params.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Helpers for initial module or kernel cmdline parsing
  4 * Copyright (C) 2001 Rusty Russell.
  5 */
  6#include <linux/ctype.h>
  7#include <linux/device.h>
  8#include <linux/err.h>
  9#include <linux/errno.h>
 10#include <linux/kernel.h>
 11#include <linux/kstrtox.h>
 12#include <linux/module.h>
 13#include <linux/moduleparam.h>
 14#include <linux/overflow.h>
 15#include <linux/security.h>
 16#include <linux/slab.h>
 17#include <linux/string.h>
 18
 19#ifdef CONFIG_SYSFS
 20/* Protects all built-in parameters, modules use their own param_lock */
 21static DEFINE_MUTEX(param_lock);
 22
 23/* Use the module's mutex, or if built-in use the built-in mutex */
 24#ifdef CONFIG_MODULES
 25#define KPARAM_MUTEX(mod)	((mod) ? &(mod)->param_lock : &param_lock)
 26#else
 27#define KPARAM_MUTEX(mod)	(&param_lock)
 28#endif
 29
 30static inline void check_kparam_locked(struct module *mod)
 31{
 32	BUG_ON(!mutex_is_locked(KPARAM_MUTEX(mod)));
 33}
 34#else
 35static inline void check_kparam_locked(struct module *mod)
 36{
 37}
 38#endif /* !CONFIG_SYSFS */
 39
 40/* This just allows us to keep track of which parameters are kmalloced. */
 41struct kmalloced_param {
 42	struct list_head list;
 43	char val[];
 44};
 45static LIST_HEAD(kmalloced_params);
 46static DEFINE_SPINLOCK(kmalloced_params_lock);
 47
 48static void *kmalloc_parameter(unsigned int size)
 49{
 50	struct kmalloced_param *p;
 51
 52	p = kmalloc(size_add(sizeof(*p), size), GFP_KERNEL);
 53	if (!p)
 54		return NULL;
 55
 56	spin_lock(&kmalloced_params_lock);
 57	list_add(&p->list, &kmalloced_params);
 58	spin_unlock(&kmalloced_params_lock);
 59
 60	return p->val;
 61}
 62
 63/* Does nothing if parameter wasn't kmalloced above. */
 64static void maybe_kfree_parameter(void *param)
 65{
 66	struct kmalloced_param *p;
 67
 68	spin_lock(&kmalloced_params_lock);
 69	list_for_each_entry(p, &kmalloced_params, list) {
 70		if (p->val == param) {
 71			list_del(&p->list);
 72			kfree(p);
 73			break;
 74		}
 75	}
 76	spin_unlock(&kmalloced_params_lock);
 77}
 78
 79static char dash2underscore(char c)
 80{
 81	if (c == '-')
 82		return '_';
 83	return c;
 84}
 85
 86bool parameqn(const char *a, const char *b, size_t n)
 87{
 88	size_t i;
 89
 90	for (i = 0; i < n; i++) {
 91		if (dash2underscore(a[i]) != dash2underscore(b[i]))
 92			return false;
 93	}
 94	return true;
 95}
 96
 97bool parameq(const char *a, const char *b)
 98{
 99	return parameqn(a, b, strlen(a)+1);
100}
101
102static bool param_check_unsafe(const struct kernel_param *kp)
103{
104	if (kp->flags & KERNEL_PARAM_FL_HWPARAM &&
105	    security_locked_down(LOCKDOWN_MODULE_PARAMETERS))
106		return false;
107
108	if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {
109		pr_notice("Setting dangerous option %s - tainting kernel\n",
110			  kp->name);
111		add_taint(TAINT_USER, LOCKDEP_STILL_OK);
112	}
113
114	return true;
115}
116
117static int parse_one(char *param,
118		     char *val,
119		     const char *doing,
120		     const struct kernel_param *params,
121		     unsigned num_params,
122		     s16 min_level,
123		     s16 max_level,
124		     void *arg, parse_unknown_fn handle_unknown)
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, parse_unknown_fn unknown)
168{
169	char *param, *val, *err = NULL;
170
171	/* Chew leading spaces */
172	args = skip_spaces(args);
173
174	if (*args)
175		pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
176
177	while (*args) {
178		int ret;
179		int irq_was_disabled;
180
181		args = next_arg(args, &param, &val);
182		/* Stop at -- */
183		if (!val && strcmp(param, "--") == 0)
184			return err ?: args;
185		irq_was_disabled = irqs_disabled();
186		ret = parse_one(param, val, doing, params, num,
187				min_level, max_level, arg, unknown);
188		if (irq_was_disabled && !irqs_disabled())
189			pr_warn("%s: option '%s' enabled irq's!\n",
190				doing, param);
191
192		switch (ret) {
193		case 0:
194			continue;
195		case -ENOENT:
196			pr_err("%s: Unknown parameter `%s'\n", doing, param);
197			break;
198		case -ENOSPC:
199			pr_err("%s: `%s' too large for parameter `%s'\n",
200			       doing, val ?: "", param);
201			break;
202		default:
203			pr_err("%s: `%s' invalid for parameter `%s'\n",
204			       doing, val ?: "", param);
205			break;
206		}
207
208		err = ERR_PTR(ret);
209	}
210
211	return err;
212}
213
214/* Lazy bastard, eh? */
215#define STANDARD_PARAM_DEF(name, type, format, strtolfn)      		\
216	int param_set_##name(const char *val, const struct kernel_param *kp) \
217	{								\
218		return strtolfn(val, 0, (type *)kp->arg);		\
219	}								\
220	int param_get_##name(char *buffer, const struct kernel_param *kp) \
221	{								\
222		return scnprintf(buffer, PAGE_SIZE, format "\n",	\
223				*((type *)kp->arg));			\
224	}								\
225	const struct kernel_param_ops param_ops_##name = {			\
226		.set = param_set_##name,				\
227		.get = param_get_##name,				\
228	};								\
229	EXPORT_SYMBOL(param_set_##name);				\
230	EXPORT_SYMBOL(param_get_##name);				\
231	EXPORT_SYMBOL(param_ops_##name)
232
233
234STANDARD_PARAM_DEF(byte,	unsigned char,		"%hhu",		kstrtou8);
235STANDARD_PARAM_DEF(short,	short,			"%hi",		kstrtos16);
236STANDARD_PARAM_DEF(ushort,	unsigned short,		"%hu",		kstrtou16);
237STANDARD_PARAM_DEF(int,		int,			"%i",		kstrtoint);
238STANDARD_PARAM_DEF(uint,	unsigned int,		"%u",		kstrtouint);
239STANDARD_PARAM_DEF(long,	long,			"%li",		kstrtol);
240STANDARD_PARAM_DEF(ulong,	unsigned long,		"%lu",		kstrtoul);
241STANDARD_PARAM_DEF(ullong,	unsigned long long,	"%llu",		kstrtoull);
242STANDARD_PARAM_DEF(hexint,	unsigned int,		"%#08x", 	kstrtouint);
243
244int param_set_uint_minmax(const char *val, const struct kernel_param *kp,
245		unsigned int min, unsigned int max)
246{
247	unsigned int num;
248	int ret;
249
250	if (!val)
251		return -EINVAL;
252	ret = kstrtouint(val, 0, &num);
253	if (ret)
254		return ret;
255	if (num < min || num > max)
256		return -EINVAL;
257	*((unsigned int *)kp->arg) = num;
258	return 0;
259}
260EXPORT_SYMBOL_GPL(param_set_uint_minmax);
261
262int param_set_charp(const char *val, const struct kernel_param *kp)
263{
264	size_t len, maxlen = 1024;
265
266	len = strnlen(val, maxlen + 1);
267	if (len == maxlen + 1) {
268		pr_err("%s: string parameter too long\n", kp->name);
269		return -ENOSPC;
270	}
271
272	maybe_kfree_parameter(*(char **)kp->arg);
273
274	/*
275	 * This is a hack. We can't kmalloc() in early boot, and we
276	 * don't need to; this mangled commandline is preserved.
277	 */
278	if (slab_is_available()) {
279		*(char **)kp->arg = kmalloc_parameter(len + 1);
280		if (!*(char **)kp->arg)
281			return -ENOMEM;
282		strcpy(*(char **)kp->arg, val);
283	} else
284		*(const char **)kp->arg = val;
285
286	return 0;
287}
288EXPORT_SYMBOL(param_set_charp);
289
290int param_get_charp(char *buffer, const struct kernel_param *kp)
291{
292	return scnprintf(buffer, PAGE_SIZE, "%s\n", *((char **)kp->arg));
293}
294EXPORT_SYMBOL(param_get_charp);
295
296void param_free_charp(void *arg)
297{
298	maybe_kfree_parameter(*((char **)arg));
299}
300EXPORT_SYMBOL(param_free_charp);
301
302const struct kernel_param_ops param_ops_charp = {
303	.set = param_set_charp,
304	.get = param_get_charp,
305	.free = param_free_charp,
306};
307EXPORT_SYMBOL(param_ops_charp);
308
309/* Actually could be a bool or an int, for historical reasons. */
310int param_set_bool(const char *val, const struct kernel_param *kp)
311{
312	/* No equals means "set"... */
313	if (!val) val = "1";
314
315	/* One of =[yYnN01] */
316	return kstrtobool(val, kp->arg);
317}
318EXPORT_SYMBOL(param_set_bool);
319
320int param_get_bool(char *buffer, const struct kernel_param *kp)
321{
322	/* Y and N chosen as being relatively non-coder friendly */
323	return sprintf(buffer, "%c\n", *(bool *)kp->arg ? 'Y' : 'N');
324}
325EXPORT_SYMBOL(param_get_bool);
326
327const struct kernel_param_ops param_ops_bool = {
328	.flags = KERNEL_PARAM_OPS_FL_NOARG,
329	.set = param_set_bool,
330	.get = param_get_bool,
331};
332EXPORT_SYMBOL(param_ops_bool);
333
334int param_set_bool_enable_only(const char *val, const struct kernel_param *kp)
335{
336	int err;
337	bool new_value;
338	bool orig_value = *(bool *)kp->arg;
339	struct kernel_param dummy_kp = *kp;
340
341	dummy_kp.arg = &new_value;
342
343	err = param_set_bool(val, &dummy_kp);
344	if (err)
345		return err;
346
347	/* Don't let them unset it once it's set! */
348	if (!new_value && orig_value)
349		return -EROFS;
350
351	if (new_value)
352		err = param_set_bool(val, kp);
353
354	return err;
355}
356EXPORT_SYMBOL_GPL(param_set_bool_enable_only);
357
358const struct kernel_param_ops param_ops_bool_enable_only = {
359	.flags = KERNEL_PARAM_OPS_FL_NOARG,
360	.set = param_set_bool_enable_only,
361	.get = param_get_bool,
362};
363EXPORT_SYMBOL_GPL(param_ops_bool_enable_only);
364
365/* This one must be bool. */
366int param_set_invbool(const char *val, const struct kernel_param *kp)
367{
368	int ret;
369	bool boolval;
370	struct kernel_param dummy;
371
372	dummy.arg = &boolval;
373	ret = param_set_bool(val, &dummy);
374	if (ret == 0)
375		*(bool *)kp->arg = !boolval;
376	return ret;
377}
378EXPORT_SYMBOL(param_set_invbool);
379
380int param_get_invbool(char *buffer, const struct kernel_param *kp)
381{
382	return sprintf(buffer, "%c\n", (*(bool *)kp->arg) ? 'N' : 'Y');
383}
384EXPORT_SYMBOL(param_get_invbool);
385
386const struct kernel_param_ops param_ops_invbool = {
387	.set = param_set_invbool,
388	.get = param_get_invbool,
389};
390EXPORT_SYMBOL(param_ops_invbool);
391
392int param_set_bint(const char *val, const struct kernel_param *kp)
393{
394	/* Match bool exactly, by re-using it. */
395	struct kernel_param boolkp = *kp;
396	bool v;
397	int ret;
398
399	boolkp.arg = &v;
400
401	ret = param_set_bool(val, &boolkp);
402	if (ret == 0)
403		*(int *)kp->arg = v;
404	return ret;
405}
406EXPORT_SYMBOL(param_set_bint);
407
408const struct kernel_param_ops param_ops_bint = {
409	.flags = KERNEL_PARAM_OPS_FL_NOARG,
410	.set = param_set_bint,
411	.get = param_get_int,
412};
413EXPORT_SYMBOL(param_ops_bint);
414
415/* We break the rule and mangle the string. */
416static int param_array(struct module *mod,
417		       const char *name,
418		       const char *val,
419		       unsigned int min, unsigned int max,
420		       void *elem, int elemsize,
421		       int (*set)(const char *, const struct kernel_param *kp),
422		       s16 level,
423		       unsigned int *num)
424{
425	int ret;
426	struct kernel_param kp;
427	char save;
428
429	/* Get the name right for errors. */
430	kp.name = name;
431	kp.arg = elem;
432	kp.level = level;
433
434	*num = 0;
435	/* We expect a comma-separated list of values. */
436	do {
437		int len;
438
439		if (*num == max) {
440			pr_err("%s: can only take %i arguments\n", name, max);
441			return -EINVAL;
442		}
443		len = strcspn(val, ",");
444
445		/* nul-terminate and parse */
446		save = val[len];
447		((char *)val)[len] = '\0';
448		check_kparam_locked(mod);
449		ret = set(val, &kp);
450
451		if (ret != 0)
452			return ret;
453		kp.arg += elemsize;
454		val += len+1;
455		(*num)++;
456	} while (save == ',');
457
458	if (*num < min) {
459		pr_err("%s: needs at least %i arguments\n", name, min);
460		return -EINVAL;
461	}
462	return 0;
463}
464
465static int param_array_set(const char *val, const struct kernel_param *kp)
466{
467	const struct kparam_array *arr = kp->arr;
468	unsigned int temp_num;
469
470	return param_array(kp->mod, kp->name, val, 1, arr->max, arr->elem,
471			   arr->elemsize, arr->ops->set, kp->level,
472			   arr->num ?: &temp_num);
473}
474
475static int param_array_get(char *buffer, const struct kernel_param *kp)
476{
477	int i, off, ret;
478	const struct kparam_array *arr = kp->arr;
479	struct kernel_param p = *kp;
480
481	for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
482		/* Replace \n with comma */
483		if (i)
484			buffer[off - 1] = ',';
485		p.arg = arr->elem + arr->elemsize * i;
486		check_kparam_locked(p.mod);
487		ret = arr->ops->get(buffer + off, &p);
488		if (ret < 0)
489			return ret;
490		off += ret;
491	}
492	buffer[off] = '\0';
493	return off;
494}
495
496static void param_array_free(void *arg)
497{
498	unsigned int i;
499	const struct kparam_array *arr = arg;
500
501	if (arr->ops->free)
502		for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
503			arr->ops->free(arr->elem + arr->elemsize * i);
504}
505
506const struct kernel_param_ops param_array_ops = {
507	.set = param_array_set,
508	.get = param_array_get,
509	.free = param_array_free,
510};
511EXPORT_SYMBOL(param_array_ops);
512
513int param_set_copystring(const char *val, const struct kernel_param *kp)
514{
515	const struct kparam_string *kps = kp->str;
516	const size_t len = strnlen(val, kps->maxlen);
517
518	if (len == kps->maxlen) {
519		pr_err("%s: string doesn't fit in %u chars.\n",
520		       kp->name, kps->maxlen-1);
521		return -ENOSPC;
522	}
523	memcpy(kps->string, val, len + 1);
524	return 0;
525}
526EXPORT_SYMBOL(param_set_copystring);
527
528int param_get_string(char *buffer, const struct kernel_param *kp)
529{
530	const struct kparam_string *kps = kp->str;
531	return scnprintf(buffer, PAGE_SIZE, "%s\n", kps->string);
532}
533EXPORT_SYMBOL(param_get_string);
534
535const struct kernel_param_ops param_ops_string = {
536	.set = param_set_copystring,
537	.get = param_get_string,
538};
539EXPORT_SYMBOL(param_ops_string);
540
541/* sysfs output in /sys/modules/XYZ/parameters/ */
542#define to_module_attr(n) container_of_const(n, struct module_attribute, attr)
543#define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
544
545struct param_attribute
546{
547	struct module_attribute mattr;
548	const struct kernel_param *param;
549};
550
551struct module_param_attrs
552{
553	unsigned int num;
554	struct attribute_group grp;
555	struct param_attribute attrs[] __counted_by(num);
556};
557
558#ifdef CONFIG_SYSFS
559#define to_param_attr(n) container_of_const(n, struct param_attribute, mattr)
560
561static ssize_t param_attr_show(const struct module_attribute *mattr,
562			       struct module_kobject *mk, char *buf)
563{
564	int count;
565	const struct param_attribute *attribute = to_param_attr(mattr);
566
567	if (!attribute->param->ops->get)
568		return -EPERM;
569
570	kernel_param_lock(mk->mod);
571	count = attribute->param->ops->get(buf, attribute->param);
572	kernel_param_unlock(mk->mod);
573	return count;
574}
575
576/* sysfs always hands a nul-terminated string in buf.  We rely on that. */
577static ssize_t param_attr_store(const struct module_attribute *mattr,
578				struct module_kobject *mk,
579				const char *buf, size_t len)
580{
581 	int err;
582	const struct param_attribute *attribute = to_param_attr(mattr);
583
584	if (!attribute->param->ops->set)
585		return -EPERM;
586
587	kernel_param_lock(mk->mod);
588	if (param_check_unsafe(attribute->param))
589		err = attribute->param->ops->set(buf, attribute->param);
590	else
591		err = -EPERM;
592	kernel_param_unlock(mk->mod);
593	if (!err)
594		return len;
595	return err;
596}
597#endif
598
599#ifdef CONFIG_MODULES
600#define __modinit
601#else
602#define __modinit __init
603#endif
604
605#ifdef CONFIG_SYSFS
606void kernel_param_lock(struct module *mod)
607{
608	mutex_lock(KPARAM_MUTEX(mod));
609}
610
611void kernel_param_unlock(struct module *mod)
612{
613	mutex_unlock(KPARAM_MUTEX(mod));
614}
615
616EXPORT_SYMBOL(kernel_param_lock);
617EXPORT_SYMBOL(kernel_param_unlock);
618
619/*
620 * add_sysfs_param - add a parameter to sysfs
621 * @mk: struct module_kobject
622 * @kp: the actual parameter definition to add to sysfs
623 * @name: name of parameter
624 *
625 * Create a kobject if for a (per-module) parameter if mp NULL, and
626 * create file in sysfs.  Returns an error on out of memory.  Always cleans up
627 * if there's an error.
628 */
629static __modinit int add_sysfs_param(struct module_kobject *mk,
630				     const struct kernel_param *kp,
631				     const char *name)
632{
633	struct module_param_attrs *new_mp;
634	struct attribute **new_attrs;
635	unsigned int i;
636
637	/* We don't bother calling this with invisible parameters. */
638	BUG_ON(!kp->perm);
639
640	if (!mk->mp) {
641		/* First allocation. */
642		mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
643		if (!mk->mp)
644			return -ENOMEM;
645		mk->mp->grp.name = "parameters";
646		/* NULL-terminated attribute array. */
647		mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
648					    GFP_KERNEL);
649		/* Caller will cleanup via free_module_param_attrs */
650		if (!mk->mp->grp.attrs)
651			return -ENOMEM;
652	}
653
654	/* Enlarge allocations. */
655	new_mp = krealloc(mk->mp, struct_size(mk->mp, attrs, mk->mp->num + 1),
656			  GFP_KERNEL);
657	if (!new_mp)
658		return -ENOMEM;
659	mk->mp = new_mp;
660	mk->mp->num++;
661
662	/* Extra pointer for NULL terminator */
663	new_attrs = krealloc_array(mk->mp->grp.attrs, mk->mp->num + 1,
664				   sizeof(mk->mp->grp.attrs[0]), GFP_KERNEL);
665	if (!new_attrs)
666		return -ENOMEM;
667	mk->mp->grp.attrs = new_attrs;
668
669	/* Tack new one on the end. */
670	memset(&mk->mp->attrs[mk->mp->num - 1], 0, sizeof(mk->mp->attrs[0]));
671	sysfs_attr_init(&mk->mp->attrs[mk->mp->num - 1].mattr.attr);
672	mk->mp->attrs[mk->mp->num - 1].param = kp;
673	mk->mp->attrs[mk->mp->num - 1].mattr.show = param_attr_show;
674	/* Do not allow runtime DAC changes to make param writable. */
675	if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
676		mk->mp->attrs[mk->mp->num - 1].mattr.store = param_attr_store;
677	else
678		mk->mp->attrs[mk->mp->num - 1].mattr.store = NULL;
679	mk->mp->attrs[mk->mp->num - 1].mattr.attr.name = (char *)name;
680	mk->mp->attrs[mk->mp->num - 1].mattr.attr.mode = kp->perm;
681
682	/* Fix up all the pointers, since krealloc can move us */
683	for (i = 0; i < mk->mp->num; i++)
684		mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
685	mk->mp->grp.attrs[mk->mp->num] = NULL;
686	return 0;
687}
688
689#ifdef CONFIG_MODULES
690static void free_module_param_attrs(struct module_kobject *mk)
691{
692	if (mk->mp)
693		kfree(mk->mp->grp.attrs);
694	kfree(mk->mp);
695	mk->mp = NULL;
696}
697
698/*
699 * module_param_sysfs_setup - setup sysfs support for one module
700 * @mod: module
701 * @kparam: module parameters (array)
702 * @num_params: number of module parameters
703 *
704 * Adds sysfs entries for module parameters under
705 * /sys/module/[mod->name]/parameters/
706 */
707int module_param_sysfs_setup(struct module *mod,
708			     const struct kernel_param *kparam,
709			     unsigned int num_params)
710{
711	int i, err;
712	bool params = false;
713
714	for (i = 0; i < num_params; i++) {
715		if (kparam[i].perm == 0)
716			continue;
717		err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
718		if (err) {
719			free_module_param_attrs(&mod->mkobj);
720			return err;
721		}
722		params = true;
723	}
724
725	if (!params)
726		return 0;
727
728	/* Create the param group. */
729	err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
730	if (err)
731		free_module_param_attrs(&mod->mkobj);
732	return err;
733}
734
735/*
736 * module_param_sysfs_remove - remove sysfs support for one module
737 * @mod: module
738 *
739 * Remove sysfs entries for module parameters and the corresponding
740 * kobject.
741 */
742void module_param_sysfs_remove(struct module *mod)
743{
744	if (mod->mkobj.mp) {
745		sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
746		/*
747		 * We are positive that no one is using any param
748		 * attrs at this point. Deallocate immediately.
749		 */
750		free_module_param_attrs(&mod->mkobj);
751	}
752}
753#endif
754
755void destroy_params(const struct kernel_param *params, unsigned num)
756{
757	unsigned int i;
758
759	for (i = 0; i < num; i++)
760		if (params[i].ops->free)
761			params[i].ops->free(params[i].arg);
762}
763
764struct module_kobject __modinit * lookup_or_create_module_kobject(const char *name)
765{
766	struct module_kobject *mk;
767	struct kobject *kobj;
768	int err;
769
770	kobj = kset_find_obj(module_kset, name);
771	if (kobj)
772		return to_module_kobject(kobj);
773
774	mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
775	if (!mk)
776		return NULL;
777
778	mk->mod = THIS_MODULE;
779	mk->kobj.kset = module_kset;
780	err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL, "%s", name);
781	if (IS_ENABLED(CONFIG_MODULES) && !err)
782		err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
783	if (err) {
784		kobject_put(&mk->kobj);
785		pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
786			name, err);
787		return NULL;
788	}
789
790	/* So that we hold reference in both cases. */
791	kobject_get(&mk->kobj);
792
793	return mk;
794}
795
796static 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 = lookup_or_create_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 */
830static 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			strscpy(modname, "kernel");
846			name_len = 0;
847		} else {
848			name_len = dot - kp->name + 1;
849			strscpy(modname, kp->name, name_len);
850		}
851		kernel_add_sysfs_param(modname, kp, name_len);
852	}
853}
854
855ssize_t __modver_version_show(const struct module_attribute *mattr,
856			      struct module_kobject *mk, char *buf)
857{
858	const struct module_version_attribute *vattr =
859		container_of_const(mattr, struct module_version_attribute, mattr);
860
861	return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
862}
863
864extern const struct module_version_attribute __start___modver[];
865extern const struct module_version_attribute __stop___modver[];
866
867static 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 = lookup_or_create_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
886static ssize_t module_attr_show(struct kobject *kobj,
887				struct attribute *attr,
888				char *buf)
889{
890	const 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
905static ssize_t module_attr_store(struct kobject *kobj,
906				struct attribute *attr,
907				const char *buf, size_t len)
908{
909	const 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
924static const struct sysfs_ops module_sysfs_ops = {
925	.show = module_attr_show,
926	.store = module_attr_store,
927};
928
929static int uevent_filter(const struct kobject *kobj)
930{
931	const struct kobj_type *ktype = get_ktype(kobj);
932
933	if (ktype == &module_ktype)
934		return 1;
935	return 0;
936}
937
938static const struct kset_uevent_ops module_uevent_ops = {
939	.filter = uevent_filter,
940};
941
942struct kset *module_kset;
943
944static void module_kobj_release(struct kobject *kobj)
945{
946	struct module_kobject *mk = to_module_kobject(kobj);
947
948	if (mk->kobj_completion)
949		complete(mk->kobj_completion);
950}
951
952const struct kobj_type module_ktype = {
953	.release   =	module_kobj_release,
954	.sysfs_ops =	&module_sysfs_ops,
955};
956
957/*
958 * param_sysfs_init - create "module" kset
959 *
960 * This must be done before the initramfs is unpacked and
961 * request_module() thus becomes possible, because otherwise the
962 * module load would fail in mod_sysfs_init.
963 */
964static int __init param_sysfs_init(void)
965{
966	module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
967	if (!module_kset) {
968		printk(KERN_WARNING "%s (%d): error creating kset\n",
969			__FILE__, __LINE__);
970		return -ENOMEM;
971	}
972
973	return 0;
974}
975subsys_initcall(param_sysfs_init);
976
977/*
978 * param_sysfs_builtin_init - add sysfs version and parameter
979 * attributes for built-in modules
980 */
981static int __init param_sysfs_builtin_init(void)
982{
983	if (!module_kset)
984		return -ENOMEM;
985
986	version_sysfs_builtin();
987	param_sysfs_builtin();
988
989	return 0;
990}
991late_initcall(param_sysfs_builtin_init);
992
993#endif /* CONFIG_SYSFS */