params.c 21.3 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927
/* Helpers for initial module or kernel cmdline parsing
   Copyright (C) 2001 Rusty Russell.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/ctype.h>

#if 0
#define DEBUGP printk
#else
#define DEBUGP(fmt, a...)
#endif

/* Protects all parameters, and incidentally kmalloced_param list. */
static DEFINE_MUTEX(param_lock);

/* This just allows us to keep track of which parameters are kmalloced. */
struct kmalloced_param {
	struct list_head list;
	char val[];
};
static LIST_HEAD(kmalloced_params);

static void *kmalloc_parameter(unsigned int size)
{
	struct kmalloced_param *p;

	p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
	if (!p)
		return NULL;

	list_add(&p->list, &kmalloced_params);
	return p->val;
}

/* Does nothing if parameter wasn't kmalloced above. */
static void maybe_kfree_parameter(void *param)
{
	struct kmalloced_param *p;

	list_for_each_entry(p, &kmalloced_params, list) {
		if (p->val == param) {
			list_del(&p->list);
			kfree(p);
			break;
		}
	}
}

static inline char dash2underscore(char c)
{
	if (c == '-')
		return '_';
	return c;
}

static inline int parameq(const char *input, const char *paramname)
{
	unsigned int i;
	for (i = 0; dash2underscore(input[i]) == paramname[i]; i++)
		if (input[i] == '\0')
			return 1;
	return 0;
}

static int parse_one(char *param,
		     char *val,
		     const struct kernel_param *params,
		     unsigned num_params,
		     int (*handle_unknown)(char *param, char *val))
{
	unsigned int i;
	int err;

	/* Find parameter */
	for (i = 0; i < num_params; i++) {
		if (parameq(param, params[i].name)) {
			/* No one handled NULL, so do it here. */
			if (!val && params[i].ops->set != param_set_bool)
				return -EINVAL;
			DEBUGP("They are equal!  Calling %p\n",
			       params[i].ops->set);
			mutex_lock(&param_lock);
			err = params[i].ops->set(val, &params[i]);
			mutex_unlock(&param_lock);
			return err;
		}
	}

	if (handle_unknown) {
		DEBUGP("Unknown argument: calling %p\n", handle_unknown);
		return handle_unknown(param, val);
	}

	DEBUGP("Unknown argument `%s'\n", param);
	return -ENOENT;
}

/* You can use " around spaces, but can't escape ". */
/* Hyphens and underscores equivalent in parameter names. */
static char *next_arg(char *args, char **param, char **val)
{
	unsigned int i, equals = 0;
	int in_quote = 0, quoted = 0;
	char *next;

	if (*args == '"') {
		args++;
		in_quote = 1;
		quoted = 1;
	}

	for (i = 0; args[i]; i++) {
		if (isspace(args[i]) && !in_quote)
			break;
		if (equals == 0) {
			if (args[i] == '=')
				equals = i;
		}
		if (args[i] == '"')
			in_quote = !in_quote;
	}

	*param = args;
	if (!equals)
		*val = NULL;
	else {
		args[equals] = '\0';
		*val = args + equals + 1;

		/* Don't include quotes in value. */
		if (**val == '"') {
			(*val)++;
			if (args[i-1] == '"')
				args[i-1] = '\0';
		}
		if (quoted && args[i-1] == '"')
			args[i-1] = '\0';
	}

	if (args[i]) {
		args[i] = '\0';
		next = args + i + 1;
	} else
		next = args + i;

	/* Chew up trailing spaces. */
	return skip_spaces(next);
}

/* Args looks like "foo=bar,bar2 baz=fuz wiz". */
int parse_args(const char *name,
	       char *args,
	       const struct kernel_param *params,
	       unsigned num,
	       int (*unknown)(char *param, char *val))
{
	char *param, *val;

	DEBUGP("Parsing ARGS: %s\n", args);

	/* Chew leading spaces */
	args = skip_spaces(args);

	while (*args) {
		int ret;
		int irq_was_disabled;

		args = next_arg(args, &param, &val);
		irq_was_disabled = irqs_disabled();
		ret = parse_one(param, val, params, num, unknown);
		if (irq_was_disabled && !irqs_disabled()) {
			printk(KERN_WARNING "parse_args(): option '%s' enabled "
					"irq's!\n", param);
		}
		switch (ret) {
		case -ENOENT:
			printk(KERN_ERR "%s: Unknown parameter `%s'\n",
			       name, param);
			return ret;
		case -ENOSPC:
			printk(KERN_ERR
			       "%s: `%s' too large for parameter `%s'\n",
			       name, val ?: "", param);
			return ret;
		case 0:
			break;
		default:
			printk(KERN_ERR
			       "%s: `%s' invalid for parameter `%s'\n",
			       name, val ?: "", param);
			return ret;
		}
	}

	/* All parsed OK. */
	return 0;
}

/* Lazy bastard, eh? */
#define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn)      	\
	int param_set_##name(const char *val, const struct kernel_param *kp) \
	{								\
		tmptype l;						\
		int ret;						\
									\
		ret = strtolfn(val, 0, &l);				\
		if (ret == -EINVAL || ((type)l != l))			\
			return -EINVAL;					\
		*((type *)kp->arg) = l;					\
		return 0;						\
	}								\
	int param_get_##name(char *buffer, const struct kernel_param *kp) \
	{								\
		return sprintf(buffer, format, *((type *)kp->arg));	\
	}								\
	struct kernel_param_ops param_ops_##name = {			\
		.set = param_set_##name,				\
		.get = param_get_##name,				\
	};								\
	EXPORT_SYMBOL(param_set_##name);				\
	EXPORT_SYMBOL(param_get_##name);				\
	EXPORT_SYMBOL(param_ops_##name)


STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, strict_strtoul);
STANDARD_PARAM_DEF(short, short, "%hi", long, strict_strtol);
STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, strict_strtoul);
STANDARD_PARAM_DEF(int, int, "%i", long, strict_strtol);
STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, strict_strtoul);
STANDARD_PARAM_DEF(long, long, "%li", long, strict_strtol);
STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, strict_strtoul);

int param_set_charp(const char *val, const struct kernel_param *kp)
{
	if (strlen(val) > 1024) {
		printk(KERN_ERR "%s: string parameter too long\n",
		       kp->name);
		return -ENOSPC;
	}

	maybe_kfree_parameter(*(char **)kp->arg);

	/* This is a hack.  We can't kmalloc in early boot, and we
	 * don't need to; this mangled commandline is preserved. */
	if (slab_is_available()) {
		*(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
		if (!*(char **)kp->arg)
			return -ENOMEM;
		strcpy(*(char **)kp->arg, val);
	} else
		*(const char **)kp->arg = val;

	return 0;
}
EXPORT_SYMBOL(param_set_charp);

int param_get_charp(char *buffer, const struct kernel_param *kp)
{
	return sprintf(buffer, "%s", *((char **)kp->arg));
}
EXPORT_SYMBOL(param_get_charp);

static void param_free_charp(void *arg)
{
	maybe_kfree_parameter(*((char **)arg));
}

struct kernel_param_ops param_ops_charp = {
	.set = param_set_charp,
	.get = param_get_charp,
	.free = param_free_charp,
};
EXPORT_SYMBOL(param_ops_charp);

/* Actually could be a bool or an int, for historical reasons. */
int param_set_bool(const char *val, const struct kernel_param *kp)
{
	bool v;

	/* No equals means "set"... */
	if (!val) val = "1";

	/* One of =[yYnN01] */
	switch (val[0]) {
	case 'y': case 'Y': case '1':
		v = true;
		break;
	case 'n': case 'N': case '0':
		v = false;
		break;
	default:
		return -EINVAL;
	}

	if (kp->flags & KPARAM_ISBOOL)
		*(bool *)kp->arg = v;
	else
		*(int *)kp->arg = v;
	return 0;
}
EXPORT_SYMBOL(param_set_bool);

int param_get_bool(char *buffer, const struct kernel_param *kp)
{
	bool val;
	if (kp->flags & KPARAM_ISBOOL)
		val = *(bool *)kp->arg;
	else
		val = *(int *)kp->arg;

	/* Y and N chosen as being relatively non-coder friendly */
	return sprintf(buffer, "%c", val ? 'Y' : 'N');
}
EXPORT_SYMBOL(param_get_bool);

struct kernel_param_ops param_ops_bool = {
	.set = param_set_bool,
	.get = param_get_bool,
};
EXPORT_SYMBOL(param_ops_bool);

/* This one must be bool. */
int param_set_invbool(const char *val, const struct kernel_param *kp)
{
	int ret;
	bool boolval;
	struct kernel_param dummy;

	dummy.arg = &boolval;
	dummy.flags = KPARAM_ISBOOL;
	ret = param_set_bool(val, &dummy);
	if (ret == 0)
		*(bool *)kp->arg = !boolval;
	return ret;
}
EXPORT_SYMBOL(param_set_invbool);

int param_get_invbool(char *buffer, const struct kernel_param *kp)
{
	return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
}
EXPORT_SYMBOL(param_get_invbool);

struct kernel_param_ops param_ops_invbool = {
	.set = param_set_invbool,
	.get = param_get_invbool,
};
EXPORT_SYMBOL(param_ops_invbool);

/* We break the rule and mangle the string. */
static int param_array(const char *name,
		       const char *val,
		       unsigned int min, unsigned int max,
		       void *elem, int elemsize,
		       int (*set)(const char *, const struct kernel_param *kp),
		       u16 flags,
		       unsigned int *num)
{
	int ret;
	struct kernel_param kp;
	char save;

	/* Get the name right for errors. */
	kp.name = name;
	kp.arg = elem;
	kp.flags = flags;

	*num = 0;
	/* We expect a comma-separated list of values. */
	do {
		int len;

		if (*num == max) {
			printk(KERN_ERR "%s: can only take %i arguments\n",
			       name, max);
			return -EINVAL;
		}
		len = strcspn(val, ",");

		/* nul-terminate and parse */
		save = val[len];
		((char *)val)[len] = '\0';
		BUG_ON(!mutex_is_locked(&param_lock));
		ret = set(val, &kp);

		if (ret != 0)
			return ret;
		kp.arg += elemsize;
		val += len+1;
		(*num)++;
	} while (save == ',');

	if (*num < min) {
		printk(KERN_ERR "%s: needs at least %i arguments\n",
		       name, min);
		return -EINVAL;
	}
	return 0;
}

static int param_array_set(const char *val, const struct kernel_param *kp)
{
	const struct kparam_array *arr = kp->arr;
	unsigned int temp_num;

	return param_array(kp->name, val, 1, arr->max, arr->elem,
			   arr->elemsize, arr->ops->set, kp->flags,
			   arr->num ?: &temp_num);
}

static int param_array_get(char *buffer, const struct kernel_param *kp)
{
	int i, off, ret;
	const struct kparam_array *arr = kp->arr;
	struct kernel_param p;

	p = *kp;
	for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
		if (i)
			buffer[off++] = ',';
		p.arg = arr->elem + arr->elemsize * i;
		BUG_ON(!mutex_is_locked(&param_lock));
		ret = arr->ops->get(buffer + off, &p);
		if (ret < 0)
			return ret;
		off += ret;
	}
	buffer[off] = '\0';
	return off;
}

static void param_array_free(void *arg)
{
	unsigned int i;
	const struct kparam_array *arr = arg;

	if (arr->ops->free)
		for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
			arr->ops->free(arr->elem + arr->elemsize * i);
}

struct kernel_param_ops param_array_ops = {
	.set = param_array_set,
	.get = param_array_get,
	.free = param_array_free,
};
EXPORT_SYMBOL(param_array_ops);

int param_set_copystring(const char *val, const struct kernel_param *kp)
{
	const struct kparam_string *kps = kp->str;

	if (strlen(val)+1 > kps->maxlen) {
		printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
		       kp->name, kps->maxlen-1);
		return -ENOSPC;
	}
	strcpy(kps->string, val);
	return 0;
}
EXPORT_SYMBOL(param_set_copystring);

int param_get_string(char *buffer, const struct kernel_param *kp)
{
	const struct kparam_string *kps = kp->str;
	return strlcpy(buffer, kps->string, kps->maxlen);
}
EXPORT_SYMBOL(param_get_string);

struct kernel_param_ops param_ops_string = {
	.set = param_set_copystring,
	.get = param_get_string,
};
EXPORT_SYMBOL(param_ops_string);

/* sysfs output in /sys/modules/XYZ/parameters/ */
#define to_module_attr(n) container_of(n, struct module_attribute, attr)
#define to_module_kobject(n) container_of(n, struct module_kobject, kobj)

extern struct kernel_param __start___param[], __stop___param[];

struct param_attribute
{
	struct module_attribute mattr;
	const struct kernel_param *param;
};

struct module_param_attrs
{
	unsigned int num;
	struct attribute_group grp;
	struct param_attribute attrs[0];
};

#ifdef CONFIG_SYSFS
#define to_param_attr(n) container_of(n, struct param_attribute, mattr)

static ssize_t param_attr_show(struct module_attribute *mattr,
			       struct module *mod, char *buf)
{
	int count;
	struct param_attribute *attribute = to_param_attr(mattr);

	if (!attribute->param->ops->get)
		return -EPERM;

	mutex_lock(&param_lock);
	count = attribute->param->ops->get(buf, attribute->param);
	mutex_unlock(&param_lock);
	if (count > 0) {
		strcat(buf, "\n");
		++count;
	}
	return count;
}

/* sysfs always hands a nul-terminated string in buf.  We rely on that. */
static ssize_t param_attr_store(struct module_attribute *mattr,
				struct module *owner,
				const char *buf, size_t len)
{
 	int err;
	struct param_attribute *attribute = to_param_attr(mattr);

	if (!attribute->param->ops->set)
		return -EPERM;

	mutex_lock(&param_lock);
	err = attribute->param->ops->set(buf, attribute->param);
	mutex_unlock(&param_lock);
	if (!err)
		return len;
	return err;
}
#endif

#ifdef CONFIG_MODULES
#define __modinit
#else
#define __modinit __init
#endif

#ifdef CONFIG_SYSFS
void __kernel_param_lock(void)
{
	mutex_lock(&param_lock);
}
EXPORT_SYMBOL(__kernel_param_lock);

void __kernel_param_unlock(void)
{
	mutex_unlock(&param_lock);
}
EXPORT_SYMBOL(__kernel_param_unlock);

/*
 * add_sysfs_param - add a parameter to sysfs
 * @mk: struct module_kobject
 * @kparam: the actual parameter definition to add to sysfs
 * @name: name of parameter
 *
 * Create a kobject if for a (per-module) parameter if mp NULL, and
 * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 * if there's an error.
 */
static __modinit int add_sysfs_param(struct module_kobject *mk,
				     const struct kernel_param *kp,
				     const char *name)
{
	struct module_param_attrs *new;
	struct attribute **attrs;
	int err, num;

	/* We don't bother calling this with invisible parameters. */
	BUG_ON(!kp->perm);

	if (!mk->mp) {
		num = 0;
		attrs = NULL;
	} else {
		num = mk->mp->num;
		attrs = mk->mp->grp.attrs;
	}

	/* Enlarge. */
	new = krealloc(mk->mp,
		       sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
		       GFP_KERNEL);
	if (!new) {
		kfree(mk->mp);
		err = -ENOMEM;
		goto fail;
	}
	attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
	if (!attrs) {
		err = -ENOMEM;
		goto fail_free_new;
	}

	/* Sysfs wants everything zeroed. */
	memset(new, 0, sizeof(*new));
	memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
	memset(&attrs[num], 0, sizeof(attrs[num]));
	new->grp.name = "parameters";
	new->grp.attrs = attrs;

	/* Tack new one on the end. */
	sysfs_attr_init(&new->attrs[num].mattr.attr);
	new->attrs[num].param = kp;
	new->attrs[num].mattr.show = param_attr_show;
	new->attrs[num].mattr.store = param_attr_store;
	new->attrs[num].mattr.attr.name = (char *)name;
	new->attrs[num].mattr.attr.mode = kp->perm;
	new->num = num+1;

	/* Fix up all the pointers, since krealloc can move us */
	for (num = 0; num < new->num; num++)
		new->grp.attrs[num] = &new->attrs[num].mattr.attr;
	new->grp.attrs[num] = NULL;

	mk->mp = new;
	return 0;

fail_free_new:
	kfree(new);
fail:
	mk->mp = NULL;
	return err;
}

#ifdef CONFIG_MODULES
static void free_module_param_attrs(struct module_kobject *mk)
{
	kfree(mk->mp->grp.attrs);
	kfree(mk->mp);
	mk->mp = NULL;
}

/*
 * module_param_sysfs_setup - setup sysfs support for one module
 * @mod: module
 * @kparam: module parameters (array)
 * @num_params: number of module parameters
 *
 * Adds sysfs entries for module parameters under
 * /sys/module/[mod->name]/parameters/
 */
int module_param_sysfs_setup(struct module *mod,
			     const struct kernel_param *kparam,
			     unsigned int num_params)
{
	int i, err;
	bool params = false;

	for (i = 0; i < num_params; i++) {
		if (kparam[i].perm == 0)
			continue;
		err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
		if (err)
			return err;
		params = true;
	}

	if (!params)
		return 0;

	/* Create the param group. */
	err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
	if (err)
		free_module_param_attrs(&mod->mkobj);
	return err;
}

/*
 * module_param_sysfs_remove - remove sysfs support for one module
 * @mod: module
 *
 * Remove sysfs entries for module parameters and the corresponding
 * kobject.
 */
void module_param_sysfs_remove(struct module *mod)
{
	if (mod->mkobj.mp) {
		sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
		/* We are positive that no one is using any param
		 * attrs at this point.  Deallocate immediately. */
		free_module_param_attrs(&mod->mkobj);
	}
}
#endif

void destroy_params(const struct kernel_param *params, unsigned num)
{
	unsigned int i;

	for (i = 0; i < num; i++)
		if (params[i].ops->free)
			params[i].ops->free(params[i].arg);
}

static struct module_kobject * __init locate_module_kobject(const char *name)
{
	struct module_kobject *mk;
	struct kobject *kobj;
	int err;

	kobj = kset_find_obj(module_kset, name);
	if (kobj) {
		mk = to_module_kobject(kobj);
	} else {
		mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
		BUG_ON(!mk);

		mk->mod = THIS_MODULE;
		mk->kobj.kset = module_kset;
		err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
					   "%s", name);
		if (err) {
			kobject_put(&mk->kobj);
			printk(KERN_ERR
				"Module '%s' failed add to sysfs, error number %d\n",
				name, err);
			printk(KERN_ERR
				"The system will be unstable now.\n");
			return NULL;
		}

		/* So that we hold reference in both cases. */
		kobject_get(&mk->kobj);
	}

	return mk;
}

static void __init kernel_add_sysfs_param(const char *name,
					  struct kernel_param *kparam,
					  unsigned int name_skip)
{
	struct module_kobject *mk;
	int err;

	mk = locate_module_kobject(name);
	if (!mk)
		return;

	/* We need to remove old parameters before adding more. */
	if (mk->mp)
		sysfs_remove_group(&mk->kobj, &mk->mp->grp);

	/* These should not fail at boot. */
	err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
	BUG_ON(err);
	err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
	BUG_ON(err);
	kobject_uevent(&mk->kobj, KOBJ_ADD);
	kobject_put(&mk->kobj);
}

/*
 * param_sysfs_builtin - add contents in /sys/parameters for built-in modules
 *
 * Add module_parameters to sysfs for "modules" built into the kernel.
 *
 * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 * "parameter" name is stored behind a dot in kernel_param->name. So,
 * extract the "module" name for all built-in kernel_param-eters,
 * and for all who have the same, call kernel_add_sysfs_param.
 */
static void __init param_sysfs_builtin(void)
{
	struct kernel_param *kp;
	unsigned int name_len;
	char modname[MODULE_NAME_LEN];

	for (kp = __start___param; kp < __stop___param; kp++) {
		char *dot;

		if (kp->perm == 0)
			continue;

		dot = strchr(kp->name, '.');
		if (!dot) {
			/* This happens for core_param() */
			strcpy(modname, "kernel");
			name_len = 0;
		} else {
			name_len = dot - kp->name + 1;
			strlcpy(modname, kp->name, name_len);
		}
		kernel_add_sysfs_param(modname, kp, name_len);
	}
}

ssize_t __modver_version_show(struct module_attribute *mattr,
			      struct module *mod, char *buf)
{
	struct module_version_attribute *vattr =
		container_of(mattr, struct module_version_attribute, mattr);

	return sprintf(buf, "%s\n", vattr->version);
}

extern struct module_version_attribute __start___modver[], __stop___modver[];

static void __init version_sysfs_builtin(void)
{
	const struct module_version_attribute *vattr;
	struct module_kobject *mk;
	int err;

	for (vattr = __start___modver; vattr < __stop___modver; vattr++) {
		mk = locate_module_kobject(vattr->module_name);
		if (mk) {
			err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
			kobject_uevent(&mk->kobj, KOBJ_ADD);
			kobject_put(&mk->kobj);
		}
	}
}

/* module-related sysfs stuff */

static ssize_t module_attr_show(struct kobject *kobj,
				struct attribute *attr,
				char *buf)
{
	struct module_attribute *attribute;
	struct module_kobject *mk;
	int ret;

	attribute = to_module_attr(attr);
	mk = to_module_kobject(kobj);

	if (!attribute->show)
		return -EIO;

	ret = attribute->show(attribute, mk->mod, buf);

	return ret;
}

static ssize_t module_attr_store(struct kobject *kobj,
				struct attribute *attr,
				const char *buf, size_t len)
{
	struct module_attribute *attribute;
	struct module_kobject *mk;
	int ret;

	attribute = to_module_attr(attr);
	mk = to_module_kobject(kobj);

	if (!attribute->store)
		return -EIO;

	ret = attribute->store(attribute, mk->mod, buf, len);

	return ret;
}

static const struct sysfs_ops module_sysfs_ops = {
	.show = module_attr_show,
	.store = module_attr_store,
};

static int uevent_filter(struct kset *kset, struct kobject *kobj)
{
	struct kobj_type *ktype = get_ktype(kobj);

	if (ktype == &module_ktype)
		return 1;
	return 0;
}

static const struct kset_uevent_ops module_uevent_ops = {
	.filter = uevent_filter,
};

struct kset *module_kset;
int module_sysfs_initialized;

struct kobj_type module_ktype = {
	.sysfs_ops =	&module_sysfs_ops,
};

/*
 * param_sysfs_init - wrapper for built-in params support
 */
static int __init param_sysfs_init(void)
{
	module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
	if (!module_kset) {
		printk(KERN_WARNING "%s (%d): error creating kset\n",
			__FILE__, __LINE__);
		return -ENOMEM;
	}
	module_sysfs_initialized = 1;

	version_sysfs_builtin();
	param_sysfs_builtin();

	return 0;
}
subsys_initcall(param_sysfs_init);

#endif /* CONFIG_SYSFS */