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/drivers/firmware/efivars.c

https://bitbucket.org/evzijst/gittest
C | 781 lines | 508 code | 126 blank | 147 comment | 80 complexity | df774e20b526f836dbe58c369f8f3ba0 MD5 | raw file
  1/*
  2 * EFI Variables - 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/config.h>
 69#include <linux/types.h>
 70#include <linux/errno.h>
 71#include <linux/init.h>
 72#include <linux/sched.h>		/* for capable() */
 73#include <linux/mm.h>
 74#include <linux/module.h>
 75#include <linux/string.h>
 76#include <linux/smp.h>
 77#include <linux/efi.h>
 78#include <linux/sysfs.h>
 79#include <linux/kobject.h>
 80#include <linux/device.h>
 81
 82#include <asm/uaccess.h>
 83
 84#define EFIVARS_VERSION "0.08"
 85#define EFIVARS_DATE "2004-May-17"
 86
 87MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
 88MODULE_DESCRIPTION("sysfs interface to EFI Variables");
 89MODULE_LICENSE("GPL");
 90MODULE_VERSION(EFIVARS_VERSION);
 91
 92/*
 93 * efivars_lock protects two things:
 94 * 1) efivar_list - adds, removals, reads, writes
 95 * 2) efi.[gs]et_variable() calls.
 96 * It must not be held when creating sysfs entries or calling kmalloc.
 97 * efi.get_next_variable() is only called from efivars_init(),
 98 * which is protected by the BKL, so that path is safe.
 99 */
100static DEFINE_SPINLOCK(efivars_lock);
101static LIST_HEAD(efivar_list);
102
103/*
104 * The maximum size of VariableName + Data = 1024
105 * Therefore, it's reasonable to save that much
106 * space in each part of the structure,
107 * and we use a page for reading/writing.
108 */
109
110struct efi_variable {
111	efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
112	efi_guid_t    VendorGuid;
113	unsigned long DataSize;
114	__u8          Data[1024];
115	efi_status_t  Status;
116	__u32         Attributes;
117} __attribute__((packed));
118
119
120struct efivar_entry {
121	struct efi_variable var;
122	struct list_head list;
123	struct kobject kobj;
124};
125
126#define get_efivar_entry(n) list_entry(n, struct efivar_entry, list)
127
128struct efivar_attribute {
129	struct attribute attr;
130	ssize_t (*show) (struct efivar_entry *entry, char *buf);
131	ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
132};
133
134
135#define EFI_ATTR(_name, _mode, _show, _store) \
136struct subsys_attribute efi_attr_##_name = { \
137	.attr = {.name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE}, \
138	.show = _show, \
139	.store = _store, \
140};
141
142#define EFIVAR_ATTR(_name, _mode, _show, _store) \
143struct efivar_attribute efivar_attr_##_name = { \
144	.attr = {.name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE}, \
145	.show = _show, \
146	.store = _store, \
147};
148
149#define VAR_SUBSYS_ATTR(_name, _mode, _show, _store) \
150struct subsys_attribute var_subsys_attr_##_name = { \
151	.attr = {.name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE}, \
152	.show = _show, \
153	.store = _store, \
154};
155
156#define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
157#define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
158
159/*
160 * Prototype for sysfs creation function
161 */
162static int
163efivar_create_sysfs_entry(unsigned long variable_name_size,
164				efi_char16_t *variable_name,
165				efi_guid_t *vendor_guid);
166
167/* Return the number of unicode characters in data */
168static unsigned long
169utf8_strlen(efi_char16_t *data, unsigned long maxlength)
170{
171	unsigned long length = 0;
172
173	while (*data++ != 0 && length < maxlength)
174		length++;
175	return length;
176}
177
178/*
179 * Return the number of bytes is the length of this string
180 * Note: this is NOT the same as the number of unicode characters
181 */
182static inline unsigned long
183utf8_strsize(efi_char16_t *data, unsigned long maxlength)
184{
185	return utf8_strlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
186}
187
188static efi_status_t
189get_var_data(struct efi_variable *var)
190{
191	efi_status_t status;
192
193	spin_lock(&efivars_lock);
194	var->DataSize = 1024;
195	status = efi.get_variable(var->VariableName,
196				&var->VendorGuid,
197				&var->Attributes,
198				&var->DataSize,
199				var->Data);
200	spin_unlock(&efivars_lock);
201	if (status != EFI_SUCCESS) {
202		printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
203			status);
204	}
205	return status;
206}
207
208static ssize_t
209efivar_guid_read(struct efivar_entry *entry, char *buf)
210{
211	struct efi_variable *var = &entry->var;
212	char *str = buf;
213
214	if (!entry || !buf)
215		return 0;
216
217	efi_guid_unparse(&var->VendorGuid, str);
218	str += strlen(str);
219	str += sprintf(str, "\n");
220
221	return str - buf;
222}
223
224static ssize_t
225efivar_attr_read(struct efivar_entry *entry, char *buf)
226{
227	struct efi_variable *var = &entry->var;
228	char *str = buf;
229	efi_status_t status;
230
231	if (!entry || !buf)
232		return -EINVAL;
233
234	status = get_var_data(var);
235	if (status != EFI_SUCCESS)
236		return -EIO;
237
238	if (var->Attributes & 0x1)
239		str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
240	if (var->Attributes & 0x2)
241		str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
242	if (var->Attributes & 0x4)
243		str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
244	return str - buf;
245}
246
247static ssize_t
248efivar_size_read(struct efivar_entry *entry, char *buf)
249{
250	struct efi_variable *var = &entry->var;
251	char *str = buf;
252	efi_status_t status;
253
254	if (!entry || !buf)
255		return -EINVAL;
256
257	status = get_var_data(var);
258	if (status != EFI_SUCCESS)
259		return -EIO;
260
261	str += sprintf(str, "0x%lx\n", var->DataSize);
262	return str - buf;
263}
264
265static ssize_t
266efivar_data_read(struct efivar_entry *entry, char *buf)
267{
268	struct efi_variable *var = &entry->var;
269	efi_status_t status;
270
271	if (!entry || !buf)
272		return -EINVAL;
273
274	status = get_var_data(var);
275	if (status != EFI_SUCCESS)
276		return -EIO;
277
278	memcpy(buf, var->Data, var->DataSize);
279	return var->DataSize;
280}
281/*
282 * We allow each variable to be edited via rewriting the
283 * entire efi variable structure.
284 */
285static ssize_t
286efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
287{
288	struct efi_variable *new_var, *var = &entry->var;
289	efi_status_t status = EFI_NOT_FOUND;
290
291	if (count != sizeof(struct efi_variable))
292		return -EINVAL;
293
294	new_var = (struct efi_variable *)buf;
295	/*
296	 * If only updating the variable data, then the name
297	 * and guid should remain the same
298	 */
299	if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
300		efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
301		printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
302		return -EINVAL;
303	}
304
305	if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
306		printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
307		return -EINVAL;
308	}
309
310	spin_lock(&efivars_lock);
311	status = efi.set_variable(new_var->VariableName,
312					&new_var->VendorGuid,
313					new_var->Attributes,
314					new_var->DataSize,
315					new_var->Data);
316
317	spin_unlock(&efivars_lock);
318
319	if (status != EFI_SUCCESS) {
320		printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
321			status);
322		return -EIO;
323	}
324
325	memcpy(&entry->var, new_var, count);
326	return count;
327}
328
329static ssize_t
330efivar_show_raw(struct efivar_entry *entry, char *buf)
331{
332	struct efi_variable *var = &entry->var;
333	efi_status_t status;
334
335	if (!entry || !buf)
336		return 0;
337
338	status = get_var_data(var);
339	if (status != EFI_SUCCESS)
340		return -EIO;
341
342	memcpy(buf, var, sizeof(*var));
343	return sizeof(*var);
344}
345
346/*
347 * Generic read/write functions that call the specific functions of
348 * the atttributes...
349 */
350static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
351				char *buf)
352{
353	struct efivar_entry *var = to_efivar_entry(kobj);
354	struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
355	ssize_t ret = 0;
356
357	if (!capable(CAP_SYS_ADMIN))
358		return -EACCES;
359
360	if (efivar_attr->show) {
361		ret = efivar_attr->show(var, buf);
362	}
363	return ret;
364}
365
366static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
367				const char *buf, size_t count)
368{
369	struct efivar_entry *var = to_efivar_entry(kobj);
370	struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
371	ssize_t ret = 0;
372
373	if (!capable(CAP_SYS_ADMIN))
374		return -EACCES;
375
376	if (efivar_attr->store)
377		ret = efivar_attr->store(var, buf, count);
378
379	return ret;
380}
381
382static struct sysfs_ops efivar_attr_ops = {
383	.show = efivar_attr_show,
384	.store = efivar_attr_store,
385};
386
387static void efivar_release(struct kobject *kobj)
388{
389	struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
390	spin_lock(&efivars_lock);
391	list_del(&var->list);
392	spin_unlock(&efivars_lock);
393	kfree(var);
394}
395
396static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
397static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
398static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
399static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
400static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
401
402static struct attribute *def_attrs[] = {
403	&efivar_attr_guid.attr,
404	&efivar_attr_size.attr,
405	&efivar_attr_attributes.attr,
406	&efivar_attr_data.attr,
407	&efivar_attr_raw_var.attr,
408	NULL,
409};
410
411static struct kobj_type ktype_efivar = {
412	.release = efivar_release,
413	.sysfs_ops = &efivar_attr_ops,
414	.default_attrs = def_attrs,
415};
416
417static ssize_t
418dummy(struct subsystem *sub, char *buf)
419{
420	return -ENODEV;
421}
422
423static inline void
424efivar_unregister(struct efivar_entry *var)
425{
426	kobject_unregister(&var->kobj);
427}
428
429
430static ssize_t
431efivar_create(struct subsystem *sub, const char *buf, size_t count)
432{
433	struct efi_variable *new_var = (struct efi_variable *)buf;
434	struct efivar_entry *search_efivar = NULL;
435	unsigned long strsize1, strsize2;
436	struct list_head *pos, *n;
437	efi_status_t status = EFI_NOT_FOUND;
438	int found = 0;
439
440	if (!capable(CAP_SYS_ADMIN))
441		return -EACCES;
442
443	spin_lock(&efivars_lock);
444
445	/*
446	 * Does this variable already exist?
447	 */
448	list_for_each_safe(pos, n, &efivar_list) {
449		search_efivar = get_efivar_entry(pos);
450		strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
451		strsize2 = utf8_strsize(new_var->VariableName, 1024);
452		if (strsize1 == strsize2 &&
453			!memcmp(&(search_efivar->var.VariableName),
454				new_var->VariableName, strsize1) &&
455			!efi_guidcmp(search_efivar->var.VendorGuid,
456				new_var->VendorGuid)) {
457			found = 1;
458			break;
459		}
460	}
461	if (found) {
462		spin_unlock(&efivars_lock);
463		return -EINVAL;
464	}
465
466	/* now *really* create the variable via EFI */
467	status = efi.set_variable(new_var->VariableName,
468			&new_var->VendorGuid,
469			new_var->Attributes,
470			new_var->DataSize,
471			new_var->Data);
472
473	if (status != EFI_SUCCESS) {
474		printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
475			status);
476		spin_unlock(&efivars_lock);
477		return -EIO;
478	}
479	spin_unlock(&efivars_lock);
480
481	/* Create the entry in sysfs.  Locking is not required here */
482	status = efivar_create_sysfs_entry(utf8_strsize(new_var->VariableName,
483			1024), new_var->VariableName, &new_var->VendorGuid);
484	if (status) {
485		printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
486	}
487	return count;
488}
489
490static ssize_t
491efivar_delete(struct subsystem *sub, const char *buf, size_t count)
492{
493	struct efi_variable *del_var = (struct efi_variable *)buf;
494	struct efivar_entry *search_efivar = NULL;
495	unsigned long strsize1, strsize2;
496	struct list_head *pos, *n;
497	efi_status_t status = EFI_NOT_FOUND;
498	int found = 0;
499
500	if (!capable(CAP_SYS_ADMIN))
501		return -EACCES;
502
503	spin_lock(&efivars_lock);
504
505	/*
506	 * Does this variable already exist?
507	 */
508	list_for_each_safe(pos, n, &efivar_list) {
509		search_efivar = get_efivar_entry(pos);
510		strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
511		strsize2 = utf8_strsize(del_var->VariableName, 1024);
512		if (strsize1 == strsize2 &&
513			!memcmp(&(search_efivar->var.VariableName),
514				del_var->VariableName, strsize1) &&
515			!efi_guidcmp(search_efivar->var.VendorGuid,
516				del_var->VendorGuid)) {
517			found = 1;
518			break;
519		}
520	}
521	if (!found) {
522		spin_unlock(&efivars_lock);
523		return -EINVAL;
524	}
525	/* force the Attributes/DataSize to 0 to ensure deletion */
526	del_var->Attributes = 0;
527	del_var->DataSize = 0;
528
529	status = efi.set_variable(del_var->VariableName,
530			&del_var->VendorGuid,
531			del_var->Attributes,
532			del_var->DataSize,
533			del_var->Data);
534
535	if (status != EFI_SUCCESS) {
536		printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
537			status);
538		spin_unlock(&efivars_lock);
539		return -EIO;
540	}
541	/* We need to release this lock before unregistering. */
542	spin_unlock(&efivars_lock);
543
544	efivar_unregister(search_efivar);
545
546	/* It's dead Jim.... */
547	return count;
548}
549
550static VAR_SUBSYS_ATTR(new_var, 0200, dummy, efivar_create);
551static VAR_SUBSYS_ATTR(del_var, 0200, dummy, efivar_delete);
552
553static struct subsys_attribute *var_subsys_attrs[] = {
554	&var_subsys_attr_new_var,
555	&var_subsys_attr_del_var,
556	NULL,
557};
558
559/*
560 * Let's not leave out systab information that snuck into
561 * the efivars driver
562 */
563static ssize_t
564systab_read(struct subsystem *entry, char *buf)
565{
566	char *str = buf;
567
568	if (!entry || !buf)
569		return -EINVAL;
570
571	if (efi.mps)
572		str += sprintf(str, "MPS=0x%lx\n", __pa(efi.mps));
573	if (efi.acpi20)
574		str += sprintf(str, "ACPI20=0x%lx\n", __pa(efi.acpi20));
575	if (efi.acpi)
576		str += sprintf(str, "ACPI=0x%lx\n", __pa(efi.acpi));
577	if (efi.smbios)
578		str += sprintf(str, "SMBIOS=0x%lx\n", __pa(efi.smbios));
579	if (efi.hcdp)
580		str += sprintf(str, "HCDP=0x%lx\n", __pa(efi.hcdp));
581	if (efi.boot_info)
582		str += sprintf(str, "BOOTINFO=0x%lx\n", __pa(efi.boot_info));
583	if (efi.uga)
584		str += sprintf(str, "UGA=0x%lx\n", __pa(efi.uga));
585
586	return str - buf;
587}
588
589static EFI_ATTR(systab, 0400, systab_read, NULL);
590
591static struct subsys_attribute *efi_subsys_attrs[] = {
592	&efi_attr_systab,
593	NULL,	/* maybe more in the future? */
594};
595
596static decl_subsys(vars, &ktype_efivar, NULL);
597static decl_subsys(efi, NULL, NULL);
598
599/*
600 * efivar_create_sysfs_entry()
601 * Requires:
602 *    variable_name_size = number of bytes required to hold
603 *                         variable_name (not counting the NULL
604 *                         character at the end.
605 *    efivars_lock is not held on entry or exit.
606 * Returns 1 on failure, 0 on success
607 */
608static int
609efivar_create_sysfs_entry(unsigned long variable_name_size,
610			efi_char16_t *variable_name,
611			efi_guid_t *vendor_guid)
612{
613	int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
614	char *short_name;
615	struct efivar_entry *new_efivar;
616
617	short_name = kmalloc(short_name_size + 1, GFP_KERNEL);
618	new_efivar = kmalloc(sizeof(struct efivar_entry), GFP_KERNEL);
619
620	if (!short_name || !new_efivar)  {
621		if (short_name)        kfree(short_name);
622		if (new_efivar)        kfree(new_efivar);
623		return 1;
624	}
625	memset(short_name, 0, short_name_size+1);
626	memset(new_efivar, 0, sizeof(struct efivar_entry));
627
628	memcpy(new_efivar->var.VariableName, variable_name,
629		variable_name_size);
630	memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
631
632	/* Convert Unicode to normal chars (assume top bits are 0),
633	   ala UTF-8 */
634	for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
635		short_name[i] = variable_name[i] & 0xFF;
636	}
637	/* This is ugly, but necessary to separate one vendor's
638	   private variables from another's.         */
639
640	*(short_name + strlen(short_name)) = '-';
641	efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
642
643	kobject_set_name(&new_efivar->kobj, "%s", short_name);
644	kobj_set_kset_s(new_efivar, vars_subsys);
645	kobject_register(&new_efivar->kobj);
646
647	kfree(short_name); short_name = NULL;
648
649	spin_lock(&efivars_lock);
650	list_add(&new_efivar->list, &efivar_list);
651	spin_unlock(&efivars_lock);
652
653	return 0;
654}
655/*
656 * For now we register the efi subsystem with the firmware subsystem
657 * and the vars subsystem with the efi subsystem.  In the future, it
658 * might make sense to split off the efi subsystem into its own
659 * driver, but for now only efivars will register with it, so just
660 * include it here.
661 */
662
663static int __init
664efivars_init(void)
665{
666	efi_status_t status = EFI_NOT_FOUND;
667	efi_guid_t vendor_guid;
668	efi_char16_t *variable_name;
669	struct subsys_attribute *attr;
670	unsigned long variable_name_size = 1024;
671	int i, error = 0;
672
673	if (!efi_enabled)
674		return -ENODEV;
675
676	variable_name = kmalloc(variable_name_size, GFP_KERNEL);
677	if (!variable_name) {
678		printk(KERN_ERR "efivars: Memory allocation failed.\n");
679		return -ENOMEM;
680	}
681
682	memset(variable_name, 0, variable_name_size);
683
684	printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
685	       EFIVARS_DATE);
686
687	/*
688	 * For now we'll register the efi subsys within this driver
689	 */
690
691	error = firmware_register(&efi_subsys);
692
693	if (error) {
694		printk(KERN_ERR "efivars: Firmware registration failed with error %d.\n", error);
695		goto out_free;
696	}
697
698	kset_set_kset_s(&vars_subsys, efi_subsys);
699
700	error = subsystem_register(&vars_subsys);
701
702	if (error) {
703		printk(KERN_ERR "efivars: Subsystem registration failed with error %d.\n", error);
704		goto out_firmware_unregister;
705	}
706
707	/*
708	 * Per EFI spec, the maximum storage allocated for both
709	 * the variable name and variable data is 1024 bytes.
710	 */
711
712	do {
713		variable_name_size = 1024;
714
715		status = efi.get_next_variable(&variable_name_size,
716						variable_name,
717						&vendor_guid);
718		switch (status) {
719		case EFI_SUCCESS:
720			efivar_create_sysfs_entry(variable_name_size,
721							variable_name,
722							&vendor_guid);
723			break;
724		case EFI_NOT_FOUND:
725			break;
726		default:
727			printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
728				status);
729			status = EFI_NOT_FOUND;
730			break;
731		}
732	} while (status != EFI_NOT_FOUND);
733
734	/*
735	 * Now add attributes to allow creation of new vars
736	 * and deletion of existing ones...
737	 */
738
739	for (i = 0; (attr = var_subsys_attrs[i]) && !error; i++) {
740		if (attr->show && attr->store)
741			error = subsys_create_file(&vars_subsys, attr);
742	}
743
744	/* Don't forget the systab entry */
745
746	for (i = 0; (attr = efi_subsys_attrs[i]) && !error; i++) {
747		if (attr->show)
748			error = subsys_create_file(&efi_subsys, attr);
749	}
750
751	if (error)
752		printk(KERN_ERR "efivars: Sysfs attribute export failed with error %d.\n", error);
753	else
754		goto out_free;
755
756	subsystem_unregister(&vars_subsys);
757
758out_firmware_unregister:
759	firmware_unregister(&efi_subsys);
760
761out_free:
762	kfree(variable_name);
763
764	return error;
765}
766
767static void __exit
768efivars_exit(void)
769{
770	struct list_head *pos, *n;
771
772	list_for_each_safe(pos, n, &efivar_list)
773		efivar_unregister(get_efivar_entry(pos));
774
775	subsystem_unregister(&vars_subsys);
776	firmware_unregister(&efi_subsys);
777}
778
779module_init(efivars_init);
780module_exit(efivars_exit);
781