1 /*
2 * lib/dynamic_debug.c
3 *
4 * make pr_debug()/dev_dbg() calls runtime configurable based upon their
5 * source module.
6 *
7 * Copyright (C) 2008 Jason Baron <jbaron@redhat.com>
8 * By Greg Banks <gnb@melbourne.sgi.com>
9 * Copyright (c) 2008 Silicon Graphics Inc. All Rights Reserved.
10 * Copyright (C) 2011 Bart Van Assche. All Rights Reserved.
11 * Copyright (C) 2013 Du, Changbin <changbin.du@gmail.com>
12 */
13
14 #define pr_fmt(fmt) "dyndbg: " fmt
15
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/moduleparam.h>
19 #include <linux/kallsyms.h>
20 #include <linux/types.h>
21 #include <linux/mutex.h>
22 #include <linux/proc_fs.h>
23 #include <linux/seq_file.h>
24 #include <linux/list.h>
25 #include <linux/sysctl.h>
26 #include <linux/ctype.h>
27 #include <linux/string.h>
28 #include <linux/parser.h>
29 #include <linux/string_helpers.h>
30 #include <linux/uaccess.h>
31 #include <linux/dynamic_debug.h>
32 #include <linux/debugfs.h>
33 #include <linux/slab.h>
34 #include <linux/jump_label.h>
35 #include <linux/hardirq.h>
36 #include <linux/sched.h>
37 #include <linux/device.h>
38 #include <linux/netdevice.h>
39
40 #include <rdma/ib_verbs.h>
41
42 extern struct _ddebug __start___dyndbg[];
43 extern struct _ddebug __stop___dyndbg[];
44
45 struct ddebug_table {
46 struct list_head link;
47 const char *mod_name;
48 unsigned int num_ddebugs;
49 struct _ddebug *ddebugs;
50 };
51
52 struct ddebug_query {
53 const char *filename;
54 const char *module;
55 const char *function;
56 const char *format;
57 unsigned int first_lineno, last_lineno;
58 };
59
60 struct ddebug_iter {
61 struct ddebug_table *table;
62 unsigned int idx;
63 };
64
65 struct flag_settings {
66 unsigned int flags;
67 unsigned int mask;
68 };
69
70 static DEFINE_MUTEX(ddebug_lock);
71 static LIST_HEAD(ddebug_tables);
72 static int verbose;
73 module_param(verbose, int, 0644);
74
75 /* Return the path relative to source root */
trim_prefix(const char * path)76 static inline const char *trim_prefix(const char *path)
77 {
78 int skip = strlen(__FILE__) - strlen("lib/dynamic_debug.c");
79
80 if (strncmp(path, __FILE__, skip))
81 skip = 0; /* prefix mismatch, don't skip */
82
83 return path + skip;
84 }
85
86 static struct { unsigned flag:8; char opt_char; } opt_array[] = {
87 { _DPRINTK_FLAGS_PRINT, 'p' },
88 { _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
89 { _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
90 { _DPRINTK_FLAGS_INCL_LINENO, 'l' },
91 { _DPRINTK_FLAGS_INCL_TID, 't' },
92 { _DPRINTK_FLAGS_NONE, '_' },
93 };
94
95 struct flagsbuf { char buf[ARRAY_SIZE(opt_array)+1]; };
96
97 /* format a string into buf[] which describes the _ddebug's flags */
ddebug_describe_flags(unsigned int flags,struct flagsbuf * fb)98 static char *ddebug_describe_flags(unsigned int flags, struct flagsbuf *fb)
99 {
100 char *p = fb->buf;
101 int i;
102
103 for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
104 if (flags & opt_array[i].flag)
105 *p++ = opt_array[i].opt_char;
106 if (p == fb->buf)
107 *p++ = '_';
108 *p = '\0';
109
110 return fb->buf;
111 }
112
113 #define vnpr_info(lvl, fmt, ...) \
114 do { \
115 if (verbose >= lvl) \
116 pr_info(fmt, ##__VA_ARGS__); \
117 } while (0)
118
119 #define vpr_info(fmt, ...) vnpr_info(1, fmt, ##__VA_ARGS__)
120 #define v2pr_info(fmt, ...) vnpr_info(2, fmt, ##__VA_ARGS__)
121
vpr_info_dq(const struct ddebug_query * query,const char * msg)122 static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
123 {
124 /* trim any trailing newlines */
125 int fmtlen = 0;
126
127 if (query->format) {
128 fmtlen = strlen(query->format);
129 while (fmtlen && query->format[fmtlen - 1] == '\n')
130 fmtlen--;
131 }
132
133 vpr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u\n",
134 msg,
135 query->function ?: "",
136 query->filename ?: "",
137 query->module ?: "",
138 fmtlen, query->format ?: "",
139 query->first_lineno, query->last_lineno);
140 }
141
142 /*
143 * Search the tables for _ddebug's which match the given `query' and
144 * apply the `flags' and `mask' to them. Returns number of matching
145 * callsites, normally the same as number of changes. If verbose,
146 * logs the changes. Takes ddebug_lock.
147 */
ddebug_change(const struct ddebug_query * query,struct flag_settings * modifiers)148 static int ddebug_change(const struct ddebug_query *query,
149 struct flag_settings *modifiers)
150 {
151 int i;
152 struct ddebug_table *dt;
153 unsigned int newflags;
154 unsigned int nfound = 0;
155 struct flagsbuf fbuf;
156
157 /* search for matching ddebugs */
158 mutex_lock(&ddebug_lock);
159 list_for_each_entry(dt, &ddebug_tables, link) {
160
161 /* match against the module name */
162 if (query->module &&
163 !match_wildcard(query->module, dt->mod_name))
164 continue;
165
166 for (i = 0; i < dt->num_ddebugs; i++) {
167 struct _ddebug *dp = &dt->ddebugs[i];
168
169 /* match against the source filename */
170 if (query->filename &&
171 !match_wildcard(query->filename, dp->filename) &&
172 !match_wildcard(query->filename,
173 kbasename(dp->filename)) &&
174 !match_wildcard(query->filename,
175 trim_prefix(dp->filename)))
176 continue;
177
178 /* match against the function */
179 if (query->function &&
180 !match_wildcard(query->function, dp->function))
181 continue;
182
183 /* match against the format */
184 if (query->format) {
185 if (*query->format == '^') {
186 char *p;
187 /* anchored search. match must be at beginning */
188 p = strstr(dp->format, query->format+1);
189 if (p != dp->format)
190 continue;
191 } else if (!strstr(dp->format, query->format))
192 continue;
193 }
194
195 /* match against the line number range */
196 if (query->first_lineno &&
197 dp->lineno < query->first_lineno)
198 continue;
199 if (query->last_lineno &&
200 dp->lineno > query->last_lineno)
201 continue;
202
203 nfound++;
204
205 newflags = (dp->flags & modifiers->mask) | modifiers->flags;
206 if (newflags == dp->flags)
207 continue;
208 #ifdef CONFIG_JUMP_LABEL
209 if (dp->flags & _DPRINTK_FLAGS_PRINT) {
210 if (!(newflags & _DPRINTK_FLAGS_PRINT))
211 static_branch_disable(&dp->key.dd_key_true);
212 } else if (newflags & _DPRINTK_FLAGS_PRINT) {
213 static_branch_enable(&dp->key.dd_key_true);
214 }
215 #endif
216 dp->flags = newflags;
217 v2pr_info("changed %s:%d [%s]%s =%s\n",
218 trim_prefix(dp->filename), dp->lineno,
219 dt->mod_name, dp->function,
220 ddebug_describe_flags(dp->flags, &fbuf));
221 }
222 }
223 mutex_unlock(&ddebug_lock);
224
225 if (!nfound && verbose)
226 pr_info("no matches for query\n");
227
228 return nfound;
229 }
230
231 /*
232 * Split the buffer `buf' into space-separated words.
233 * Handles simple " and ' quoting, i.e. without nested,
234 * embedded or escaped \". Return the number of words
235 * or <0 on error.
236 */
ddebug_tokenize(char * buf,char * words[],int maxwords)237 static int ddebug_tokenize(char *buf, char *words[], int maxwords)
238 {
239 int nwords = 0;
240
241 while (*buf) {
242 char *end;
243
244 /* Skip leading whitespace */
245 buf = skip_spaces(buf);
246 if (!*buf)
247 break; /* oh, it was trailing whitespace */
248 if (*buf == '#')
249 break; /* token starts comment, skip rest of line */
250
251 /* find `end' of word, whitespace separated or quoted */
252 if (*buf == '"' || *buf == '\'') {
253 int quote = *buf++;
254 for (end = buf; *end && *end != quote; end++)
255 ;
256 if (!*end) {
257 pr_err("unclosed quote: %s\n", buf);
258 return -EINVAL; /* unclosed quote */
259 }
260 } else {
261 for (end = buf; *end && !isspace(*end); end++)
262 ;
263 BUG_ON(end == buf);
264 }
265
266 /* `buf' is start of word, `end' is one past its end */
267 if (nwords == maxwords) {
268 pr_err("too many words, legal max <=%d\n", maxwords);
269 return -EINVAL; /* ran out of words[] before bytes */
270 }
271 if (*end)
272 *end++ = '\0'; /* terminate the word */
273 words[nwords++] = buf;
274 buf = end;
275 }
276
277 if (verbose) {
278 int i;
279 pr_info("split into words:");
280 for (i = 0; i < nwords; i++)
281 pr_cont(" \"%s\"", words[i]);
282 pr_cont("\n");
283 }
284
285 return nwords;
286 }
287
288 /*
289 * Parse a single line number. Note that the empty string ""
290 * is treated as a special case and converted to zero, which
291 * is later treated as a "don't care" value.
292 */
parse_lineno(const char * str,unsigned int * val)293 static inline int parse_lineno(const char *str, unsigned int *val)
294 {
295 BUG_ON(str == NULL);
296 if (*str == '\0') {
297 *val = 0;
298 return 0;
299 }
300 if (kstrtouint(str, 10, val) < 0) {
301 pr_err("bad line-number: %s\n", str);
302 return -EINVAL;
303 }
304 return 0;
305 }
306
parse_linerange(struct ddebug_query * query,const char * first)307 static int parse_linerange(struct ddebug_query *query, const char *first)
308 {
309 char *last = strchr(first, '-');
310
311 if (query->first_lineno || query->last_lineno) {
312 pr_err("match-spec: line used 2x\n");
313 return -EINVAL;
314 }
315 if (last)
316 *last++ = '\0';
317 if (parse_lineno(first, &query->first_lineno) < 0)
318 return -EINVAL;
319 if (last) {
320 /* range <first>-<last> */
321 if (parse_lineno(last, &query->last_lineno) < 0)
322 return -EINVAL;
323
324 /* special case for last lineno not specified */
325 if (query->last_lineno == 0)
326 query->last_lineno = UINT_MAX;
327
328 if (query->last_lineno < query->first_lineno) {
329 pr_err("last-line:%d < 1st-line:%d\n",
330 query->last_lineno,
331 query->first_lineno);
332 return -EINVAL;
333 }
334 } else {
335 query->last_lineno = query->first_lineno;
336 }
337 vpr_info("parsed line %d-%d\n", query->first_lineno,
338 query->last_lineno);
339 return 0;
340 }
341
check_set(const char ** dest,char * src,char * name)342 static int check_set(const char **dest, char *src, char *name)
343 {
344 int rc = 0;
345
346 if (*dest) {
347 rc = -EINVAL;
348 pr_err("match-spec:%s val:%s overridden by %s\n",
349 name, *dest, src);
350 }
351 *dest = src;
352 return rc;
353 }
354
355 /*
356 * Parse words[] as a ddebug query specification, which is a series
357 * of (keyword, value) pairs chosen from these possibilities:
358 *
359 * func <function-name>
360 * file <full-pathname>
361 * file <base-filename>
362 * module <module-name>
363 * format <escaped-string-to-find-in-format>
364 * line <lineno>
365 * line <first-lineno>-<last-lineno> // where either may be empty
366 *
367 * Only 1 of each type is allowed.
368 * Returns 0 on success, <0 on error.
369 */
ddebug_parse_query(char * words[],int nwords,struct ddebug_query * query,const char * modname)370 static int ddebug_parse_query(char *words[], int nwords,
371 struct ddebug_query *query, const char *modname)
372 {
373 unsigned int i;
374 int rc = 0;
375 char *fline;
376
377 /* check we have an even number of words */
378 if (nwords % 2 != 0) {
379 pr_err("expecting pairs of match-spec <value>\n");
380 return -EINVAL;
381 }
382
383 for (i = 0; i < nwords; i += 2) {
384 char *keyword = words[i];
385 char *arg = words[i+1];
386
387 if (!strcmp(keyword, "func")) {
388 rc = check_set(&query->function, arg, "func");
389 } else if (!strcmp(keyword, "file")) {
390 if (check_set(&query->filename, arg, "file"))
391 return -EINVAL;
392
393 /* tail :$info is function or line-range */
394 fline = strchr(query->filename, ':');
395 if (!fline)
396 continue;
397 *fline++ = '\0';
398 if (isalpha(*fline) || *fline == '*' || *fline == '?') {
399 /* take as function name */
400 if (check_set(&query->function, fline, "func"))
401 return -EINVAL;
402 } else {
403 if (parse_linerange(query, fline))
404 return -EINVAL;
405 }
406 } else if (!strcmp(keyword, "module")) {
407 rc = check_set(&query->module, arg, "module");
408 } else if (!strcmp(keyword, "format")) {
409 string_unescape_inplace(arg, UNESCAPE_SPACE |
410 UNESCAPE_OCTAL |
411 UNESCAPE_SPECIAL);
412 rc = check_set(&query->format, arg, "format");
413 } else if (!strcmp(keyword, "line")) {
414 if (parse_linerange(query, arg))
415 return -EINVAL;
416 } else {
417 pr_err("unknown keyword \"%s\"\n", keyword);
418 return -EINVAL;
419 }
420 if (rc)
421 return rc;
422 }
423 if (!query->module && modname)
424 /*
425 * support $modname.dyndbg=<multiple queries>, when
426 * not given in the query itself
427 */
428 query->module = modname;
429
430 vpr_info_dq(query, "parsed");
431 return 0;
432 }
433
434 /*
435 * Parse `str' as a flags specification, format [-+=][p]+.
436 * Sets up *maskp and *flagsp to be used when changing the
437 * flags fields of matched _ddebug's. Returns 0 on success
438 * or <0 on error.
439 */
ddebug_parse_flags(const char * str,struct flag_settings * modifiers)440 static int ddebug_parse_flags(const char *str, struct flag_settings *modifiers)
441 {
442 int op, i;
443
444 switch (*str) {
445 case '+':
446 case '-':
447 case '=':
448 op = *str++;
449 break;
450 default:
451 pr_err("bad flag-op %c, at start of %s\n", *str, str);
452 return -EINVAL;
453 }
454 vpr_info("op='%c'\n", op);
455
456 for (; *str ; ++str) {
457 for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
458 if (*str == opt_array[i].opt_char) {
459 modifiers->flags |= opt_array[i].flag;
460 break;
461 }
462 }
463 if (i < 0) {
464 pr_err("unknown flag '%c'\n", *str);
465 return -EINVAL;
466 }
467 }
468 vpr_info("flags=0x%x\n", modifiers->flags);
469
470 /* calculate final flags, mask based upon op */
471 switch (op) {
472 case '=':
473 /* modifiers->flags already set */
474 modifiers->mask = 0;
475 break;
476 case '+':
477 modifiers->mask = ~0U;
478 break;
479 case '-':
480 modifiers->mask = ~modifiers->flags;
481 modifiers->flags = 0;
482 break;
483 }
484 vpr_info("*flagsp=0x%x *maskp=0x%x\n", modifiers->flags, modifiers->mask);
485
486 return 0;
487 }
488
ddebug_exec_query(char * query_string,const char * modname)489 static int ddebug_exec_query(char *query_string, const char *modname)
490 {
491 struct flag_settings modifiers = {};
492 struct ddebug_query query = {};
493 #define MAXWORDS 9
494 int nwords, nfound;
495 char *words[MAXWORDS];
496
497 nwords = ddebug_tokenize(query_string, words, MAXWORDS);
498 if (nwords <= 0) {
499 pr_err("tokenize failed\n");
500 return -EINVAL;
501 }
502 /* check flags 1st (last arg) so query is pairs of spec,val */
503 if (ddebug_parse_flags(words[nwords-1], &modifiers)) {
504 pr_err("flags parse failed\n");
505 return -EINVAL;
506 }
507 if (ddebug_parse_query(words, nwords-1, &query, modname)) {
508 pr_err("query parse failed\n");
509 return -EINVAL;
510 }
511 /* actually go and implement the change */
512 nfound = ddebug_change(&query, &modifiers);
513 vpr_info_dq(&query, nfound ? "applied" : "no-match");
514
515 return nfound;
516 }
517
518 /* handle multiple queries in query string, continue on error, return
519 last error or number of matching callsites. Module name is either
520 in param (for boot arg) or perhaps in query string.
521 */
ddebug_exec_queries(char * query,const char * modname)522 static int ddebug_exec_queries(char *query, const char *modname)
523 {
524 char *split;
525 int i, errs = 0, exitcode = 0, rc, nfound = 0;
526
527 for (i = 0; query; query = split) {
528 split = strpbrk(query, ";\n");
529 if (split)
530 *split++ = '\0';
531
532 query = skip_spaces(query);
533 if (!query || !*query || *query == '#')
534 continue;
535
536 vpr_info("query %d: \"%s\"\n", i, query);
537
538 rc = ddebug_exec_query(query, modname);
539 if (rc < 0) {
540 errs++;
541 exitcode = rc;
542 } else {
543 nfound += rc;
544 }
545 i++;
546 }
547 vpr_info("processed %d queries, with %d matches, %d errs\n",
548 i, nfound, errs);
549
550 if (exitcode)
551 return exitcode;
552 return nfound;
553 }
554
555 #define PREFIX_SIZE 64
556
remaining(int wrote)557 static int remaining(int wrote)
558 {
559 if (PREFIX_SIZE - wrote > 0)
560 return PREFIX_SIZE - wrote;
561 return 0;
562 }
563
dynamic_emit_prefix(const struct _ddebug * desc,char * buf)564 static char *dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
565 {
566 int pos_after_tid;
567 int pos = 0;
568
569 *buf = '\0';
570
571 if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
572 if (in_interrupt())
573 pos += snprintf(buf + pos, remaining(pos), "<intr> ");
574 else
575 pos += snprintf(buf + pos, remaining(pos), "[%d] ",
576 task_pid_vnr(current));
577 }
578 pos_after_tid = pos;
579 if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
580 pos += snprintf(buf + pos, remaining(pos), "%s:",
581 desc->modname);
582 if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
583 pos += snprintf(buf + pos, remaining(pos), "%s:",
584 desc->function);
585 if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
586 pos += snprintf(buf + pos, remaining(pos), "%d:",
587 desc->lineno);
588 if (pos - pos_after_tid)
589 pos += snprintf(buf + pos, remaining(pos), " ");
590 if (pos >= PREFIX_SIZE)
591 buf[PREFIX_SIZE - 1] = '\0';
592
593 return buf;
594 }
595
__dynamic_pr_debug(struct _ddebug * descriptor,const char * fmt,...)596 void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
597 {
598 va_list args;
599 struct va_format vaf;
600 char buf[PREFIX_SIZE];
601
602 BUG_ON(!descriptor);
603 BUG_ON(!fmt);
604
605 va_start(args, fmt);
606
607 vaf.fmt = fmt;
608 vaf.va = &args;
609
610 printk(KERN_DEBUG "%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);
611
612 va_end(args);
613 }
614 EXPORT_SYMBOL(__dynamic_pr_debug);
615
__dynamic_dev_dbg(struct _ddebug * descriptor,const struct device * dev,const char * fmt,...)616 void __dynamic_dev_dbg(struct _ddebug *descriptor,
617 const struct device *dev, const char *fmt, ...)
618 {
619 struct va_format vaf;
620 va_list args;
621
622 BUG_ON(!descriptor);
623 BUG_ON(!fmt);
624
625 va_start(args, fmt);
626
627 vaf.fmt = fmt;
628 vaf.va = &args;
629
630 if (!dev) {
631 printk(KERN_DEBUG "(NULL device *): %pV", &vaf);
632 } else {
633 char buf[PREFIX_SIZE];
634
635 dev_printk_emit(LOGLEVEL_DEBUG, dev, "%s%s %s: %pV",
636 dynamic_emit_prefix(descriptor, buf),
637 dev_driver_string(dev), dev_name(dev),
638 &vaf);
639 }
640
641 va_end(args);
642 }
643 EXPORT_SYMBOL(__dynamic_dev_dbg);
644
645 #ifdef CONFIG_NET
646
__dynamic_netdev_dbg(struct _ddebug * descriptor,const struct net_device * dev,const char * fmt,...)647 void __dynamic_netdev_dbg(struct _ddebug *descriptor,
648 const struct net_device *dev, const char *fmt, ...)
649 {
650 struct va_format vaf;
651 va_list args;
652
653 BUG_ON(!descriptor);
654 BUG_ON(!fmt);
655
656 va_start(args, fmt);
657
658 vaf.fmt = fmt;
659 vaf.va = &args;
660
661 if (dev && dev->dev.parent) {
662 char buf[PREFIX_SIZE];
663
664 dev_printk_emit(LOGLEVEL_DEBUG, dev->dev.parent,
665 "%s%s %s %s%s: %pV",
666 dynamic_emit_prefix(descriptor, buf),
667 dev_driver_string(dev->dev.parent),
668 dev_name(dev->dev.parent),
669 netdev_name(dev), netdev_reg_state(dev),
670 &vaf);
671 } else if (dev) {
672 printk(KERN_DEBUG "%s%s: %pV", netdev_name(dev),
673 netdev_reg_state(dev), &vaf);
674 } else {
675 printk(KERN_DEBUG "(NULL net_device): %pV", &vaf);
676 }
677
678 va_end(args);
679 }
680 EXPORT_SYMBOL(__dynamic_netdev_dbg);
681
682 #endif
683
684 #if IS_ENABLED(CONFIG_INFINIBAND)
685
__dynamic_ibdev_dbg(struct _ddebug * descriptor,const struct ib_device * ibdev,const char * fmt,...)686 void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
687 const struct ib_device *ibdev, const char *fmt, ...)
688 {
689 struct va_format vaf;
690 va_list args;
691
692 va_start(args, fmt);
693
694 vaf.fmt = fmt;
695 vaf.va = &args;
696
697 if (ibdev && ibdev->dev.parent) {
698 char buf[PREFIX_SIZE];
699
700 dev_printk_emit(LOGLEVEL_DEBUG, ibdev->dev.parent,
701 "%s%s %s %s: %pV",
702 dynamic_emit_prefix(descriptor, buf),
703 dev_driver_string(ibdev->dev.parent),
704 dev_name(ibdev->dev.parent),
705 dev_name(&ibdev->dev),
706 &vaf);
707 } else if (ibdev) {
708 printk(KERN_DEBUG "%s: %pV", dev_name(&ibdev->dev), &vaf);
709 } else {
710 printk(KERN_DEBUG "(NULL ib_device): %pV", &vaf);
711 }
712
713 va_end(args);
714 }
715 EXPORT_SYMBOL(__dynamic_ibdev_dbg);
716
717 #endif
718
719 #define DDEBUG_STRING_SIZE 1024
720 static __initdata char ddebug_setup_string[DDEBUG_STRING_SIZE];
721
ddebug_setup_query(char * str)722 static __init int ddebug_setup_query(char *str)
723 {
724 if (strlen(str) >= DDEBUG_STRING_SIZE) {
725 pr_warn("ddebug boot param string too large\n");
726 return 0;
727 }
728 strlcpy(ddebug_setup_string, str, DDEBUG_STRING_SIZE);
729 return 1;
730 }
731
732 __setup("ddebug_query=", ddebug_setup_query);
733
734 /*
735 * File_ops->write method for <debugfs>/dynamic_debug/control. Gathers the
736 * command text from userspace, parses and executes it.
737 */
738 #define USER_BUF_PAGE 4096
ddebug_proc_write(struct file * file,const char __user * ubuf,size_t len,loff_t * offp)739 static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
740 size_t len, loff_t *offp)
741 {
742 char *tmpbuf;
743 int ret;
744
745 if (len == 0)
746 return 0;
747 if (len > USER_BUF_PAGE - 1) {
748 pr_warn("expected <%d bytes into control\n", USER_BUF_PAGE);
749 return -E2BIG;
750 }
751 tmpbuf = memdup_user_nul(ubuf, len);
752 if (IS_ERR(tmpbuf))
753 return PTR_ERR(tmpbuf);
754 vpr_info("read %d bytes from userspace\n", (int)len);
755
756 ret = ddebug_exec_queries(tmpbuf, NULL);
757 kfree(tmpbuf);
758 if (ret < 0)
759 return ret;
760
761 *offp += len;
762 return len;
763 }
764
765 /*
766 * Set the iterator to point to the first _ddebug object
767 * and return a pointer to that first object. Returns
768 * NULL if there are no _ddebugs at all.
769 */
ddebug_iter_first(struct ddebug_iter * iter)770 static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
771 {
772 if (list_empty(&ddebug_tables)) {
773 iter->table = NULL;
774 iter->idx = 0;
775 return NULL;
776 }
777 iter->table = list_entry(ddebug_tables.next,
778 struct ddebug_table, link);
779 iter->idx = 0;
780 return &iter->table->ddebugs[iter->idx];
781 }
782
783 /*
784 * Advance the iterator to point to the next _ddebug
785 * object from the one the iterator currently points at,
786 * and returns a pointer to the new _ddebug. Returns
787 * NULL if the iterator has seen all the _ddebugs.
788 */
ddebug_iter_next(struct ddebug_iter * iter)789 static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
790 {
791 if (iter->table == NULL)
792 return NULL;
793 if (++iter->idx == iter->table->num_ddebugs) {
794 /* iterate to next table */
795 iter->idx = 0;
796 if (list_is_last(&iter->table->link, &ddebug_tables)) {
797 iter->table = NULL;
798 return NULL;
799 }
800 iter->table = list_entry(iter->table->link.next,
801 struct ddebug_table, link);
802 }
803 return &iter->table->ddebugs[iter->idx];
804 }
805
806 /*
807 * Seq_ops start method. Called at the start of every
808 * read() call from userspace. Takes the ddebug_lock and
809 * seeks the seq_file's iterator to the given position.
810 */
ddebug_proc_start(struct seq_file * m,loff_t * pos)811 static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
812 {
813 struct ddebug_iter *iter = m->private;
814 struct _ddebug *dp;
815 int n = *pos;
816
817 mutex_lock(&ddebug_lock);
818
819 if (!n)
820 return SEQ_START_TOKEN;
821 if (n < 0)
822 return NULL;
823 dp = ddebug_iter_first(iter);
824 while (dp != NULL && --n > 0)
825 dp = ddebug_iter_next(iter);
826 return dp;
827 }
828
829 /*
830 * Seq_ops next method. Called several times within a read()
831 * call from userspace, with ddebug_lock held. Walks to the
832 * next _ddebug object with a special case for the header line.
833 */
ddebug_proc_next(struct seq_file * m,void * p,loff_t * pos)834 static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
835 {
836 struct ddebug_iter *iter = m->private;
837 struct _ddebug *dp;
838
839 if (p == SEQ_START_TOKEN)
840 dp = ddebug_iter_first(iter);
841 else
842 dp = ddebug_iter_next(iter);
843 ++*pos;
844 return dp;
845 }
846
847 /*
848 * Seq_ops show method. Called several times within a read()
849 * call from userspace, with ddebug_lock held. Formats the
850 * current _ddebug as a single human-readable line, with a
851 * special case for the header line.
852 */
ddebug_proc_show(struct seq_file * m,void * p)853 static int ddebug_proc_show(struct seq_file *m, void *p)
854 {
855 struct ddebug_iter *iter = m->private;
856 struct _ddebug *dp = p;
857 struct flagsbuf flags;
858
859 if (p == SEQ_START_TOKEN) {
860 seq_puts(m,
861 "# filename:lineno [module]function flags format\n");
862 return 0;
863 }
864
865 seq_printf(m, "%s:%u [%s]%s =%s \"",
866 trim_prefix(dp->filename), dp->lineno,
867 iter->table->mod_name, dp->function,
868 ddebug_describe_flags(dp->flags, &flags));
869 seq_escape(m, dp->format, "\t\r\n\"");
870 seq_puts(m, "\"\n");
871
872 return 0;
873 }
874
875 /*
876 * Seq_ops stop method. Called at the end of each read()
877 * call from userspace. Drops ddebug_lock.
878 */
ddebug_proc_stop(struct seq_file * m,void * p)879 static void ddebug_proc_stop(struct seq_file *m, void *p)
880 {
881 mutex_unlock(&ddebug_lock);
882 }
883
884 static const struct seq_operations ddebug_proc_seqops = {
885 .start = ddebug_proc_start,
886 .next = ddebug_proc_next,
887 .show = ddebug_proc_show,
888 .stop = ddebug_proc_stop
889 };
890
ddebug_proc_open(struct inode * inode,struct file * file)891 static int ddebug_proc_open(struct inode *inode, struct file *file)
892 {
893 vpr_info("called\n");
894 return seq_open_private(file, &ddebug_proc_seqops,
895 sizeof(struct ddebug_iter));
896 }
897
898 static const struct file_operations ddebug_proc_fops = {
899 .owner = THIS_MODULE,
900 .open = ddebug_proc_open,
901 .read = seq_read,
902 .llseek = seq_lseek,
903 .release = seq_release_private,
904 .write = ddebug_proc_write
905 };
906
907 static const struct proc_ops proc_fops = {
908 .proc_open = ddebug_proc_open,
909 .proc_read = seq_read,
910 .proc_lseek = seq_lseek,
911 .proc_release = seq_release_private,
912 .proc_write = ddebug_proc_write
913 };
914
915 /*
916 * Allocate a new ddebug_table for the given module
917 * and add it to the global list.
918 */
ddebug_add_module(struct _ddebug * tab,unsigned int n,const char * name)919 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
920 const char *name)
921 {
922 struct ddebug_table *dt;
923
924 dt = kzalloc(sizeof(*dt), GFP_KERNEL);
925 if (dt == NULL) {
926 pr_err("error adding module: %s\n", name);
927 return -ENOMEM;
928 }
929 /*
930 * For built-in modules, name lives in .rodata and is
931 * immortal. For loaded modules, name points at the name[]
932 * member of struct module, which lives at least as long as
933 * this struct ddebug_table.
934 */
935 dt->mod_name = name;
936 dt->num_ddebugs = n;
937 dt->ddebugs = tab;
938
939 mutex_lock(&ddebug_lock);
940 list_add(&dt->link, &ddebug_tables);
941 mutex_unlock(&ddebug_lock);
942
943 v2pr_info("%3u debug prints in module %s\n", n, dt->mod_name);
944 return 0;
945 }
946
947 /* helper for ddebug_dyndbg_(boot|module)_param_cb */
ddebug_dyndbg_param_cb(char * param,char * val,const char * modname,int on_err)948 static int ddebug_dyndbg_param_cb(char *param, char *val,
949 const char *modname, int on_err)
950 {
951 char *sep;
952
953 sep = strchr(param, '.');
954 if (sep) {
955 /* needed only for ddebug_dyndbg_boot_param_cb */
956 *sep = '\0';
957 modname = param;
958 param = sep + 1;
959 }
960 if (strcmp(param, "dyndbg"))
961 return on_err; /* determined by caller */
962
963 ddebug_exec_queries((val ? val : "+p"), modname);
964
965 return 0; /* query failure shouldnt stop module load */
966 }
967
968 /* handle both dyndbg and $module.dyndbg params at boot */
ddebug_dyndbg_boot_param_cb(char * param,char * val,const char * unused,void * arg)969 static int ddebug_dyndbg_boot_param_cb(char *param, char *val,
970 const char *unused, void *arg)
971 {
972 vpr_info("%s=\"%s\"\n", param, val);
973 return ddebug_dyndbg_param_cb(param, val, NULL, 0);
974 }
975
976 /*
977 * modprobe foo finds foo.params in boot-args, strips "foo.", and
978 * passes them to load_module(). This callback gets unknown params,
979 * processes dyndbg params, rejects others.
980 */
ddebug_dyndbg_module_param_cb(char * param,char * val,const char * module)981 int ddebug_dyndbg_module_param_cb(char *param, char *val, const char *module)
982 {
983 vpr_info("module: %s %s=\"%s\"\n", module, param, val);
984 return ddebug_dyndbg_param_cb(param, val, module, -ENOENT);
985 }
986
ddebug_table_free(struct ddebug_table * dt)987 static void ddebug_table_free(struct ddebug_table *dt)
988 {
989 list_del_init(&dt->link);
990 kfree(dt);
991 }
992
993 /*
994 * Called in response to a module being unloaded. Removes
995 * any ddebug_table's which point at the module.
996 */
ddebug_remove_module(const char * mod_name)997 int ddebug_remove_module(const char *mod_name)
998 {
999 struct ddebug_table *dt, *nextdt;
1000 int ret = -ENOENT;
1001
1002 v2pr_info("removing module \"%s\"\n", mod_name);
1003
1004 mutex_lock(&ddebug_lock);
1005 list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
1006 if (dt->mod_name == mod_name) {
1007 ddebug_table_free(dt);
1008 ret = 0;
1009 break;
1010 }
1011 }
1012 mutex_unlock(&ddebug_lock);
1013 return ret;
1014 }
1015
ddebug_remove_all_tables(void)1016 static void ddebug_remove_all_tables(void)
1017 {
1018 mutex_lock(&ddebug_lock);
1019 while (!list_empty(&ddebug_tables)) {
1020 struct ddebug_table *dt = list_entry(ddebug_tables.next,
1021 struct ddebug_table,
1022 link);
1023 ddebug_table_free(dt);
1024 }
1025 mutex_unlock(&ddebug_lock);
1026 }
1027
1028 static __initdata int ddebug_init_success;
1029
dynamic_debug_init_control(void)1030 static int __init dynamic_debug_init_control(void)
1031 {
1032 struct proc_dir_entry *procfs_dir;
1033 struct dentry *debugfs_dir;
1034
1035 if (!ddebug_init_success)
1036 return -ENODEV;
1037
1038 /* Create the control file in debugfs if it is enabled */
1039 if (debugfs_initialized()) {
1040 debugfs_dir = debugfs_create_dir("dynamic_debug", NULL);
1041 debugfs_create_file("control", 0644, debugfs_dir, NULL,
1042 &ddebug_proc_fops);
1043 }
1044
1045 /* Also create the control file in procfs */
1046 procfs_dir = proc_mkdir("dynamic_debug", NULL);
1047 if (procfs_dir)
1048 proc_create("control", 0644, procfs_dir, &proc_fops);
1049
1050 return 0;
1051 }
1052
dynamic_debug_init(void)1053 static int __init dynamic_debug_init(void)
1054 {
1055 struct _ddebug *iter, *iter_start;
1056 const char *modname = NULL;
1057 char *cmdline;
1058 int ret = 0;
1059 int n = 0, entries = 0, modct = 0;
1060
1061 if (&__start___dyndbg == &__stop___dyndbg) {
1062 if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
1063 pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
1064 return 1;
1065 }
1066 pr_info("Ignore empty _ddebug table in a CONFIG_DYNAMIC_DEBUG_CORE build\n");
1067 ddebug_init_success = 1;
1068 return 0;
1069 }
1070 iter = __start___dyndbg;
1071 modname = iter->modname;
1072 iter_start = iter;
1073 for (; iter < __stop___dyndbg; iter++) {
1074 entries++;
1075 if (strcmp(modname, iter->modname)) {
1076 modct++;
1077 ret = ddebug_add_module(iter_start, n, modname);
1078 if (ret)
1079 goto out_err;
1080 n = 0;
1081 modname = iter->modname;
1082 iter_start = iter;
1083 }
1084 n++;
1085 }
1086 ret = ddebug_add_module(iter_start, n, modname);
1087 if (ret)
1088 goto out_err;
1089
1090 ddebug_init_success = 1;
1091 vpr_info("%d modules, %d entries and %d bytes in ddebug tables, %d bytes in __dyndbg section\n",
1092 modct, entries, (int)(modct * sizeof(struct ddebug_table)),
1093 (int)(entries * sizeof(struct _ddebug)));
1094
1095 /* apply ddebug_query boot param, dont unload tables on err */
1096 if (ddebug_setup_string[0] != '\0') {
1097 pr_warn("ddebug_query param name is deprecated, change it to dyndbg\n");
1098 ret = ddebug_exec_queries(ddebug_setup_string, NULL);
1099 if (ret < 0)
1100 pr_warn("Invalid ddebug boot param %s\n",
1101 ddebug_setup_string);
1102 else
1103 pr_info("%d changes by ddebug_query\n", ret);
1104 }
1105 /* now that ddebug tables are loaded, process all boot args
1106 * again to find and activate queries given in dyndbg params.
1107 * While this has already been done for known boot params, it
1108 * ignored the unknown ones (dyndbg in particular). Reusing
1109 * parse_args avoids ad-hoc parsing. This will also attempt
1110 * to activate queries for not-yet-loaded modules, which is
1111 * slightly noisy if verbose, but harmless.
1112 */
1113 cmdline = kstrdup(saved_command_line, GFP_KERNEL);
1114 parse_args("dyndbg params", cmdline, NULL,
1115 0, 0, 0, NULL, &ddebug_dyndbg_boot_param_cb);
1116 kfree(cmdline);
1117 return 0;
1118
1119 out_err:
1120 ddebug_remove_all_tables();
1121 return 0;
1122 }
1123 /* Allow early initialization for boot messages via boot param */
1124 early_initcall(dynamic_debug_init);
1125
1126 /* Debugfs setup must be done later */
1127 fs_initcall(dynamic_debug_init_control);
1128