev_dbg);

#endif

#if IS_ENABLED(CONFIG_INFINIBAND)

void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
			 const struct ib_device *ibdev, const char *fmt, ...)
{
	struct va_format vaf;
	va_list args;

	va_start(args, fmt);

	vaf.fmt = fmt;
	vaf.va = &args;

	if (ibdev && ibdev->dev.parent) {
		char buf[PREFIX_SIZE] = "";

		dev_printk_emit(LOGLEVEL_DEBUG, ibdev->dev.parent,
				"%s%s %s %s: %pV",
				dynamic_emit_prefix(descriptor, buf),
				dev_driver_string(ibdev->dev.parent),
				dev_name(ibdev->dev.parent),
				dev_name(&ibdev->dev),
				&vaf);
	} else if (ibdev) {
		printk(KERN_DEBUG "%s: %pV", dev_name(&ibdev->dev), &vaf);
	} else {
		printk(KERN_DEBUG "(NULL ib_device): %pV", &vaf);
	}

	va_end(args);
}
EXPORT_SYMBOL(__dynamic_ibdev_dbg);

#endif

/*
 * Install a noop handler to make dyndbg look like a normal kernel cli param.
 * This avoids warnings about dyndbg being an unknown cli param when supplied
 * by a user.
 */
static __init int dyndbg_setup(char *str)
{
	return 1;
}

__setup("dyndbg=", dyndbg_setup);

/*
 * File_ops->write method for <debugfs>/dynamic_debug/control.  Gathers the
 * command text from userspace, parses and executes it.
 */
#define USER_BUF_PAGE 4096
static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
				  size_t len, loff_t *offp)
{
	char *tmpbuf;
	int ret;

	if (len == 0)
		return 0;
	if (len > USER_BUF_PAGE - 1) {
		pr_warn("expected <%d bytes into control\n", USER_BUF_PAGE);
		return -E2BIG;
	}
	tmpbuf = memdup_user_nul(ubuf, len);
	if (IS_ERR(tmpbuf))
		return PTR_ERR(tmpbuf);
	v2pr_info("read %zu bytes from userspace\n", len);

	ret = ddebug_exec_queries(tmpbuf, NULL);
	kfree(tmpbuf);
	if (ret < 0)
		return ret;

	*offp += len;
	return len;
}

/*
 * Set the iterator to point to the first _ddebug object
 * and return a pointer to that first object.  Returns
 * NULL if there are no _ddebugs at all.
 */
static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
{
	if (list_empty(&ddebug_tables)) {
		iter->table = NULL;
		return NULL;
	}
	iter->table = list_entry(ddebug_tables.next,
				 struct ddebug_table, link);
	iter->idx = iter->table->num_ddebugs;
	return &iter->table->ddebugs[--iter->idx];
}

/*
 * Advance the iterator to point to the next _ddebug
 * object from the one the iterator currently points at,
 * and returns a pointer to the new _ddebug.  Returns
 * NULL if the iterator has seen all the _ddebugs.
 */
static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
{
	if (iter->table == NULL)
		return NULL;
	if (--iter->idx < 0) {
		/* iterate to next table */
		if (list_is_last(&iter->table->link, &ddebug_tables)) {
			iter->table = NULL;
			return NULL;
		}
		iter->table = list_entry(iter->table->link.next,
					 struct ddebug_table, link);
		iter->idx = iter->table->num_ddebugs;
		--iter->idx;
	}
	return &iter->table->ddebugs[iter->idx];
}

/*
 * Seq_ops start method.  Called at the start of every
 * read() call from userspace.  Takes the ddebug_lock and
 * seeks the seq_file's iterator to the given position.
 */
static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
{
	struct ddebug_iter *iter = m->private;
	struct _ddebug *dp;
	int n = *pos;

	mutex_lock(&ddebug_lock);

	if (!n)
		return SEQ_START_TOKEN;
	if (n < 0)
		return NULL;
	dp = ddebug_iter_first(iter);
	while (dp != NULL && --n > 0)
		dp = ddebug_iter_next(iter);
	return dp;
}

/*
 * Seq_ops next method.  Called several times within a read()
 * call from userspace, with ddebug_lock held.  Walks to the
 * next _ddebug object with a special case for the header line.
 */
static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
{
	struct ddebug_iter *iter = m->private;
	struct _ddebug *dp;

	if (p == SEQ_START_TOKEN)
		dp = ddebug_iter_first(iter);
	else
		dp = ddebug_iter_next(iter);
	++*pos;
	return dp;
}

#define class_in_range(class_id, map)					\
	(class_id >= map->base && class_id < map->base + map->length)

static const char *ddebug_class_name(struct ddebug_iter *iter, struct _ddebug *dp)
{
	struct ddebug_class_map *map;

	list_for_each_entry(map, &iter->table->maps, link)
		if (class_in_range(dp->class_id, map))
			return map->class_names[dp->class_id - map->base];

	return NULL;
}

/*
 * Seq_ops show method.  Called several times within a read()
 * call from userspace, with ddebug_lock held.  Formats the
 * current _ddebug as a single human-readable line, with a
 * special case for the header line.
 */
static int ddebug_proc_show(struct seq_file *m, void *p)
{
	struct ddebug_iter *iter = m->private;
	struct _ddebug *dp = p;
	struct flagsbuf flags;
	char const *class;

	if (p == SEQ_START_TOKEN) {
		seq_puts(m,
			 "# filename:lineno [module]function flags format\n");
		return 0;
	}

	seq_printf(m, "%s:%u [%s]%s =%s \"",
		   trim_prefix(dp->filename), dp->lineno,
		   iter->table->mod_name, dp->function,
		   ddebug_describe_flags(dp->flags, &flags));
	seq_escape_str(m, dp->format, ESCAPE_SPACE, "\t\r\n\"");
	seq_puts(m, "\"");

	if (dp->class_id != _DPRINTK_CLASS_DFLT) {
		class = ddebug_class_name(iter, dp);
		if (class)
			seq_printf(m, " class:%s", class);
		else
			seq_printf(m, " class unknown, _id:%d", dp->class_id);
	}
	seq_puts(m, "\n");

	return 0;
}

/*
 * Seq_ops stop method.  Called at the end of each read()
 * call from userspace.  Drops ddebug_lock.
 */
static void ddebug_proc_stop(struct seq_file *m, void *p)
{
	mutex_unlock(&ddebug_lock);
}

static const struct seq_operations ddebug_proc_seqops = {
	.start = ddebug_proc_start,
	.next = ddebug_proc_next,
	.show = ddebug_proc_show,
	.stop = ddebug_proc_stop
};

static int ddebug_proc_open(struct inode *inode, struct file *file)
{
	return seq_open_private(file, &ddebug_proc_seqops,
				sizeof(struct ddebug_iter));
}

static const struct file_operations ddebug_proc_fops = {
	.owner = THIS_MODULE,
	.open = ddebug_proc_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = seq_release_private,
	.write = ddebug_proc_write
};

static const struct proc_ops proc_fops = {
	.proc_open = ddebug_proc_open,
	.proc_read = seq_read,
	.proc_lseek = seq_lseek,
	.proc_release = seq_release_private,
	.proc_write = ddebug_proc_write
};

static void ddebug_attach_module_classes(struct ddebug_table *dt,
					 struct ddebug_class_map *classes,
					 int num_classes)
{
	struct ddebug_class_map *cm;
	int i, j, ct = 0;

	for (cm = classes, i = 0; i < num_classes; i++, cm++) {

		if (!strcmp(cm->mod_name, dt->mod_name)) {

			v2pr_info("class[%d]: module:%s base:%d len:%d ty:%d\n", i,
				  cm->mod_name, cm->base, cm->length, cm->map_type);

			for (j = 0; j < cm->length; j++)
				v3pr_info(" %d: %d %s\n", j + cm->base, j,
					  cm->class_names[j]);

			list_add(&cm->link, &dt->maps);
			ct++;
		}
	}
	if (ct)
		vpr_info("module:%s attached %d classes\n", dt->mod_name, ct);
}

/*
 * Allocate a new ddebug_table for the given module
 * and add it to the global list.
 */
static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
{
	struct ddebug_table *dt;

	v3pr_info("add-module: %s.%d sites\n", modname, di->num_descs);
	if (!di->num_descs) {
		v3pr_info(" skip %s\n", modname);
		return 0;
	}

	dt = kzalloc(sizeof(*dt), GFP_KERNEL);
	if (dt == NULL) {
		pr_err("error adding module: %s\n", modname);
		return -ENOMEM;
	}
	/*
	 * For built-in modules, name lives in .rodata and is
	 * immortal. For loaded modules, name points at the name[]
	 * member of struct module, which lives at least as long as
	 * this struct ddebug_table.
	 */
	dt->mod_name = modname;
	dt->ddebugs = di->descs;
	dt->num_ddebugs = di->num_descs;

	INIT_LIST_HEAD(&dt->link);
	INIT_LIST_HEAD(&dt->maps);

	if (di->classes && di->num_classes)
		ddebug_attach_module_classes(dt, di->classes, di->num_classes);

	mutex_lock(&ddebug_lock);
	list_add_tail(&dt->link, &ddebug_tables);
	mutex_unlock(&ddebug_lock);

	vpr_info("%3u debug prints in module %s\n", di->num_descs, modname);
	return 0;
}

/* helper for ddebug_dyndbg_(boot|module)_param_cb */
static int ddebug_dyndbg_param_cb(char *param, char *val,
				const char *modname, int on_err)
{
	char *sep;

	sep = strchr(param, '.');
	if (sep) {
		/* needed only for ddebug_dyndbg_boot_param_cb */
		*sep = '\0';
		modname = param;
		param = sep + 1;
	}
	if (strcmp(param, "dyndbg"))
		return on_err; /* determined by caller */

	ddebug_exec_queries((val ? val : "+p"), modname);

	return 0; /* query failure shouldn't stop module load */
}

/* handle both dyndbg and $module.dyndbg params at boot */
static int ddebug_dyndbg_boot_param_cb(char *param, char *val,
				const char *unused, void *arg)
{
	vpr_info("%s=\"%s\"\n", param, val);
	return ddebug_dyndbg_param_cb(param, val, NULL, 0);
}

/*
 * modprobe foo finds foo.params in boot-args, strips "foo.", and
 * passes them to load_module().  This callback gets unknown params,
 * processes dyndbg params, rejects others.
 */
int ddebug_dyndbg_module_param_cb(char *param, char *val, const char *module)
{
	vpr_info("module: %s %s=\"%s\"\n", module, param, val);
	return ddebug_dyndbg_param_cb(param, val, module, -ENOENT);
}

static void ddebug_table_free(struct ddebug_table *dt)
{
	list_del_init(&dt->link);
	kfree(dt);
}

#ifdef CONFIG_MODULES

/*
 * Called in response to a module being unloaded.  Removes
 * any ddebug_table's which point at the module.
 */
static int ddebug_remove_module(const char *mod_name)
{
	struct ddebug_table *dt, *nextdt;
	int ret = -ENOENT;

	mutex_lock(&ddebug_lock);
	list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
		if (dt->mod_name == mod_name) {
			ddebug_table_free(dt);
			ret = 0;
			break;
		}
	}
	mutex_unlock(&ddebug_lock);
	if (!ret)
		v2pr_info("removed module \"%s\"\n", mod_name);
	return ret;
}

static int ddebug_module_notify(struct notifier_block *self, unsigned long val,
				void *data)
{
	struct module *mod = data;
	int ret = 0;

	switch (val) {
	case MODULE_STATE_COMING:
		ret = ddebug_add_module(&mod->dyndbg_info, mod->name);
		if (ret)
			WARN(1, "Failed to allocate memory: dyndbg may not work properly.\n");
		break;
	case MODULE_STATE_GOING:
		ddebug_remove_module(mod->name);
		break;
	}

	return notifier_from_errno(ret);
}

static struct notifier_block ddebug_module_nb = {
	.notifier_call = ddebug_module_notify,
	.priority = 0, /* dynamic debug depends on jump label */
};

#endif /* CONFIG_MODULES */

static void ddebug_remove_all_tables(void)
{
	mutex_lock(&ddebug_lock);
	while (!list_empty(&ddebug_tables)) {
		struct ddebug_table *dt = list_entry(ddebug_tables.next,
						      struct ddebug_table,
						      link);
		ddebug_table_free(dt);
	}
	mutex_unlock(&ddebug_lock);
}

static __initdata int ddebug_init_success;

static int __init dynamic_debug_init_control(void)
{
	struct proc_dir_entry *procfs_dir;
	struct dentry *debugfs_dir;

	if (!ddebug_init_success)
		return -ENODEV;

	/* Create the control file in debugfs if it is enabled */
	if (debugfs_initialized()) {
		debugfs_dir = debugfs_create_dir("dynamic_debug", NULL);
		debugfs_create_file("control", 0644, debugfs_dir, NULL,
				    &ddebug_proc_fops);
	}

	/* Also create the control file in procfs */
	procfs_dir = proc_mkdir("dynamic_debug", NULL);
	if (procfs_dir)
		proc_create("control", 0644, procfs_dir, &proc_fops);

	return 0;
}

static int __init dynamic_debug_init(void)
{
	struct _ddebug *iter, *iter_mod_start;
	int ret, i, mod_sites, mod_ct;
	const char *modname;
	char *cmdline;

	struct _ddebug_info di = {
		.descs = __start___dyndbg,
		.classes = __start___dyndbg_classes,
		.num_descs = __stop___dyndbg - __start___dyndbg,
		.num_classes = __stop___dyndbg_classes - __start___dyndbg_classes,
	};

#ifdef CONFIG_MODULES
	ret = register_module_notifier(&ddebug_module_nb);
	if (ret) {
		pr_warn("Failed to register dynamic debug module notifier\n");
		return ret;
	}
#endif /* CONFIG_MODULES */

	if (&__start___dyndbg == &__stop___dyndbg) {
		if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
			pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
			return 1;
		}
		pr_info("Ignore empty _ddebug table in a CONFIG_DYNAMIC_DEBUG_CORE build\n");
		ddebug_init_success = 1;
		return 0;
	}

	iter = iter_mod_start = __start___dyndbg;
	modname = iter->modname;
	i = mod_sites = mod_ct = 0;

	for (; iter < __stop___dyndbg; iter++, i++, mod_sites++) {

		if (strcmp(modname, iter->modname)) {
			mod_ct++;
			di.num_descs = mod_sites;
			di.descs = iter_mod_start;
			ret = ddebug_add_module(&di, modname);
			if (ret)
				goto out_err;

			mod_sites = 0;
			modname = iter->modname;
			iter_mod_start = iter;
		}
	}
	di.num_descs = mod_sites;
	di.descs = iter_mod_start;
	ret = ddebug_add_module(&di, modname);
	if (ret)
		goto out_err;

	ddebug_init_success = 1;
	vpr_info("%d prdebugs in %d modules, %d KiB in ddebug tables, %d kiB in __dyndbg section\n",
		 i, mod_ct, (int)((mod_ct * sizeof(struct ddebug_table)) >> 10),
		 (int)((i * sizeof(struct _ddebug)) >> 10));

	if (di.num_classes)
		v2pr_info("  %d builtin ddebug class-maps\n", di.num_classes);

	/* now that ddebug tables are loaded, process all boot args
	 * again to find and activate queries given in dyndbg params.
	 * While this has already been done for known boot params, it
	 * ignored the unknown ones (dyndbg in particular).  Reusing
	 * parse_args avoids ad-hoc parsing.  This will also attempt
	 * to activate queries for not-yet-loaded modules, which is
	 * slightly noisy if verbose, but harmless.
	 */
	cmdline = kstrdup(saved_command_line, GFP_KERNEL);
	parse_args("dyndbg params", cmdline, NULL,
		   0, 0, 0, NULL, &ddebug_dyndbg_boot_param_cb);
	kfree(cmdline);
	return 0;

out_err:
	ddebug_remove_all_tables();
	return 0;
}
/* Allow early initialization for boot messages via boot param */
early_initcall(dynamic_debug_init);

/* Debugfs setup must be done later */
fs_initcall(dynamic_debug_init_control);