lib/dynamic_debug.c

   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  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/moduleparam.h>
  15 #include <linux/kallsyms.h>
  16 #include <linux/version.h>
  17 #include <linux/types.h>
  18 #include <linux/mutex.h>
  19 #include <linux/proc_fs.h>
  20 #include <linux/seq_file.h>
  21 #include <linux/list.h>
  22 #include <linux/sysctl.h>
  23 #include <linux/ctype.h>
  24 #include <linux/string.h>
  25 #include <linux/uaccess.h>
  26 #include <linux/dynamic_debug.h>
  27 #include <linux/debugfs.h>
  28 #include <linux/slab.h>
  29 #include <linux/jump_label.h>
  30
  31 extern struct _ddebug __start___verbose[];
  32 extern struct _ddebug __stop___verbose[];
  33
  34 struct ddebug_table {
  35         struct list_head link;
  36         char *mod_name;
  37         unsigned int num_ddebugs;
  38         unsigned int num_enabled;
  39         struct _ddebug *ddebugs;
  40 };
  41
  42 struct ddebug_query {
  43         const char *filename;
  44         const char *module;
  45         const char *function;
  46         const char *format;
  47         unsigned int first_lineno, last_lineno;
  48 };
  49
  50 struct ddebug_iter {
  51         struct ddebug_table *table;
  52         unsigned int idx;
  53 };
  54
  55 static DEFINE_MUTEX(ddebug_lock);
  56 static LIST_HEAD(ddebug_tables);
  57 static int verbose = 0;
  58
  59 /* Return the last part of a pathname */
  60 static inline const char *basename(const char *path)
  61 {
  62         const char *tail = strrchr(path, '/');
  63         return tail ? tail+1 : path;
  64 }
  65
  66 /* format a string into buf[] which describes the _ddebug's flags */
  67 static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
  68                                     size_t maxlen)
  69 {
  70         char *p = buf;
  71
  72         BUG_ON(maxlen < 4);
  73         if (dp->flags & _DPRINTK_FLAGS_PRINT)
  74                 *p++ = 'p';
  75         if (p == buf)
  76                 *p++ = '-';
  77         *p = '\0';
  78
  79         return buf;
  80 }
  81
  82 /*
  83  * Search the tables for _ddebug's which match the given
  84  * `query' and apply the `flags' and `mask' to them.  Tells
  85  * the user which ddebug's were changed, or whether none
  86  * were matched.
  87  */
  88 static void ddebug_change(const struct ddebug_query *query,
  89                            unsigned int flags, unsigned int mask)
  90 {
  91         int i;
  92         struct ddebug_table *dt;
  93         unsigned int newflags;
  94         unsigned int nfound = 0;
  95         char flagbuf[8];
  96
  97         /* search for matching ddebugs */
  98         mutex_lock(&ddebug_lock);
  99         list_for_each_entry(dt, &ddebug_tables, link) {
 100
 101                 /* match against the module name */
 102                 if (query->module != NULL &&
 103                     strcmp(query->module, dt->mod_name))
 104                         continue;
 105
 106                 for (i = 0 ; i < dt->num_ddebugs ; i++) {
 107                         struct _ddebug *dp = &dt->ddebugs[i];
 108
 109                         /* match against the source filename */
 110                         if (query->filename != NULL &&
 111                             strcmp(query->filename, dp->filename) &&
 112                             strcmp(query->filename, basename(dp->filename)))
 113                                 continue;
 114
 115                         /* match against the function */
 116                         if (query->function != NULL &&
 117                             strcmp(query->function, dp->function))
 118                                 continue;
 119
 120                         /* match against the format */
 121                         if (query->format != NULL &&
 122                             strstr(dp->format, query->format) == NULL)
 123                                 continue;
 124
 125                         /* match against the line number range */
 126                         if (query->first_lineno &&
 127                             dp->lineno < query->first_lineno)
 128                                 continue;
 129                         if (query->last_lineno &&
 130                             dp->lineno > query->last_lineno)
 131                                 continue;
 132
 133                         nfound++;
 134
 135                         newflags = (dp->flags & mask) | flags;
 136                         if (newflags == dp->flags)
 137                                 continue;
 138
 139                         if (!newflags)
 140                                 dt->num_enabled--;
 141                         else if (!dp->flags)
 142                                 dt->num_enabled++;
 143                         dp->flags = newflags;
 144                         if (newflags)
 145                                 dp->enabled = 1;
 146                         else
 147                                 dp->enabled = 0;
 148                         if (verbose)
 149                                 printk(KERN_INFO
 150                                         "ddebug: changed %s:%d [%s]%s %s\n",
 151                                         dp->filename, dp->lineno,
 152                                         dt->mod_name, dp->function,
 153                                         ddebug_describe_flags(dp, flagbuf,
 154                                                         sizeof(flagbuf)));
 155                 }
 156         }
 157         mutex_unlock(&ddebug_lock);
 158
 159         if (!nfound && verbose)
 160                 printk(KERN_INFO "ddebug: no matches for query\n");
 161 }
 162
 163 /*
 164  * Split the buffer `buf' into space-separated words.
 165  * Handles simple " and ' quoting, i.e. without nested,
 166  * embedded or escaped \".  Return the number of words
 167  * or <0 on error.
 168  */
 169 static int ddebug_tokenize(char *buf, char *words[], int maxwords)
 170 {
 171         int nwords = 0;
 172
 173         while (*buf) {
 174                 char *end;
 175
 176                 /* Skip leading whitespace */
 177                 buf = skip_spaces(buf);
 178                 if (!*buf)
 179                         break;  /* oh, it was trailing whitespace */
 180
 181                 /* Run `end' over a word, either whitespace separated or quoted */
 182                 if (*buf == '"' || *buf == '\'') {
 183                         int quote = *buf++;
 184                         for (end = buf ; *end && *end != quote ; end++)
 185                                 ;
 186                         if (!*end)
 187                                 return -EINVAL; /* unclosed quote */
 188                 } else {
 189                         for (end = buf ; *end && !isspace(*end) ; end++)
 190                                 ;
 191                         BUG_ON(end == buf);
 192                 }
 193                 /* Here `buf' is the start of the word, `end' is one past the end */
 194
 195                 if (nwords == maxwords)
 196                         return -EINVAL; /* ran out of words[] before bytes */
 197                 if (*end)
 198                         *end++ = '\0';  /* terminate the word */
 199                 words[nwords++] = buf;
 200                 buf = end;
 201         }
 202
 203         if (verbose) {
 204                 int i;
 205                 printk(KERN_INFO "%s: split into words:", __func__);
 206                 for (i = 0 ; i < nwords ; i++)
 207                         printk(" \"%s\"", words[i]);
 208                 printk("\n");
 209         }
 210
 211         return nwords;
 212 }
 213
 214 /*
 215  * Parse a single line number.  Note that the empty string ""
 216  * is treated as a special case and converted to zero, which
 217  * is later treated as a "don't care" value.
 218  */
 219 static inline int parse_lineno(const char *str, unsigned int *val)
 220 {
 221         char *end = NULL;
 222         BUG_ON(str == NULL);
 223         if (*str == '\0') {
 224                 *val = 0;
 225                 return 0;
 226         }
 227         *val = simple_strtoul(str, &end, 10);
 228         return end == NULL || end == str || *end != '\0' ? -EINVAL : 0;
 229 }
 230
 231 /*
 232  * Undo octal escaping in a string, inplace.  This is useful to
 233  * allow the user to express a query which matches a format
 234  * containing embedded spaces.
 235  */
 236 #define isodigit(c)             ((c) >= '0' && (c) <= '7')
 237 static char *unescape(char *str)
 238 {
 239         char *in = str;
 240         char *out = str;
 241
 242         while (*in) {
 243                 if (*in == '\\') {
 244                         if (in[1] == '\\') {
 245                                 *out++ = '\\';
 246                                 in += 2;
 247                                 continue;
 248                         } else if (in[1] == 't') {
 249                                 *out++ = '\t';
 250                                 in += 2;
 251                                 continue;
 252                         } else if (in[1] == 'n') {
 253                                 *out++ = '\n';
 254                                 in += 2;
 255                                 continue;
 256                         } else if (isodigit(in[1]) &&
 257                                  isodigit(in[2]) &&
 258                                  isodigit(in[3])) {
 259                                 *out++ = ((in[1] - '0')<<6) |
 260                                           ((in[2] - '0')<<3) |
 261                                           (in[3] - '0');
 262                                 in += 4;
 263                                 continue;
 264                         }
 265                 }
 266                 *out++ = *in++;
 267         }
 268         *out = '\0';
 269
 270         return str;
 271 }
 272
 273 /*
 274  * Parse words[] as a ddebug query specification, which is a series
 275  * of (keyword, value) pairs chosen from these possibilities:
 276  *
 277  * func <function-name>
 278  * file <full-pathname>
 279  * file <base-filename>
 280  * module <module-name>
 281  * format <escaped-string-to-find-in-format>
 282  * line <lineno>
 283  * line <first-lineno>-<last-lineno> // where either may be empty
 284  */
 285 static int ddebug_parse_query(char *words[], int nwords,
 286                                struct ddebug_query *query)
 287 {
 288         unsigned int i;
 289
 290         /* check we have an even number of words */
 291         if (nwords % 2 != 0)
 292                 return -EINVAL;
 293         memset(query, 0, sizeof(*query));
 294
 295         for (i = 0 ; i < nwords ; i += 2) {
 296                 if (!strcmp(words[i], "func"))
 297                         query->function = words[i+1];
 298                 else if (!strcmp(words[i], "file"))
 299                         query->filename = words[i+1];
 300                 else if (!strcmp(words[i], "module"))
 301                         query->module = words[i+1];
 302                 else if (!strcmp(words[i], "format"))
 303                         query->format = unescape(words[i+1]);
 304                 else if (!strcmp(words[i], "line")) {
 305                         char *first = words[i+1];
 306                         char *last = strchr(first, '-');
 307                         if (last)
 308                                 *last++ = '\0';
 309                         if (parse_lineno(first, &query->first_lineno) < 0)
 310                                 return -EINVAL;
 311                         if (last != NULL) {
 312                                 /* range <first>-<last> */
 313                                 if (parse_lineno(last, &query->last_lineno) < 0)
 314                                         return -EINVAL;
 315                         } else {
 316                                 query->last_lineno = query->first_lineno;
 317                         }
 318                 } else {
 319                         if (verbose)
 320                                 printk(KERN_ERR "%s: unknown keyword \"%s\"\n",
 321                                         __func__, words[i]);
 322                         return -EINVAL;
 323                 }
 324         }
 325
 326         if (verbose)
 327                 printk(KERN_INFO "%s: q->function=\"%s\" q->filename=\"%s\" "
 328                        "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",
 329                         __func__, query->function, query->filename,
 330                         query->module, query->format, query->first_lineno,
 331                         query->last_lineno);
 332
 333         return 0;
 334 }
 335
 336 /*
 337  * Parse `str' as a flags specification, format [-+=][p]+.
 338  * Sets up *maskp and *flagsp to be used when changing the
 339  * flags fields of matched _ddebug's.  Returns 0 on success
 340  * or <0 on error.
 341  */
 342 static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
 343                                unsigned int *maskp)
 344 {
 345         unsigned flags = 0;
 346         int op = '=';
 347
 348         switch (*str) {
 349         case '+':
 350         case '-':
 351         case '=':
 352                 op = *str++;
 353                 break;
 354         default:
 355                 return -EINVAL;
 356         }
 357         if (verbose)
 358                 printk(KERN_INFO "%s: op='%c'\n", __func__, op);
 359
 360         for ( ; *str ; ++str) {
 361                 switch (*str) {
 362                 case 'p':
 363                         flags |= _DPRINTK_FLAGS_PRINT;
 364                         break;
 365                 default:
 366                         return -EINVAL;
 367                 }
 368         }
 369         if (flags == 0)
 370                 return -EINVAL;
 371         if (verbose)
 372                 printk(KERN_INFO "%s: flags=0x%x\n", __func__, flags);
 373
 374         /* calculate final *flagsp, *maskp according to mask and op */
 375         switch (op) {
 376         case '=':
 377                 *maskp = 0;
 378                 *flagsp = flags;
 379                 break;
 380         case '+':
 381                 *maskp = ~0U;
 382                 *flagsp = flags;
 383                 break;
 384         case '-':
 385                 *maskp = ~flags;
 386                 *flagsp = 0;
 387                 break;
 388         }
 389         if (verbose)
 390                 printk(KERN_INFO "%s: *flagsp=0x%x *maskp=0x%x\n",
 391                         __func__, *flagsp, *maskp);
 392         return 0;
 393 }
 394
 395 static int ddebug_exec_query(char *query_string)
 396 {
 397         unsigned int flags = 0, mask = 0;
 398         struct ddebug_query query;
 399 #define MAXWORDS 9
 400         int nwords;
 401         char *words[MAXWORDS];
 402
 403         nwords = ddebug_tokenize(query_string, words, MAXWORDS);
 404         if (nwords <= 0)
 405                 return -EINVAL;
 406         if (ddebug_parse_query(words, nwords-1, &query))
 407                 return -EINVAL;
 408         if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
 409                 return -EINVAL;
 410
 411         /* actually go and implement the change */
 412         ddebug_change(&query, flags, mask);
 413         return 0;
 414 }
 415
 416 static __initdata char ddebug_setup_string[1024];
 417 static __init int ddebug_setup_query(char *str)
 418 {
 419         if (strlen(str) >= 1024) {
 420                 pr_warning("ddebug boot param string too large\n");
 421                 return 0;
 422         }
 423         strcpy(ddebug_setup_string, str);
 424         return 1;
 425 }
 426
 427 __setup("ddebug_query=", ddebug_setup_query);
 428
 429 /*
 430  * File_ops->write method for <debugfs>/dynamic_debug/conrol.  Gathers the
 431  * command text from userspace, parses and executes it.
 432  */
 433 static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
 434                                   size_t len, loff_t *offp)
 435 {
 436         char tmpbuf[256];
 437         int ret;
 438
 439         if (len == 0)
 440                 return 0;
 441         /* we don't check *offp -- multiple writes() are allowed */
 442         if (len > sizeof(tmpbuf)-1)
 443                 return -E2BIG;
 444         if (copy_from_user(tmpbuf, ubuf, len))
 445                 return -EFAULT;
 446         tmpbuf[len] = '\0';
 447         if (verbose)
 448                 printk(KERN_INFO "%s: read %d bytes from userspace\n",
 449                         __func__, (int)len);
 450
 451         ret = ddebug_exec_query(tmpbuf);
 452         if (ret)
 453                 return ret;
 454
 455         *offp += len;
 456         return len;
 457 }
 458
 459 /*
 460  * Set the iterator to point to the first _ddebug object
 461  * and return a pointer to that first object.  Returns
 462  * NULL if there are no _ddebugs at all.
 463  */
 464 static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
 465 {
 466         if (list_empty(&ddebug_tables)) {
 467                 iter->table = NULL;
 468                 iter->idx = 0;
 469                 return NULL;
 470         }
 471         iter->table = list_entry(ddebug_tables.next,
 472                                  struct ddebug_table, link);
 473         iter->idx = 0;
 474         return &iter->table->ddebugs[iter->idx];
 475 }
 476
 477 /*
 478  * Advance the iterator to point to the next _ddebug
 479  * object from the one the iterator currently points at,
 480  * and returns a pointer to the new _ddebug.  Returns
 481  * NULL if the iterator has seen all the _ddebugs.
 482  */
 483 static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
 484 {
 485         if (iter->table == NULL)
 486                 return NULL;
 487         if (++iter->idx == iter->table->num_ddebugs) {
 488                 /* iterate to next table */
 489                 iter->idx = 0;
 490                 if (list_is_last(&iter->table->link, &ddebug_tables)) {
 491                         iter->table = NULL;
 492                         return NULL;
 493                 }
 494                 iter->table = list_entry(iter->table->link.next,
 495                                          struct ddebug_table, link);
 496         }
 497         return &iter->table->ddebugs[iter->idx];
 498 }
 499
 500 /*
 501  * Seq_ops start method.  Called at the start of every
 502  * read() call from userspace.  Takes the ddebug_lock and
 503  * seeks the seq_file's iterator to the given position.
 504  */
 505 static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
 506 {
 507         struct ddebug_iter *iter = m->private;
 508         struct _ddebug *dp;
 509         int n = *pos;
 510
 511         if (verbose)
 512                 printk(KERN_INFO "%s: called m=%p *pos=%lld\n",
 513                         __func__, m, (unsigned long long)*pos);
 514
 515         mutex_lock(&ddebug_lock);
 516
 517         if (!n)
 518                 return SEQ_START_TOKEN;
 519         if (n < 0)
 520                 return NULL;
 521         dp = ddebug_iter_first(iter);
 522         while (dp != NULL && --n > 0)
 523                 dp = ddebug_iter_next(iter);
 524         return dp;
 525 }
 526
 527 /*
 528  * Seq_ops next method.  Called several times within a read()
 529  * call from userspace, with ddebug_lock held.  Walks to the
 530  * next _ddebug object with a special case for the header line.
 531  */
 532 static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
 533 {
 534         struct ddebug_iter *iter = m->private;
 535         struct _ddebug *dp;
 536
 537         if (verbose)
 538                 printk(KERN_INFO "%s: called m=%p p=%p *pos=%lld\n",
 539                         __func__, m, p, (unsigned long long)*pos);
 540
 541         if (p == SEQ_START_TOKEN)
 542                 dp = ddebug_iter_first(iter);
 543         else
 544                 dp = ddebug_iter_next(iter);
 545         ++*pos;
 546         return dp;
 547 }
 548
 549 /*
 550  * Seq_ops show method.  Called several times within a read()
 551  * call from userspace, with ddebug_lock held.  Formats the
 552  * current _ddebug as a single human-readable line, with a
 553  * special case for the header line.
 554  */
 555 static int ddebug_proc_show(struct seq_file *m, void *p)
 556 {
 557         struct ddebug_iter *iter = m->private;
 558         struct _ddebug *dp = p;
 559         char flagsbuf[8];
 560
 561         if (verbose)
 562                 printk(KERN_INFO "%s: called m=%p p=%p\n",
 563                         __func__, m, p);
 564
 565         if (p == SEQ_START_TOKEN) {
 566                 seq_puts(m,
 567                         "# filename:lineno [module]function flags format\n");
 568                 return 0;
 569         }
 570
 571         seq_printf(m, "%s:%u [%s]%s %s \"",
 572                    dp->filename, dp->lineno,
 573                    iter->table->mod_name, dp->function,
 574                    ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
 575         seq_escape(m, dp->format, "\t\r\n\"");
 576         seq_puts(m, "\"\n");
 577
 578         return 0;
 579 }
 580
 581 /*
 582  * Seq_ops stop method.  Called at the end of each read()
 583  * call from userspace.  Drops ddebug_lock.
 584  */
 585 static void ddebug_proc_stop(struct seq_file *m, void *p)
 586 {
 587         if (verbose)
 588                 printk(KERN_INFO "%s: called m=%p p=%p\n",
 589                         __func__, m, p);
 590         mutex_unlock(&ddebug_lock);
 591 }
 592
 593 static const struct seq_operations ddebug_proc_seqops = {
 594         .start = ddebug_proc_start,
 595         .next = ddebug_proc_next,
 596         .show = ddebug_proc_show,
 597         .stop = ddebug_proc_stop
 598 };
 599
 600 /*
 601  * File_ops->open method for <debugfs>/dynamic_debug/control.  Does the seq_file
 602  * setup dance, and also creates an iterator to walk the _ddebugs.
 603  * Note that we create a seq_file always, even for O_WRONLY files
 604  * where it's not needed, as doing so simplifies the ->release method.
 605  */
 606 static int ddebug_proc_open(struct inode *inode, struct file *file)
 607 {
 608         struct ddebug_iter *iter;
 609         int err;
 610
 611         if (verbose)
 612                 printk(KERN_INFO "%s: called\n", __func__);
 613
 614         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 615         if (iter == NULL)
 616                 return -ENOMEM;
 617
 618         err = seq_open(file, &ddebug_proc_seqops);
 619         if (err) {
 620                 kfree(iter);
 621                 return err;
 622         }
 623         ((struct seq_file *) file->private_data)->private = iter;
 624         return 0;
 625 }
 626
 627 static const struct file_operations ddebug_proc_fops = {
 628         .owner = THIS_MODULE,
 629         .open = ddebug_proc_open,
 630         .read = seq_read,
 631         .llseek = seq_lseek,
 632         .release = seq_release_private,
 633         .write = ddebug_proc_write
 634 };
 635
 636 /*
 637  * Allocate a new ddebug_table for the given module
 638  * and add it to the global list.
 639  */
 640 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
 641                              const char *name)
 642 {
 643         struct ddebug_table *dt;
 644         char *new_name;
 645
 646         dt = kzalloc(sizeof(*dt), GFP_KERNEL);
 647         if (dt == NULL)
 648                 return -ENOMEM;
 649         new_name = kstrdup(name, GFP_KERNEL);
 650         if (new_name == NULL) {
 651                 kfree(dt);
 652                 return -ENOMEM;
 653         }
 654         dt->mod_name = new_name;
 655         dt->num_ddebugs = n;
 656         dt->num_enabled = 0;
 657         dt->ddebugs = tab;
 658
 659         mutex_lock(&ddebug_lock);
 660         list_add_tail(&dt->link, &ddebug_tables);
 661         mutex_unlock(&ddebug_lock);
 662
 663         if (verbose)
 664                 printk(KERN_INFO "%u debug prints in module %s\n",
 665                                  n, dt->mod_name);
 666         return 0;
 667 }
 668 EXPORT_SYMBOL_GPL(ddebug_add_module);
 669
 670 static void ddebug_table_free(struct ddebug_table *dt)
 671 {
 672         list_del_init(&dt->link);
 673         kfree(dt->mod_name);
 674         kfree(dt);
 675 }
 676
 677 /*
 678  * Called in response to a module being unloaded.  Removes
 679  * any ddebug_table's which point at the module.
 680  */
 681 int ddebug_remove_module(const char *mod_name)
 682 {
 683         struct ddebug_table *dt, *nextdt;
 684         int ret = -ENOENT;
 685
 686         if (verbose)
 687                 printk(KERN_INFO "%s: removing module \"%s\"\n",
 688                                 __func__, mod_name);
 689
 690         mutex_lock(&ddebug_lock);
 691         list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
 692                 if (!strcmp(dt->mod_name, mod_name)) {
 693                         ddebug_table_free(dt);
 694                         ret = 0;
 695                 }
 696         }
 697         mutex_unlock(&ddebug_lock);
 698         return ret;
 699 }
 700 EXPORT_SYMBOL_GPL(ddebug_remove_module);
 701
 702 static void ddebug_remove_all_tables(void)
 703 {
 704         mutex_lock(&ddebug_lock);
 705         while (!list_empty(&ddebug_tables)) {
 706                 struct ddebug_table *dt = list_entry(ddebug_tables.next,
 707                                                       struct ddebug_table,
 708                                                       link);
 709                 ddebug_table_free(dt);
 710         }
 711         mutex_unlock(&ddebug_lock);
 712 }
 713
 714 static __initdata int ddebug_init_success;
 715
 716 static int __init dynamic_debug_init_debugfs(void)
 717 {
 718         struct dentry *dir, *file;
 719
 720         if (!ddebug_init_success)
 721                 return -ENODEV;
 722
 723         dir = debugfs_create_dir("dynamic_debug", NULL);
 724         if (!dir)
 725                 return -ENOMEM;
 726         file = debugfs_create_file("control", 0644, dir, NULL,
 727                                         &ddebug_proc_fops);
 728         if (!file) {
 729                 debugfs_remove(dir);
 730                 return -ENOMEM;
 731         }
 732         return 0;
 733 }
 734
 735 static int __init dynamic_debug_init(void)
 736 {
 737         struct _ddebug *iter, *iter_start;
 738         const char *modname = NULL;
 739         int ret = 0;
 740         int n = 0;
 741
 742         if (__start___verbose != __stop___verbose) {
 743                 iter = __start___verbose;
 744                 modname = iter->modname;
 745                 iter_start = iter;
 746                 for (; iter < __stop___verbose; iter++) {
 747                         if (strcmp(modname, iter->modname)) {
 748                                 ret = ddebug_add_module(iter_start, n, modname);
 749                                 if (ret)
 750                                         goto out_free;
 751                                 n = 0;
 752                                 modname = iter->modname;
 753                                 iter_start = iter;
 754                         }
 755                         n++;
 756                 }
 757                 ret = ddebug_add_module(iter_start, n, modname);
 758         }
 759
 760         /* ddebug_query boot param got passed -> set it up */
 761         if (ddebug_setup_string[0] != '\0') {
 762                 ret = ddebug_exec_query(ddebug_setup_string);
 763                 if (ret)
 764                         pr_warning("Invalid ddebug boot param %s",
 765                                    ddebug_setup_string);
 766                 else
 767                         pr_info("ddebug initialized with string %s",
 768                                 ddebug_setup_string);
 769         }
 770
 771 out_free:
 772         if (ret)
 773                 ddebug_remove_all_tables();
 774         else
 775                 ddebug_init_success = 1;
 776         return 0;
 777 }
 778 /* Allow early initialization for boot messages via boot param */
 779 arch_initcall(dynamic_debug_init);
 780 /* Debugfs setup must be done later */
 781 module_init(dynamic_debug_init_debugfs);