efivars: Expose efivars functionality to external drivers.
[linux-3.10.git] / drivers / firmware / efivars.c
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/capability.h>
69 #include <linux/types.h>
70 #include <linux/errno.h>
71 #include <linux/init.h>
72 #include <linux/mm.h>
73 #include <linux/module.h>
74 #include <linux/string.h>
75 #include <linux/smp.h>
76 #include <linux/efi.h>
77 #include <linux/sysfs.h>
78 #include <linux/kobject.h>
79 #include <linux/device.h>
80 #include <linux/slab.h>
81
82 #include <asm/uaccess.h>
83
84 #define EFIVARS_VERSION "0.08"
85 #define EFIVARS_DATE "2004-May-17"
86
87 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
88 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
89 MODULE_LICENSE("GPL");
90 MODULE_VERSION(EFIVARS_VERSION);
91
92 /*
93  * The maximum size of VariableName + Data = 1024
94  * Therefore, it's reasonable to save that much
95  * space in each part of the structure,
96  * and we use a page for reading/writing.
97  */
98
99 struct efi_variable {
100         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
101         efi_guid_t    VendorGuid;
102         unsigned long DataSize;
103         __u8          Data[1024];
104         efi_status_t  Status;
105         __u32         Attributes;
106 } __attribute__((packed));
107
108
109 struct efivar_entry {
110         struct efivars *efivars;
111         struct efi_variable var;
112         struct list_head list;
113         struct kobject kobj;
114 };
115
116 struct efivar_attribute {
117         struct attribute attr;
118         ssize_t (*show) (struct efivar_entry *entry, char *buf);
119         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
120 };
121
122
123 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
124 struct efivar_attribute efivar_attr_##_name = { \
125         .attr = {.name = __stringify(_name), .mode = _mode}, \
126         .show = _show, \
127         .store = _store, \
128 };
129
130 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
131 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
132
133 /*
134  * Prototype for sysfs creation function
135  */
136 static int
137 efivar_create_sysfs_entry(struct efivars *efivars,
138                           unsigned long variable_name_size,
139                           efi_char16_t *variable_name,
140                           efi_guid_t *vendor_guid);
141
142 /* Return the number of unicode characters in data */
143 static unsigned long
144 utf8_strlen(efi_char16_t *data, unsigned long maxlength)
145 {
146         unsigned long length = 0;
147
148         while (*data++ != 0 && length < maxlength)
149                 length++;
150         return length;
151 }
152
153 /*
154  * Return the number of bytes is the length of this string
155  * Note: this is NOT the same as the number of unicode characters
156  */
157 static inline unsigned long
158 utf8_strsize(efi_char16_t *data, unsigned long maxlength)
159 {
160         return utf8_strlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
161 }
162
163 static efi_status_t
164 get_var_data(struct efivars *efivars, struct efi_variable *var)
165 {
166         efi_status_t status;
167
168         spin_lock(&efivars->lock);
169         var->DataSize = 1024;
170         status = efivars->ops->get_variable(var->VariableName,
171                                             &var->VendorGuid,
172                                             &var->Attributes,
173                                             &var->DataSize,
174                                             var->Data);
175         spin_unlock(&efivars->lock);
176         if (status != EFI_SUCCESS) {
177                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
178                         status);
179         }
180         return status;
181 }
182
183 static ssize_t
184 efivar_guid_read(struct efivar_entry *entry, char *buf)
185 {
186         struct efi_variable *var = &entry->var;
187         char *str = buf;
188
189         if (!entry || !buf)
190                 return 0;
191
192         efi_guid_unparse(&var->VendorGuid, str);
193         str += strlen(str);
194         str += sprintf(str, "\n");
195
196         return str - buf;
197 }
198
199 static ssize_t
200 efivar_attr_read(struct efivar_entry *entry, char *buf)
201 {
202         struct efi_variable *var = &entry->var;
203         char *str = buf;
204         efi_status_t status;
205
206         if (!entry || !buf)
207                 return -EINVAL;
208
209         status = get_var_data(entry->efivars, var);
210         if (status != EFI_SUCCESS)
211                 return -EIO;
212
213         if (var->Attributes & 0x1)
214                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
215         if (var->Attributes & 0x2)
216                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
217         if (var->Attributes & 0x4)
218                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
219         return str - buf;
220 }
221
222 static ssize_t
223 efivar_size_read(struct efivar_entry *entry, char *buf)
224 {
225         struct efi_variable *var = &entry->var;
226         char *str = buf;
227         efi_status_t status;
228
229         if (!entry || !buf)
230                 return -EINVAL;
231
232         status = get_var_data(entry->efivars, var);
233         if (status != EFI_SUCCESS)
234                 return -EIO;
235
236         str += sprintf(str, "0x%lx\n", var->DataSize);
237         return str - buf;
238 }
239
240 static ssize_t
241 efivar_data_read(struct efivar_entry *entry, char *buf)
242 {
243         struct efi_variable *var = &entry->var;
244         efi_status_t status;
245
246         if (!entry || !buf)
247                 return -EINVAL;
248
249         status = get_var_data(entry->efivars, var);
250         if (status != EFI_SUCCESS)
251                 return -EIO;
252
253         memcpy(buf, var->Data, var->DataSize);
254         return var->DataSize;
255 }
256 /*
257  * We allow each variable to be edited via rewriting the
258  * entire efi variable structure.
259  */
260 static ssize_t
261 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
262 {
263         struct efi_variable *new_var, *var = &entry->var;
264         struct efivars *efivars = entry->efivars;
265         efi_status_t status = EFI_NOT_FOUND;
266
267         if (count != sizeof(struct efi_variable))
268                 return -EINVAL;
269
270         new_var = (struct efi_variable *)buf;
271         /*
272          * If only updating the variable data, then the name
273          * and guid should remain the same
274          */
275         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
276                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
277                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
278                 return -EINVAL;
279         }
280
281         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
282                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
283                 return -EINVAL;
284         }
285
286         spin_lock(&efivars->lock);
287         status = efivars->ops->set_variable(new_var->VariableName,
288                                             &new_var->VendorGuid,
289                                             new_var->Attributes,
290                                             new_var->DataSize,
291                                             new_var->Data);
292
293         spin_unlock(&efivars->lock);
294
295         if (status != EFI_SUCCESS) {
296                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
297                         status);
298                 return -EIO;
299         }
300
301         memcpy(&entry->var, new_var, count);
302         return count;
303 }
304
305 static ssize_t
306 efivar_show_raw(struct efivar_entry *entry, char *buf)
307 {
308         struct efi_variable *var = &entry->var;
309         efi_status_t status;
310
311         if (!entry || !buf)
312                 return 0;
313
314         status = get_var_data(entry->efivars, var);
315         if (status != EFI_SUCCESS)
316                 return -EIO;
317
318         memcpy(buf, var, sizeof(*var));
319         return sizeof(*var);
320 }
321
322 /*
323  * Generic read/write functions that call the specific functions of
324  * the atttributes...
325  */
326 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
327                                 char *buf)
328 {
329         struct efivar_entry *var = to_efivar_entry(kobj);
330         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
331         ssize_t ret = -EIO;
332
333         if (!capable(CAP_SYS_ADMIN))
334                 return -EACCES;
335
336         if (efivar_attr->show) {
337                 ret = efivar_attr->show(var, buf);
338         }
339         return ret;
340 }
341
342 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
343                                 const char *buf, size_t count)
344 {
345         struct efivar_entry *var = to_efivar_entry(kobj);
346         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
347         ssize_t ret = -EIO;
348
349         if (!capable(CAP_SYS_ADMIN))
350                 return -EACCES;
351
352         if (efivar_attr->store)
353                 ret = efivar_attr->store(var, buf, count);
354
355         return ret;
356 }
357
358 static const struct sysfs_ops efivar_attr_ops = {
359         .show = efivar_attr_show,
360         .store = efivar_attr_store,
361 };
362
363 static void efivar_release(struct kobject *kobj)
364 {
365         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
366         kfree(var);
367 }
368
369 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
370 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
371 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
372 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
373 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
374
375 static struct attribute *def_attrs[] = {
376         &efivar_attr_guid.attr,
377         &efivar_attr_size.attr,
378         &efivar_attr_attributes.attr,
379         &efivar_attr_data.attr,
380         &efivar_attr_raw_var.attr,
381         NULL,
382 };
383
384 static struct kobj_type efivar_ktype = {
385         .release = efivar_release,
386         .sysfs_ops = &efivar_attr_ops,
387         .default_attrs = def_attrs,
388 };
389
390 static inline void
391 efivar_unregister(struct efivar_entry *var)
392 {
393         kobject_put(&var->kobj);
394 }
395
396
397 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
398                              struct bin_attribute *bin_attr,
399                              char *buf, loff_t pos, size_t count)
400 {
401         struct efi_variable *new_var = (struct efi_variable *)buf;
402         struct efivars *efivars = bin_attr->private;
403         struct efivar_entry *search_efivar, *n;
404         unsigned long strsize1, strsize2;
405         efi_status_t status = EFI_NOT_FOUND;
406         int found = 0;
407
408         if (!capable(CAP_SYS_ADMIN))
409                 return -EACCES;
410
411         spin_lock(&efivars->lock);
412
413         /*
414          * Does this variable already exist?
415          */
416         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
417                 strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
418                 strsize2 = utf8_strsize(new_var->VariableName, 1024);
419                 if (strsize1 == strsize2 &&
420                         !memcmp(&(search_efivar->var.VariableName),
421                                 new_var->VariableName, strsize1) &&
422                         !efi_guidcmp(search_efivar->var.VendorGuid,
423                                 new_var->VendorGuid)) {
424                         found = 1;
425                         break;
426                 }
427         }
428         if (found) {
429                 spin_unlock(&efivars->lock);
430                 return -EINVAL;
431         }
432
433         /* now *really* create the variable via EFI */
434         status = efivars->ops->set_variable(new_var->VariableName,
435                                             &new_var->VendorGuid,
436                                             new_var->Attributes,
437                                             new_var->DataSize,
438                                             new_var->Data);
439
440         if (status != EFI_SUCCESS) {
441                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
442                         status);
443                 spin_unlock(&efivars->lock);
444                 return -EIO;
445         }
446         spin_unlock(&efivars->lock);
447
448         /* Create the entry in sysfs.  Locking is not required here */
449         status = efivar_create_sysfs_entry(efivars,
450                                            utf8_strsize(new_var->VariableName,
451                                                         1024),
452                                            new_var->VariableName,
453                                            &new_var->VendorGuid);
454         if (status) {
455                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
456         }
457         return count;
458 }
459
460 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
461                              struct bin_attribute *bin_attr,
462                              char *buf, loff_t pos, size_t count)
463 {
464         struct efi_variable *del_var = (struct efi_variable *)buf;
465         struct efivars *efivars = bin_attr->private;
466         struct efivar_entry *search_efivar, *n;
467         unsigned long strsize1, strsize2;
468         efi_status_t status = EFI_NOT_FOUND;
469         int found = 0;
470
471         if (!capable(CAP_SYS_ADMIN))
472                 return -EACCES;
473
474         spin_lock(&efivars->lock);
475
476         /*
477          * Does this variable already exist?
478          */
479         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
480                 strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
481                 strsize2 = utf8_strsize(del_var->VariableName, 1024);
482                 if (strsize1 == strsize2 &&
483                         !memcmp(&(search_efivar->var.VariableName),
484                                 del_var->VariableName, strsize1) &&
485                         !efi_guidcmp(search_efivar->var.VendorGuid,
486                                 del_var->VendorGuid)) {
487                         found = 1;
488                         break;
489                 }
490         }
491         if (!found) {
492                 spin_unlock(&efivars->lock);
493                 return -EINVAL;
494         }
495         /* force the Attributes/DataSize to 0 to ensure deletion */
496         del_var->Attributes = 0;
497         del_var->DataSize = 0;
498
499         status = efivars->ops->set_variable(del_var->VariableName,
500                                             &del_var->VendorGuid,
501                                             del_var->Attributes,
502                                             del_var->DataSize,
503                                             del_var->Data);
504
505         if (status != EFI_SUCCESS) {
506                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
507                         status);
508                 spin_unlock(&efivars->lock);
509                 return -EIO;
510         }
511         list_del(&search_efivar->list);
512         /* We need to release this lock before unregistering. */
513         spin_unlock(&efivars->lock);
514         efivar_unregister(search_efivar);
515
516         /* It's dead Jim.... */
517         return count;
518 }
519
520 /*
521  * Let's not leave out systab information that snuck into
522  * the efivars driver
523  */
524 static ssize_t systab_show(struct kobject *kobj,
525                            struct kobj_attribute *attr, char *buf)
526 {
527         char *str = buf;
528
529         if (!kobj || !buf)
530                 return -EINVAL;
531
532         if (efi.mps != EFI_INVALID_TABLE_ADDR)
533                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
534         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
535                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
536         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
537                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
538         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
539                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
540         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
541                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
542         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
543                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
544         if (efi.uga != EFI_INVALID_TABLE_ADDR)
545                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
546
547         return str - buf;
548 }
549
550 static struct kobj_attribute efi_attr_systab =
551                         __ATTR(systab, 0400, systab_show, NULL);
552
553 static struct attribute *efi_subsys_attrs[] = {
554         &efi_attr_systab.attr,
555         NULL,   /* maybe more in the future? */
556 };
557
558 static struct attribute_group efi_subsys_attr_group = {
559         .attrs = efi_subsys_attrs,
560 };
561
562 static struct kobject *efi_kobj;
563
564 /*
565  * efivar_create_sysfs_entry()
566  * Requires:
567  *    variable_name_size = number of bytes required to hold
568  *                         variable_name (not counting the NULL
569  *                         character at the end.
570  *    efivars->lock is not held on entry or exit.
571  * Returns 1 on failure, 0 on success
572  */
573 static int
574 efivar_create_sysfs_entry(struct efivars *efivars,
575                           unsigned long variable_name_size,
576                           efi_char16_t *variable_name,
577                           efi_guid_t *vendor_guid)
578 {
579         int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
580         char *short_name;
581         struct efivar_entry *new_efivar;
582
583         short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
584         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
585
586         if (!short_name || !new_efivar)  {
587                 kfree(short_name);
588                 kfree(new_efivar);
589                 return 1;
590         }
591
592         new_efivar->efivars = efivars;
593         memcpy(new_efivar->var.VariableName, variable_name,
594                 variable_name_size);
595         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
596
597         /* Convert Unicode to normal chars (assume top bits are 0),
598            ala UTF-8 */
599         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
600                 short_name[i] = variable_name[i] & 0xFF;
601         }
602         /* This is ugly, but necessary to separate one vendor's
603            private variables from another's.         */
604
605         *(short_name + strlen(short_name)) = '-';
606         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
607
608         new_efivar->kobj.kset = efivars->kset;
609         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
610                                  "%s", short_name);
611         if (i) {
612                 kfree(short_name);
613                 kfree(new_efivar);
614                 return 1;
615         }
616
617         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
618         kfree(short_name);
619         short_name = NULL;
620
621         spin_lock(&efivars->lock);
622         list_add(&new_efivar->list, &efivars->list);
623         spin_unlock(&efivars->lock);
624
625         return 0;
626 }
627
628 static int
629 create_efivars_bin_attributes(struct efivars *efivars)
630 {
631         struct bin_attribute *attr;
632         int error;
633
634         /* new_var */
635         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
636         if (!attr)
637                 return -ENOMEM;
638
639         attr->attr.name = "new_var";
640         attr->attr.mode = 0200;
641         attr->write = efivar_create;
642         attr->private = efivars;
643         efivars->new_var = attr;
644
645         /* del_var */
646         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
647         if (!attr) {
648                 error = -ENOMEM;
649                 goto out_free;
650         }
651         attr->attr.name = "del_var";
652         attr->attr.mode = 0200;
653         attr->write = efivar_delete;
654         attr->private = efivars;
655         efivars->del_var = attr;
656
657         sysfs_bin_attr_init(efivars->new_var);
658         sysfs_bin_attr_init(efivars->del_var);
659
660         /* Register */
661         error = sysfs_create_bin_file(&efivars->kset->kobj,
662                                       efivars->new_var);
663         if (error) {
664                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
665                         " due to error %d\n", error);
666                 goto out_free;
667         }
668         error = sysfs_create_bin_file(&efivars->kset->kobj,
669                                       efivars->del_var);
670         if (error) {
671                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
672                         " due to error %d\n", error);
673                 sysfs_remove_bin_file(&efivars->kset->kobj,
674                                       efivars->new_var);
675                 goto out_free;
676         }
677
678         return 0;
679 out_free:
680         kfree(efivars->new_var);
681         efivars->new_var = NULL;
682         kfree(efivars->new_var);
683         efivars->new_var = NULL;
684         return error;
685 }
686
687 void unregister_efivars(struct efivars *efivars)
688 {
689         struct efivar_entry *entry, *n;
690
691         list_for_each_entry_safe(entry, n, &efivars->list, list) {
692                 spin_lock(&efivars->lock);
693                 list_del(&entry->list);
694                 spin_unlock(&efivars->lock);
695                 efivar_unregister(entry);
696         }
697         if (efivars->new_var)
698                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
699         if (efivars->del_var)
700                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
701         kfree(efivars->new_var);
702         kfree(efivars->del_var);
703         kset_unregister(efivars->kset);
704 }
705 EXPORT_SYMBOL_GPL(unregister_efivars);
706
707 int register_efivars(struct efivars *efivars,
708                      const struct efivar_operations *ops,
709                      struct kobject *parent_kobj)
710 {
711         efi_status_t status = EFI_NOT_FOUND;
712         efi_guid_t vendor_guid;
713         efi_char16_t *variable_name;
714         unsigned long variable_name_size = 1024;
715         int error = 0;
716
717         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
718         if (!variable_name) {
719                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
720                 return -ENOMEM;
721         }
722
723         spin_lock_init(&efivars->lock);
724         INIT_LIST_HEAD(&efivars->list);
725         efivars->ops = ops;
726
727         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
728         if (!efivars->kset) {
729                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
730                 error = -ENOMEM;
731                 goto out;
732         }
733
734         /*
735          * Per EFI spec, the maximum storage allocated for both
736          * the variable name and variable data is 1024 bytes.
737          */
738
739         do {
740                 variable_name_size = 1024;
741
742                 status = ops->get_next_variable(&variable_name_size,
743                                                 variable_name,
744                                                 &vendor_guid);
745                 switch (status) {
746                 case EFI_SUCCESS:
747                         efivar_create_sysfs_entry(efivars,
748                                                   variable_name_size,
749                                                   variable_name,
750                                                   &vendor_guid);
751                         break;
752                 case EFI_NOT_FOUND:
753                         break;
754                 default:
755                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
756                                 status);
757                         status = EFI_NOT_FOUND;
758                         break;
759                 }
760         } while (status != EFI_NOT_FOUND);
761
762         error = create_efivars_bin_attributes(efivars);
763         if (error)
764                 unregister_efivars(efivars);
765
766 out:
767         kfree(variable_name);
768
769         return error;
770 }
771 EXPORT_SYMBOL_GPL(register_efivars);
772
773 static struct efivars __efivars;
774 static struct efivar_operations ops;
775
776 /*
777  * For now we register the efi subsystem with the firmware subsystem
778  * and the vars subsystem with the efi subsystem.  In the future, it
779  * might make sense to split off the efi subsystem into its own
780  * driver, but for now only efivars will register with it, so just
781  * include it here.
782  */
783
784 static int __init
785 efivars_init(void)
786 {
787         int error = 0;
788
789         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
790                EFIVARS_DATE);
791
792         if (!efi_enabled)
793                 return 0;
794
795         /* For now we'll register the efi directory at /sys/firmware/efi */
796         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
797         if (!efi_kobj) {
798                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
799                 return -ENOMEM;
800         }
801
802         ops.get_variable = efi.get_variable;
803         ops.set_variable = efi.set_variable;
804         ops.get_next_variable = efi.get_next_variable;
805         error = register_efivars(&__efivars, &ops, efi_kobj);
806
807         /* Don't forget the systab entry */
808         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
809         if (error) {
810                 printk(KERN_ERR
811                        "efivars: Sysfs attribute export failed with error %d.\n",
812                        error);
813                 unregister_efivars(&__efivars);
814                 kobject_put(efi_kobj);
815         }
816
817         return error;
818 }
819
820 static void __exit
821 efivars_exit(void)
822 {
823         unregister_efivars(&__efivars);
824         kobject_put(efi_kobj);
825 }
826
827 module_init(efivars_init);
828 module_exit(efivars_exit);
829