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 */
 19static 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
 28static inline void check_kparam_locked(struct module *mod)
 29{
 30	BUG_ON(!mutex_is_locked(KPARAM_MUTEX(mod)));
 31}
 32#else
 33static 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. */
 39struct kmalloced_param {
 40	struct list_head list;
 41	char val[];
 42};
 43static LIST_HEAD(kmalloced_params);
 44static DEFINE_SPINLOCK(kmalloced_params_lock);
 45
 46static 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. */
 62static 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
 77static char dash2underscore(char c)
 78{
 79	if (c == '-')
 80		return '_';
 81	return c;
 82}
 83
 84bool 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
 95bool parameq(const char *a, const char *b)
 96{
 97	return parameqn(a, b, strlen(a)+1);
 98}
 99
100static 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
115static 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". */
161char *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
236STANDARD_PARAM_DEF(byte,	unsigned char,		"%hhu", kstrtou8);
237STANDARD_PARAM_DEF(short,	short,			"%hi",  kstrtos16);
238STANDARD_PARAM_DEF(ushort,	unsigned short,		"%hu",  kstrtou16);
239STANDARD_PARAM_DEF(int,		int,			"%i",   kstrtoint);
240STANDARD_PARAM_DEF(uint,	unsigned int,		"%u",   kstrtouint);
241STANDARD_PARAM_DEF(long,	long,			"%li",  kstrtol);
242STANDARD_PARAM_DEF(ulong,	unsigned long,		"%lu",  kstrtoul);
243STANDARD_PARAM_DEF(ullong,	unsigned long long,	"%llu", kstrtoull);
244
245int param_set_charp(const char *val, const struct kernel_param *kp)
246{
247	if (strlen(val) > 1024) {
248		pr_err("%s: string parameter too long\n", kp->name);
249		return -ENOSPC;
250	}
251
252	maybe_kfree_parameter(*(char **)kp->arg);
253
254	/* This is a hack.  We can't kmalloc in early boot, and we
255	 * don't need to; this mangled commandline is preserved. */
256	if (slab_is_available()) {
257		*(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
258		if (!*(char **)kp->arg)
259			return -ENOMEM;
260		strcpy(*(char **)kp->arg, val);
261	} else
262		*(const char **)kp->arg = val;
263
264	return 0;
265}
266EXPORT_SYMBOL(param_set_charp);
267
268int param_get_charp(char *buffer, const struct kernel_param *kp)
269{
270	return scnprintf(buffer, PAGE_SIZE, "%s\n", *((char **)kp->arg));
271}
272EXPORT_SYMBOL(param_get_charp);
273
274void param_free_charp(void *arg)
275{
276	maybe_kfree_parameter(*((char **)arg));
277}
278EXPORT_SYMBOL(param_free_charp);
279
280const struct kernel_param_ops param_ops_charp = {
281	.set = param_set_charp,
282	.get = param_get_charp,
283	.free = param_free_charp,
284};
285EXPORT_SYMBOL(param_ops_charp);
286
287/* Actually could be a bool or an int, for historical reasons. */
288int param_set_bool(const char *val, const struct kernel_param *kp)
289{
290	/* No equals means "set"... */
291	if (!val) val = "1";
292
293	/* One of =[yYnN01] */
294	return strtobool(val, kp->arg);
295}
296EXPORT_SYMBOL(param_set_bool);
297
298int param_get_bool(char *buffer, const struct kernel_param *kp)
299{
300	/* Y and N chosen as being relatively non-coder friendly */
301	return sprintf(buffer, "%c\n", *(bool *)kp->arg ? 'Y' : 'N');
302}
303EXPORT_SYMBOL(param_get_bool);
304
305const struct kernel_param_ops param_ops_bool = {
306	.flags = KERNEL_PARAM_OPS_FL_NOARG,
307	.set = param_set_bool,
308	.get = param_get_bool,
309};
310EXPORT_SYMBOL(param_ops_bool);
311
312int param_set_bool_enable_only(const char *val, const struct kernel_param *kp)
313{
314	int err = 0;
315	bool new_value;
316	bool orig_value = *(bool *)kp->arg;
317	struct kernel_param dummy_kp = *kp;
318
319	dummy_kp.arg = &new_value;
320
321	err = param_set_bool(val, &dummy_kp);
322	if (err)
323		return err;
324
325	/* Don't let them unset it once it's set! */
326	if (!new_value && orig_value)
327		return -EROFS;
328
329	if (new_value)
330		err = param_set_bool(val, kp);
331
332	return err;
333}
334EXPORT_SYMBOL_GPL(param_set_bool_enable_only);
335
336const struct kernel_param_ops param_ops_bool_enable_only = {
337	.flags = KERNEL_PARAM_OPS_FL_NOARG,
338	.set = param_set_bool_enable_only,
339	.get = param_get_bool,
340};
341EXPORT_SYMBOL_GPL(param_ops_bool_enable_only);
342
343/* This one must be bool. */
344int param_set_invbool(const char *val, const struct kernel_param *kp)
345{
346	int ret;
347	bool boolval;
348	struct kernel_param dummy;
349
350	dummy.arg = &boolval;
351	ret = param_set_bool(val, &dummy);
352	if (ret == 0)
353		*(bool *)kp->arg = !boolval;
354	return ret;
355}
356EXPORT_SYMBOL(param_set_invbool);
357
358int param_get_invbool(char *buffer, const struct kernel_param *kp)
359{
360	return sprintf(buffer, "%c\n", (*(bool *)kp->arg) ? 'N' : 'Y');
361}
362EXPORT_SYMBOL(param_get_invbool);
363
364const struct kernel_param_ops param_ops_invbool = {
365	.set = param_set_invbool,
366	.get = param_get_invbool,
367};
368EXPORT_SYMBOL(param_ops_invbool);
369
370int param_set_bint(const char *val, const struct kernel_param *kp)
371{
372	/* Match bool exactly, by re-using it. */
373	struct kernel_param boolkp = *kp;
374	bool v;
375	int ret;
376
377	boolkp.arg = &v;
378
379	ret = param_set_bool(val, &boolkp);
380	if (ret == 0)
381		*(int *)kp->arg = v;
382	return ret;
383}
384EXPORT_SYMBOL(param_set_bint);
385
386const struct kernel_param_ops param_ops_bint = {
387	.flags = KERNEL_PARAM_OPS_FL_NOARG,
388	.set = param_set_bint,
389	.get = param_get_int,
390};
391EXPORT_SYMBOL(param_ops_bint);
392
393/* We break the rule and mangle the string. */
394static int param_array(struct module *mod,
395		       const char *name,
396		       const char *val,
397		       unsigned int min, unsigned int max,
398		       void *elem, int elemsize,
399		       int (*set)(const char *, const struct kernel_param *kp),
400		       s16 level,
401		       unsigned int *num)
402{
403	int ret;
404	struct kernel_param kp;
405	char save;
406
407	/* Get the name right for errors. */
408	kp.name = name;
409	kp.arg = elem;
410	kp.level = level;
411
412	*num = 0;
413	/* We expect a comma-separated list of values. */
414	do {
415		int len;
416
417		if (*num == max) {
418			pr_err("%s: can only take %i arguments\n", name, max);
419			return -EINVAL;
420		}
421		len = strcspn(val, ",");
422
423		/* nul-terminate and parse */
424		save = val[len];
425		((char *)val)[len] = '\0';
426		check_kparam_locked(mod);
427		ret = set(val, &kp);
428
429		if (ret != 0)
430			return ret;
431		kp.arg += elemsize;
432		val += len+1;
433		(*num)++;
434	} while (save == ',');
435
436	if (*num < min) {
437		pr_err("%s: needs at least %i arguments\n", name, min);
438		return -EINVAL;
439	}
440	return 0;
441}
442
443static int param_array_set(const char *val, const struct kernel_param *kp)
444{
445	const struct kparam_array *arr = kp->arr;
446	unsigned int temp_num;
447
448	return param_array(kp->mod, kp->name, val, 1, arr->max, arr->elem,
449			   arr->elemsize, arr->ops->set, kp->level,
450			   arr->num ?: &temp_num);
451}
452
453static int param_array_get(char *buffer, const struct kernel_param *kp)
454{
455	int i, off, ret;
456	const struct kparam_array *arr = kp->arr;
457	struct kernel_param p = *kp;
458
459	for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
460		/* Replace \n with comma */
461		if (i)
462			buffer[off - 1] = ',';
463		p.arg = arr->elem + arr->elemsize * i;
464		check_kparam_locked(p.mod);
465		ret = arr->ops->get(buffer + off, &p);
466		if (ret < 0)
467			return ret;
468		off += ret;
469	}
470	buffer[off] = '\0';
471	return off;
472}
473
474static void param_array_free(void *arg)
475{
476	unsigned int i;
477	const struct kparam_array *arr = arg;
478
479	if (arr->ops->free)
480		for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
481			arr->ops->free(arr->elem + arr->elemsize * i);
482}
483
484const struct kernel_param_ops param_array_ops = {
485	.set = param_array_set,
486	.get = param_array_get,
487	.free = param_array_free,
488};
489EXPORT_SYMBOL(param_array_ops);
490
491int param_set_copystring(const char *val, const struct kernel_param *kp)
492{
493	const struct kparam_string *kps = kp->str;
494
495	if (strlen(val)+1 > kps->maxlen) {
496		pr_err("%s: string doesn't fit in %u chars.\n",
497		       kp->name, kps->maxlen-1);
498		return -ENOSPC;
499	}
500	strcpy(kps->string, val);
501	return 0;
502}
503EXPORT_SYMBOL(param_set_copystring);
504
505int param_get_string(char *buffer, const struct kernel_param *kp)
506{
507	const struct kparam_string *kps = kp->str;
508	return scnprintf(buffer, PAGE_SIZE, "%s\n", kps->string);
509}
510EXPORT_SYMBOL(param_get_string);
511
512const struct kernel_param_ops param_ops_string = {
513	.set = param_set_copystring,
514	.get = param_get_string,
515};
516EXPORT_SYMBOL(param_ops_string);
517
518/* sysfs output in /sys/modules/XYZ/parameters/ */
519#define to_module_attr(n) container_of(n, struct module_attribute, attr)
520#define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
521
522struct param_attribute
523{
524	struct module_attribute mattr;
525	const struct kernel_param *param;
526};
527
528struct module_param_attrs
529{
530	unsigned int num;
531	struct attribute_group grp;
532	struct param_attribute attrs[0];
533};
534
535#ifdef CONFIG_SYSFS
536#define to_param_attr(n) container_of(n, struct param_attribute, mattr)
537
538static ssize_t param_attr_show(struct module_attribute *mattr,
539			       struct module_kobject *mk, char *buf)
540{
541	int count;
542	struct param_attribute *attribute = to_param_attr(mattr);
543
544	if (!attribute->param->ops->get)
545		return -EPERM;
546
547	kernel_param_lock(mk->mod);
548	count = attribute->param->ops->get(buf, attribute->param);
549	kernel_param_unlock(mk->mod);
550	return count;
551}
552
553/* sysfs always hands a nul-terminated string in buf.  We rely on that. */
554static ssize_t param_attr_store(struct module_attribute *mattr,
555				struct module_kobject *mk,
556				const char *buf, size_t len)
557{
558 	int err;
559	struct param_attribute *attribute = to_param_attr(mattr);
560
561	if (!attribute->param->ops->set)
562		return -EPERM;
563
564	kernel_param_lock(mk->mod);
565	if (param_check_unsafe(attribute->param))
566		err = attribute->param->ops->set(buf, attribute->param);
567	else
568		err = -EPERM;
569	kernel_param_unlock(mk->mod);
570	if (!err)
571		return len;
572	return err;
573}
574#endif
575
576#ifdef CONFIG_MODULES
577#define __modinit
578#else
579#define __modinit __init
580#endif
581
582#ifdef CONFIG_SYSFS
583void kernel_param_lock(struct module *mod)
584{
585	mutex_lock(KPARAM_MUTEX(mod));
586}
587
588void kernel_param_unlock(struct module *mod)
589{
590	mutex_unlock(KPARAM_MUTEX(mod));
591}
592
593EXPORT_SYMBOL(kernel_param_lock);
594EXPORT_SYMBOL(kernel_param_unlock);
595
596/*
597 * add_sysfs_param - add a parameter to sysfs
598 * @mk: struct module_kobject
599 * @kp: the actual parameter definition to add to sysfs
600 * @name: name of parameter
601 *
602 * Create a kobject if for a (per-module) parameter if mp NULL, and
603 * create file in sysfs.  Returns an error on out of memory.  Always cleans up
604 * if there's an error.
605 */
606static __modinit int add_sysfs_param(struct module_kobject *mk,
607				     const struct kernel_param *kp,
608				     const char *name)
609{
610	struct module_param_attrs *new_mp;
611	struct attribute **new_attrs;
612	unsigned int i;
613
614	/* We don't bother calling this with invisible parameters. */
615	BUG_ON(!kp->perm);
616
617	if (!mk->mp) {
618		/* First allocation. */
619		mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
620		if (!mk->mp)
621			return -ENOMEM;
622		mk->mp->grp.name = "parameters";
623		/* NULL-terminated attribute array. */
624		mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
625					    GFP_KERNEL);
626		/* Caller will cleanup via free_module_param_attrs */
627		if (!mk->mp->grp.attrs)
628			return -ENOMEM;
629	}
630
631	/* Enlarge allocations. */
632	new_mp = krealloc(mk->mp,
633			  sizeof(*mk->mp) +
634			  sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1),
635			  GFP_KERNEL);
636	if (!new_mp)
637		return -ENOMEM;
638	mk->mp = new_mp;
639
640	/* Extra pointer for NULL terminator */
641	new_attrs = krealloc(mk->mp->grp.attrs,
642			     sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2),
643			     GFP_KERNEL);
644	if (!new_attrs)
645		return -ENOMEM;
646	mk->mp->grp.attrs = new_attrs;
647
648	/* Tack new one on the end. */
649	memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0]));
650	sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
651	mk->mp->attrs[mk->mp->num].param = kp;
652	mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
653	/* Do not allow runtime DAC changes to make param writable. */
654	if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
655		mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
656	else
657		mk->mp->attrs[mk->mp->num].mattr.store = NULL;
658	mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
659	mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
660	mk->mp->num++;
661
662	/* Fix up all the pointers, since krealloc can move us */
663	for (i = 0; i < mk->mp->num; i++)
664		mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
665	mk->mp->grp.attrs[mk->mp->num] = NULL;
666	return 0;
667}
668
669#ifdef CONFIG_MODULES
670static void free_module_param_attrs(struct module_kobject *mk)
671{
672	if (mk->mp)
673		kfree(mk->mp->grp.attrs);
674	kfree(mk->mp);
675	mk->mp = NULL;
676}
677
678/*
679 * module_param_sysfs_setup - setup sysfs support for one module
680 * @mod: module
681 * @kparam: module parameters (array)
682 * @num_params: number of module parameters
683 *
684 * Adds sysfs entries for module parameters under
685 * /sys/module/[mod->name]/parameters/
686 */
687int module_param_sysfs_setup(struct module *mod,
688			     const struct kernel_param *kparam,
689			     unsigned int num_params)
690{
691	int i, err;
692	bool params = false;
693
694	for (i = 0; i < num_params; i++) {
695		if (kparam[i].perm == 0)
696			continue;
697		err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
698		if (err) {
699			free_module_param_attrs(&mod->mkobj);
700			return err;
701		}
702		params = true;
703	}
704
705	if (!params)
706		return 0;
707
708	/* Create the param group. */
709	err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
710	if (err)
711		free_module_param_attrs(&mod->mkobj);
712	return err;
713}
714
715/*
716 * module_param_sysfs_remove - remove sysfs support for one module
717 * @mod: module
718 *
719 * Remove sysfs entries for module parameters and the corresponding
720 * kobject.
721 */
722void module_param_sysfs_remove(struct module *mod)
723{
724	if (mod->mkobj.mp) {
725		sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
726		/* We are positive that no one is using any param
727		 * attrs at this point.  Deallocate immediately. */
728		free_module_param_attrs(&mod->mkobj);
729	}
730}
731#endif
732
733void destroy_params(const struct kernel_param *params, unsigned num)
734{
735	unsigned int i;
736
737	for (i = 0; i < num; i++)
738		if (params[i].ops->free)
739			params[i].ops->free(params[i].arg);
740}
741
742static struct module_kobject * __init locate_module_kobject(const char *name)
743{
744	struct module_kobject *mk;
745	struct kobject *kobj;
746	int err;
747
748	kobj = kset_find_obj(module_kset, name);
749	if (kobj) {
750		mk = to_module_kobject(kobj);
751	} else {
752		mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
753		BUG_ON(!mk);
754
755		mk->mod = THIS_MODULE;
756		mk->kobj.kset = module_kset;
757		err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
758					   "%s", name);
759#ifdef CONFIG_MODULES
760		if (!err)
761			err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
762#endif
763		if (err) {
764			kobject_put(&mk->kobj);
765			pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
766				name, err);
767			return NULL;
768		}
769
770		/* So that we hold reference in both cases. */
771		kobject_get(&mk->kobj);
772	}
773
774	return mk;
775}
776
777static void __init kernel_add_sysfs_param(const char *name,
778					  const struct kernel_param *kparam,
779					  unsigned int name_skip)
780{
781	struct module_kobject *mk;
782	int err;
783
784	mk = locate_module_kobject(name);
785	if (!mk)
786		return;
787
788	/* We need to remove old parameters before adding more. */
789	if (mk->mp)
790		sysfs_remove_group(&mk->kobj, &mk->mp->grp);
791
792	/* These should not fail at boot. */
793	err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
794	BUG_ON(err);
795	err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
796	BUG_ON(err);
797	kobject_uevent(&mk->kobj, KOBJ_ADD);
798	kobject_put(&mk->kobj);
799}
800
801/*
802 * param_sysfs_builtin - add sysfs parameters for built-in modules
803 *
804 * Add module_parameters to sysfs for "modules" built into the kernel.
805 *
806 * The "module" name (KBUILD_MODNAME) is stored before a dot, the
807 * "parameter" name is stored behind a dot in kernel_param->name. So,
808 * extract the "module" name for all built-in kernel_param-eters,
809 * and for all who have the same, call kernel_add_sysfs_param.
810 */
811static void __init param_sysfs_builtin(void)
812{
813	const struct kernel_param *kp;
814	unsigned int name_len;
815	char modname[MODULE_NAME_LEN];
816
817	for (kp = __start___param; kp < __stop___param; kp++) {
818		char *dot;
819
820		if (kp->perm == 0)
821			continue;
822
823		dot = strchr(kp->name, '.');
824		if (!dot) {
825			/* This happens for core_param() */
826			strcpy(modname, "kernel");
827			name_len = 0;
828		} else {
829			name_len = dot - kp->name + 1;
830			strlcpy(modname, kp->name, name_len);
831		}
832		kernel_add_sysfs_param(modname, kp, name_len);
833	}
834}
835
836ssize_t __modver_version_show(struct module_attribute *mattr,
837			      struct module_kobject *mk, char *buf)
838{
839	struct module_version_attribute *vattr =
840		container_of(mattr, struct module_version_attribute, mattr);
841
842	return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
843}
844
845extern const struct module_version_attribute *__start___modver[];
846extern const struct module_version_attribute *__stop___modver[];
847
848static void __init version_sysfs_builtin(void)
849{
850	const struct module_version_attribute **p;
851	struct module_kobject *mk;
852	int err;
853
854	for (p = __start___modver; p < __stop___modver; p++) {
855		const struct module_version_attribute *vattr = *p;
856
857		mk = locate_module_kobject(vattr->module_name);
858		if (mk) {
859			err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
860			WARN_ON_ONCE(err);
861			kobject_uevent(&mk->kobj, KOBJ_ADD);
862			kobject_put(&mk->kobj);
863		}
864	}
865}
866
867/* module-related sysfs stuff */
868
869static ssize_t module_attr_show(struct kobject *kobj,
870				struct attribute *attr,
871				char *buf)
872{
873	struct module_attribute *attribute;
874	struct module_kobject *mk;
875	int ret;
876
877	attribute = to_module_attr(attr);
878	mk = to_module_kobject(kobj);
879
880	if (!attribute->show)
881		return -EIO;
882
883	ret = attribute->show(attribute, mk, buf);
884
885	return ret;
886}
887
888static ssize_t module_attr_store(struct kobject *kobj,
889				struct attribute *attr,
890				const char *buf, size_t len)
891{
892	struct module_attribute *attribute;
893	struct module_kobject *mk;
894	int ret;
895
896	attribute = to_module_attr(attr);
897	mk = to_module_kobject(kobj);
898
899	if (!attribute->store)
900		return -EIO;
901
902	ret = attribute->store(attribute, mk, buf, len);
903
904	return ret;
905}
906
907static const struct sysfs_ops module_sysfs_ops = {
908	.show = module_attr_show,
909	.store = module_attr_store,
910};
911
912static int uevent_filter(struct kset *kset, struct kobject *kobj)
913{
914	struct kobj_type *ktype = get_ktype(kobj);
915
916	if (ktype == &module_ktype)
917		return 1;
918	return 0;
919}
920
921static const struct kset_uevent_ops module_uevent_ops = {
922	.filter = uevent_filter,
923};
924
925struct kset *module_kset;
926int module_sysfs_initialized;
927
928static void module_kobj_release(struct kobject *kobj)
929{
930	struct module_kobject *mk = to_module_kobject(kobj);
931	complete(mk->kobj_completion);
932}
933
934struct kobj_type module_ktype = {
935	.release   =	module_kobj_release,
936	.sysfs_ops =	&module_sysfs_ops,
937};
938
939/*
940 * param_sysfs_init - wrapper for built-in params support
941 */
942static int __init param_sysfs_init(void)
943{
944	module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
945	if (!module_kset) {
946		printk(KERN_WARNING "%s (%d): error creating kset\n",
947			__FILE__, __LINE__);
948		return -ENOMEM;
949	}
950	module_sysfs_initialized = 1;
951
952	version_sysfs_builtin();
953	param_sysfs_builtin();
954
955	return 0;
956}
957subsys_initcall(param_sysfs_init);
958
959#endif /* CONFIG_SYSFS */