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/moduleparam.h>
  19 #include <linux/kernel.h>
  20 #include <linux/string.h>
  21 #include <linux/errno.h>
  22 #include <linux/module.h>
  23 #include <linux/device.h>
  24 #include <linux/err.h>
  25 #include <linux/slab.h>
  26
  27 #if 0
  28 #define DEBUGP printk
  29 #else
  30 #define DEBUGP(fmt, a...)
  31 #endif
  32
  33 static inline char dash2underscore(char c)
  34 {
  35         if (c == '-')
  36                 return '_';
  37         return c;
  38 }
  39
  40 static inline int parameq(const char *input, const char *paramname)
  41 {
  42         unsigned int i;
  43         for (i = 0; dash2underscore(input[i]) == paramname[i]; i++)
  44                 if (input[i] == '\0')
  45                         return 1;
  46         return 0;
  47 }
  48
  49 static int parse_one(char *param,
  50                      char *val,
  51                      struct kernel_param *params,
  52                      unsigned num_params,
  53                      int (*handle_unknown)(char *param, char *val))
  54 {
  55         unsigned int i;
  56
  57         /* Find parameter */
  58         for (i = 0; i < num_params; i++) {
  59                 if (parameq(param, params[i].name)) {
  60                         DEBUGP("They are equal!  Calling %p\n",
  61                                params[i].set);
  62                         return params[i].set(val, &params[i]);
  63                 }
  64         }
  65
  66         if (handle_unknown) {
  67                 DEBUGP("Unknown argument: calling %p\n", handle_unknown);
  68                 return handle_unknown(param, val);
  69         }
  70
  71         DEBUGP("Unknown argument `%s'\n", param);
  72         return -ENOENT;
  73 }
  74
  75 /* You can use " around spaces, but can't escape ". */
  76 /* Hyphens and underscores equivalent in parameter names. */
  77 static char *next_arg(char *args, char **param, char **val)
  78 {
  79         unsigned int i, equals = 0;
  80         int in_quote = 0, quoted = 0;
  81         char *next;
  82
  83         if (*args == '"') {
  84                 args++;
  85                 in_quote = 1;
  86                 quoted = 1;
  87         }
  88
  89         for (i = 0; args[i]; i++) {
  90                 if (args[i] == ' ' && !in_quote)
  91                         break;
  92                 if (equals == 0) {
  93                         if (args[i] == '=')
  94                                 equals = i;
  95                 }
  96                 if (args[i] == '"')
  97                         in_quote = !in_quote;
  98         }
  99
 100         *param = args;
 101         if (!equals)
 102                 *val = NULL;
 103         else {
 104                 args[equals] = '\0';
 105                 *val = args + equals + 1;
 106
 107                 /* Don't include quotes in value. */
 108                 if (**val == '"') {
 109                         (*val)++;
 110                         if (args[i-1] == '"')
 111                                 args[i-1] = '\0';
 112                 }
 113                 if (quoted && args[i-1] == '"')
 114                         args[i-1] = '\0';
 115         }
 116
 117         if (args[i]) {
 118                 args[i] = '\0';
 119                 next = args + i + 1;
 120         } else
 121                 next = args + i;
 122
 123         /* Chew up trailing spaces. */
 124         while (*next == ' ')
 125                 next++;
 126         return next;
 127 }
 128
 129 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 130 int parse_args(const char *name,
 131                char *args,
 132                struct kernel_param *params,
 133                unsigned num,
 134                int (*unknown)(char *param, char *val))
 135 {
 136         char *param, *val;
 137
 138         DEBUGP("Parsing ARGS: %s\n", args);
 139
 140         /* Chew leading spaces */
 141         while (*args == ' ')
 142                 args++;
 143
 144         while (*args) {
 145                 int ret;
 146
 147                 args = next_arg(args, &param, &val);
 148                 ret = parse_one(param, val, params, num, unknown);
 149                 switch (ret) {
 150                 case -ENOENT:
 151                         printk(KERN_ERR "%s: Unknown parameter `%s'\n",
 152                                name, param);
 153                         return ret;
 154                 case -ENOSPC:
 155                         printk(KERN_ERR
 156                                "%s: `%s' too large for parameter `%s'\n",
 157                                name, val ?: "", param);
 158                         return ret;
 159                 case 0:
 160                         break;
 161                 default:
 162                         printk(KERN_ERR
 163                                "%s: `%s' invalid for parameter `%s'\n",
 164                                name, val ?: "", param);
 165                         return ret;
 166                 }
 167         }
 168
 169         /* All parsed OK. */
 170         return 0;
 171 }
 172
 173 /* Lazy bastard, eh? */
 174 #define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn)       \
 175         int param_set_##name(const char *val, struct kernel_param *kp)  \
 176         {                                                               \
 177                 char *endp;                                             \
 178                 tmptype l;                                              \
 179                                                                         \
 180                 if (!val) return -EINVAL;                               \
 181                 l = strtolfn(val, &endp, 0);                            \
 182                 if (endp == val || ((type)l != l))                      \
 183                         return -EINVAL;                                 \
 184                 *((type *)kp->arg) = l;                                 \
 185                 return 0;                                               \
 186         }                                                               \
 187         int param_get_##name(char *buffer, struct kernel_param *kp)     \
 188         {                                                               \
 189                 return sprintf(buffer, format, *((type *)kp->arg));     \
 190         }
 191
 192 STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, simple_strtoul);
 193 STANDARD_PARAM_DEF(short, short, "%hi", long, simple_strtol);
 194 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, simple_strtoul);
 195 STANDARD_PARAM_DEF(int, int, "%i", long, simple_strtol);
 196 STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, simple_strtoul);
 197 STANDARD_PARAM_DEF(long, long, "%li", long, simple_strtol);
 198 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, simple_strtoul);
 199
 200 int param_set_charp(const char *val, struct kernel_param *kp)
 201 {
 202         if (!val) {
 203                 printk(KERN_ERR "%s: string parameter expected\n",
 204                        kp->name);
 205                 return -EINVAL;
 206         }
 207
 208         if (strlen(val) > 1024) {
 209                 printk(KERN_ERR "%s: string parameter too long\n",
 210                        kp->name);
 211                 return -ENOSPC;
 212         }
 213
 214         *(char **)kp->arg = (char *)val;
 215         return 0;
 216 }
 217
 218 int param_get_charp(char *buffer, struct kernel_param *kp)
 219 {
 220         return sprintf(buffer, "%s", *((char **)kp->arg));
 221 }
 222
 223 int param_set_bool(const char *val, struct kernel_param *kp)
 224 {
 225         /* No equals means "set"... */
 226         if (!val) val = "1";
 227
 228         /* One of =[yYnN01] */
 229         switch (val[0]) {
 230         case 'y': case 'Y': case '1':
 231                 *(int *)kp->arg = 1;
 232                 return 0;
 233         case 'n': case 'N': case '0':
 234                 *(int *)kp->arg = 0;
 235                 return 0;
 236         }
 237         return -EINVAL;
 238 }
 239
 240 int param_get_bool(char *buffer, struct kernel_param *kp)
 241 {
 242         /* Y and N chosen as being relatively non-coder friendly */
 243         return sprintf(buffer, "%c", (*(int *)kp->arg) ? 'Y' : 'N');
 244 }
 245
 246 int param_set_invbool(const char *val, struct kernel_param *kp)
 247 {
 248         int boolval, ret;
 249         struct kernel_param dummy = { .arg = &boolval };
 250
 251         ret = param_set_bool(val, &dummy);
 252         if (ret == 0)
 253                 *(int *)kp->arg = !boolval;
 254         return ret;
 255 }
 256
 257 int param_get_invbool(char *buffer, struct kernel_param *kp)
 258 {
 259         int val;
 260         struct kernel_param dummy = { .arg = &val };
 261
 262         val = !*(int *)kp->arg;
 263         return param_get_bool(buffer, &dummy);
 264 }
 265
 266 /* We cheat here and temporarily mangle the string. */
 267 static int param_array(const char *name,
 268                        const char *val,
 269                        unsigned int min, unsigned int max,
 270                        void *elem, int elemsize,
 271                        int (*set)(const char *, struct kernel_param *kp),
 272                        int *num)
 273 {
 274         int ret;
 275         struct kernel_param kp;
 276         char save;
 277
 278         /* Get the name right for errors. */
 279         kp.name = name;
 280         kp.arg = elem;
 281
 282         /* No equals sign? */
 283         if (!val) {
 284                 printk(KERN_ERR "%s: expects arguments\n", name);
 285                 return -EINVAL;
 286         }
 287
 288         *num = 0;
 289         /* We expect a comma-separated list of values. */
 290         do {
 291                 int len;
 292
 293                 if (*num == max) {
 294                         printk(KERN_ERR "%s: can only take %i arguments\n",
 295                                name, max);
 296                         return -EINVAL;
 297                 }
 298                 len = strcspn(val, ",");
 299
 300                 /* nul-terminate and parse */
 301                 save = val[len];
 302                 ((char *)val)[len] = '\0';
 303                 ret = set(val, &kp);
 304
 305                 if (ret != 0)
 306                         return ret;
 307                 kp.arg += elemsize;
 308                 val += len+1;
 309                 (*num)++;
 310         } while (save == ',');
 311
 312         if (*num < min) {
 313                 printk(KERN_ERR "%s: needs at least %i arguments\n",
 314                        name, min);
 315                 return -EINVAL;
 316         }
 317         return 0;
 318 }
 319
 320 int param_array_set(const char *val, struct kernel_param *kp)
 321 {
 322         struct kparam_array *arr = kp->arg;
 323         unsigned int temp_num;
 324
 325         return param_array(kp->name, val, 1, arr->max, arr->elem,
 326                            arr->elemsize, arr->set, arr->num ?: &temp_num);
 327 }
 328
 329 int param_array_get(char *buffer, struct kernel_param *kp)
 330 {
 331         int i, off, ret;
 332         struct kparam_array *arr = kp->arg;
 333         struct kernel_param p;
 334
 335         p = *kp;
 336         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 337                 if (i)
 338                         buffer[off++] = ',';
 339                 p.arg = arr->elem + arr->elemsize * i;
 340                 ret = arr->get(buffer + off, &p);
 341                 if (ret < 0)
 342                         return ret;
 343                 off += ret;
 344         }
 345         buffer[off] = '\0';
 346         return off;
 347 }
 348
 349 int param_set_copystring(const char *val, struct kernel_param *kp)
 350 {
 351         struct kparam_string *kps = kp->arg;
 352
 353         if (strlen(val)+1 > kps->maxlen) {
 354                 printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
 355                        kp->name, kps->maxlen-1);
 356                 return -ENOSPC;
 357         }
 358         strcpy(kps->string, val);
 359         return 0;
 360 }
 361
 362 int param_get_string(char *buffer, struct kernel_param *kp)
 363 {
 364         struct kparam_string *kps = kp->arg;
 365         return strlcpy(buffer, kps->string, kps->maxlen);
 366 }
 367
 368 /* sysfs output in /sys/modules/XYZ/parameters/ */
 369
 370 extern struct kernel_param __start___param[], __stop___param[];
 371
 372 #define MAX_KBUILD_MODNAME KOBJ_NAME_LEN
 373
 374 struct param_attribute
 375 {
 376         struct module_attribute mattr;
 377         struct kernel_param *param;
 378 };
 379
 380 struct module_param_attrs
 381 {
 382         struct attribute_group grp;
 383         struct param_attribute attrs[0];
 384 };
 385
 386 #define to_param_attr(n) container_of(n, struct param_attribute, mattr);
 387
 388 static ssize_t param_attr_show(struct module_attribute *mattr,
 389                                struct module *mod, char *buf)
 390 {
 391         int count;
 392         struct param_attribute *attribute = to_param_attr(mattr);
 393
 394         if (!attribute->param->get)
 395                 return -EPERM;
 396
 397         count = attribute->param->get(buf, attribute->param);
 398         if (count > 0) {
 399                 strcat(buf, "\n");
 400                 ++count;
 401         }
 402         return count;
 403 }
 404
 405 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 406 static ssize_t param_attr_store(struct module_attribute *mattr,
 407                                 struct module *owner,
 408                                 const char *buf, size_t len)
 409 {
 410         int err;
 411         struct param_attribute *attribute = to_param_attr(mattr);
 412
 413         if (!attribute->param->set)
 414                 return -EPERM;
 415
 416         err = attribute->param->set(buf, attribute->param);
 417         if (!err)
 418                 return len;
 419         return err;
 420 }
 421
 422 #ifdef CONFIG_MODULES
 423 #define __modinit
 424 #else
 425 #define __modinit __init
 426 #endif
 427
 428 /*
 429  * param_sysfs_setup - setup sysfs support for one module or KBUILD_MODNAME
 430  * @mk: struct module_kobject (contains parent kobject)
 431  * @kparam: array of struct kernel_param, the actual parameter definitions
 432  * @num_params: number of entries in array
 433  * @name_skip: offset where the parameter name start in kparam[].name. Needed for built-in "modules"
 434  *
 435  * Create a kobject for a (per-module) group of parameters, and create files
 436  * in sysfs. A pointer to the param_kobject is returned on success,
 437  * NULL if there's no parameter to export, or other ERR_PTR(err).
 438  */
 439 static __modinit struct module_param_attrs *
 440 param_sysfs_setup(struct module_kobject *mk,
 441                   struct kernel_param *kparam,
 442                   unsigned int num_params,
 443                   unsigned int name_skip)
 444 {
 445         struct module_param_attrs *mp;
 446         unsigned int valid_attrs = 0;
 447         unsigned int i, size[2];
 448         struct param_attribute *pattr;
 449         struct attribute **gattr;
 450         int err;
 451
 452         for (i=0; i<num_params; i++) {
 453                 if (kparam[i].perm)
 454                         valid_attrs++;
 455         }
 456
 457         if (!valid_attrs)
 458                 return NULL;
 459
 460         size[0] = ALIGN(sizeof(*mp) +
 461                         valid_attrs * sizeof(mp->attrs[0]),
 462                         sizeof(mp->grp.attrs[0]));
 463         size[1] = (valid_attrs + 1) * sizeof(mp->grp.attrs[0]);
 464
 465         mp = kmalloc(size[0] + size[1], GFP_KERNEL);
 466         if (!mp)
 467                 return ERR_PTR(-ENOMEM);
 468
 469         mp->grp.name = "parameters";
 470         mp->grp.attrs = (void *)mp + size[0];
 471
 472         pattr = &mp->attrs[0];
 473         gattr = &mp->grp.attrs[0];
 474         for (i = 0; i < num_params; i++) {
 475                 struct kernel_param *kp = &kparam[i];
 476                 if (kp->perm) {
 477                         pattr->param = kp;
 478                         pattr->mattr.show = param_attr_show;
 479                         pattr->mattr.store = param_attr_store;
 480                         pattr->mattr.attr.name = (char *)&kp->name[name_skip];
 481                         pattr->mattr.attr.owner = mk->mod;
 482                         pattr->mattr.attr.mode = kp->perm;
 483                         *(gattr++) = &(pattr++)->mattr.attr;
 484                 }
 485         }
 486         *gattr = NULL;
 487
 488         if ((err = sysfs_create_group(&mk->kobj, &mp->grp))) {
 489                 kfree(mp);
 490                 return ERR_PTR(err);
 491         }
 492         return mp;
 493 }
 494
 495
 496 #ifdef CONFIG_MODULES
 497
 498 /*
 499  * module_param_sysfs_setup - setup sysfs support for one module
 500  * @mod: module
 501  * @kparam: module parameters (array)
 502  * @num_params: number of module parameters
 503  *
 504  * Adds sysfs entries for module parameters, and creates a link from
 505  * /sys/module/[mod->name]/parameters to /sys/parameters/[mod->name]/
 506  */
 507 int module_param_sysfs_setup(struct module *mod,
 508                              struct kernel_param *kparam,
 509                              unsigned int num_params)
 510 {
 511         struct module_param_attrs *mp;
 512
 513         mp = param_sysfs_setup(&mod->mkobj, kparam, num_params, 0);
 514         if (IS_ERR(mp))
 515                 return PTR_ERR(mp);
 516
 517         mod->param_attrs = mp;
 518         return 0;
 519 }
 520
 521 /*
 522  * module_param_sysfs_remove - remove sysfs support for one module
 523  * @mod: module
 524  *
 525  * Remove sysfs entries for module parameters and the corresponding
 526  * kobject.
 527  */
 528 void module_param_sysfs_remove(struct module *mod)
 529 {
 530         if (mod->param_attrs) {
 531                 sysfs_remove_group(&mod->mkobj.kobj,
 532                                    &mod->param_attrs->grp);
 533                 /* We are positive that no one is using any param
 534                  * attrs at this point.  Deallocate immediately. */
 535                 kfree(mod->param_attrs);
 536                 mod->param_attrs = NULL;
 537         }
 538 }
 539 #endif
 540
 541 /*
 542  * kernel_param_sysfs_setup - wrapper for built-in params support
 543  */
 544 static void __init kernel_param_sysfs_setup(const char *name,
 545                                             struct kernel_param *kparam,
 546                                             unsigned int num_params,
 547                                             unsigned int name_skip)
 548 {
 549         struct module_kobject *mk;
 550         int ret;
 551
 552         mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 553         BUG_ON(!mk);
 554
 555         mk->mod = THIS_MODULE;
 556         kobj_set_kset_s(mk, module_subsys);
 557         kobject_set_name(&mk->kobj, name);
 558         ret = kobject_register(&mk->kobj);
 559         BUG_ON(ret < 0);
 560
 561         /* no need to keep the kobject if no parameter is exported */
 562         if (!param_sysfs_setup(mk, kparam, num_params, name_skip)) {
 563                 kobject_unregister(&mk->kobj);
 564                 kfree(mk);
 565         }
 566 }
 567
 568 /*
 569  * param_sysfs_builtin - add contents in /sys/parameters for built-in modules
 570  *
 571  * Add module_parameters to sysfs for "modules" built into the kernel.
 572  *
 573  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 574  * "parameter" name is stored behind a dot in kernel_param->name. So,
 575  * extract the "module" name for all built-in kernel_param-eters,
 576  * and for all who have the same, call kernel_param_sysfs_setup.
 577  */
 578 static void __init param_sysfs_builtin(void)
 579 {
 580         struct kernel_param *kp, *kp_begin = NULL;
 581         unsigned int i, name_len, count = 0;
 582         char modname[MAX_KBUILD_MODNAME + 1] = "";
 583
 584         for (i=0; i < __stop___param - __start___param; i++) {
 585                 char *dot;
 586
 587                 kp = &__start___param[i];
 588
 589                 /* We do not handle args without periods. */
 590                 dot = memchr(kp->name, '.', MAX_KBUILD_MODNAME);
 591                 if (!dot) {
 592                         DEBUGP("couldn't find period in %s\n", kp->name);
 593                         continue;
 594                 }
 595                 name_len = dot - kp->name;
 596
 597                 /* new kbuild_modname? */
 598                 if (strlen(modname) != name_len
 599                     || strncmp(modname, kp->name, name_len) != 0) {
 600                         /* add a new kobject for previous kernel_params. */
 601                         if (count)
 602                                 kernel_param_sysfs_setup(modname,
 603                                                          kp_begin,
 604                                                          count,
 605                                                          strlen(modname)+1);
 606
 607                         strncpy(modname, kp->name, name_len);
 608                         modname[name_len] = '\0';
 609                         count = 0;
 610                         kp_begin = kp;
 611                 }
 612                 count++;
 613         }
 614
 615         /* last kernel_params need to be registered as well */
 616         if (count)
 617                 kernel_param_sysfs_setup(modname, kp_begin, count,
 618                                          strlen(modname)+1);
 619 }
 620
 621
 622 /* module-related sysfs stuff */
 623 #ifdef CONFIG_SYSFS
 624
 625 #define to_module_attr(n) container_of(n, struct module_attribute, attr);
 626 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj);
 627
 628 static ssize_t module_attr_show(struct kobject *kobj,
 629                                 struct attribute *attr,
 630                                 char *buf)
 631 {
 632         struct module_attribute *attribute;
 633         struct module_kobject *mk;
 634         int ret;
 635
 636         attribute = to_module_attr(attr);
 637         mk = to_module_kobject(kobj);
 638
 639         if (!attribute->show)
 640                 return -EIO;
 641
 642         ret = attribute->show(attribute, mk->mod, buf);
 643
 644         return ret;
 645 }
 646
 647 static ssize_t module_attr_store(struct kobject *kobj,
 648                                 struct attribute *attr,
 649                                 const char *buf, size_t len)
 650 {
 651         struct module_attribute *attribute;
 652         struct module_kobject *mk;
 653         int ret;
 654
 655         attribute = to_module_attr(attr);
 656         mk = to_module_kobject(kobj);
 657
 658         if (!attribute->store)
 659                 return -EIO;
 660
 661         ret = attribute->store(attribute, mk->mod, buf, len);
 662
 663         return ret;
 664 }
 665
 666 static struct sysfs_ops module_sysfs_ops = {
 667         .show = module_attr_show,
 668         .store = module_attr_store,
 669 };
 670
 671 #else
 672 static struct sysfs_ops module_sysfs_ops = {
 673         .show = NULL,
 674         .store = NULL,
 675 };
 676 #endif
 677
 678 static struct kobj_type module_ktype = {
 679         .sysfs_ops =    &module_sysfs_ops,
 680 };
 681
 682 decl_subsys(module, &module_ktype, NULL);
 683
 684 /*
 685  * param_sysfs_init - wrapper for built-in params support
 686  */
 687 static int __init param_sysfs_init(void)
 688 {
 689         int ret;
 690
 691         ret = subsystem_register(&module_subsys);
 692         if (ret < 0) {
 693                 printk(KERN_WARNING "%s (%d): subsystem_register error: %d\n",
 694                         __FILE__, __LINE__, ret);
 695                 return ret;
 696         }
 697
 698         param_sysfs_builtin();
 699
 700         return 0;
 701 }
 702 subsys_initcall(param_sysfs_init);
 703
 704 EXPORT_SYMBOL(param_set_byte);
 705 EXPORT_SYMBOL(param_get_byte);
 706 EXPORT_SYMBOL(param_set_short);
 707 EXPORT_SYMBOL(param_get_short);
 708 EXPORT_SYMBOL(param_set_ushort);
 709 EXPORT_SYMBOL(param_get_ushort);
 710 EXPORT_SYMBOL(param_set_int);
 711 EXPORT_SYMBOL(param_get_int);
 712 EXPORT_SYMBOL(param_set_uint);
 713 EXPORT_SYMBOL(param_get_uint);
 714 EXPORT_SYMBOL(param_set_long);
 715 EXPORT_SYMBOL(param_get_long);
 716 EXPORT_SYMBOL(param_set_ulong);
 717 EXPORT_SYMBOL(param_get_ulong);
 718 EXPORT_SYMBOL(param_set_charp);
 719 EXPORT_SYMBOL(param_get_charp);
 720 EXPORT_SYMBOL(param_set_bool);
 721 EXPORT_SYMBOL(param_get_bool);
 722 EXPORT_SYMBOL(param_set_invbool);
 723 EXPORT_SYMBOL(param_get_invbool);
 724 EXPORT_SYMBOL(param_array_set);
 725 EXPORT_SYMBOL(param_array_get);
 726 EXPORT_SYMBOL(param_set_copystring);
 727 EXPORT_SYMBOL(param_get_string);