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