kernel/params.c

   1 /* Helpers for initial module or kernel cmdline parsing
   2    Copyright (C) 2001 Rusty Russell.
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17 */
  18 #include <linux/kernel.h>
  19 #include <linux/string.h>
  20 #include <linux/errno.h>
  21 #include <linux/module.h>
  22 #include <linux/device.h>
  23 #include <linux/err.h>
  24 #include <linux/slab.h>
  25 #include <linux/ctype.h>
  26
  27 /* Protects all parameters, and incidentally kmalloced_param list. */
  28 static DEFINE_MUTEX(param_lock);
  29
  30 /* This just allows us to keep track of which parameters are kmalloced. */
  31 struct kmalloced_param {
  32         struct list_head list;
  33         char val[];
  34 };
  35 static LIST_HEAD(kmalloced_params);
  36
  37 static void *kmalloc_parameter(unsigned int size)
  38 {
  39         struct kmalloced_param *p;
  40
  41         p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
  42         if (!p)
  43                 return NULL;
  44
  45         list_add(&p->list, &kmalloced_params);
  46         return p->val;
  47 }
  48
  49 /* Does nothing if parameter wasn't kmalloced above. */
  50 static void maybe_kfree_parameter(void *param)
  51 {
  52         struct kmalloced_param *p;
  53
  54         list_for_each_entry(p, &kmalloced_params, list) {
  55                 if (p->val == param) {
  56                         list_del(&p->list);
  57                         kfree(p);
  58                         break;
  59                 }
  60         }
  61 }
  62
  63 static char dash2underscore(char c)
  64 {
  65         if (c == '-')
  66                 return '_';
  67         return c;
  68 }
  69
  70 bool parameqn(const char *a, const char *b, size_t n)
  71 {
  72         size_t i;
  73
  74         for (i = 0; i < n; i++) {
  75                 if (dash2underscore(a[i]) != dash2underscore(b[i]))
  76                         return false;
  77         }
  78         return true;
  79 }
  80
  81 bool parameq(const char *a, const char *b)
  82 {
  83         return parameqn(a, b, strlen(a)+1);
  84 }
  85
  86 static int parse_one(char *param,
  87                      char *val,
  88                      const char *doing,
  89                      const struct kernel_param *params,
  90                      unsigned num_params,
  91                      s16 min_level,
  92                      s16 max_level,
  93                      int (*handle_unknown)(char *param, char *val,
  94                                      const char *doing))
  95 {
  96         unsigned int i;
  97         int err;
  98
  99         /* Find parameter */
 100         for (i = 0; i < num_params; i++) {
 101                 if (parameq(param, params[i].name)) {
 102                         if (params[i].level < min_level
 103                             || params[i].level > max_level)
 104                                 return 0;
 105                         /* No one handled NULL, so do it here. */
 106                         if (!val &&
 107                             !(params[i].ops->flags & KERNEL_PARAM_FL_NOARG))
 108                                 return -EINVAL;
 109                         pr_debug("handling %s with %p\n", param,
 110                                 params[i].ops->set);
 111                         mutex_lock(&param_lock);
 112                         err = params[i].ops->set(val, &params[i]);
 113                         mutex_unlock(&param_lock);
 114                         return err;
 115                 }
 116         }
 117
 118         if (handle_unknown) {
 119                 pr_debug("doing %s: %s='%s'\n", doing, param, val);
 120                 return handle_unknown(param, val, doing);
 121         }
 122
 123         pr_debug("Unknown argument '%s'\n", param);
 124         return -ENOENT;
 125 }
 126
 127 /* You can use " around spaces, but can't escape ". */
 128 /* Hyphens and underscores equivalent in parameter names. */
 129 static char *next_arg(char *args, char **param, char **val)
 130 {
 131         unsigned int i, equals = 0;
 132         int in_quote = 0, quoted = 0;
 133         char *next;
 134
 135         if (*args == '"') {
 136                 args++;
 137                 in_quote = 1;
 138                 quoted = 1;
 139         }
 140
 141         for (i = 0; args[i]; i++) {
 142                 if (isspace(args[i]) && !in_quote)
 143                         break;
 144                 if (equals == 0) {
 145                         if (args[i] == '=')
 146                                 equals = i;
 147                 }
 148                 if (args[i] == '"')
 149                         in_quote = !in_quote;
 150         }
 151
 152         *param = args;
 153         if (!equals)
 154                 *val = NULL;
 155         else {
 156                 args[equals] = '\0';
 157                 *val = args + equals + 1;
 158
 159                 /* Don't include quotes in value. */
 160                 if (**val == '"') {
 161                         (*val)++;
 162                         if (args[i-1] == '"')
 163                                 args[i-1] = '\0';
 164                 }
 165                 if (quoted && args[i-1] == '"')
 166                         args[i-1] = '\0';
 167         }
 168
 169         if (args[i]) {
 170                 args[i] = '\0';
 171                 next = args + i + 1;
 172         } else
 173                 next = args + i;
 174
 175         /* Chew up trailing spaces. */
 176         return skip_spaces(next);
 177 }
 178
 179 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 180 int parse_args(const char *doing,
 181                char *args,
 182                const struct kernel_param *params,
 183                unsigned num,
 184                s16 min_level,
 185                s16 max_level,
 186                int (*unknown)(char *param, char *val, const char *doing))
 187 {
 188         char *param, *val;
 189
 190         /* Chew leading spaces */
 191         args = skip_spaces(args);
 192
 193         if (*args)
 194                 pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
 195
 196         while (*args) {
 197                 int ret;
 198                 int irq_was_disabled;
 199
 200                 args = next_arg(args, &param, &val);
 201                 irq_was_disabled = irqs_disabled();
 202                 ret = parse_one(param, val, doing, params, num,
 203                                 min_level, max_level, unknown);
 204                 if (irq_was_disabled && !irqs_disabled())
 205                         pr_warn("%s: option '%s' enabled irq's!\n",
 206                                 doing, param);
 207
 208                 switch (ret) {
 209                 case -ENOENT:
 210                         pr_err("%s: Unknown parameter `%s'\n", doing, param);
 211                         return ret;
 212                 case -ENOSPC:
 213                         pr_err("%s: `%s' too large for parameter `%s'\n",
 214                                doing, val ?: "", param);
 215                         return ret;
 216                 case 0:
 217                         break;
 218                 default:
 219                         pr_err("%s: `%s' invalid for parameter `%s'\n",
 220                                doing, val ?: "", param);
 221                         return ret;
 222                 }
 223         }
 224
 225         /* All parsed OK. */
 226         return 0;
 227 }
 228
 229 /* Lazy bastard, eh? */
 230 #define STANDARD_PARAM_DEF(name, type, format, strtolfn)                \
 231         int param_set_##name(const char *val, const struct kernel_param *kp) \
 232         {                                                               \
 233                 return strtolfn(val, 0, (type *)kp->arg);               \
 234         }                                                               \
 235         int param_get_##name(char *buffer, const struct kernel_param *kp) \
 236         {                                                               \
 237                 return scnprintf(buffer, PAGE_SIZE, format,             \
 238                                 *((type *)kp->arg));                    \
 239         }                                                               \
 240         struct kernel_param_ops param_ops_##name = {                    \
 241                 .set = param_set_##name,                                \
 242                 .get = param_get_##name,                                \
 243         };                                                              \
 244         EXPORT_SYMBOL(param_set_##name);                                \
 245         EXPORT_SYMBOL(param_get_##name);                                \
 246         EXPORT_SYMBOL(param_ops_##name)
 247
 248
 249 STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", kstrtou8);
 250 STANDARD_PARAM_DEF(short, short, "%hi", kstrtos16);
 251 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", kstrtou16);
 252 STANDARD_PARAM_DEF(int, int, "%i", kstrtoint);
 253 STANDARD_PARAM_DEF(uint, unsigned int, "%u", kstrtouint);
 254 STANDARD_PARAM_DEF(long, long, "%li", kstrtol);
 255 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", kstrtoul);
 256
 257 int param_set_charp(const char *val, const struct kernel_param *kp)
 258 {
 259         if (strlen(val) > 1024) {
 260                 pr_err("%s: string parameter too long\n", kp->name);
 261                 return -ENOSPC;
 262         }
 263
 264         maybe_kfree_parameter(*(char **)kp->arg);
 265
 266         /* This is a hack.  We can't kmalloc in early boot, and we
 267          * don't need to; this mangled commandline is preserved. */
 268         if (slab_is_available()) {
 269                 *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
 270                 if (!*(char **)kp->arg)
 271                         return -ENOMEM;
 272                 strcpy(*(char **)kp->arg, val);
 273         } else
 274                 *(const char **)kp->arg = val;
 275
 276         return 0;
 277 }
 278 EXPORT_SYMBOL(param_set_charp);
 279
 280 int param_get_charp(char *buffer, const struct kernel_param *kp)
 281 {
 282         return scnprintf(buffer, PAGE_SIZE, "%s", *((char **)kp->arg));
 283 }
 284 EXPORT_SYMBOL(param_get_charp);
 285
 286 static void param_free_charp(void *arg)
 287 {
 288         maybe_kfree_parameter(*((char **)arg));
 289 }
 290
 291 struct kernel_param_ops param_ops_charp = {
 292         .set = param_set_charp,
 293         .get = param_get_charp,
 294         .free = param_free_charp,
 295 };
 296 EXPORT_SYMBOL(param_ops_charp);
 297
 298 /* Actually could be a bool or an int, for historical reasons. */
 299 int param_set_bool(const char *val, const struct kernel_param *kp)
 300 {
 301         /* No equals means "set"... */
 302         if (!val) val = "1";
 303
 304         /* One of =[yYnN01] */
 305         return strtobool(val, kp->arg);
 306 }
 307 EXPORT_SYMBOL(param_set_bool);
 308
 309 int param_get_bool(char *buffer, const struct kernel_param *kp)
 310 {
 311         /* Y and N chosen as being relatively non-coder friendly */
 312         return sprintf(buffer, "%c", *(bool *)kp->arg ? 'Y' : 'N');
 313 }
 314 EXPORT_SYMBOL(param_get_bool);
 315
 316 struct kernel_param_ops param_ops_bool = {
 317         .flags = KERNEL_PARAM_FL_NOARG,
 318         .set = param_set_bool,
 319         .get = param_get_bool,
 320 };
 321 EXPORT_SYMBOL(param_ops_bool);
 322
 323 /* This one must be bool. */
 324 int param_set_invbool(const char *val, const struct kernel_param *kp)
 325 {
 326         int ret;
 327         bool boolval;
 328         struct kernel_param dummy;
 329
 330         dummy.arg = &boolval;
 331         ret = param_set_bool(val, &dummy);
 332         if (ret == 0)
 333                 *(bool *)kp->arg = !boolval;
 334         return ret;
 335 }
 336 EXPORT_SYMBOL(param_set_invbool);
 337
 338 int param_get_invbool(char *buffer, const struct kernel_param *kp)
 339 {
 340         return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
 341 }
 342 EXPORT_SYMBOL(param_get_invbool);
 343
 344 struct kernel_param_ops param_ops_invbool = {
 345         .set = param_set_invbool,
 346         .get = param_get_invbool,
 347 };
 348 EXPORT_SYMBOL(param_ops_invbool);
 349
 350 int param_set_bint(const char *val, const struct kernel_param *kp)
 351 {
 352         struct kernel_param boolkp;
 353         bool v;
 354         int ret;
 355
 356         /* Match bool exactly, by re-using it. */
 357         boolkp = *kp;
 358         boolkp.arg = &v;
 359
 360         ret = param_set_bool(val, &boolkp);
 361         if (ret == 0)
 362                 *(int *)kp->arg = v;
 363         return ret;
 364 }
 365 EXPORT_SYMBOL(param_set_bint);
 366
 367 struct kernel_param_ops param_ops_bint = {
 368         .flags = KERNEL_PARAM_FL_NOARG,
 369         .set = param_set_bint,
 370         .get = param_get_int,
 371 };
 372 EXPORT_SYMBOL(param_ops_bint);
 373
 374 /* We break the rule and mangle the string. */
 375 static int param_array(const char *name,
 376                        const char *val,
 377                        unsigned int min, unsigned int max,
 378                        void *elem, int elemsize,
 379                        int (*set)(const char *, const struct kernel_param *kp),
 380                        s16 level,
 381                        unsigned int *num)
 382 {
 383         int ret;
 384         struct kernel_param kp;
 385         char save;
 386
 387         /* Get the name right for errors. */
 388         kp.name = name;
 389         kp.arg = elem;
 390         kp.level = level;
 391
 392         *num = 0;
 393         /* We expect a comma-separated list of values. */
 394         do {
 395                 int len;
 396
 397                 if (*num == max) {
 398                         pr_err("%s: can only take %i arguments\n", name, max);
 399                         return -EINVAL;
 400                 }
 401                 len = strcspn(val, ",");
 402
 403                 /* nul-terminate and parse */
 404                 save = val[len];
 405                 ((char *)val)[len] = '\0';
 406                 BUG_ON(!mutex_is_locked(&param_lock));
 407                 ret = set(val, &kp);
 408
 409                 if (ret != 0)
 410                         return ret;
 411                 kp.arg += elemsize;
 412                 val += len+1;
 413                 (*num)++;
 414         } while (save == ',');
 415
 416         if (*num < min) {
 417                 pr_err("%s: needs at least %i arguments\n", name, min);
 418                 return -EINVAL;
 419         }
 420         return 0;
 421 }
 422
 423 static int param_array_set(const char *val, const struct kernel_param *kp)
 424 {
 425         const struct kparam_array *arr = kp->arr;
 426         unsigned int temp_num;
 427
 428         return param_array(kp->name, val, 1, arr->max, arr->elem,
 429                            arr->elemsize, arr->ops->set, kp->level,
 430                            arr->num ?: &temp_num);
 431 }
 432
 433 static int param_array_get(char *buffer, const struct kernel_param *kp)
 434 {
 435         int i, off, ret;
 436         const struct kparam_array *arr = kp->arr;
 437         struct kernel_param p;
 438
 439         p = *kp;
 440         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 441                 if (i)
 442                         buffer[off++] = ',';
 443                 p.arg = arr->elem + arr->elemsize * i;
 444                 BUG_ON(!mutex_is_locked(&param_lock));
 445                 ret = arr->ops->get(buffer + off, &p);
 446                 if (ret < 0)
 447                         return ret;
 448                 off += ret;
 449         }
 450         buffer[off] = '\0';
 451         return off;
 452 }
 453
 454 static void param_array_free(void *arg)
 455 {
 456         unsigned int i;
 457         const struct kparam_array *arr = arg;
 458
 459         if (arr->ops->free)
 460                 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 461                         arr->ops->free(arr->elem + arr->elemsize * i);
 462 }
 463
 464 struct kernel_param_ops param_array_ops = {
 465         .set = param_array_set,
 466         .get = param_array_get,
 467         .free = param_array_free,
 468 };
 469 EXPORT_SYMBOL(param_array_ops);
 470
 471 int param_set_copystring(const char *val, const struct kernel_param *kp)
 472 {
 473         const struct kparam_string *kps = kp->str;
 474
 475         if (strlen(val)+1 > kps->maxlen) {
 476                 pr_err("%s: string doesn't fit in %u chars.\n",
 477                        kp->name, kps->maxlen-1);
 478                 return -ENOSPC;
 479         }
 480         strcpy(kps->string, val);
 481         return 0;
 482 }
 483 EXPORT_SYMBOL(param_set_copystring);
 484
 485 int param_get_string(char *buffer, const struct kernel_param *kp)
 486 {
 487         const struct kparam_string *kps = kp->str;
 488         return strlcpy(buffer, kps->string, kps->maxlen);
 489 }
 490 EXPORT_SYMBOL(param_get_string);
 491
 492 struct kernel_param_ops param_ops_string = {
 493         .set = param_set_copystring,
 494         .get = param_get_string,
 495 };
 496 EXPORT_SYMBOL(param_ops_string);
 497
 498 /* sysfs output in /sys/modules/XYZ/parameters/ */
 499 #define to_module_attr(n) container_of(n, struct module_attribute, attr)
 500 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 501
 502 extern struct kernel_param __start___param[], __stop___param[];
 503
 504 struct param_attribute
 505 {
 506         struct module_attribute mattr;
 507         const struct kernel_param *param;
 508 };
 509
 510 struct module_param_attrs
 511 {
 512         unsigned int num;
 513         struct attribute_group grp;
 514         struct param_attribute attrs[0];
 515 };
 516
 517 #ifdef CONFIG_SYSFS
 518 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 519
 520 static ssize_t param_attr_show(struct module_attribute *mattr,
 521                                struct module_kobject *mk, char *buf)
 522 {
 523         int count;
 524         struct param_attribute *attribute = to_param_attr(mattr);
 525
 526         if (!attribute->param->ops->get)
 527                 return -EPERM;
 528
 529         mutex_lock(&param_lock);
 530         count = attribute->param->ops->get(buf, attribute->param);
 531         mutex_unlock(&param_lock);
 532         if (count > 0) {
 533                 strcat(buf, "\n");
 534                 ++count;
 535         }
 536         return count;
 537 }
 538
 539 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 540 static ssize_t param_attr_store(struct module_attribute *mattr,
 541                                 struct module_kobject *km,
 542                                 const char *buf, size_t len)
 543 {
 544         int err;
 545         struct param_attribute *attribute = to_param_attr(mattr);
 546
 547         if (!attribute->param->ops->set)
 548                 return -EPERM;
 549
 550         mutex_lock(&param_lock);
 551         err = attribute->param->ops->set(buf, attribute->param);
 552         mutex_unlock(&param_lock);
 553         if (!err)
 554                 return len;
 555         return err;
 556 }
 557 #endif
 558
 559 #ifdef CONFIG_MODULES
 560 #define __modinit
 561 #else
 562 #define __modinit __init
 563 #endif
 564
 565 #ifdef CONFIG_SYSFS
 566 void __kernel_param_lock(void)
 567 {
 568         mutex_lock(&param_lock);
 569 }
 570 EXPORT_SYMBOL(__kernel_param_lock);
 571
 572 void __kernel_param_unlock(void)
 573 {
 574         mutex_unlock(&param_lock);
 575 }
 576 EXPORT_SYMBOL(__kernel_param_unlock);
 577
 578 /*
 579  * add_sysfs_param - add a parameter to sysfs
 580  * @mk: struct module_kobject
 581  * @kparam: the actual parameter definition to add to sysfs
 582  * @name: name of parameter
 583  *
 584  * Create a kobject if for a (per-module) parameter if mp NULL, and
 585  * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 586  * if there's an error.
 587  */
 588 static __modinit int add_sysfs_param(struct module_kobject *mk,
 589                                      const struct kernel_param *kp,
 590                                      const char *name)
 591 {
 592         struct module_param_attrs *new;
 593         struct attribute **attrs;
 594         int err, num;
 595
 596         /* We don't bother calling this with invisible parameters. */
 597         BUG_ON(!kp->perm);
 598
 599         if (!mk->mp) {
 600                 num = 0;
 601                 attrs = NULL;
 602         } else {
 603                 num = mk->mp->num;
 604                 attrs = mk->mp->grp.attrs;
 605         }
 606
 607         /* Enlarge. */
 608         new = krealloc(mk->mp,
 609                        sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
 610                        GFP_KERNEL);
 611         if (!new) {
 612                 kfree(attrs);
 613                 err = -ENOMEM;
 614                 goto fail;
 615         }
 616         /* Despite looking like the typical realloc() bug, this is safe.
 617          * We *want* the old 'attrs' to be freed either way, and we'll store
 618          * the new one in the success case. */
 619         attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
 620         if (!attrs) {
 621                 err = -ENOMEM;
 622                 goto fail_free_new;
 623         }
 624
 625         /* Sysfs wants everything zeroed. */
 626         memset(new, 0, sizeof(*new));
 627         memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
 628         memset(&attrs[num], 0, sizeof(attrs[num]));
 629         new->grp.name = "parameters";
 630         new->grp.attrs = attrs;
 631
 632         /* Tack new one on the end. */
 633         sysfs_attr_init(&new->attrs[num].mattr.attr);
 634         new->attrs[num].param = kp;
 635         new->attrs[num].mattr.show = param_attr_show;
 636         new->attrs[num].mattr.store = param_attr_store;
 637         new->attrs[num].mattr.attr.name = (char *)name;
 638         new->attrs[num].mattr.attr.mode = kp->perm;
 639         new->num = num+1;
 640
 641         /* Fix up all the pointers, since krealloc can move us */
 642         for (num = 0; num < new->num; num++)
 643                 new->grp.attrs[num] = &new->attrs[num].mattr.attr;
 644         new->grp.attrs[num] = NULL;
 645
 646         mk->mp = new;
 647         return 0;
 648
 649 fail_free_new:
 650         kfree(new);
 651 fail:
 652         mk->mp = NULL;
 653         return err;
 654 }
 655
 656 #ifdef CONFIG_MODULES
 657 static void free_module_param_attrs(struct module_kobject *mk)
 658 {
 659         kfree(mk->mp->grp.attrs);
 660         kfree(mk->mp);
 661         mk->mp = NULL;
 662 }
 663
 664 /*
 665  * module_param_sysfs_setup - setup sysfs support for one module
 666  * @mod: module
 667  * @kparam: module parameters (array)
 668  * @num_params: number of module parameters
 669  *
 670  * Adds sysfs entries for module parameters under
 671  * /sys/module/[mod->name]/parameters/
 672  */
 673 int module_param_sysfs_setup(struct module *mod,
 674                              const struct kernel_param *kparam,
 675                              unsigned int num_params)
 676 {
 677         int i, err;
 678         bool params = false;
 679
 680         for (i = 0; i < num_params; i++) {
 681                 if (kparam[i].perm == 0)
 682                         continue;
 683                 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 684                 if (err)
 685                         return err;
 686                 params = true;
 687         }
 688
 689         if (!params)
 690                 return 0;
 691
 692         /* Create the param group. */
 693         err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 694         if (err)
 695                 free_module_param_attrs(&mod->mkobj);
 696         return err;
 697 }
 698
 699 /*
 700  * module_param_sysfs_remove - remove sysfs support for one module
 701  * @mod: module
 702  *
 703  * Remove sysfs entries for module parameters and the corresponding
 704  * kobject.
 705  */
 706 void module_param_sysfs_remove(struct module *mod)
 707 {
 708         if (mod->mkobj.mp) {
 709                 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 710                 /* We are positive that no one is using any param
 711                  * attrs at this point.  Deallocate immediately. */
 712                 free_module_param_attrs(&mod->mkobj);
 713         }
 714 }
 715 #endif
 716
 717 void destroy_params(const struct kernel_param *params, unsigned num)
 718 {
 719         unsigned int i;
 720
 721         for (i = 0; i < num; i++)
 722                 if (params[i].ops->free)
 723                         params[i].ops->free(params[i].arg);
 724 }
 725
 726 static struct module_kobject * __init locate_module_kobject(const char *name)
 727 {
 728         struct module_kobject *mk;
 729         struct kobject *kobj;
 730         int err;
 731
 732         kobj = kset_find_obj(module_kset, name);
 733         if (kobj) {
 734                 mk = to_module_kobject(kobj);
 735         } else {
 736                 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 737                 BUG_ON(!mk);
 738
 739                 mk->mod = THIS_MODULE;
 740                 mk->kobj.kset = module_kset;
 741                 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 742                                            "%s", name);
 743 #ifdef CONFIG_MODULES
 744                 if (!err)
 745                         err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 746 #endif
 747                 if (err) {
 748                         kobject_put(&mk->kobj);
 749                         pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
 750                                 name, err);
 751                         return NULL;
 752                 }
 753
 754                 /* So that we hold reference in both cases. */
 755                 kobject_get(&mk->kobj);
 756         }
 757
 758         return mk;
 759 }
 760
 761 static void __init kernel_add_sysfs_param(const char *name,
 762                                           struct kernel_param *kparam,
 763                                           unsigned int name_skip)
 764 {
 765         struct module_kobject *mk;
 766         int err;
 767
 768         mk = locate_module_kobject(name);
 769         if (!mk)
 770                 return;
 771
 772         /* We need to remove old parameters before adding more. */
 773         if (mk->mp)
 774                 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 775
 776         /* These should not fail at boot. */
 777         err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 778         BUG_ON(err);
 779         err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 780         BUG_ON(err);
 781         kobject_uevent(&mk->kobj, KOBJ_ADD);
 782         kobject_put(&mk->kobj);
 783 }
 784
 785 /*
 786  * param_sysfs_builtin - add sysfs parameters for built-in modules
 787  *
 788  * Add module_parameters to sysfs for "modules" built into the kernel.
 789  *
 790  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 791  * "parameter" name is stored behind a dot in kernel_param->name. So,
 792  * extract the "module" name for all built-in kernel_param-eters,
 793  * and for all who have the same, call kernel_add_sysfs_param.
 794  */
 795 static void __init param_sysfs_builtin(void)
 796 {
 797         struct kernel_param *kp;
 798         unsigned int name_len;
 799         char modname[MODULE_NAME_LEN];
 800
 801         for (kp = __start___param; kp < __stop___param; kp++) {
 802                 char *dot;
 803
 804                 if (kp->perm == 0)
 805                         continue;
 806
 807                 dot = strchr(kp->name, '.');
 808                 if (!dot) {
 809                         /* This happens for core_param() */
 810                         strcpy(modname, "kernel");
 811                         name_len = 0;
 812                 } else {
 813                         name_len = dot - kp->name + 1;
 814                         strlcpy(modname, kp->name, name_len);
 815                 }
 816                 kernel_add_sysfs_param(modname, kp, name_len);
 817         }
 818 }
 819
 820 ssize_t __modver_version_show(struct module_attribute *mattr,
 821                               struct module_kobject *mk, char *buf)
 822 {
 823         struct module_version_attribute *vattr =
 824                 container_of(mattr, struct module_version_attribute, mattr);
 825
 826         return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
 827 }
 828
 829 extern const struct module_version_attribute *__start___modver[];
 830 extern const struct module_version_attribute *__stop___modver[];
 831
 832 static void __init version_sysfs_builtin(void)
 833 {
 834         const struct module_version_attribute **p;
 835         struct module_kobject *mk;
 836         int err;
 837
 838         for (p = __start___modver; p < __stop___modver; p++) {
 839                 const struct module_version_attribute *vattr = *p;
 840
 841                 mk = locate_module_kobject(vattr->module_name);
 842                 if (mk) {
 843                         err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 844                         kobject_uevent(&mk->kobj, KOBJ_ADD);
 845                         kobject_put(&mk->kobj);
 846                 }
 847         }
 848 }
 849
 850 /* module-related sysfs stuff */
 851
 852 static ssize_t module_attr_show(struct kobject *kobj,
 853                                 struct attribute *attr,
 854                                 char *buf)
 855 {
 856         struct module_attribute *attribute;
 857         struct module_kobject *mk;
 858         int ret;
 859
 860         attribute = to_module_attr(attr);
 861         mk = to_module_kobject(kobj);
 862
 863         if (!attribute->show)
 864                 return -EIO;
 865
 866         ret = attribute->show(attribute, mk, buf);
 867
 868         return ret;
 869 }
 870
 871 static ssize_t module_attr_store(struct kobject *kobj,
 872                                 struct attribute *attr,
 873                                 const char *buf, size_t len)
 874 {
 875         struct module_attribute *attribute;
 876         struct module_kobject *mk;
 877         int ret;
 878
 879         attribute = to_module_attr(attr);
 880         mk = to_module_kobject(kobj);
 881
 882         if (!attribute->store)
 883                 return -EIO;
 884
 885         ret = attribute->store(attribute, mk, buf, len);
 886
 887         return ret;
 888 }
 889
 890 static const struct sysfs_ops module_sysfs_ops = {
 891         .show = module_attr_show,
 892         .store = module_attr_store,
 893 };
 894
 895 static int uevent_filter(struct kset *kset, struct kobject *kobj)
 896 {
 897         struct kobj_type *ktype = get_ktype(kobj);
 898
 899         if (ktype == &module_ktype)
 900                 return 1;
 901         return 0;
 902 }
 903
 904 static const struct kset_uevent_ops module_uevent_ops = {
 905         .filter = uevent_filter,
 906 };
 907
 908 struct kset *module_kset;
 909 int module_sysfs_initialized;
 910
 911 static void module_kobj_release(struct kobject *kobj)
 912 {
 913         struct module_kobject *mk = to_module_kobject(kobj);
 914         complete(mk->kobj_completion);
 915 }
 916
 917 struct kobj_type module_ktype = {
 918         .release   =    module_kobj_release,
 919         .sysfs_ops =    &module_sysfs_ops,
 920 };
 921
 922 /*
 923  * param_sysfs_init - wrapper for built-in params support
 924  */
 925 static int __init param_sysfs_init(void)
 926 {
 927         module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
 928         if (!module_kset) {
 929                 printk(KERN_WARNING "%s (%d): error creating kset\n",
 930                         __FILE__, __LINE__);
 931                 return -ENOMEM;
 932         }
 933         module_sysfs_initialized = 1;
 934
 935         version_sysfs_builtin();
 936         param_sysfs_builtin();
 937
 938         return 0;
 939 }
 940 subsys_initcall(param_sysfs_init);
 941
 942 #endif /* CONFIG_SYSFS */