kernel/params.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* Helpers for initial module or kernel cmdline parsing
   3    Copyright (C) 2001 Rusty Russell.
   4
   5 */
   6 #include <linux/kernel.h>
   7 #include <linux/string.h>
   8 #include <linux/errno.h>
   9 #include <linux/module.h>
  10 #include <linux/moduleparam.h>
  11 #include <linux/device.h>
  12 #include <linux/err.h>
  13 #include <linux/slab.h>
  14 #include <linux/ctype.h>
  15 #include <linux/security.h>
  16
  17 #ifdef CONFIG_SYSFS
  18 /* Protects all built-in parameters, modules use their own param_lock */
  19 static DEFINE_MUTEX(param_lock);
  20
  21 /* Use the module's mutex, or if built-in use the built-in mutex */
  22 #ifdef CONFIG_MODULES
  23 #define KPARAM_MUTEX(mod)       ((mod) ? &(mod)->param_lock : &param_lock)
  24 #else
  25 #define KPARAM_MUTEX(mod)       (&param_lock)
  26 #endif
  27
  28 static inline void check_kparam_locked(struct module *mod)
  29 {
  30         BUG_ON(!mutex_is_locked(KPARAM_MUTEX(mod)));
  31 }
  32 #else
  33 static inline void check_kparam_locked(struct module *mod)
  34 {
  35 }
  36 #endif /* !CONFIG_SYSFS */
  37
  38 /* This just allows us to keep track of which parameters are kmalloced. */
  39 struct kmalloced_param {
  40         struct list_head list;
  41         char val[];
  42 };
  43 static LIST_HEAD(kmalloced_params);
  44 static DEFINE_SPINLOCK(kmalloced_params_lock);
  45
  46 static void *kmalloc_parameter(unsigned int size)
  47 {
  48         struct kmalloced_param *p;
  49
  50         p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
  51         if (!p)
  52                 return NULL;
  53
  54         spin_lock(&kmalloced_params_lock);
  55         list_add(&p->list, &kmalloced_params);
  56         spin_unlock(&kmalloced_params_lock);
  57
  58         return p->val;
  59 }
  60
  61 /* Does nothing if parameter wasn't kmalloced above. */
  62 static void maybe_kfree_parameter(void *param)
  63 {
  64         struct kmalloced_param *p;
  65
  66         spin_lock(&kmalloced_params_lock);
  67         list_for_each_entry(p, &kmalloced_params, list) {
  68                 if (p->val == param) {
  69                         list_del(&p->list);
  70                         kfree(p);
  71                         break;
  72                 }
  73         }
  74         spin_unlock(&kmalloced_params_lock);
  75 }
  76
  77 static char dash2underscore(char c)
  78 {
  79         if (c == '-')
  80                 return '_';
  81         return c;
  82 }
  83
  84 bool parameqn(const char *a, const char *b, size_t n)
  85 {
  86         size_t i;
  87
  88         for (i = 0; i < n; i++) {
  89                 if (dash2underscore(a[i]) != dash2underscore(b[i]))
  90                         return false;
  91         }
  92         return true;
  93 }
  94
  95 bool parameq(const char *a, const char *b)
  96 {
  97         return parameqn(a, b, strlen(a)+1);
  98 }
  99
 100 static bool param_check_unsafe(const struct kernel_param *kp)
 101 {
 102         if (kp->flags & KERNEL_PARAM_FL_HWPARAM &&
 103             security_locked_down(LOCKDOWN_MODULE_PARAMETERS))
 104                 return false;
 105
 106         if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {
 107                 pr_notice("Setting dangerous option %s - tainting kernel\n",
 108                           kp->name);
 109                 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 110         }
 111
 112         return true;
 113 }
 114
 115 static int parse_one(char *param,
 116                      char *val,
 117                      const char *doing,
 118                      const struct kernel_param *params,
 119                      unsigned num_params,
 120                      s16 min_level,
 121                      s16 max_level,
 122                      void *arg,
 123                      int (*handle_unknown)(char *param, char *val,
 124                                      const char *doing, void *arg))
 125 {
 126         unsigned int i;
 127         int err;
 128
 129         /* Find parameter */
 130         for (i = 0; i < num_params; i++) {
 131                 if (parameq(param, params[i].name)) {
 132                         if (params[i].level < min_level
 133                             || params[i].level > max_level)
 134                                 return 0;
 135                         /* No one handled NULL, so do it here. */
 136                         if (!val &&
 137                             !(params[i].ops->flags & KERNEL_PARAM_OPS_FL_NOARG))
 138                                 return -EINVAL;
 139                         pr_debug("handling %s with %p\n", param,
 140                                 params[i].ops->set);
 141                         kernel_param_lock(params[i].mod);
 142                         if (param_check_unsafe(&params[i]))
 143                                 err = params[i].ops->set(val, &params[i]);
 144                         else
 145                                 err = -EPERM;
 146                         kernel_param_unlock(params[i].mod);
 147                         return err;
 148                 }
 149         }
 150
 151         if (handle_unknown) {
 152                 pr_debug("doing %s: %s='%s'\n", doing, param, val);
 153                 return handle_unknown(param, val, doing, arg);
 154         }
 155
 156         pr_debug("Unknown argument '%s'\n", param);
 157         return -ENOENT;
 158 }
 159
 160 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 161 char *parse_args(const char *doing,
 162                  char *args,
 163                  const struct kernel_param *params,
 164                  unsigned num,
 165                  s16 min_level,
 166                  s16 max_level,
 167                  void *arg,
 168                  int (*unknown)(char *param, char *val,
 169                                 const char *doing, void *arg))
 170 {
 171         char *param, *val, *err = NULL;
 172
 173         /* Chew leading spaces */
 174         args = skip_spaces(args);
 175
 176         if (*args)
 177                 pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
 178
 179         while (*args) {
 180                 int ret;
 181                 int irq_was_disabled;
 182
 183                 args = next_arg(args, &param, &val);
 184                 /* Stop at -- */
 185                 if (!val && strcmp(param, "--") == 0)
 186                         return err ?: args;
 187                 irq_was_disabled = irqs_disabled();
 188                 ret = parse_one(param, val, doing, params, num,
 189                                 min_level, max_level, arg, unknown);
 190                 if (irq_was_disabled && !irqs_disabled())
 191                         pr_warn("%s: option '%s' enabled irq's!\n",
 192                                 doing, param);
 193
 194                 switch (ret) {
 195                 case 0:
 196                         continue;
 197                 case -ENOENT:
 198                         pr_err("%s: Unknown parameter `%s'\n", doing, param);
 199                         break;
 200                 case -ENOSPC:
 201                         pr_err("%s: `%s' too large for parameter `%s'\n",
 202                                doing, val ?: "", param);
 203                         break;
 204                 default:
 205                         pr_err("%s: `%s' invalid for parameter `%s'\n",
 206                                doing, val ?: "", param);
 207                         break;
 208                 }
 209
 210                 err = ERR_PTR(ret);
 211         }
 212
 213         return err;
 214 }
 215
 216 /* Lazy bastard, eh? */
 217 #define STANDARD_PARAM_DEF(name, type, format, strtolfn)                \
 218         int param_set_##name(const char *val, const struct kernel_param *kp) \
 219         {                                                               \
 220                 return strtolfn(val, 0, (type *)kp->arg);               \
 221         }                                                               \
 222         int param_get_##name(char *buffer, const struct kernel_param *kp) \
 223         {                                                               \
 224                 return scnprintf(buffer, PAGE_SIZE, format "\n",        \
 225                                 *((type *)kp->arg));                    \
 226         }                                                               \
 227         const struct kernel_param_ops param_ops_##name = {                      \
 228                 .set = param_set_##name,                                \
 229                 .get = param_get_##name,                                \
 230         };                                                              \
 231         EXPORT_SYMBOL(param_set_##name);                                \
 232         EXPORT_SYMBOL(param_get_##name);                                \
 233         EXPORT_SYMBOL(param_ops_##name)
 234
 235
 236 STANDARD_PARAM_DEF(byte,        unsigned char,          "%hhu",         kstrtou8);
 237 STANDARD_PARAM_DEF(short,       short,                  "%hi",          kstrtos16);
 238 STANDARD_PARAM_DEF(ushort,      unsigned short,         "%hu",          kstrtou16);
 239 STANDARD_PARAM_DEF(int,         int,                    "%i",           kstrtoint);
 240 STANDARD_PARAM_DEF(uint,        unsigned int,           "%u",           kstrtouint);
 241 STANDARD_PARAM_DEF(long,        long,                   "%li",          kstrtol);
 242 STANDARD_PARAM_DEF(ulong,       unsigned long,          "%lu",          kstrtoul);
 243 STANDARD_PARAM_DEF(ullong,      unsigned long long,     "%llu",         kstrtoull);
 244 STANDARD_PARAM_DEF(hexint,      unsigned int,           "%#08x",        kstrtouint);
 245
 246 int param_set_uint_minmax(const char *val, const struct kernel_param *kp,
 247                 unsigned int min, unsigned int max)
 248 {
 249         unsigned int num;
 250         int ret;
 251
 252         if (!val)
 253                 return -EINVAL;
 254         ret = kstrtouint(val, 0, &num);
 255         if (ret)
 256                 return ret;
 257         if (num < min || num > max)
 258                 return -EINVAL;
 259         *((unsigned int *)kp->arg) = num;
 260         return 0;
 261 }
 262 EXPORT_SYMBOL_GPL(param_set_uint_minmax);
 263
 264 int param_set_charp(const char *val, const struct kernel_param *kp)
 265 {
 266         if (strlen(val) > 1024) {
 267                 pr_err("%s: string parameter too long\n", kp->name);
 268                 return -ENOSPC;
 269         }
 270
 271         maybe_kfree_parameter(*(char **)kp->arg);
 272
 273         /* This is a hack.  We can't kmalloc in early boot, and we
 274          * don't need to; this mangled commandline is preserved. */
 275         if (slab_is_available()) {
 276                 *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
 277                 if (!*(char **)kp->arg)
 278                         return -ENOMEM;
 279                 strcpy(*(char **)kp->arg, val);
 280         } else
 281                 *(const char **)kp->arg = val;
 282
 283         return 0;
 284 }
 285 EXPORT_SYMBOL(param_set_charp);
 286
 287 int param_get_charp(char *buffer, const struct kernel_param *kp)
 288 {
 289         return scnprintf(buffer, PAGE_SIZE, "%s\n", *((char **)kp->arg));
 290 }
 291 EXPORT_SYMBOL(param_get_charp);
 292
 293 void param_free_charp(void *arg)
 294 {
 295         maybe_kfree_parameter(*((char **)arg));
 296 }
 297 EXPORT_SYMBOL(param_free_charp);
 298
 299 const struct kernel_param_ops param_ops_charp = {
 300         .set = param_set_charp,
 301         .get = param_get_charp,
 302         .free = param_free_charp,
 303 };
 304 EXPORT_SYMBOL(param_ops_charp);
 305
 306 /* Actually could be a bool or an int, for historical reasons. */
 307 int param_set_bool(const char *val, const struct kernel_param *kp)
 308 {
 309         /* No equals means "set"... */
 310         if (!val) val = "1";
 311
 312         /* One of =[yYnN01] */
 313         return strtobool(val, kp->arg);
 314 }
 315 EXPORT_SYMBOL(param_set_bool);
 316
 317 int param_get_bool(char *buffer, const struct kernel_param *kp)
 318 {
 319         /* Y and N chosen as being relatively non-coder friendly */
 320         return sprintf(buffer, "%c\n", *(bool *)kp->arg ? 'Y' : 'N');
 321 }
 322 EXPORT_SYMBOL(param_get_bool);
 323
 324 const struct kernel_param_ops param_ops_bool = {
 325         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 326         .set = param_set_bool,
 327         .get = param_get_bool,
 328 };
 329 EXPORT_SYMBOL(param_ops_bool);
 330
 331 int param_set_bool_enable_only(const char *val, const struct kernel_param *kp)
 332 {
 333         int err = 0;
 334         bool new_value;
 335         bool orig_value = *(bool *)kp->arg;
 336         struct kernel_param dummy_kp = *kp;
 337
 338         dummy_kp.arg = &new_value;
 339
 340         err = param_set_bool(val, &dummy_kp);
 341         if (err)
 342                 return err;
 343
 344         /* Don't let them unset it once it's set! */
 345         if (!new_value && orig_value)
 346                 return -EROFS;
 347
 348         if (new_value)
 349                 err = param_set_bool(val, kp);
 350
 351         return err;
 352 }
 353 EXPORT_SYMBOL_GPL(param_set_bool_enable_only);
 354
 355 const struct kernel_param_ops param_ops_bool_enable_only = {
 356         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 357         .set = param_set_bool_enable_only,
 358         .get = param_get_bool,
 359 };
 360 EXPORT_SYMBOL_GPL(param_ops_bool_enable_only);
 361
 362 /* This one must be bool. */
 363 int param_set_invbool(const char *val, const struct kernel_param *kp)
 364 {
 365         int ret;
 366         bool boolval;
 367         struct kernel_param dummy;
 368
 369         dummy.arg = &boolval;
 370         ret = param_set_bool(val, &dummy);
 371         if (ret == 0)
 372                 *(bool *)kp->arg = !boolval;
 373         return ret;
 374 }
 375 EXPORT_SYMBOL(param_set_invbool);
 376
 377 int param_get_invbool(char *buffer, const struct kernel_param *kp)
 378 {
 379         return sprintf(buffer, "%c\n", (*(bool *)kp->arg) ? 'N' : 'Y');
 380 }
 381 EXPORT_SYMBOL(param_get_invbool);
 382
 383 const struct kernel_param_ops param_ops_invbool = {
 384         .set = param_set_invbool,
 385         .get = param_get_invbool,
 386 };
 387 EXPORT_SYMBOL(param_ops_invbool);
 388
 389 int param_set_bint(const char *val, const struct kernel_param *kp)
 390 {
 391         /* Match bool exactly, by re-using it. */
 392         struct kernel_param boolkp = *kp;
 393         bool v;
 394         int ret;
 395
 396         boolkp.arg = &v;
 397
 398         ret = param_set_bool(val, &boolkp);
 399         if (ret == 0)
 400                 *(int *)kp->arg = v;
 401         return ret;
 402 }
 403 EXPORT_SYMBOL(param_set_bint);
 404
 405 const struct kernel_param_ops param_ops_bint = {
 406         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 407         .set = param_set_bint,
 408         .get = param_get_int,
 409 };
 410 EXPORT_SYMBOL(param_ops_bint);
 411
 412 /* We break the rule and mangle the string. */
 413 static int param_array(struct module *mod,
 414                        const char *name,
 415                        const char *val,
 416                        unsigned int min, unsigned int max,
 417                        void *elem, int elemsize,
 418                        int (*set)(const char *, const struct kernel_param *kp),
 419                        s16 level,
 420                        unsigned int *num)
 421 {
 422         int ret;
 423         struct kernel_param kp;
 424         char save;
 425
 426         /* Get the name right for errors. */
 427         kp.name = name;
 428         kp.arg = elem;
 429         kp.level = level;
 430
 431         *num = 0;
 432         /* We expect a comma-separated list of values. */
 433         do {
 434                 int len;
 435
 436                 if (*num == max) {
 437                         pr_err("%s: can only take %i arguments\n", name, max);
 438                         return -EINVAL;
 439                 }
 440                 len = strcspn(val, ",");
 441
 442                 /* nul-terminate and parse */
 443                 save = val[len];
 444                 ((char *)val)[len] = '\0';
 445                 check_kparam_locked(mod);
 446                 ret = set(val, &kp);
 447
 448                 if (ret != 0)
 449                         return ret;
 450                 kp.arg += elemsize;
 451                 val += len+1;
 452                 (*num)++;
 453         } while (save == ',');
 454
 455         if (*num < min) {
 456                 pr_err("%s: needs at least %i arguments\n", name, min);
 457                 return -EINVAL;
 458         }
 459         return 0;
 460 }
 461
 462 static int param_array_set(const char *val, const struct kernel_param *kp)
 463 {
 464         const struct kparam_array *arr = kp->arr;
 465         unsigned int temp_num;
 466
 467         return param_array(kp->mod, kp->name, val, 1, arr->max, arr->elem,
 468                            arr->elemsize, arr->ops->set, kp->level,
 469                            arr->num ?: &temp_num);
 470 }
 471
 472 static int param_array_get(char *buffer, const struct kernel_param *kp)
 473 {
 474         int i, off, ret;
 475         const struct kparam_array *arr = kp->arr;
 476         struct kernel_param p = *kp;
 477
 478         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 479                 /* Replace \n with comma */
 480                 if (i)
 481                         buffer[off - 1] = ',';
 482                 p.arg = arr->elem + arr->elemsize * i;
 483                 check_kparam_locked(p.mod);
 484                 ret = arr->ops->get(buffer + off, &p);
 485                 if (ret < 0)
 486                         return ret;
 487                 off += ret;
 488         }
 489         buffer[off] = '\0';
 490         return off;
 491 }
 492
 493 static void param_array_free(void *arg)
 494 {
 495         unsigned int i;
 496         const struct kparam_array *arr = arg;
 497
 498         if (arr->ops->free)
 499                 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 500                         arr->ops->free(arr->elem + arr->elemsize * i);
 501 }
 502
 503 const struct kernel_param_ops param_array_ops = {
 504         .set = param_array_set,
 505         .get = param_array_get,
 506         .free = param_array_free,
 507 };
 508 EXPORT_SYMBOL(param_array_ops);
 509
 510 int param_set_copystring(const char *val, const struct kernel_param *kp)
 511 {
 512         const struct kparam_string *kps = kp->str;
 513
 514         if (strlen(val)+1 > kps->maxlen) {
 515                 pr_err("%s: string doesn't fit in %u chars.\n",
 516                        kp->name, kps->maxlen-1);
 517                 return -ENOSPC;
 518         }
 519         strcpy(kps->string, val);
 520         return 0;
 521 }
 522 EXPORT_SYMBOL(param_set_copystring);
 523
 524 int param_get_string(char *buffer, const struct kernel_param *kp)
 525 {
 526         const struct kparam_string *kps = kp->str;
 527         return scnprintf(buffer, PAGE_SIZE, "%s\n", kps->string);
 528 }
 529 EXPORT_SYMBOL(param_get_string);
 530
 531 const struct kernel_param_ops param_ops_string = {
 532         .set = param_set_copystring,
 533         .get = param_get_string,
 534 };
 535 EXPORT_SYMBOL(param_ops_string);
 536
 537 /* sysfs output in /sys/modules/XYZ/parameters/ */
 538 #define to_module_attr(n) container_of(n, struct module_attribute, attr)
 539 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 540
 541 struct param_attribute
 542 {
 543         struct module_attribute mattr;
 544         const struct kernel_param *param;
 545 };
 546
 547 struct module_param_attrs
 548 {
 549         unsigned int num;
 550         struct attribute_group grp;
 551         struct param_attribute attrs[];
 552 };
 553
 554 #ifdef CONFIG_SYSFS
 555 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 556
 557 static ssize_t param_attr_show(struct module_attribute *mattr,
 558                                struct module_kobject *mk, char *buf)
 559 {
 560         int count;
 561         struct param_attribute *attribute = to_param_attr(mattr);
 562
 563         if (!attribute->param->ops->get)
 564                 return -EPERM;
 565
 566         kernel_param_lock(mk->mod);
 567         count = attribute->param->ops->get(buf, attribute->param);
 568         kernel_param_unlock(mk->mod);
 569         return count;
 570 }
 571
 572 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 573 static ssize_t param_attr_store(struct module_attribute *mattr,
 574                                 struct module_kobject *mk,
 575                                 const char *buf, size_t len)
 576 {
 577         int err;
 578         struct param_attribute *attribute = to_param_attr(mattr);
 579
 580         if (!attribute->param->ops->set)
 581                 return -EPERM;
 582
 583         kernel_param_lock(mk->mod);
 584         if (param_check_unsafe(attribute->param))
 585                 err = attribute->param->ops->set(buf, attribute->param);
 586         else
 587                 err = -EPERM;
 588         kernel_param_unlock(mk->mod);
 589         if (!err)
 590                 return len;
 591         return err;
 592 }
 593 #endif
 594
 595 #ifdef CONFIG_MODULES
 596 #define __modinit
 597 #else
 598 #define __modinit __init
 599 #endif
 600
 601 #ifdef CONFIG_SYSFS
 602 void kernel_param_lock(struct module *mod)
 603 {
 604         mutex_lock(KPARAM_MUTEX(mod));
 605 }
 606
 607 void kernel_param_unlock(struct module *mod)
 608 {
 609         mutex_unlock(KPARAM_MUTEX(mod));
 610 }
 611
 612 EXPORT_SYMBOL(kernel_param_lock);
 613 EXPORT_SYMBOL(kernel_param_unlock);
 614
 615 /*
 616  * add_sysfs_param - add a parameter to sysfs
 617  * @mk: struct module_kobject
 618  * @kp: the actual parameter definition to add to sysfs
 619  * @name: name of parameter
 620  *
 621  * Create a kobject if for a (per-module) parameter if mp NULL, and
 622  * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 623  * if there's an error.
 624  */
 625 static __modinit int add_sysfs_param(struct module_kobject *mk,
 626                                      const struct kernel_param *kp,
 627                                      const char *name)
 628 {
 629         struct module_param_attrs *new_mp;
 630         struct attribute **new_attrs;
 631         unsigned int i;
 632
 633         /* We don't bother calling this with invisible parameters. */
 634         BUG_ON(!kp->perm);
 635
 636         if (!mk->mp) {
 637                 /* First allocation. */
 638                 mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
 639                 if (!mk->mp)
 640                         return -ENOMEM;
 641                 mk->mp->grp.name = "parameters";
 642                 /* NULL-terminated attribute array. */
 643                 mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
 644                                             GFP_KERNEL);
 645                 /* Caller will cleanup via free_module_param_attrs */
 646                 if (!mk->mp->grp.attrs)
 647                         return -ENOMEM;
 648         }
 649
 650         /* Enlarge allocations. */
 651         new_mp = krealloc(mk->mp,
 652                           sizeof(*mk->mp) +
 653                           sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1),
 654                           GFP_KERNEL);
 655         if (!new_mp)
 656                 return -ENOMEM;
 657         mk->mp = new_mp;
 658
 659         /* Extra pointer for NULL terminator */
 660         new_attrs = krealloc(mk->mp->grp.attrs,
 661                              sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2),
 662                              GFP_KERNEL);
 663         if (!new_attrs)
 664                 return -ENOMEM;
 665         mk->mp->grp.attrs = new_attrs;
 666
 667         /* Tack new one on the end. */
 668         memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0]));
 669         sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
 670         mk->mp->attrs[mk->mp->num].param = kp;
 671         mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
 672         /* Do not allow runtime DAC changes to make param writable. */
 673         if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
 674                 mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
 675         else
 676                 mk->mp->attrs[mk->mp->num].mattr.store = NULL;
 677         mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
 678         mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
 679         mk->mp->num++;
 680
 681         /* Fix up all the pointers, since krealloc can move us */
 682         for (i = 0; i < mk->mp->num; i++)
 683                 mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
 684         mk->mp->grp.attrs[mk->mp->num] = NULL;
 685         return 0;
 686 }
 687
 688 #ifdef CONFIG_MODULES
 689 static void free_module_param_attrs(struct module_kobject *mk)
 690 {
 691         if (mk->mp)
 692                 kfree(mk->mp->grp.attrs);
 693         kfree(mk->mp);
 694         mk->mp = NULL;
 695 }
 696
 697 /*
 698  * module_param_sysfs_setup - setup sysfs support for one module
 699  * @mod: module
 700  * @kparam: module parameters (array)
 701  * @num_params: number of module parameters
 702  *
 703  * Adds sysfs entries for module parameters under
 704  * /sys/module/[mod->name]/parameters/
 705  */
 706 int module_param_sysfs_setup(struct module *mod,
 707                              const struct kernel_param *kparam,
 708                              unsigned int num_params)
 709 {
 710         int i, err;
 711         bool params = false;
 712
 713         for (i = 0; i < num_params; i++) {
 714                 if (kparam[i].perm == 0)
 715                         continue;
 716                 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 717                 if (err) {
 718                         free_module_param_attrs(&mod->mkobj);
 719                         return err;
 720                 }
 721                 params = true;
 722         }
 723
 724         if (!params)
 725                 return 0;
 726
 727         /* Create the param group. */
 728         err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 729         if (err)
 730                 free_module_param_attrs(&mod->mkobj);
 731         return err;
 732 }
 733
 734 /*
 735  * module_param_sysfs_remove - remove sysfs support for one module
 736  * @mod: module
 737  *
 738  * Remove sysfs entries for module parameters and the corresponding
 739  * kobject.
 740  */
 741 void module_param_sysfs_remove(struct module *mod)
 742 {
 743         if (mod->mkobj.mp) {
 744                 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 745                 /* We are positive that no one is using any param
 746                  * attrs at this point.  Deallocate immediately. */
 747                 free_module_param_attrs(&mod->mkobj);
 748         }
 749 }
 750 #endif
 751
 752 void destroy_params(const struct kernel_param *params, unsigned num)
 753 {
 754         unsigned int i;
 755
 756         for (i = 0; i < num; i++)
 757                 if (params[i].ops->free)
 758                         params[i].ops->free(params[i].arg);
 759 }
 760
 761 static struct module_kobject * __init locate_module_kobject(const char *name)
 762 {
 763         struct module_kobject *mk;
 764         struct kobject *kobj;
 765         int err;
 766
 767         kobj = kset_find_obj(module_kset, name);
 768         if (kobj) {
 769                 mk = to_module_kobject(kobj);
 770         } else {
 771                 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 772                 BUG_ON(!mk);
 773
 774                 mk->mod = THIS_MODULE;
 775                 mk->kobj.kset = module_kset;
 776                 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 777                                            "%s", name);
 778 #ifdef CONFIG_MODULES
 779                 if (!err)
 780                         err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 781 #endif
 782                 if (err) {
 783                         kobject_put(&mk->kobj);
 784                         pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
 785                                 name, err);
 786                         return NULL;
 787                 }
 788
 789                 /* So that we hold reference in both cases. */
 790                 kobject_get(&mk->kobj);
 791         }
 792
 793         return mk;
 794 }
 795
 796 static void __init kernel_add_sysfs_param(const char *name,
 797                                           const struct kernel_param *kparam,
 798                                           unsigned int name_skip)
 799 {
 800         struct module_kobject *mk;
 801         int err;
 802
 803         mk = locate_module_kobject(name);
 804         if (!mk)
 805                 return;
 806
 807         /* We need to remove old parameters before adding more. */
 808         if (mk->mp)
 809                 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 810
 811         /* These should not fail at boot. */
 812         err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 813         BUG_ON(err);
 814         err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 815         BUG_ON(err);
 816         kobject_uevent(&mk->kobj, KOBJ_ADD);
 817         kobject_put(&mk->kobj);
 818 }
 819
 820 /*
 821  * param_sysfs_builtin - add sysfs parameters for built-in modules
 822  *
 823  * Add module_parameters to sysfs for "modules" built into the kernel.
 824  *
 825  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 826  * "parameter" name is stored behind a dot in kernel_param->name. So,
 827  * extract the "module" name for all built-in kernel_param-eters,
 828  * and for all who have the same, call kernel_add_sysfs_param.
 829  */
 830 static void __init param_sysfs_builtin(void)
 831 {
 832         const struct kernel_param *kp;
 833         unsigned int name_len;
 834         char modname[MODULE_NAME_LEN];
 835
 836         for (kp = __start___param; kp < __stop___param; kp++) {
 837                 char *dot;
 838
 839                 if (kp->perm == 0)
 840                         continue;
 841
 842                 dot = strchr(kp->name, '.');
 843                 if (!dot) {
 844                         /* This happens for core_param() */
 845                         strcpy(modname, "kernel");
 846                         name_len = 0;
 847                 } else {
 848                         name_len = dot - kp->name + 1;
 849                         strlcpy(modname, kp->name, name_len);
 850                 }
 851                 kernel_add_sysfs_param(modname, kp, name_len);
 852         }
 853 }
 854
 855 ssize_t __modver_version_show(struct module_attribute *mattr,
 856                               struct module_kobject *mk, char *buf)
 857 {
 858         struct module_version_attribute *vattr =
 859                 container_of(mattr, struct module_version_attribute, mattr);
 860
 861         return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
 862 }
 863
 864 extern const struct module_version_attribute __start___modver[];
 865 extern const struct module_version_attribute __stop___modver[];
 866
 867 static void __init version_sysfs_builtin(void)
 868 {
 869         const struct module_version_attribute *vattr;
 870         struct module_kobject *mk;
 871         int err;
 872
 873         for (vattr = __start___modver; vattr < __stop___modver; vattr++) {
 874                 mk = locate_module_kobject(vattr->module_name);
 875                 if (mk) {
 876                         err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 877                         WARN_ON_ONCE(err);
 878                         kobject_uevent(&mk->kobj, KOBJ_ADD);
 879                         kobject_put(&mk->kobj);
 880                 }
 881         }
 882 }
 883
 884 /* module-related sysfs stuff */
 885
 886 static ssize_t module_attr_show(struct kobject *kobj,
 887                                 struct attribute *attr,
 888                                 char *buf)
 889 {
 890         struct module_attribute *attribute;
 891         struct module_kobject *mk;
 892         int ret;
 893
 894         attribute = to_module_attr(attr);
 895         mk = to_module_kobject(kobj);
 896
 897         if (!attribute->show)
 898                 return -EIO;
 899
 900         ret = attribute->show(attribute, mk, buf);
 901
 902         return ret;
 903 }
 904
 905 static ssize_t module_attr_store(struct kobject *kobj,
 906                                 struct attribute *attr,
 907                                 const char *buf, size_t len)
 908 {
 909         struct module_attribute *attribute;
 910         struct module_kobject *mk;
 911         int ret;
 912
 913         attribute = to_module_attr(attr);
 914         mk = to_module_kobject(kobj);
 915
 916         if (!attribute->store)
 917                 return -EIO;
 918
 919         ret = attribute->store(attribute, mk, buf, len);
 920
 921         return ret;
 922 }
 923
 924 static const struct sysfs_ops module_sysfs_ops = {
 925         .show = module_attr_show,
 926         .store = module_attr_store,
 927 };
 928
 929 static int uevent_filter(struct kset *kset, struct kobject *kobj)
 930 {
 931         struct kobj_type *ktype = get_ktype(kobj);
 932
 933         if (ktype == &module_ktype)
 934                 return 1;
 935         return 0;
 936 }
 937
 938 static const struct kset_uevent_ops module_uevent_ops = {
 939         .filter = uevent_filter,
 940 };
 941
 942 struct kset *module_kset;
 943 int module_sysfs_initialized;
 944
 945 static void module_kobj_release(struct kobject *kobj)
 946 {
 947         struct module_kobject *mk = to_module_kobject(kobj);
 948         complete(mk->kobj_completion);
 949 }
 950
 951 struct kobj_type module_ktype = {
 952         .release   =    module_kobj_release,
 953         .sysfs_ops =    &module_sysfs_ops,
 954 };
 955
 956 /*
 957  * param_sysfs_init - wrapper for built-in params support
 958  */
 959 static int __init param_sysfs_init(void)
 960 {
 961         module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
 962         if (!module_kset) {
 963                 printk(KERN_WARNING "%s (%d): error creating kset\n",
 964                         __FILE__, __LINE__);
 965                 return -ENOMEM;
 966         }
 967         module_sysfs_initialized = 1;
 968
 969         version_sysfs_builtin();
 970         param_sysfs_builtin();
 971
 972         return 0;
 973 }
 974 subsys_initcall(param_sysfs_init);
 975
 976 #endif /* CONFIG_SYSFS */