efivars.c revision e33655a386ed3b26ad36fb97a47ebb1c2ca1e928 
1/*
2 * Originally from efivars.c,
3 *
4 * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
5 * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
6 *
7 * This code takes all variables accessible from EFI runtime and
8 *  exports them via sysfs
9 *
10 *  This program is free software; you can redistribute it and/or modify
11 *  it under the terms of the GNU General Public License as published by
12 *  the Free Software Foundation; either version 2 of the License, or
13 *  (at your option) any later version.
14 *
15 *  This program is distributed in the hope that it will be useful,
16 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
17 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18 *  GNU General Public License for more details.
19 *
20 *  You should have received a copy of the GNU General Public License
21 *  along with this program; if not, write to the Free Software
22 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
23 *
24 * Changelog:
25 *
26 *  17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
27 *   remove check for efi_enabled in exit
28 *   add MODULE_VERSION
29 *
30 *  26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com>
31 *   minor bug fixes
32 *
33 *  21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com)
34 *   converted driver to export variable information via sysfs
35 *   and moved to drivers/firmware directory
36 *   bumped revision number to v0.07 to reflect conversion & move
37 *
38 *  10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com>
39 *   fix locking per Peter Chubb's findings
40 *
41 *  25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com>
42 *   move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_unparse()
43 *
44 *  12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com>
45 *   use list_for_each_safe when deleting vars.
46 *   remove ifdef CONFIG_SMP around include <linux/smp.h>
47 *   v0.04 release to linux-ia64@linuxia64.org
48 *
49 *  20 April 2001 - Matt Domsch <Matt_Domsch@dell.com>
50 *   Moved vars from /proc/efi to /proc/efi/vars, and made
51 *   efi.c own the /proc/efi directory.
52 *   v0.03 release to linux-ia64@linuxia64.org
53 *
54 *  26 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
55 *   At the request of Stephane, moved ownership of /proc/efi
56 *   to efi.c, and now efivars lives under /proc/efi/vars.
57 *
58 *  12 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
59 *   Feedback received from Stephane Eranian incorporated.
60 *   efivar_write() checks copy_from_user() return value.
61 *   efivar_read/write() returns proper errno.
62 *   v0.02 release to linux-ia64@linuxia64.org
63 *
64 *  26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
65 *   v0.01 release to linux-ia64@linuxia64.org
66 */
67
68#include <linux/efi.h>
69#include <linux/module.h>
70#include <linux/slab.h>
71#include <linux/ucs2_string.h>
72#include <linux/compat.h>
73
74#define EFIVARS_VERSION "0.08"
75#define EFIVARS_DATE "2004-May-17"
76
77MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
78MODULE_DESCRIPTION("sysfs interface to EFI Variables");
79MODULE_LICENSE("GPL");
80MODULE_VERSION(EFIVARS_VERSION);
81
82LIST_HEAD(efivar_sysfs_list);
83EXPORT_SYMBOL_GPL(efivar_sysfs_list);
84
85static struct kset *efivars_kset;
86
87static struct bin_attribute *efivars_new_var;
88static struct bin_attribute *efivars_del_var;
89
90struct compat_efi_variable {
91	efi_char16_t  VariableName[EFI_VAR_NAME_LEN/sizeof(efi_char16_t)];
92	efi_guid_t    VendorGuid;
93	__u32         DataSize;
94	__u8          Data[1024];
95	__u32         Status;
96	__u32         Attributes;
97} __packed;
98
99struct efivar_attribute {
100	struct attribute attr;
101	ssize_t (*show) (struct efivar_entry *entry, char *buf);
102	ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
103};
104
105#define EFIVAR_ATTR(_name, _mode, _show, _store) \
106struct efivar_attribute efivar_attr_##_name = { \
107	.attr = {.name = __stringify(_name), .mode = _mode}, \
108	.show = _show, \
109	.store = _store, \
110};
111
112#define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
113#define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
114
115/*
116 * Prototype for sysfs creation function
117 */
118static int
119efivar_create_sysfs_entry(struct efivar_entry *new_var);
120
121static ssize_t
122efivar_guid_read(struct efivar_entry *entry, char *buf)
123{
124	struct efi_variable *var = &entry->var;
125	char *str = buf;
126
127	if (!entry || !buf)
128		return 0;
129
130	efi_guid_unparse(&var->VendorGuid, str);
131	str += strlen(str);
132	str += sprintf(str, "\n");
133
134	return str - buf;
135}
136
137static ssize_t
138efivar_attr_read(struct efivar_entry *entry, char *buf)
139{
140	struct efi_variable *var = &entry->var;
141	char *str = buf;
142
143	if (!entry || !buf)
144		return -EINVAL;
145
146	var->DataSize = 1024;
147	if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
148		return -EIO;
149
150	if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
151		str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
152	if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
153		str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
154	if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
155		str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
156	if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
157		str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
158	if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
159		str += sprintf(str,
160			"EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
161	if (var->Attributes &
162			EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
163		str += sprintf(str,
164			"EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
165	if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
166		str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
167	return str - buf;
168}
169
170static ssize_t
171efivar_size_read(struct efivar_entry *entry, char *buf)
172{
173	struct efi_variable *var = &entry->var;
174	char *str = buf;
175
176	if (!entry || !buf)
177		return -EINVAL;
178
179	var->DataSize = 1024;
180	if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
181		return -EIO;
182
183	str += sprintf(str, "0x%lx\n", var->DataSize);
184	return str - buf;
185}
186
187static ssize_t
188efivar_data_read(struct efivar_entry *entry, char *buf)
189{
190	struct efi_variable *var = &entry->var;
191
192	if (!entry || !buf)
193		return -EINVAL;
194
195	var->DataSize = 1024;
196	if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data))
197		return -EIO;
198
199	memcpy(buf, var->Data, var->DataSize);
200	return var->DataSize;
201}
202
203static inline int
204sanity_check(struct efi_variable *var, efi_char16_t *name, efi_guid_t vendor,
205	     unsigned long size, u32 attributes, u8 *data)
206{
207	/*
208	 * If only updating the variable data, then the name
209	 * and guid should remain the same
210	 */
211	if (memcmp(name, var->VariableName, sizeof(var->VariableName)) ||
212		efi_guidcmp(vendor, var->VendorGuid)) {
213		printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
214		return -EINVAL;
215	}
216
217	if ((size <= 0) || (attributes == 0)){
218		printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
219		return -EINVAL;
220	}
221
222	if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
223	    efivar_validate(name, data, size) == false) {
224		printk(KERN_ERR "efivars: Malformed variable content\n");
225		return -EINVAL;
226	}
227
228	return 0;
229}
230
231static inline bool is_compat(void)
232{
233	if (IS_ENABLED(CONFIG_COMPAT) && is_compat_task())
234		return true;
235
236	return false;
237}
238
239static void
240copy_out_compat(struct efi_variable *dst, struct compat_efi_variable *src)
241{
242	memcpy(dst->VariableName, src->VariableName, EFI_VAR_NAME_LEN);
243	memcpy(dst->Data, src->Data, sizeof(src->Data));
244
245	dst->VendorGuid = src->VendorGuid;
246	dst->DataSize = src->DataSize;
247	dst->Attributes = src->Attributes;
248}
249
250/*
251 * We allow each variable to be edited via rewriting the
252 * entire efi variable structure.
253 */
254static ssize_t
255efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
256{
257	struct efi_variable *new_var, *var = &entry->var;
258	efi_char16_t *name;
259	unsigned long size;
260	efi_guid_t vendor;
261	u32 attributes;
262	u8 *data;
263	int err;
264
265	if (is_compat()) {
266		struct compat_efi_variable *compat;
267
268		if (count != sizeof(*compat))
269			return -EINVAL;
270
271		compat = (struct compat_efi_variable *)buf;
272		attributes = compat->Attributes;
273		vendor = compat->VendorGuid;
274		name = compat->VariableName;
275		size = compat->DataSize;
276		data = compat->Data;
277
278		err = sanity_check(var, name, vendor, size, attributes, data);
279		if (err)
280			return err;
281
282		copy_out_compat(&entry->var, compat);
283	} else {
284		if (count != sizeof(struct efi_variable))
285			return -EINVAL;
286
287		new_var = (struct efi_variable *)buf;
288
289		attributes = new_var->Attributes;
290		vendor = new_var->VendorGuid;
291		name = new_var->VariableName;
292		size = new_var->DataSize;
293		data = new_var->Data;
294
295		err = sanity_check(var, name, vendor, size, attributes, data);
296		if (err)
297			return err;
298
299		memcpy(&entry->var, new_var, count);
300	}
301
302	err = efivar_entry_set(entry, attributes, size, data, NULL);
303	if (err) {
304		printk(KERN_WARNING "efivars: set_variable() failed: status=%d\n", err);
305		return -EIO;
306	}
307
308	return count;
309}
310
311static ssize_t
312efivar_show_raw(struct efivar_entry *entry, char *buf)
313{
314	struct efi_variable *var = &entry->var;
315	struct compat_efi_variable *compat;
316	size_t size;
317
318	if (!entry || !buf)
319		return 0;
320
321	var->DataSize = 1024;
322	if (efivar_entry_get(entry, &entry->var.Attributes,
323			     &entry->var.DataSize, entry->var.Data))
324		return -EIO;
325
326	if (is_compat()) {
327		compat = (struct compat_efi_variable *)buf;
328
329		size = sizeof(*compat);
330		memcpy(compat->VariableName, var->VariableName,
331			EFI_VAR_NAME_LEN);
332		memcpy(compat->Data, var->Data, sizeof(compat->Data));
333
334		compat->VendorGuid = var->VendorGuid;
335		compat->DataSize = var->DataSize;
336		compat->Attributes = var->Attributes;
337	} else {
338		size = sizeof(*var);
339		memcpy(buf, var, size);
340	}
341
342	return size;
343}
344
345/*
346 * Generic read/write functions that call the specific functions of
347 * the attributes...
348 */
349static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
350				char *buf)
351{
352	struct efivar_entry *var = to_efivar_entry(kobj);
353	struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
354	ssize_t ret = -EIO;
355
356	if (!capable(CAP_SYS_ADMIN))
357		return -EACCES;
358
359	if (efivar_attr->show) {
360		ret = efivar_attr->show(var, buf);
361	}
362	return ret;
363}
364
365static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
366				const char *buf, size_t count)
367{
368	struct efivar_entry *var = to_efivar_entry(kobj);
369	struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
370	ssize_t ret = -EIO;
371
372	if (!capable(CAP_SYS_ADMIN))
373		return -EACCES;
374
375	if (efivar_attr->store)
376		ret = efivar_attr->store(var, buf, count);
377
378	return ret;
379}
380
381static const struct sysfs_ops efivar_attr_ops = {
382	.show = efivar_attr_show,
383	.store = efivar_attr_store,
384};
385
386static void efivar_release(struct kobject *kobj)
387{
388	struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
389	kfree(var);
390}
391
392static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
393static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
394static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
395static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
396static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
397
398static struct attribute *def_attrs[] = {
399	&efivar_attr_guid.attr,
400	&efivar_attr_size.attr,
401	&efivar_attr_attributes.attr,
402	&efivar_attr_data.attr,
403	&efivar_attr_raw_var.attr,
404	NULL,
405};
406
407static struct kobj_type efivar_ktype = {
408	.release = efivar_release,
409	.sysfs_ops = &efivar_attr_ops,
410	.default_attrs = def_attrs,
411};
412
413static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
414			     struct bin_attribute *bin_attr,
415			     char *buf, loff_t pos, size_t count)
416{
417	struct compat_efi_variable *compat = (struct compat_efi_variable *)buf;
418	struct efi_variable *new_var = (struct efi_variable *)buf;
419	struct efivar_entry *new_entry;
420	bool need_compat = is_compat();
421	efi_char16_t *name;
422	unsigned long size;
423	u32 attributes;
424	u8 *data;
425	int err;
426
427	if (!capable(CAP_SYS_ADMIN))
428		return -EACCES;
429
430	if (need_compat) {
431		if (count != sizeof(*compat))
432			return -EINVAL;
433
434		attributes = compat->Attributes;
435		name = compat->VariableName;
436		size = compat->DataSize;
437		data = compat->Data;
438	} else {
439		if (count != sizeof(*new_var))
440			return -EINVAL;
441
442		attributes = new_var->Attributes;
443		name = new_var->VariableName;
444		size = new_var->DataSize;
445		data = new_var->Data;
446	}
447
448	if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
449	    efivar_validate(name, data, size) == false) {
450		printk(KERN_ERR "efivars: Malformed variable content\n");
451		return -EINVAL;
452	}
453
454	new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL);
455	if (!new_entry)
456		return -ENOMEM;
457
458	if (need_compat)
459		copy_out_compat(&new_entry->var, compat);
460	else
461		memcpy(&new_entry->var, new_var, sizeof(*new_var));
462
463	err = efivar_entry_set(new_entry, attributes, size,
464			       data, &efivar_sysfs_list);
465	if (err) {
466		if (err == -EEXIST)
467			err = -EINVAL;
468		goto out;
469	}
470
471	if (efivar_create_sysfs_entry(new_entry)) {
472		printk(KERN_WARNING "efivars: failed to create sysfs entry.\n");
473		kfree(new_entry);
474	}
475	return count;
476
477out:
478	kfree(new_entry);
479	return err;
480}
481
482static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
483			     struct bin_attribute *bin_attr,
484			     char *buf, loff_t pos, size_t count)
485{
486	struct efi_variable *del_var = (struct efi_variable *)buf;
487	struct compat_efi_variable *compat;
488	struct efivar_entry *entry;
489	efi_char16_t *name;
490	efi_guid_t vendor;
491	int err = 0;
492
493	if (!capable(CAP_SYS_ADMIN))
494		return -EACCES;
495
496	if (is_compat()) {
497		if (count != sizeof(*compat))
498			return -EINVAL;
499
500		compat = (struct compat_efi_variable *)buf;
501		name = compat->VariableName;
502		vendor = compat->VendorGuid;
503	} else {
504		if (count != sizeof(*del_var))
505			return -EINVAL;
506
507		name = del_var->VariableName;
508		vendor = del_var->VendorGuid;
509	}
510
511	efivar_entry_iter_begin();
512	entry = efivar_entry_find(name, vendor, &efivar_sysfs_list, true);
513	if (!entry)
514		err = -EINVAL;
515	else if (__efivar_entry_delete(entry))
516		err = -EIO;
517
518	if (err) {
519		efivar_entry_iter_end();
520		return err;
521	}
522
523	if (!entry->scanning) {
524		efivar_entry_iter_end();
525		efivar_unregister(entry);
526	} else
527		efivar_entry_iter_end();
528
529	/* It's dead Jim.... */
530	return count;
531}
532
533/**
534 * efivar_create_sysfs_entry - create a new entry in sysfs
535 * @new_var: efivar entry to create
536 *
537 * Returns 1 on failure, 0 on success
538 */
539static int
540efivar_create_sysfs_entry(struct efivar_entry *new_var)
541{
542	int i, short_name_size;
543	char *short_name;
544	unsigned long variable_name_size;
545	efi_char16_t *variable_name;
546
547	variable_name = new_var->var.VariableName;
548	variable_name_size = ucs2_strlen(variable_name) * sizeof(efi_char16_t);
549
550	/*
551	 * Length of the variable bytes in ASCII, plus the '-' separator,
552	 * plus the GUID, plus trailing NUL
553	 */
554	short_name_size = variable_name_size / sizeof(efi_char16_t)
555				+ 1 + EFI_VARIABLE_GUID_LEN + 1;
556
557	short_name = kzalloc(short_name_size, GFP_KERNEL);
558
559	if (!short_name)
560		return 1;
561
562	/* Convert Unicode to normal chars (assume top bits are 0),
563	   ala UTF-8 */
564	for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
565		short_name[i] = variable_name[i] & 0xFF;
566	}
567	/* This is ugly, but necessary to separate one vendor's
568	   private variables from another's.         */
569
570	*(short_name + strlen(short_name)) = '-';
571	efi_guid_unparse(&new_var->var.VendorGuid,
572			 short_name + strlen(short_name));
573
574	new_var->kobj.kset = efivars_kset;
575
576	i = kobject_init_and_add(&new_var->kobj, &efivar_ktype,
577				   NULL, "%s", short_name);
578	kfree(short_name);
579	if (i)
580		return 1;
581
582	kobject_uevent(&new_var->kobj, KOBJ_ADD);
583	efivar_entry_add(new_var, &efivar_sysfs_list);
584
585	return 0;
586}
587
588static int
589create_efivars_bin_attributes(void)
590{
591	struct bin_attribute *attr;
592	int error;
593
594	/* new_var */
595	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
596	if (!attr)
597		return -ENOMEM;
598
599	attr->attr.name = "new_var";
600	attr->attr.mode = 0200;
601	attr->write = efivar_create;
602	efivars_new_var = attr;
603
604	/* del_var */
605	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
606	if (!attr) {
607		error = -ENOMEM;
608		goto out_free;
609	}
610	attr->attr.name = "del_var";
611	attr->attr.mode = 0200;
612	attr->write = efivar_delete;
613	efivars_del_var = attr;
614
615	sysfs_bin_attr_init(efivars_new_var);
616	sysfs_bin_attr_init(efivars_del_var);
617
618	/* Register */
619	error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_new_var);
620	if (error) {
621		printk(KERN_ERR "efivars: unable to create new_var sysfs file"
622			" due to error %d\n", error);
623		goto out_free;
624	}
625
626	error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_del_var);
627	if (error) {
628		printk(KERN_ERR "efivars: unable to create del_var sysfs file"
629			" due to error %d\n", error);
630		sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var);
631		goto out_free;
632	}
633
634	return 0;
635out_free:
636	kfree(efivars_del_var);
637	efivars_del_var = NULL;
638	kfree(efivars_new_var);
639	efivars_new_var = NULL;
640	return error;
641}
642
643static int efivar_update_sysfs_entry(efi_char16_t *name, efi_guid_t vendor,
644				     unsigned long name_size, void *data)
645{
646	struct efivar_entry *entry = data;
647
648	if (efivar_entry_find(name, vendor, &efivar_sysfs_list, false))
649		return 0;
650
651	memcpy(entry->var.VariableName, name, name_size);
652	memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
653
654	return 1;
655}
656
657static void efivar_update_sysfs_entries(struct work_struct *work)
658{
659	struct efivar_entry *entry;
660	int err;
661
662	/* Add new sysfs entries */
663	while (1) {
664		entry = kzalloc(sizeof(*entry), GFP_KERNEL);
665		if (!entry)
666			return;
667
668		err = efivar_init(efivar_update_sysfs_entry, entry,
669				  true, false, &efivar_sysfs_list);
670		if (!err)
671			break;
672
673		efivar_create_sysfs_entry(entry);
674	}
675
676	kfree(entry);
677}
678
679static int efivars_sysfs_callback(efi_char16_t *name, efi_guid_t vendor,
680				  unsigned long name_size, void *data)
681{
682	struct efivar_entry *entry;
683
684	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
685	if (!entry)
686		return -ENOMEM;
687
688	memcpy(entry->var.VariableName, name, name_size);
689	memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
690
691	efivar_create_sysfs_entry(entry);
692
693	return 0;
694}
695
696static int efivar_sysfs_destroy(struct efivar_entry *entry, void *data)
697{
698	efivar_entry_remove(entry);
699	efivar_unregister(entry);
700	return 0;
701}
702
703static void efivars_sysfs_exit(void)
704{
705	/* Remove all entries and destroy */
706	__efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list, NULL, NULL);
707
708	if (efivars_new_var)
709		sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var);
710	if (efivars_del_var)
711		sysfs_remove_bin_file(&efivars_kset->kobj, efivars_del_var);
712	kfree(efivars_new_var);
713	kfree(efivars_del_var);
714	kset_unregister(efivars_kset);
715}
716
717int efivars_sysfs_init(void)
718{
719	struct kobject *parent_kobj = efivars_kobject();
720	int error = 0;
721
722	if (!efi_enabled(EFI_RUNTIME_SERVICES))
723		return -ENODEV;
724
725	/* No efivars has been registered yet */
726	if (!parent_kobj)
727		return 0;
728
729	printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
730	       EFIVARS_DATE);
731
732	efivars_kset = kset_create_and_add("vars", NULL, parent_kobj);
733	if (!efivars_kset) {
734		printk(KERN_ERR "efivars: Subsystem registration failed.\n");
735		return -ENOMEM;
736	}
737
738	efivar_init(efivars_sysfs_callback, NULL, false,
739		    true, &efivar_sysfs_list);
740
741	error = create_efivars_bin_attributes();
742	if (error) {
743		efivars_sysfs_exit();
744		return error;
745	}
746
747	INIT_WORK(&efivar_work, efivar_update_sysfs_entries);
748
749	return 0;
750}
751EXPORT_SYMBOL_GPL(efivars_sysfs_init);
752
753module_init(efivars_sysfs_init);
754module_exit(efivars_sysfs_exit);
755