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TOMOYO Linux Cross Reference
Linux/lib/dynamic_debug.c

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  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  */
 12 
 13 #include <linux/kernel.h>
 14 #include <linux/module.h>
 15 #include <linux/moduleparam.h>
 16 #include <linux/kallsyms.h>
 17 #include <linux/version.h>
 18 #include <linux/types.h>
 19 #include <linux/mutex.h>
 20 #include <linux/proc_fs.h>
 21 #include <linux/seq_file.h>
 22 #include <linux/list.h>
 23 #include <linux/sysctl.h>
 24 #include <linux/ctype.h>
 25 #include <linux/string.h>
 26 #include <linux/uaccess.h>
 27 #include <linux/dynamic_debug.h>
 28 #include <linux/debugfs.h>
 29 #include <linux/slab.h>
 30 #include <linux/jump_label.h>
 31 #include <linux/hardirq.h>
 32 #include <linux/sched.h>
 33 
 34 extern struct _ddebug __start___verbose[];
 35 extern struct _ddebug __stop___verbose[];
 36 
 37 struct ddebug_table {
 38         struct list_head link;
 39         char *mod_name;
 40         unsigned int num_ddebugs;
 41         unsigned int num_enabled;
 42         struct _ddebug *ddebugs;
 43 };
 44 
 45 struct ddebug_query {
 46         const char *filename;
 47         const char *module;
 48         const char *function;
 49         const char *format;
 50         unsigned int first_lineno, last_lineno;
 51 };
 52 
 53 struct ddebug_iter {
 54         struct ddebug_table *table;
 55         unsigned int idx;
 56 };
 57 
 58 static DEFINE_MUTEX(ddebug_lock);
 59 static LIST_HEAD(ddebug_tables);
 60 static int verbose = 0;
 61 
 62 /* Return the last part of a pathname */
 63 static inline const char *basename(const char *path)
 64 {
 65         const char *tail = strrchr(path, '/');
 66         return tail ? tail+1 : path;
 67 }
 68 
 69 static struct { unsigned flag:8; char opt_char; } opt_array[] = {
 70         { _DPRINTK_FLAGS_PRINT, 'p' },
 71         { _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
 72         { _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
 73         { _DPRINTK_FLAGS_INCL_LINENO, 'l' },
 74         { _DPRINTK_FLAGS_INCL_TID, 't' },
 75 };
 76 
 77 /* format a string into buf[] which describes the _ddebug's flags */
 78 static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
 79                                     size_t maxlen)
 80 {
 81         char *p = buf;
 82         int i;
 83 
 84         BUG_ON(maxlen < 4);
 85         for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
 86                 if (dp->flags & opt_array[i].flag)
 87                         *p++ = opt_array[i].opt_char;
 88         if (p == buf)
 89                 *p++ = '-';
 90         *p = '\0';
 91 
 92         return buf;
 93 }
 94 
 95 /*
 96  * Search the tables for _ddebug's which match the given
 97  * `query' and apply the `flags' and `mask' to them.  Tells
 98  * the user which ddebug's were changed, or whether none
 99  * were matched.
100  */
101 static void ddebug_change(const struct ddebug_query *query,
102                            unsigned int flags, unsigned int mask)
103 {
104         int i;
105         struct ddebug_table *dt;
106         unsigned int newflags;
107         unsigned int nfound = 0;
108         char flagbuf[8];
109 
110         /* search for matching ddebugs */
111         mutex_lock(&ddebug_lock);
112         list_for_each_entry(dt, &ddebug_tables, link) {
113 
114                 /* match against the module name */
115                 if (query->module != NULL &&
116                     strcmp(query->module, dt->mod_name))
117                         continue;
118 
119                 for (i = 0 ; i < dt->num_ddebugs ; i++) {
120                         struct _ddebug *dp = &dt->ddebugs[i];
121 
122                         /* match against the source filename */
123                         if (query->filename != NULL &&
124                             strcmp(query->filename, dp->filename) &&
125                             strcmp(query->filename, basename(dp->filename)))
126                                 continue;
127 
128                         /* match against the function */
129                         if (query->function != NULL &&
130                             strcmp(query->function, dp->function))
131                                 continue;
132 
133                         /* match against the format */
134                         if (query->format != NULL &&
135                             strstr(dp->format, query->format) == NULL)
136                                 continue;
137 
138                         /* match against the line number range */
139                         if (query->first_lineno &&
140                             dp->lineno < query->first_lineno)
141                                 continue;
142                         if (query->last_lineno &&
143                             dp->lineno > query->last_lineno)
144                                 continue;
145 
146                         nfound++;
147 
148                         newflags = (dp->flags & mask) | flags;
149                         if (newflags == dp->flags)
150                                 continue;
151 
152                         if (!newflags)
153                                 dt->num_enabled--;
154                         else if (!dp->flags)
155                                 dt->num_enabled++;
156                         dp->flags = newflags;
157                         if (newflags)
158                                 dp->enabled = 1;
159                         else
160                                 dp->enabled = 0;
161                         if (verbose)
162                                 printk(KERN_INFO
163                                         "ddebug: changed %s:%d [%s]%s %s\n",
164                                         dp->filename, dp->lineno,
165                                         dt->mod_name, dp->function,
166                                         ddebug_describe_flags(dp, flagbuf,
167                                                         sizeof(flagbuf)));
168                 }
169         }
170         mutex_unlock(&ddebug_lock);
171 
172         if (!nfound && verbose)
173                 printk(KERN_INFO "ddebug: no matches for query\n");
174 }
175 
176 /*
177  * Split the buffer `buf' into space-separated words.
178  * Handles simple " and ' quoting, i.e. without nested,
179  * embedded or escaped \".  Return the number of words
180  * or <0 on error.
181  */
182 static int ddebug_tokenize(char *buf, char *words[], int maxwords)
183 {
184         int nwords = 0;
185 
186         while (*buf) {
187                 char *end;
188 
189                 /* Skip leading whitespace */
190                 buf = skip_spaces(buf);
191                 if (!*buf)
192                         break;  /* oh, it was trailing whitespace */
193 
194                 /* Run `end' over a word, either whitespace separated or quoted */
195                 if (*buf == '"' || *buf == '\'') {
196                         int quote = *buf++;
197                         for (end = buf ; *end && *end != quote ; end++)
198                                 ;
199                         if (!*end)
200                                 return -EINVAL; /* unclosed quote */
201                 } else {
202                         for (end = buf ; *end && !isspace(*end) ; end++)
203                                 ;
204                         BUG_ON(end == buf);
205                 }
206                 /* Here `buf' is the start of the word, `end' is one past the end */
207 
208                 if (nwords == maxwords)
209                         return -EINVAL; /* ran out of words[] before bytes */
210                 if (*end)
211                         *end++ = '\0';  /* terminate the word */
212                 words[nwords++] = buf;
213                 buf = end;
214         }
215 
216         if (verbose) {
217                 int i;
218                 printk(KERN_INFO "%s: split into words:", __func__);
219                 for (i = 0 ; i < nwords ; i++)
220                         printk(" \"%s\"", words[i]);
221                 printk("\n");
222         }
223 
224         return nwords;
225 }
226 
227 /*
228  * Parse a single line number.  Note that the empty string ""
229  * is treated as a special case and converted to zero, which
230  * is later treated as a "don't care" value.
231  */
232 static inline int parse_lineno(const char *str, unsigned int *val)
233 {
234         char *end = NULL;
235         BUG_ON(str == NULL);
236         if (*str == '\0') {
237                 *val = 0;
238                 return 0;
239         }
240         *val = simple_strtoul(str, &end, 10);
241         return end == NULL || end == str || *end != '\0' ? -EINVAL : 0;
242 }
243 
244 /*
245  * Undo octal escaping in a string, inplace.  This is useful to
246  * allow the user to express a query which matches a format
247  * containing embedded spaces.
248  */
249 #define isodigit(c)             ((c) >= '' && (c) <= '7')
250 static char *unescape(char *str)
251 {
252         char *in = str;
253         char *out = str;
254 
255         while (*in) {
256                 if (*in == '\\') {
257                         if (in[1] == '\\') {
258                                 *out++ = '\\';
259                                 in += 2;
260                                 continue;
261                         } else if (in[1] == 't') {
262                                 *out++ = '\t';
263                                 in += 2;
264                                 continue;
265                         } else if (in[1] == 'n') {
266                                 *out++ = '\n';
267                                 in += 2;
268                                 continue;
269                         } else if (isodigit(in[1]) &&
270                                  isodigit(in[2]) &&
271                                  isodigit(in[3])) {
272                                 *out++ = ((in[1] - '')<<6) |
273                                           ((in[2] - '')<<3) |
274                                           (in[3] - '');
275                                 in += 4;
276                                 continue;
277                         }
278                 }
279                 *out++ = *in++;
280         }
281         *out = '\0';
282 
283         return str;
284 }
285 
286 /*
287  * Parse words[] as a ddebug query specification, which is a series
288  * of (keyword, value) pairs chosen from these possibilities:
289  *
290  * func <function-name>
291  * file <full-pathname>
292  * file <base-filename>
293  * module <module-name>
294  * format <escaped-string-to-find-in-format>
295  * line <lineno>
296  * line <first-lineno>-<last-lineno> // where either may be empty
297  */
298 static int ddebug_parse_query(char *words[], int nwords,
299                                struct ddebug_query *query)
300 {
301         unsigned int i;
302 
303         /* check we have an even number of words */
304         if (nwords % 2 != 0)
305                 return -EINVAL;
306         memset(query, 0, sizeof(*query));
307 
308         for (i = 0 ; i < nwords ; i += 2) {
309                 if (!strcmp(words[i], "func"))
310                         query->function = words[i+1];
311                 else if (!strcmp(words[i], "file"))
312                         query->filename = words[i+1];
313                 else if (!strcmp(words[i], "module"))
314                         query->module = words[i+1];
315                 else if (!strcmp(words[i], "format"))
316                         query->format = unescape(words[i+1]);
317                 else if (!strcmp(words[i], "line")) {
318                         char *first = words[i+1];
319                         char *last = strchr(first, '-');
320                         if (last)
321                                 *last++ = '\0';
322                         if (parse_lineno(first, &query->first_lineno) < 0)
323                                 return -EINVAL;
324                         if (last != NULL) {
325                                 /* range <first>-<last> */
326                                 if (parse_lineno(last, &query->last_lineno) < 0)
327                                         return -EINVAL;
328                         } else {
329                                 query->last_lineno = query->first_lineno;
330                         }
331                 } else {
332                         if (verbose)
333                                 printk(KERN_ERR "%s: unknown keyword \"%s\"\n",
334                                         __func__, words[i]);
335                         return -EINVAL;
336                 }
337         }
338 
339         if (verbose)
340                 printk(KERN_INFO "%s: q->function=\"%s\" q->filename=\"%s\" "
341                        "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",
342                         __func__, query->function, query->filename,
343                         query->module, query->format, query->first_lineno,
344                         query->last_lineno);
345 
346         return 0;
347 }
348 
349 /*
350  * Parse `str' as a flags specification, format [-+=][p]+.
351  * Sets up *maskp and *flagsp to be used when changing the
352  * flags fields of matched _ddebug's.  Returns 0 on success
353  * or <0 on error.
354  */
355 static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
356                                unsigned int *maskp)
357 {
358         unsigned flags = 0;
359         int op = '=', i;
360 
361         switch (*str) {
362         case '+':
363         case '-':
364         case '=':
365                 op = *str++;
366                 break;
367         default:
368                 return -EINVAL;
369         }
370         if (verbose)
371                 printk(KERN_INFO "%s: op='%c'\n", __func__, op);
372 
373         for ( ; *str ; ++str) {
374                 for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
375                         if (*str == opt_array[i].opt_char) {
376                                 flags |= opt_array[i].flag;
377                                 break;
378                         }
379                 }
380                 if (i < 0)
381                         return -EINVAL;
382         }
383         if (flags == 0)
384                 return -EINVAL;
385         if (verbose)
386                 printk(KERN_INFO "%s: flags=0x%x\n", __func__, flags);
387 
388         /* calculate final *flagsp, *maskp according to mask and op */
389         switch (op) {
390         case '=':
391                 *maskp = 0;
392                 *flagsp = flags;
393                 break;
394         case '+':
395                 *maskp = ~0U;
396                 *flagsp = flags;
397                 break;
398         case '-':
399                 *maskp = ~flags;
400                 *flagsp = 0;
401                 break;
402         }
403         if (verbose)
404                 printk(KERN_INFO "%s: *flagsp=0x%x *maskp=0x%x\n",
405                         __func__, *flagsp, *maskp);
406         return 0;
407 }
408 
409 static int ddebug_exec_query(char *query_string)
410 {
411         unsigned int flags = 0, mask = 0;
412         struct ddebug_query query;
413 #define MAXWORDS 9
414         int nwords;
415         char *words[MAXWORDS];
416 
417         nwords = ddebug_tokenize(query_string, words, MAXWORDS);
418         if (nwords <= 0)
419                 return -EINVAL;
420         if (ddebug_parse_query(words, nwords-1, &query))
421                 return -EINVAL;
422         if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
423                 return -EINVAL;
424 
425         /* actually go and implement the change */
426         ddebug_change(&query, flags, mask);
427         return 0;
428 }
429 
430 int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
431 {
432         va_list args;
433         int res;
434 
435         BUG_ON(!descriptor);
436         BUG_ON(!fmt);
437 
438         va_start(args, fmt);
439         res = printk(KERN_DEBUG);
440         if (descriptor->flags & _DPRINTK_FLAGS_INCL_TID) {
441                 if (in_interrupt())
442                         res += printk(KERN_CONT "<intr> ");
443                 else
444                         res += printk(KERN_CONT "[%d] ", task_pid_vnr(current));
445         }
446         if (descriptor->flags & _DPRINTK_FLAGS_INCL_MODNAME)
447                 res += printk(KERN_CONT "%s:", descriptor->modname);
448         if (descriptor->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
449                 res += printk(KERN_CONT "%s:", descriptor->function);
450         if (descriptor->flags & _DPRINTK_FLAGS_INCL_LINENO)
451                 res += printk(KERN_CONT "%d ", descriptor->lineno);
452         res += vprintk(fmt, args);
453         va_end(args);
454 
455         return res;
456 }
457 EXPORT_SYMBOL(__dynamic_pr_debug);
458 
459 static __initdata char ddebug_setup_string[1024];
460 static __init int ddebug_setup_query(char *str)
461 {
462         if (strlen(str) >= 1024) {
463                 pr_warning("ddebug boot param string too large\n");
464                 return 0;
465         }
466         strcpy(ddebug_setup_string, str);
467         return 1;
468 }
469 
470 __setup("ddebug_query=", ddebug_setup_query);
471 
472 /*
473  * File_ops->write method for <debugfs>/dynamic_debug/conrol.  Gathers the
474  * command text from userspace, parses and executes it.
475  */
476 static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
477                                   size_t len, loff_t *offp)
478 {
479         char tmpbuf[256];
480         int ret;
481 
482         if (len == 0)
483                 return 0;
484         /* we don't check *offp -- multiple writes() are allowed */
485         if (len > sizeof(tmpbuf)-1)
486                 return -E2BIG;
487         if (copy_from_user(tmpbuf, ubuf, len))
488                 return -EFAULT;
489         tmpbuf[len] = '\0';
490         if (verbose)
491                 printk(KERN_INFO "%s: read %d bytes from userspace\n",
492                         __func__, (int)len);
493 
494         ret = ddebug_exec_query(tmpbuf);
495         if (ret)
496                 return ret;
497 
498         *offp += len;
499         return len;
500 }
501 
502 /*
503  * Set the iterator to point to the first _ddebug object
504  * and return a pointer to that first object.  Returns
505  * NULL if there are no _ddebugs at all.
506  */
507 static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
508 {
509         if (list_empty(&ddebug_tables)) {
510                 iter->table = NULL;
511                 iter->idx = 0;
512                 return NULL;
513         }
514         iter->table = list_entry(ddebug_tables.next,
515                                  struct ddebug_table, link);
516         iter->idx = 0;
517         return &iter->table->ddebugs[iter->idx];
518 }
519 
520 /*
521  * Advance the iterator to point to the next _ddebug
522  * object from the one the iterator currently points at,
523  * and returns a pointer to the new _ddebug.  Returns
524  * NULL if the iterator has seen all the _ddebugs.
525  */
526 static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
527 {
528         if (iter->table == NULL)
529                 return NULL;
530         if (++iter->idx == iter->table->num_ddebugs) {
531                 /* iterate to next table */
532                 iter->idx = 0;
533                 if (list_is_last(&iter->table->link, &ddebug_tables)) {
534                         iter->table = NULL;
535                         return NULL;
536                 }
537                 iter->table = list_entry(iter->table->link.next,
538                                          struct ddebug_table, link);
539         }
540         return &iter->table->ddebugs[iter->idx];
541 }
542 
543 /*
544  * Seq_ops start method.  Called at the start of every
545  * read() call from userspace.  Takes the ddebug_lock and
546  * seeks the seq_file's iterator to the given position.
547  */
548 static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
549 {
550         struct ddebug_iter *iter = m->private;
551         struct _ddebug *dp;
552         int n = *pos;
553 
554         if (verbose)
555                 printk(KERN_INFO "%s: called m=%p *pos=%lld\n",
556                         __func__, m, (unsigned long long)*pos);
557 
558         mutex_lock(&ddebug_lock);
559 
560         if (!n)
561                 return SEQ_START_TOKEN;
562         if (n < 0)
563                 return NULL;
564         dp = ddebug_iter_first(iter);
565         while (dp != NULL && --n > 0)
566                 dp = ddebug_iter_next(iter);
567         return dp;
568 }
569 
570 /*
571  * Seq_ops next method.  Called several times within a read()
572  * call from userspace, with ddebug_lock held.  Walks to the
573  * next _ddebug object with a special case for the header line.
574  */
575 static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
576 {
577         struct ddebug_iter *iter = m->private;
578         struct _ddebug *dp;
579 
580         if (verbose)
581                 printk(KERN_INFO "%s: called m=%p p=%p *pos=%lld\n",
582                         __func__, m, p, (unsigned long long)*pos);
583 
584         if (p == SEQ_START_TOKEN)
585                 dp = ddebug_iter_first(iter);
586         else
587                 dp = ddebug_iter_next(iter);
588         ++*pos;
589         return dp;
590 }
591 
592 /*
593  * Seq_ops show method.  Called several times within a read()
594  * call from userspace, with ddebug_lock held.  Formats the
595  * current _ddebug as a single human-readable line, with a
596  * special case for the header line.
597  */
598 static int ddebug_proc_show(struct seq_file *m, void *p)
599 {
600         struct ddebug_iter *iter = m->private;
601         struct _ddebug *dp = p;
602         char flagsbuf[8];
603 
604         if (verbose)
605                 printk(KERN_INFO "%s: called m=%p p=%p\n",
606                         __func__, m, p);
607 
608         if (p == SEQ_START_TOKEN) {
609                 seq_puts(m,
610                         "# filename:lineno [module]function flags format\n");
611                 return 0;
612         }
613 
614         seq_printf(m, "%s:%u [%s]%s %s \"",
615                    dp->filename, dp->lineno,
616                    iter->table->mod_name, dp->function,
617                    ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
618         seq_escape(m, dp->format, "\t\r\n\"");
619         seq_puts(m, "\"\n");
620 
621         return 0;
622 }
623 
624 /*
625  * Seq_ops stop method.  Called at the end of each read()
626  * call from userspace.  Drops ddebug_lock.
627  */
628 static void ddebug_proc_stop(struct seq_file *m, void *p)
629 {
630         if (verbose)
631                 printk(KERN_INFO "%s: called m=%p p=%p\n",
632                         __func__, m, p);
633         mutex_unlock(&ddebug_lock);
634 }
635 
636 static const struct seq_operations ddebug_proc_seqops = {
637         .start = ddebug_proc_start,
638         .next = ddebug_proc_next,
639         .show = ddebug_proc_show,
640         .stop = ddebug_proc_stop
641 };
642 
643 /*
644  * File_ops->open method for <debugfs>/dynamic_debug/control.  Does the seq_file
645  * setup dance, and also creates an iterator to walk the _ddebugs.
646  * Note that we create a seq_file always, even for O_WRONLY files
647  * where it's not needed, as doing so simplifies the ->release method.
648  */
649 static int ddebug_proc_open(struct inode *inode, struct file *file)
650 {
651         struct ddebug_iter *iter;
652         int err;
653 
654         if (verbose)
655                 printk(KERN_INFO "%s: called\n", __func__);
656 
657         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
658         if (iter == NULL)
659                 return -ENOMEM;
660 
661         err = seq_open(file, &ddebug_proc_seqops);
662         if (err) {
663                 kfree(iter);
664                 return err;
665         }
666         ((struct seq_file *) file->private_data)->private = iter;
667         return 0;
668 }
669 
670 static const struct file_operations ddebug_proc_fops = {
671         .owner = THIS_MODULE,
672         .open = ddebug_proc_open,
673         .read = seq_read,
674         .llseek = seq_lseek,
675         .release = seq_release_private,
676         .write = ddebug_proc_write
677 };
678 
679 /*
680  * Allocate a new ddebug_table for the given module
681  * and add it to the global list.
682  */
683 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
684                              const char *name)
685 {
686         struct ddebug_table *dt;
687         char *new_name;
688 
689         dt = kzalloc(sizeof(*dt), GFP_KERNEL);
690         if (dt == NULL)
691                 return -ENOMEM;
692         new_name = kstrdup(name, GFP_KERNEL);
693         if (new_name == NULL) {
694                 kfree(dt);
695                 return -ENOMEM;
696         }
697         dt->mod_name = new_name;
698         dt->num_ddebugs = n;
699         dt->num_enabled = 0;
700         dt->ddebugs = tab;
701 
702         mutex_lock(&ddebug_lock);
703         list_add_tail(&dt->link, &ddebug_tables);
704         mutex_unlock(&ddebug_lock);
705 
706         if (verbose)
707                 printk(KERN_INFO "%u debug prints in module %s\n",
708                                  n, dt->mod_name);
709         return 0;
710 }
711 EXPORT_SYMBOL_GPL(ddebug_add_module);
712 
713 static void ddebug_table_free(struct ddebug_table *dt)
714 {
715         list_del_init(&dt->link);
716         kfree(dt->mod_name);
717         kfree(dt);
718 }
719 
720 /*
721  * Called in response to a module being unloaded.  Removes
722  * any ddebug_table's which point at the module.
723  */
724 int ddebug_remove_module(const char *mod_name)
725 {
726         struct ddebug_table *dt, *nextdt;
727         int ret = -ENOENT;
728 
729         if (verbose)
730                 printk(KERN_INFO "%s: removing module \"%s\"\n",
731                                 __func__, mod_name);
732 
733         mutex_lock(&ddebug_lock);
734         list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
735                 if (!strcmp(dt->mod_name, mod_name)) {
736                         ddebug_table_free(dt);
737                         ret = 0;
738                 }
739         }
740         mutex_unlock(&ddebug_lock);
741         return ret;
742 }
743 EXPORT_SYMBOL_GPL(ddebug_remove_module);
744 
745 static void ddebug_remove_all_tables(void)
746 {
747         mutex_lock(&ddebug_lock);
748         while (!list_empty(&ddebug_tables)) {
749                 struct ddebug_table *dt = list_entry(ddebug_tables.next,
750                                                       struct ddebug_table,
751                                                       link);
752                 ddebug_table_free(dt);
753         }
754         mutex_unlock(&ddebug_lock);
755 }
756 
757 static __initdata int ddebug_init_success;
758 
759 static int __init dynamic_debug_init_debugfs(void)
760 {
761         struct dentry *dir, *file;
762 
763         if (!ddebug_init_success)
764                 return -ENODEV;
765 
766         dir = debugfs_create_dir("dynamic_debug", NULL);
767         if (!dir)
768                 return -ENOMEM;
769         file = debugfs_create_file("control", 0644, dir, NULL,
770                                         &ddebug_proc_fops);
771         if (!file) {
772                 debugfs_remove(dir);
773                 return -ENOMEM;
774         }
775         return 0;
776 }
777 
778 static int __init dynamic_debug_init(void)
779 {
780         struct _ddebug *iter, *iter_start;
781         const char *modname = NULL;
782         int ret = 0;
783         int n = 0;
784 
785         if (__start___verbose != __stop___verbose) {
786                 iter = __start___verbose;
787                 modname = iter->modname;
788                 iter_start = iter;
789                 for (; iter < __stop___verbose; iter++) {
790                         if (strcmp(modname, iter->modname)) {
791                                 ret = ddebug_add_module(iter_start, n, modname);
792                                 if (ret)
793                                         goto out_free;
794                                 n = 0;
795                                 modname = iter->modname;
796                                 iter_start = iter;
797                         }
798                         n++;
799                 }
800                 ret = ddebug_add_module(iter_start, n, modname);
801         }
802 
803         /* ddebug_query boot param got passed -> set it up */
804         if (ddebug_setup_string[0] != '\0') {
805                 ret = ddebug_exec_query(ddebug_setup_string);
806                 if (ret)
807                         pr_warning("Invalid ddebug boot param %s",
808                                    ddebug_setup_string);
809                 else
810                         pr_info("ddebug initialized with string %s",
811                                 ddebug_setup_string);
812         }
813 
814 out_free:
815         if (ret)
816                 ddebug_remove_all_tables();
817         else
818                 ddebug_init_success = 1;
819         return 0;
820 }
821 /* Allow early initialization for boot messages via boot param */
822 arch_initcall(dynamic_debug_init);
823 /* Debugfs setup must be done later */
824 module_init(dynamic_debug_init_debugfs);
825 

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