efi: move utf16 string functions to efi.h
[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 #include <linux/pstore.h>
82 #include <linux/ctype.h>
83
84 #include <linux/fs.h>
85 #include <linux/ramfs.h>
86 #include <linux/pagemap.h>
87
88 #include <asm/uaccess.h>
89
90 #define EFIVARS_VERSION "0.08"
91 #define EFIVARS_DATE "2004-May-17"
92
93 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
94 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
95 MODULE_LICENSE("GPL");
96 MODULE_VERSION(EFIVARS_VERSION);
97
98 #define DUMP_NAME_LEN 52
99
100 /*
101  * Length of a GUID string (strlen("aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"))
102  * not including trailing NUL
103  */
104 #define GUID_LEN 36
105
106 static bool efivars_pstore_disable =
107         IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
108
109 module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644);
110
111 /*
112  * The maximum size of VariableName + Data = 1024
113  * Therefore, it's reasonable to save that much
114  * space in each part of the structure,
115  * and we use a page for reading/writing.
116  */
117
118 struct efi_variable {
119         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
120         efi_guid_t    VendorGuid;
121         unsigned long DataSize;
122         __u8          Data[1024];
123         efi_status_t  Status;
124         __u32         Attributes;
125 } __attribute__((packed));
126
127 struct efivar_entry {
128         struct efivars *efivars;
129         struct efi_variable var;
130         struct list_head list;
131         struct kobject kobj;
132 };
133
134 struct efivar_attribute {
135         struct attribute attr;
136         ssize_t (*show) (struct efivar_entry *entry, char *buf);
137         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
138 };
139
140 static struct efivars __efivars;
141 static struct efivar_operations ops;
142
143 #define PSTORE_EFI_ATTRIBUTES \
144         (EFI_VARIABLE_NON_VOLATILE | \
145          EFI_VARIABLE_BOOTSERVICE_ACCESS | \
146          EFI_VARIABLE_RUNTIME_ACCESS)
147
148 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
149 struct efivar_attribute efivar_attr_##_name = { \
150         .attr = {.name = __stringify(_name), .mode = _mode}, \
151         .show = _show, \
152         .store = _store, \
153 };
154
155 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
156 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
157
158 /*
159  * Prototype for sysfs creation function
160  */
161 static int
162 efivar_create_sysfs_entry(struct efivars *efivars,
163                           unsigned long variable_name_size,
164                           efi_char16_t *variable_name,
165                           efi_guid_t *vendor_guid);
166
167 /*
168  * Prototype for workqueue functions updating sysfs entry
169  */
170
171 static void efivar_update_sysfs_entries(struct work_struct *);
172 static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
173 static bool efivar_wq_enabled = true;
174
175 /*
176  * Return the number of bytes is the length of this string
177  * Note: this is NOT the same as the number of unicode characters
178  */
179 static inline unsigned long
180 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
181 {
182         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
183 }
184
185 static inline int
186 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
187 {
188         while (1) {
189                 if (len == 0)
190                         return 0;
191                 if (*a < *b)
192                         return -1;
193                 if (*a > *b)
194                         return 1;
195                 if (*a == 0) /* implies *b == 0 */
196                         return 0;
197                 a++;
198                 b++;
199                 len--;
200         }
201 }
202
203 static bool
204 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
205                      unsigned long len)
206 {
207         struct efi_generic_dev_path *node;
208         int offset = 0;
209
210         node = (struct efi_generic_dev_path *)buffer;
211
212         if (len < sizeof(*node))
213                 return false;
214
215         while (offset <= len - sizeof(*node) &&
216                node->length >= sizeof(*node) &&
217                 node->length <= len - offset) {
218                 offset += node->length;
219
220                 if ((node->type == EFI_DEV_END_PATH ||
221                      node->type == EFI_DEV_END_PATH2) &&
222                     node->sub_type == EFI_DEV_END_ENTIRE)
223                         return true;
224
225                 node = (struct efi_generic_dev_path *)(buffer + offset);
226         }
227
228         /*
229          * If we're here then either node->length pointed past the end
230          * of the buffer or we reached the end of the buffer without
231          * finding a device path end node.
232          */
233         return false;
234 }
235
236 static bool
237 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
238                     unsigned long len)
239 {
240         /* An array of 16-bit integers */
241         if ((len % 2) != 0)
242                 return false;
243
244         return true;
245 }
246
247 static bool
248 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
249                      unsigned long len)
250 {
251         u16 filepathlength;
252         int i, desclength = 0, namelen;
253
254         namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
255
256         /* Either "Boot" or "Driver" followed by four digits of hex */
257         for (i = match; i < match+4; i++) {
258                 if (var->VariableName[i] > 127 ||
259                     hex_to_bin(var->VariableName[i] & 0xff) < 0)
260                         return true;
261         }
262
263         /* Reject it if there's 4 digits of hex and then further content */
264         if (namelen > match + 4)
265                 return false;
266
267         /* A valid entry must be at least 8 bytes */
268         if (len < 8)
269                 return false;
270
271         filepathlength = buffer[4] | buffer[5] << 8;
272
273         /*
274          * There's no stored length for the description, so it has to be
275          * found by hand
276          */
277         desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
278
279         /* Each boot entry must have a descriptor */
280         if (!desclength)
281                 return false;
282
283         /*
284          * If the sum of the length of the description, the claimed filepath
285          * length and the original header are greater than the length of the
286          * variable, it's malformed
287          */
288         if ((desclength + filepathlength + 6) > len)
289                 return false;
290
291         /*
292          * And, finally, check the filepath
293          */
294         return validate_device_path(var, match, buffer + desclength + 6,
295                                     filepathlength);
296 }
297
298 static bool
299 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
300                 unsigned long len)
301 {
302         /* A single 16-bit integer */
303         if (len != 2)
304                 return false;
305
306         return true;
307 }
308
309 static bool
310 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
311                       unsigned long len)
312 {
313         int i;
314
315         for (i = 0; i < len; i++) {
316                 if (buffer[i] > 127)
317                         return false;
318
319                 if (buffer[i] == 0)
320                         return true;
321         }
322
323         return false;
324 }
325
326 struct variable_validate {
327         char *name;
328         bool (*validate)(struct efi_variable *var, int match, u8 *data,
329                          unsigned long len);
330 };
331
332 static const struct variable_validate variable_validate[] = {
333         { "BootNext", validate_uint16 },
334         { "BootOrder", validate_boot_order },
335         { "DriverOrder", validate_boot_order },
336         { "Boot*", validate_load_option },
337         { "Driver*", validate_load_option },
338         { "ConIn", validate_device_path },
339         { "ConInDev", validate_device_path },
340         { "ConOut", validate_device_path },
341         { "ConOutDev", validate_device_path },
342         { "ErrOut", validate_device_path },
343         { "ErrOutDev", validate_device_path },
344         { "Timeout", validate_uint16 },
345         { "Lang", validate_ascii_string },
346         { "PlatformLang", validate_ascii_string },
347         { "", NULL },
348 };
349
350 static bool
351 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
352 {
353         int i;
354         u16 *unicode_name = var->VariableName;
355
356         for (i = 0; variable_validate[i].validate != NULL; i++) {
357                 const char *name = variable_validate[i].name;
358                 int match;
359
360                 for (match = 0; ; match++) {
361                         char c = name[match];
362                         u16 u = unicode_name[match];
363
364                         /* All special variables are plain ascii */
365                         if (u > 127)
366                                 return true;
367
368                         /* Wildcard in the matching name means we've matched */
369                         if (c == '*')
370                                 return variable_validate[i].validate(var,
371                                                              match, data, len);
372
373                         /* Case sensitive match */
374                         if (c != u)
375                                 break;
376
377                         /* Reached the end of the string while matching */
378                         if (!c)
379                                 return variable_validate[i].validate(var,
380                                                              match, data, len);
381                 }
382         }
383
384         return true;
385 }
386
387 static efi_status_t
388 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
389 {
390         efi_status_t status;
391
392         var->DataSize = 1024;
393         status = efivars->ops->get_variable(var->VariableName,
394                                             &var->VendorGuid,
395                                             &var->Attributes,
396                                             &var->DataSize,
397                                             var->Data);
398         return status;
399 }
400
401 static efi_status_t
402 get_var_data(struct efivars *efivars, struct efi_variable *var)
403 {
404         efi_status_t status;
405         unsigned long flags;
406
407         spin_lock_irqsave(&efivars->lock, flags);
408         status = get_var_data_locked(efivars, var);
409         spin_unlock_irqrestore(&efivars->lock, flags);
410
411         if (status != EFI_SUCCESS) {
412                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
413                         status);
414         }
415         return status;
416 }
417
418 static efi_status_t
419 check_var_size_locked(struct efivars *efivars, u32 attributes,
420                         unsigned long size)
421 {
422         u64 storage_size, remaining_size, max_size;
423         efi_status_t status;
424         const struct efivar_operations *fops = efivars->ops;
425
426         if (!efivars->ops->query_variable_info)
427                 return EFI_UNSUPPORTED;
428
429         status = fops->query_variable_info(attributes, &storage_size,
430                                            &remaining_size, &max_size);
431
432         if (status != EFI_SUCCESS)
433                 return status;
434
435         if (!storage_size || size > remaining_size || size > max_size ||
436             (remaining_size - size) < (storage_size / 2))
437                 return EFI_OUT_OF_RESOURCES;
438
439         return status;
440 }
441
442
443 static efi_status_t
444 check_var_size(struct efivars *efivars, u32 attributes, unsigned long size)
445 {
446         efi_status_t status;
447         unsigned long flags;
448
449         spin_lock_irqsave(&efivars->lock, flags);
450         status = check_var_size_locked(efivars, attributes, size);
451         spin_unlock_irqrestore(&efivars->lock, flags);
452
453         return status;
454 }
455
456 static ssize_t
457 efivar_guid_read(struct efivar_entry *entry, char *buf)
458 {
459         struct efi_variable *var = &entry->var;
460         char *str = buf;
461
462         if (!entry || !buf)
463                 return 0;
464
465         efi_guid_unparse(&var->VendorGuid, str);
466         str += strlen(str);
467         str += sprintf(str, "\n");
468
469         return str - buf;
470 }
471
472 static ssize_t
473 efivar_attr_read(struct efivar_entry *entry, char *buf)
474 {
475         struct efi_variable *var = &entry->var;
476         char *str = buf;
477         efi_status_t status;
478
479         if (!entry || !buf)
480                 return -EINVAL;
481
482         status = get_var_data(entry->efivars, var);
483         if (status != EFI_SUCCESS)
484                 return -EIO;
485
486         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
487                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
488         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
489                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
490         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
491                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
492         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
493                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
494         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
495                 str += sprintf(str,
496                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
497         if (var->Attributes &
498                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
499                 str += sprintf(str,
500                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
501         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
502                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
503         return str - buf;
504 }
505
506 static ssize_t
507 efivar_size_read(struct efivar_entry *entry, char *buf)
508 {
509         struct efi_variable *var = &entry->var;
510         char *str = buf;
511         efi_status_t status;
512
513         if (!entry || !buf)
514                 return -EINVAL;
515
516         status = get_var_data(entry->efivars, var);
517         if (status != EFI_SUCCESS)
518                 return -EIO;
519
520         str += sprintf(str, "0x%lx\n", var->DataSize);
521         return str - buf;
522 }
523
524 static ssize_t
525 efivar_data_read(struct efivar_entry *entry, char *buf)
526 {
527         struct efi_variable *var = &entry->var;
528         efi_status_t status;
529
530         if (!entry || !buf)
531                 return -EINVAL;
532
533         status = get_var_data(entry->efivars, var);
534         if (status != EFI_SUCCESS)
535                 return -EIO;
536
537         memcpy(buf, var->Data, var->DataSize);
538         return var->DataSize;
539 }
540 /*
541  * We allow each variable to be edited via rewriting the
542  * entire efi variable structure.
543  */
544 static ssize_t
545 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
546 {
547         struct efi_variable *new_var, *var = &entry->var;
548         struct efivars *efivars = entry->efivars;
549         efi_status_t status = EFI_NOT_FOUND;
550
551         if (count != sizeof(struct efi_variable))
552                 return -EINVAL;
553
554         new_var = (struct efi_variable *)buf;
555         /*
556          * If only updating the variable data, then the name
557          * and guid should remain the same
558          */
559         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
560                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
561                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
562                 return -EINVAL;
563         }
564
565         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
566                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
567                 return -EINVAL;
568         }
569
570         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
571             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
572                 printk(KERN_ERR "efivars: Malformed variable content\n");
573                 return -EINVAL;
574         }
575
576         spin_lock_irq(&efivars->lock);
577
578         status = check_var_size_locked(efivars, new_var->Attributes,
579                new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
580
581         if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
582                 status = efivars->ops->set_variable(new_var->VariableName,
583                                                     &new_var->VendorGuid,
584                                                     new_var->Attributes,
585                                                     new_var->DataSize,
586                                                     new_var->Data);
587
588         spin_unlock_irq(&efivars->lock);
589
590         if (status != EFI_SUCCESS) {
591                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
592                         status);
593                 return -EIO;
594         }
595
596         memcpy(&entry->var, new_var, count);
597         return count;
598 }
599
600 static ssize_t
601 efivar_show_raw(struct efivar_entry *entry, char *buf)
602 {
603         struct efi_variable *var = &entry->var;
604         efi_status_t status;
605
606         if (!entry || !buf)
607                 return 0;
608
609         status = get_var_data(entry->efivars, var);
610         if (status != EFI_SUCCESS)
611                 return -EIO;
612
613         memcpy(buf, var, sizeof(*var));
614         return sizeof(*var);
615 }
616
617 /*
618  * Generic read/write functions that call the specific functions of
619  * the attributes...
620  */
621 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
622                                 char *buf)
623 {
624         struct efivar_entry *var = to_efivar_entry(kobj);
625         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
626         ssize_t ret = -EIO;
627
628         if (!capable(CAP_SYS_ADMIN))
629                 return -EACCES;
630
631         if (efivar_attr->show) {
632                 ret = efivar_attr->show(var, buf);
633         }
634         return ret;
635 }
636
637 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
638                                 const char *buf, size_t count)
639 {
640         struct efivar_entry *var = to_efivar_entry(kobj);
641         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
642         ssize_t ret = -EIO;
643
644         if (!capable(CAP_SYS_ADMIN))
645                 return -EACCES;
646
647         if (efivar_attr->store)
648                 ret = efivar_attr->store(var, buf, count);
649
650         return ret;
651 }
652
653 static const struct sysfs_ops efivar_attr_ops = {
654         .show = efivar_attr_show,
655         .store = efivar_attr_store,
656 };
657
658 static void efivar_release(struct kobject *kobj)
659 {
660         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
661         kfree(var);
662 }
663
664 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
665 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
666 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
667 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
668 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
669
670 static struct attribute *def_attrs[] = {
671         &efivar_attr_guid.attr,
672         &efivar_attr_size.attr,
673         &efivar_attr_attributes.attr,
674         &efivar_attr_data.attr,
675         &efivar_attr_raw_var.attr,
676         NULL,
677 };
678
679 static struct kobj_type efivar_ktype = {
680         .release = efivar_release,
681         .sysfs_ops = &efivar_attr_ops,
682         .default_attrs = def_attrs,
683 };
684
685 static inline void
686 efivar_unregister(struct efivar_entry *var)
687 {
688         kobject_put(&var->kobj);
689 }
690
691 static int efivarfs_file_open(struct inode *inode, struct file *file)
692 {
693         file->private_data = inode->i_private;
694         return 0;
695 }
696
697 static int efi_status_to_err(efi_status_t status)
698 {
699         int err;
700
701         switch (status) {
702         case EFI_INVALID_PARAMETER:
703                 err = -EINVAL;
704                 break;
705         case EFI_OUT_OF_RESOURCES:
706                 err = -ENOSPC;
707                 break;
708         case EFI_DEVICE_ERROR:
709                 err = -EIO;
710                 break;
711         case EFI_WRITE_PROTECTED:
712                 err = -EROFS;
713                 break;
714         case EFI_SECURITY_VIOLATION:
715                 err = -EACCES;
716                 break;
717         case EFI_NOT_FOUND:
718                 err = -EIO;
719                 break;
720         default:
721                 err = -EINVAL;
722         }
723
724         return err;
725 }
726
727 static ssize_t efivarfs_file_write(struct file *file,
728                 const char __user *userbuf, size_t count, loff_t *ppos)
729 {
730         struct efivar_entry *var = file->private_data;
731         struct efivars *efivars;
732         efi_status_t status;
733         void *data;
734         u32 attributes;
735         struct inode *inode = file->f_mapping->host;
736         unsigned long datasize = count - sizeof(attributes);
737         unsigned long newdatasize, varsize;
738         ssize_t bytes = 0;
739
740         if (count < sizeof(attributes))
741                 return -EINVAL;
742
743         if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
744                 return -EFAULT;
745
746         if (attributes & ~(EFI_VARIABLE_MASK))
747                 return -EINVAL;
748
749         efivars = var->efivars;
750
751         /*
752          * Ensure that the user can't allocate arbitrarily large
753          * amounts of memory. Pick a default size of 64K if
754          * QueryVariableInfo() isn't supported by the firmware.
755          */
756
757         varsize = datasize + utf16_strsize(var->var.VariableName, 1024);
758         status = check_var_size(efivars, attributes, varsize);
759
760         if (status != EFI_SUCCESS) {
761                 if (status != EFI_UNSUPPORTED)
762                         return efi_status_to_err(status);
763
764                 if (datasize > 65536)
765                         return -ENOSPC;
766         }
767
768         data = kmalloc(datasize, GFP_KERNEL);
769         if (!data)
770                 return -ENOMEM;
771
772         if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
773                 bytes = -EFAULT;
774                 goto out;
775         }
776
777         if (validate_var(&var->var, data, datasize) == false) {
778                 bytes = -EINVAL;
779                 goto out;
780         }
781
782         /*
783          * The lock here protects the get_variable call, the conditional
784          * set_variable call, and removal of the variable from the efivars
785          * list (in the case of an authenticated delete).
786          */
787         spin_lock_irq(&efivars->lock);
788
789         /*
790          * Ensure that the available space hasn't shrunk below the safe level
791          */
792
793         status = check_var_size_locked(efivars, attributes, varsize);
794
795         if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED) {
796                 spin_unlock_irq(&efivars->lock);
797                 kfree(data);
798
799                 return efi_status_to_err(status);
800         }
801
802         status = efivars->ops->set_variable(var->var.VariableName,
803                                             &var->var.VendorGuid,
804                                             attributes, datasize,
805                                             data);
806
807         if (status != EFI_SUCCESS) {
808                 spin_unlock_irq(&efivars->lock);
809                 kfree(data);
810
811                 return efi_status_to_err(status);
812         }
813
814         bytes = count;
815
816         /*
817          * Writing to the variable may have caused a change in size (which
818          * could either be an append or an overwrite), or the variable to be
819          * deleted. Perform a GetVariable() so we can tell what actually
820          * happened.
821          */
822         newdatasize = 0;
823         status = efivars->ops->get_variable(var->var.VariableName,
824                                             &var->var.VendorGuid,
825                                             NULL, &newdatasize,
826                                             NULL);
827
828         if (status == EFI_BUFFER_TOO_SMALL) {
829                 spin_unlock_irq(&efivars->lock);
830                 mutex_lock(&inode->i_mutex);
831                 i_size_write(inode, newdatasize + sizeof(attributes));
832                 mutex_unlock(&inode->i_mutex);
833
834         } else if (status == EFI_NOT_FOUND) {
835                 list_del(&var->list);
836                 spin_unlock_irq(&efivars->lock);
837                 efivar_unregister(var);
838                 drop_nlink(inode);
839                 d_delete(file->f_dentry);
840                 dput(file->f_dentry);
841
842         } else {
843                 spin_unlock_irq(&efivars->lock);
844                 pr_warn("efivarfs: inconsistent EFI variable implementation? "
845                                 "status = %lx\n", status);
846         }
847
848 out:
849         kfree(data);
850
851         return bytes;
852 }
853
854 static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
855                 size_t count, loff_t *ppos)
856 {
857         struct efivar_entry *var = file->private_data;
858         struct efivars *efivars = var->efivars;
859         efi_status_t status;
860         unsigned long datasize = 0;
861         u32 attributes;
862         void *data;
863         ssize_t size = 0;
864
865         spin_lock_irq(&efivars->lock);
866         status = efivars->ops->get_variable(var->var.VariableName,
867                                             &var->var.VendorGuid,
868                                             &attributes, &datasize, NULL);
869         spin_unlock_irq(&efivars->lock);
870
871         if (status != EFI_BUFFER_TOO_SMALL)
872                 return efi_status_to_err(status);
873
874         data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
875
876         if (!data)
877                 return -ENOMEM;
878
879         spin_lock_irq(&efivars->lock);
880         status = efivars->ops->get_variable(var->var.VariableName,
881                                             &var->var.VendorGuid,
882                                             &attributes, &datasize,
883                                             (data + sizeof(attributes)));
884         spin_unlock_irq(&efivars->lock);
885
886         if (status != EFI_SUCCESS) {
887                 size = efi_status_to_err(status);
888                 goto out_free;
889         }
890
891         memcpy(data, &attributes, sizeof(attributes));
892         size = simple_read_from_buffer(userbuf, count, ppos,
893                                        data, datasize + sizeof(attributes));
894 out_free:
895         kfree(data);
896
897         return size;
898 }
899
900 static void efivarfs_evict_inode(struct inode *inode)
901 {
902         clear_inode(inode);
903 }
904
905 static const struct super_operations efivarfs_ops = {
906         .statfs = simple_statfs,
907         .drop_inode = generic_delete_inode,
908         .evict_inode = efivarfs_evict_inode,
909         .show_options = generic_show_options,
910 };
911
912 static struct super_block *efivarfs_sb;
913
914 static const struct inode_operations efivarfs_dir_inode_operations;
915
916 static const struct file_operations efivarfs_file_operations = {
917         .open   = efivarfs_file_open,
918         .read   = efivarfs_file_read,
919         .write  = efivarfs_file_write,
920         .llseek = no_llseek,
921 };
922
923 static struct inode *efivarfs_get_inode(struct super_block *sb,
924                                 const struct inode *dir, int mode, dev_t dev)
925 {
926         struct inode *inode = new_inode(sb);
927
928         if (inode) {
929                 inode->i_ino = get_next_ino();
930                 inode->i_mode = mode;
931                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
932                 switch (mode & S_IFMT) {
933                 case S_IFREG:
934                         inode->i_fop = &efivarfs_file_operations;
935                         break;
936                 case S_IFDIR:
937                         inode->i_op = &efivarfs_dir_inode_operations;
938                         inode->i_fop = &simple_dir_operations;
939                         inc_nlink(inode);
940                         break;
941                 }
942         }
943         return inode;
944 }
945
946 /*
947  * Return true if 'str' is a valid efivarfs filename of the form,
948  *
949  *      VariableName-12345678-1234-1234-1234-1234567891bc
950  */
951 static bool efivarfs_valid_name(const char *str, int len)
952 {
953         static const char dashes[GUID_LEN] = {
954                 [8] = 1, [13] = 1, [18] = 1, [23] = 1
955         };
956         const char *s = str + len - GUID_LEN;
957         int i;
958
959         /*
960          * We need a GUID, plus at least one letter for the variable name,
961          * plus the '-' separator
962          */
963         if (len < GUID_LEN + 2)
964                 return false;
965
966         /* GUID must be preceded by a '-' */
967         if (*(s - 1) != '-')
968                 return false;
969
970         /*
971          * Validate that 's' is of the correct format, e.g.
972          *
973          *      12345678-1234-1234-1234-123456789abc
974          */
975         for (i = 0; i < GUID_LEN; i++) {
976                 if (dashes[i]) {
977                         if (*s++ != '-')
978                                 return false;
979                 } else {
980                         if (!isxdigit(*s++))
981                                 return false;
982                 }
983         }
984
985         return true;
986 }
987
988 static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
989 {
990         guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
991         guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
992         guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
993         guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
994         guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
995         guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
996         guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
997         guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
998         guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
999         guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
1000         guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
1001         guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
1002         guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
1003         guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
1004         guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
1005         guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
1006 }
1007
1008 static int efivarfs_create(struct inode *dir, struct dentry *dentry,
1009                           umode_t mode, bool excl)
1010 {
1011         struct inode *inode;
1012         struct efivars *efivars = &__efivars;
1013         struct efivar_entry *var;
1014         int namelen, i = 0, err = 0;
1015
1016         if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
1017                 return -EINVAL;
1018
1019         inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
1020         if (!inode)
1021                 return -ENOMEM;
1022
1023         var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1024         if (!var) {
1025                 err = -ENOMEM;
1026                 goto out;
1027         }
1028
1029         /* length of the variable name itself: remove GUID and separator */
1030         namelen = dentry->d_name.len - GUID_LEN - 1;
1031
1032         efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
1033                         &var->var.VendorGuid);
1034
1035         for (i = 0; i < namelen; i++)
1036                 var->var.VariableName[i] = dentry->d_name.name[i];
1037
1038         var->var.VariableName[i] = '\0';
1039
1040         inode->i_private = var;
1041         var->efivars = efivars;
1042         var->kobj.kset = efivars->kset;
1043
1044         err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
1045                              dentry->d_name.name);
1046         if (err)
1047                 goto out;
1048
1049         kobject_uevent(&var->kobj, KOBJ_ADD);
1050         spin_lock_irq(&efivars->lock);
1051         list_add(&var->list, &efivars->list);
1052         spin_unlock_irq(&efivars->lock);
1053         d_instantiate(dentry, inode);
1054         dget(dentry);
1055 out:
1056         if (err) {
1057                 kfree(var);
1058                 iput(inode);
1059         }
1060         return err;
1061 }
1062
1063 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
1064 {
1065         struct efivar_entry *var = dentry->d_inode->i_private;
1066         struct efivars *efivars = var->efivars;
1067         efi_status_t status;
1068
1069         spin_lock_irq(&efivars->lock);
1070
1071         status = efivars->ops->set_variable(var->var.VariableName,
1072                                             &var->var.VendorGuid,
1073                                             0, 0, NULL);
1074
1075         if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
1076                 list_del(&var->list);
1077                 spin_unlock_irq(&efivars->lock);
1078                 efivar_unregister(var);
1079                 drop_nlink(dentry->d_inode);
1080                 dput(dentry);
1081                 return 0;
1082         }
1083
1084         spin_unlock_irq(&efivars->lock);
1085         return -EINVAL;
1086 };
1087
1088 /*
1089  * Compare two efivarfs file names.
1090  *
1091  * An efivarfs filename is composed of two parts,
1092  *
1093  *      1. A case-sensitive variable name
1094  *      2. A case-insensitive GUID
1095  *
1096  * So we need to perform a case-sensitive match on part 1 and a
1097  * case-insensitive match on part 2.
1098  */
1099 static int efivarfs_d_compare(const struct dentry *parent, const struct inode *pinode,
1100                               const struct dentry *dentry, const struct inode *inode,
1101                               unsigned int len, const char *str,
1102                               const struct qstr *name)
1103 {
1104         int guid = len - GUID_LEN;
1105
1106         if (name->len != len)
1107                 return 1;
1108
1109         /* Case-sensitive compare for the variable name */
1110         if (memcmp(str, name->name, guid))
1111                 return 1;
1112
1113         /* Case-insensitive compare for the GUID */
1114         return strncasecmp(name->name + guid, str + guid, GUID_LEN);
1115 }
1116
1117 static int efivarfs_d_hash(const struct dentry *dentry,
1118                            const struct inode *inode, struct qstr *qstr)
1119 {
1120         unsigned long hash = init_name_hash();
1121         const unsigned char *s = qstr->name;
1122         unsigned int len = qstr->len;
1123
1124         if (!efivarfs_valid_name(s, len))
1125                 return -EINVAL;
1126
1127         while (len-- > GUID_LEN)
1128                 hash = partial_name_hash(*s++, hash);
1129
1130         /* GUID is case-insensitive. */
1131         while (len--)
1132                 hash = partial_name_hash(tolower(*s++), hash);
1133
1134         qstr->hash = end_name_hash(hash);
1135         return 0;
1136 }
1137
1138 /*
1139  * Retaining negative dentries for an in-memory filesystem just wastes
1140  * memory and lookup time: arrange for them to be deleted immediately.
1141  */
1142 static int efivarfs_delete_dentry(const struct dentry *dentry)
1143 {
1144         return 1;
1145 }
1146
1147 static struct dentry_operations efivarfs_d_ops = {
1148         .d_compare = efivarfs_d_compare,
1149         .d_hash = efivarfs_d_hash,
1150         .d_delete = efivarfs_delete_dentry,
1151 };
1152
1153 static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
1154 {
1155         struct dentry *d;
1156         struct qstr q;
1157         int err;
1158
1159         q.name = name;
1160         q.len = strlen(name);
1161
1162         err = efivarfs_d_hash(NULL, NULL, &q);
1163         if (err)
1164                 return ERR_PTR(err);
1165
1166         d = d_alloc(parent, &q);
1167         if (d)
1168                 return d;
1169
1170         return ERR_PTR(-ENOMEM);
1171 }
1172
1173 static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
1174 {
1175         struct inode *inode = NULL;
1176         struct dentry *root;
1177         struct efivar_entry *entry, *n;
1178         struct efivars *efivars = &__efivars;
1179         char *name;
1180         int err = -ENOMEM;
1181
1182         efivarfs_sb = sb;
1183
1184         sb->s_maxbytes          = MAX_LFS_FILESIZE;
1185         sb->s_blocksize         = PAGE_CACHE_SIZE;
1186         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
1187         sb->s_magic             = EFIVARFS_MAGIC;
1188         sb->s_op                = &efivarfs_ops;
1189         sb->s_d_op              = &efivarfs_d_ops;
1190         sb->s_time_gran         = 1;
1191
1192         inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
1193         if (!inode)
1194                 return -ENOMEM;
1195         inode->i_op = &efivarfs_dir_inode_operations;
1196
1197         root = d_make_root(inode);
1198         sb->s_root = root;
1199         if (!root)
1200                 return -ENOMEM;
1201
1202         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1203                 struct dentry *dentry, *root = efivarfs_sb->s_root;
1204                 unsigned long size = 0;
1205                 int len, i;
1206
1207                 inode = NULL;
1208
1209                 len = utf16_strlen(entry->var.VariableName);
1210
1211                 /* name, plus '-', plus GUID, plus NUL*/
1212                 name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
1213                 if (!name)
1214                         goto fail;
1215
1216                 for (i = 0; i < len; i++)
1217                         name[i] = entry->var.VariableName[i] & 0xFF;
1218
1219                 name[len] = '-';
1220
1221                 efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
1222
1223                 name[len+GUID_LEN+1] = '\0';
1224
1225                 inode = efivarfs_get_inode(efivarfs_sb, root->d_inode,
1226                                           S_IFREG | 0644, 0);
1227                 if (!inode)
1228                         goto fail_name;
1229
1230                 dentry = efivarfs_alloc_dentry(root, name);
1231                 if (IS_ERR(dentry)) {
1232                         err = PTR_ERR(dentry);
1233                         goto fail_inode;
1234                 }
1235
1236                 /* copied by the above to local storage in the dentry. */
1237                 kfree(name);
1238
1239                 spin_lock_irq(&efivars->lock);
1240                 efivars->ops->get_variable(entry->var.VariableName,
1241                                            &entry->var.VendorGuid,
1242                                            &entry->var.Attributes,
1243                                            &size,
1244                                            NULL);
1245                 spin_unlock_irq(&efivars->lock);
1246
1247                 mutex_lock(&inode->i_mutex);
1248                 inode->i_private = entry;
1249                 i_size_write(inode, size + sizeof(entry->var.Attributes));
1250                 mutex_unlock(&inode->i_mutex);
1251                 d_add(dentry, inode);
1252         }
1253
1254         return 0;
1255
1256 fail_inode:
1257         iput(inode);
1258 fail_name:
1259         kfree(name);
1260 fail:
1261         return err;
1262 }
1263
1264 static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
1265                                     int flags, const char *dev_name, void *data)
1266 {
1267         return mount_single(fs_type, flags, data, efivarfs_fill_super);
1268 }
1269
1270 static void efivarfs_kill_sb(struct super_block *sb)
1271 {
1272         kill_litter_super(sb);
1273         efivarfs_sb = NULL;
1274 }
1275
1276 static struct file_system_type efivarfs_type = {
1277         .name    = "efivarfs",
1278         .mount   = efivarfs_mount,
1279         .kill_sb = efivarfs_kill_sb,
1280 };
1281 MODULE_ALIAS_FS("efivarfs");
1282
1283 /*
1284  * Handle negative dentry.
1285  */
1286 static struct dentry *efivarfs_lookup(struct inode *dir, struct dentry *dentry,
1287                                       unsigned int flags)
1288 {
1289         if (dentry->d_name.len > NAME_MAX)
1290                 return ERR_PTR(-ENAMETOOLONG);
1291         d_add(dentry, NULL);
1292         return NULL;
1293 }
1294
1295 static const struct inode_operations efivarfs_dir_inode_operations = {
1296         .lookup = efivarfs_lookup,
1297         .unlink = efivarfs_unlink,
1298         .create = efivarfs_create,
1299 };
1300
1301 #ifdef CONFIG_EFI_VARS_PSTORE
1302
1303 static int efi_pstore_open(struct pstore_info *psi)
1304 {
1305         struct efivars *efivars = psi->data;
1306
1307         spin_lock_irq(&efivars->lock);
1308         efivars->walk_entry = list_first_entry(&efivars->list,
1309                                                struct efivar_entry, list);
1310         return 0;
1311 }
1312
1313 static int efi_pstore_close(struct pstore_info *psi)
1314 {
1315         struct efivars *efivars = psi->data;
1316
1317         spin_unlock_irq(&efivars->lock);
1318         return 0;
1319 }
1320
1321 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1322                                int *count, struct timespec *timespec,
1323                                char **buf, struct pstore_info *psi)
1324 {
1325         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1326         struct efivars *efivars = psi->data;
1327         char name[DUMP_NAME_LEN];
1328         int i;
1329         int cnt;
1330         unsigned int part, size;
1331         unsigned long time;
1332
1333         while (&efivars->walk_entry->list != &efivars->list) {
1334                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
1335                                  vendor)) {
1336                         for (i = 0; i < DUMP_NAME_LEN; i++) {
1337                                 name[i] = efivars->walk_entry->var.VariableName[i];
1338                         }
1339                         if (sscanf(name, "dump-type%u-%u-%d-%lu",
1340                                    type, &part, &cnt, &time) == 4) {
1341                                 *id = part;
1342                                 *count = cnt;
1343                                 timespec->tv_sec = time;
1344                                 timespec->tv_nsec = 0;
1345                         } else if (sscanf(name, "dump-type%u-%u-%lu",
1346                                    type, &part, &time) == 3) {
1347                                 /*
1348                                  * Check if an old format,
1349                                  * which doesn't support holding
1350                                  * multiple logs, remains.
1351                                  */
1352                                 *id = part;
1353                                 *count = 0;
1354                                 timespec->tv_sec = time;
1355                                 timespec->tv_nsec = 0;
1356                         } else {
1357                                 efivars->walk_entry = list_entry(
1358                                                 efivars->walk_entry->list.next,
1359                                                 struct efivar_entry, list);
1360                                 continue;
1361                         }
1362
1363                         get_var_data_locked(efivars, &efivars->walk_entry->var);
1364                         size = efivars->walk_entry->var.DataSize;
1365                         *buf = kmalloc(size, GFP_KERNEL);
1366                         if (*buf == NULL)
1367                                 return -ENOMEM;
1368                         memcpy(*buf, efivars->walk_entry->var.Data,
1369                                size);
1370                         efivars->walk_entry = list_entry(
1371                                         efivars->walk_entry->list.next,
1372                                         struct efivar_entry, list);
1373                         return size;
1374                 }
1375                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1376                                                  struct efivar_entry, list);
1377         }
1378         return 0;
1379 }
1380
1381 static int efi_pstore_write(enum pstore_type_id type,
1382                 enum kmsg_dump_reason reason, u64 *id,
1383                 unsigned int part, int count, size_t size,
1384                 struct pstore_info *psi)
1385 {
1386         char name[DUMP_NAME_LEN];
1387         efi_char16_t efi_name[DUMP_NAME_LEN];
1388         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1389         struct efivars *efivars = psi->data;
1390         int i, ret = 0;
1391         efi_status_t status = EFI_NOT_FOUND;
1392         unsigned long flags;
1393
1394         if (pstore_cannot_block_path(reason)) {
1395                 /*
1396                  * If the lock is taken by another cpu in non-blocking path,
1397                  * this driver returns without entering firmware to avoid
1398                  * hanging up.
1399                  */
1400                 if (!spin_trylock_irqsave(&efivars->lock, flags))
1401                         return -EBUSY;
1402         } else
1403                 spin_lock_irqsave(&efivars->lock, flags);
1404
1405         /*
1406          * Check if there is a space enough to log.
1407          * size: a size of logging data
1408          * DUMP_NAME_LEN * 2: a maximum size of variable name
1409          */
1410
1411         status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
1412                                          size + DUMP_NAME_LEN * 2);
1413
1414         if (status) {
1415                 spin_unlock_irqrestore(&efivars->lock, flags);
1416                 *id = part;
1417                 return -ENOSPC;
1418         }
1419
1420         sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
1421                 get_seconds());
1422
1423         for (i = 0; i < DUMP_NAME_LEN; i++)
1424                 efi_name[i] = name[i];
1425
1426         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
1427                                    size, psi->buf);
1428
1429         spin_unlock_irqrestore(&efivars->lock, flags);
1430
1431         if (reason == KMSG_DUMP_OOPS && efivar_wq_enabled)
1432                 schedule_work(&efivar_work);
1433
1434         *id = part;
1435         return ret;
1436 };
1437
1438 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1439                             struct timespec time, struct pstore_info *psi)
1440 {
1441         char name[DUMP_NAME_LEN];
1442         efi_char16_t efi_name[DUMP_NAME_LEN];
1443         char name_old[DUMP_NAME_LEN];
1444         efi_char16_t efi_name_old[DUMP_NAME_LEN];
1445         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1446         struct efivars *efivars = psi->data;
1447         struct efivar_entry *entry, *found = NULL;
1448         int i;
1449
1450         sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
1451                 time.tv_sec);
1452
1453         spin_lock_irq(&efivars->lock);
1454
1455         for (i = 0; i < DUMP_NAME_LEN; i++)
1456                 efi_name[i] = name[i];
1457
1458         /*
1459          * Clean up an entry with the same name
1460          */
1461
1462         list_for_each_entry(entry, &efivars->list, list) {
1463                 get_var_data_locked(efivars, &entry->var);
1464
1465                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
1466                         continue;
1467                 if (utf16_strncmp(entry->var.VariableName, efi_name,
1468                                   utf16_strlen(efi_name))) {
1469                         /*
1470                          * Check if an old format,
1471                          * which doesn't support holding
1472                          * multiple logs, remains.
1473                          */
1474                         sprintf(name_old, "dump-type%u-%u-%lu", type,
1475                                 (unsigned int)id, time.tv_sec);
1476
1477                         for (i = 0; i < DUMP_NAME_LEN; i++)
1478                                 efi_name_old[i] = name_old[i];
1479
1480                         if (utf16_strncmp(entry->var.VariableName, efi_name_old,
1481                                           utf16_strlen(efi_name_old)))
1482                                 continue;
1483                 }
1484
1485                 /* found */
1486                 found = entry;
1487                 efivars->ops->set_variable(entry->var.VariableName,
1488                                            &entry->var.VendorGuid,
1489                                            PSTORE_EFI_ATTRIBUTES,
1490                                            0, NULL);
1491                 break;
1492         }
1493
1494         if (found)
1495                 list_del(&found->list);
1496
1497         spin_unlock_irq(&efivars->lock);
1498
1499         if (found)
1500                 efivar_unregister(found);
1501
1502         return 0;
1503 }
1504
1505 static struct pstore_info efi_pstore_info = {
1506         .owner          = THIS_MODULE,
1507         .name           = "efi",
1508         .open           = efi_pstore_open,
1509         .close          = efi_pstore_close,
1510         .read           = efi_pstore_read,
1511         .write          = efi_pstore_write,
1512         .erase          = efi_pstore_erase,
1513 };
1514
1515 static void efivar_pstore_register(struct efivars *efivars)
1516 {
1517         efivars->efi_pstore_info = efi_pstore_info;
1518         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1519         if (efivars->efi_pstore_info.buf) {
1520                 efivars->efi_pstore_info.bufsize = 1024;
1521                 efivars->efi_pstore_info.data = efivars;
1522                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1523                 pstore_register(&efivars->efi_pstore_info);
1524         }
1525 }
1526 #else
1527 static void efivar_pstore_register(struct efivars *efivars)
1528 {
1529         return;
1530 }
1531 #endif
1532
1533 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
1534                              struct bin_attribute *bin_attr,
1535                              char *buf, loff_t pos, size_t count)
1536 {
1537         struct efi_variable *new_var = (struct efi_variable *)buf;
1538         struct efivars *efivars = bin_attr->private;
1539         struct efivar_entry *search_efivar, *n;
1540         unsigned long strsize1, strsize2;
1541         efi_status_t status = EFI_NOT_FOUND;
1542         int found = 0;
1543
1544         if (!capable(CAP_SYS_ADMIN))
1545                 return -EACCES;
1546
1547         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
1548             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
1549                 printk(KERN_ERR "efivars: Malformed variable content\n");
1550                 return -EINVAL;
1551         }
1552
1553         spin_lock_irq(&efivars->lock);
1554
1555         /*
1556          * Does this variable already exist?
1557          */
1558         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1559                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1560                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
1561                 if (strsize1 == strsize2 &&
1562                         !memcmp(&(search_efivar->var.VariableName),
1563                                 new_var->VariableName, strsize1) &&
1564                         !efi_guidcmp(search_efivar->var.VendorGuid,
1565                                 new_var->VendorGuid)) {
1566                         found = 1;
1567                         break;
1568                 }
1569         }
1570         if (found) {
1571                 spin_unlock_irq(&efivars->lock);
1572                 return -EINVAL;
1573         }
1574
1575         status = check_var_size_locked(efivars, new_var->Attributes,
1576                new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
1577
1578         if (status && status != EFI_UNSUPPORTED) {
1579                 spin_unlock_irq(&efivars->lock);
1580                 return efi_status_to_err(status);
1581         }
1582
1583         /* now *really* create the variable via EFI */
1584         status = efivars->ops->set_variable(new_var->VariableName,
1585                                             &new_var->VendorGuid,
1586                                             new_var->Attributes,
1587                                             new_var->DataSize,
1588                                             new_var->Data);
1589
1590         if (status != EFI_SUCCESS) {
1591                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1592                         status);
1593                 spin_unlock_irq(&efivars->lock);
1594                 return -EIO;
1595         }
1596         spin_unlock_irq(&efivars->lock);
1597
1598         /* Create the entry in sysfs.  Locking is not required here */
1599         status = efivar_create_sysfs_entry(efivars,
1600                                            utf16_strsize(new_var->VariableName,
1601                                                          1024),
1602                                            new_var->VariableName,
1603                                            &new_var->VendorGuid);
1604         if (status) {
1605                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
1606         }
1607         return count;
1608 }
1609
1610 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
1611                              struct bin_attribute *bin_attr,
1612                              char *buf, loff_t pos, size_t count)
1613 {
1614         struct efi_variable *del_var = (struct efi_variable *)buf;
1615         struct efivars *efivars = bin_attr->private;
1616         struct efivar_entry *search_efivar, *n;
1617         unsigned long strsize1, strsize2;
1618         efi_status_t status = EFI_NOT_FOUND;
1619         int found = 0;
1620
1621         if (!capable(CAP_SYS_ADMIN))
1622                 return -EACCES;
1623
1624         spin_lock_irq(&efivars->lock);
1625
1626         /*
1627          * Does this variable already exist?
1628          */
1629         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1630                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1631                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
1632                 if (strsize1 == strsize2 &&
1633                         !memcmp(&(search_efivar->var.VariableName),
1634                                 del_var->VariableName, strsize1) &&
1635                         !efi_guidcmp(search_efivar->var.VendorGuid,
1636                                 del_var->VendorGuid)) {
1637                         found = 1;
1638                         break;
1639                 }
1640         }
1641         if (!found) {
1642                 spin_unlock_irq(&efivars->lock);
1643                 return -EINVAL;
1644         }
1645         /* force the Attributes/DataSize to 0 to ensure deletion */
1646         del_var->Attributes = 0;
1647         del_var->DataSize = 0;
1648
1649         status = efivars->ops->set_variable(del_var->VariableName,
1650                                             &del_var->VendorGuid,
1651                                             del_var->Attributes,
1652                                             del_var->DataSize,
1653                                             del_var->Data);
1654
1655         if (status != EFI_SUCCESS) {
1656                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1657                         status);
1658                 spin_unlock_irq(&efivars->lock);
1659                 return -EIO;
1660         }
1661         list_del(&search_efivar->list);
1662         /* We need to release this lock before unregistering. */
1663         spin_unlock_irq(&efivars->lock);
1664         efivar_unregister(search_efivar);
1665
1666         /* It's dead Jim.... */
1667         return count;
1668 }
1669
1670 static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
1671 {
1672         struct efivar_entry *entry, *n;
1673         struct efivars *efivars = &__efivars;
1674         unsigned long strsize1, strsize2;
1675         bool found = false;
1676
1677         strsize1 = utf16_strsize(variable_name, 1024);
1678         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1679                 strsize2 = utf16_strsize(entry->var.VariableName, 1024);
1680                 if (strsize1 == strsize2 &&
1681                         !memcmp(variable_name, &(entry->var.VariableName),
1682                                 strsize2) &&
1683                         !efi_guidcmp(entry->var.VendorGuid,
1684                                 *vendor)) {
1685                         found = true;
1686                         break;
1687                 }
1688         }
1689         return found;
1690 }
1691
1692 /*
1693  * Returns the size of variable_name, in bytes, including the
1694  * terminating NULL character, or variable_name_size if no NULL
1695  * character is found among the first variable_name_size bytes.
1696  */
1697 static unsigned long var_name_strnsize(efi_char16_t *variable_name,
1698                                        unsigned long variable_name_size)
1699 {
1700         unsigned long len;
1701         efi_char16_t c;
1702
1703         /*
1704          * The variable name is, by definition, a NULL-terminated
1705          * string, so make absolutely sure that variable_name_size is
1706          * the value we expect it to be. If not, return the real size.
1707          */
1708         for (len = 2; len <= variable_name_size; len += sizeof(c)) {
1709                 c = variable_name[(len / sizeof(c)) - 1];
1710                 if (!c)
1711                         break;
1712         }
1713
1714         return min(len, variable_name_size);
1715 }
1716
1717 static void efivar_update_sysfs_entries(struct work_struct *work)
1718 {
1719         struct efivars *efivars = &__efivars;
1720         efi_guid_t vendor;
1721         efi_char16_t *variable_name;
1722         unsigned long variable_name_size = 1024;
1723         efi_status_t status = EFI_NOT_FOUND;
1724         bool found;
1725
1726         /* Add new sysfs entries */
1727         while (1) {
1728                 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1729                 if (!variable_name) {
1730                         pr_err("efivars: Memory allocation failed.\n");
1731                         return;
1732                 }
1733
1734                 spin_lock_irq(&efivars->lock);
1735                 found = false;
1736                 while (1) {
1737                         variable_name_size = 1024;
1738                         status = efivars->ops->get_next_variable(
1739                                                         &variable_name_size,
1740                                                         variable_name,
1741                                                         &vendor);
1742                         if (status != EFI_SUCCESS) {
1743                                 break;
1744                         } else {
1745                                 if (!variable_is_present(variable_name,
1746                                     &vendor)) {
1747                                         found = true;
1748                                         break;
1749                                 }
1750                         }
1751                 }
1752                 spin_unlock_irq(&efivars->lock);
1753
1754                 if (!found) {
1755                         kfree(variable_name);
1756                         break;
1757                 } else {
1758                         variable_name_size = var_name_strnsize(variable_name,
1759                                                                variable_name_size);
1760                         efivar_create_sysfs_entry(efivars,
1761                                                   variable_name_size,
1762                                                   variable_name, &vendor);
1763                 }
1764         }
1765 }
1766
1767 /*
1768  * Let's not leave out systab information that snuck into
1769  * the efivars driver
1770  */
1771 static ssize_t systab_show(struct kobject *kobj,
1772                            struct kobj_attribute *attr, char *buf)
1773 {
1774         char *str = buf;
1775
1776         if (!kobj || !buf)
1777                 return -EINVAL;
1778
1779         if (efi.mps != EFI_INVALID_TABLE_ADDR)
1780                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1781         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1782                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1783         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1784                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1785         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1786                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1787         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1788                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1789         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1790                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1791         if (efi.uga != EFI_INVALID_TABLE_ADDR)
1792                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1793
1794         return str - buf;
1795 }
1796
1797 static struct kobj_attribute efi_attr_systab =
1798                         __ATTR(systab, 0400, systab_show, NULL);
1799
1800 static struct attribute *efi_subsys_attrs[] = {
1801         &efi_attr_systab.attr,
1802         NULL,   /* maybe more in the future? */
1803 };
1804
1805 static struct attribute_group efi_subsys_attr_group = {
1806         .attrs = efi_subsys_attrs,
1807 };
1808
1809 static struct kobject *efi_kobj;
1810
1811 /*
1812  * efivar_create_sysfs_entry()
1813  * Requires:
1814  *    variable_name_size = number of bytes required to hold
1815  *                         variable_name (not counting the NULL
1816  *                         character at the end.
1817  *    efivars->lock is not held on entry or exit.
1818  * Returns 1 on failure, 0 on success
1819  */
1820 static int
1821 efivar_create_sysfs_entry(struct efivars *efivars,
1822                           unsigned long variable_name_size,
1823                           efi_char16_t *variable_name,
1824                           efi_guid_t *vendor_guid)
1825 {
1826         int i, short_name_size;
1827         char *short_name;
1828         struct efivar_entry *new_efivar;
1829
1830         /*
1831          * Length of the variable bytes in ASCII, plus the '-' separator,
1832          * plus the GUID, plus trailing NUL
1833          */
1834         short_name_size = variable_name_size / sizeof(efi_char16_t)
1835                                 + 1 + GUID_LEN + 1;
1836
1837         short_name = kzalloc(short_name_size, GFP_KERNEL);
1838         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1839
1840         if (!short_name || !new_efivar)  {
1841                 kfree(short_name);
1842                 kfree(new_efivar);
1843                 return 1;
1844         }
1845
1846         new_efivar->efivars = efivars;
1847         memcpy(new_efivar->var.VariableName, variable_name,
1848                 variable_name_size);
1849         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1850
1851         /* Convert Unicode to normal chars (assume top bits are 0),
1852            ala UTF-8 */
1853         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1854                 short_name[i] = variable_name[i] & 0xFF;
1855         }
1856         /* This is ugly, but necessary to separate one vendor's
1857            private variables from another's.         */
1858
1859         *(short_name + strlen(short_name)) = '-';
1860         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1861
1862         new_efivar->kobj.kset = efivars->kset;
1863         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1864                                  "%s", short_name);
1865         if (i) {
1866                 kfree(short_name);
1867                 kfree(new_efivar);
1868                 return 1;
1869         }
1870
1871         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1872         kfree(short_name);
1873         short_name = NULL;
1874
1875         spin_lock_irq(&efivars->lock);
1876         list_add(&new_efivar->list, &efivars->list);
1877         spin_unlock_irq(&efivars->lock);
1878
1879         return 0;
1880 }
1881
1882 static int
1883 create_efivars_bin_attributes(struct efivars *efivars)
1884 {
1885         struct bin_attribute *attr;
1886         int error;
1887
1888         /* new_var */
1889         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1890         if (!attr)
1891                 return -ENOMEM;
1892
1893         attr->attr.name = "new_var";
1894         attr->attr.mode = 0200;
1895         attr->write = efivar_create;
1896         attr->private = efivars;
1897         efivars->new_var = attr;
1898
1899         /* del_var */
1900         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1901         if (!attr) {
1902                 error = -ENOMEM;
1903                 goto out_free;
1904         }
1905         attr->attr.name = "del_var";
1906         attr->attr.mode = 0200;
1907         attr->write = efivar_delete;
1908         attr->private = efivars;
1909         efivars->del_var = attr;
1910
1911         sysfs_bin_attr_init(efivars->new_var);
1912         sysfs_bin_attr_init(efivars->del_var);
1913
1914         /* Register */
1915         error = sysfs_create_bin_file(&efivars->kset->kobj,
1916                                       efivars->new_var);
1917         if (error) {
1918                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1919                         " due to error %d\n", error);
1920                 goto out_free;
1921         }
1922         error = sysfs_create_bin_file(&efivars->kset->kobj,
1923                                       efivars->del_var);
1924         if (error) {
1925                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1926                         " due to error %d\n", error);
1927                 sysfs_remove_bin_file(&efivars->kset->kobj,
1928                                       efivars->new_var);
1929                 goto out_free;
1930         }
1931
1932         return 0;
1933 out_free:
1934         kfree(efivars->del_var);
1935         efivars->del_var = NULL;
1936         kfree(efivars->new_var);
1937         efivars->new_var = NULL;
1938         return error;
1939 }
1940
1941 void unregister_efivars(struct efivars *efivars)
1942 {
1943         struct efivar_entry *entry, *n;
1944
1945         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1946                 spin_lock_irq(&efivars->lock);
1947                 list_del(&entry->list);
1948                 spin_unlock_irq(&efivars->lock);
1949                 efivar_unregister(entry);
1950         }
1951         if (efivars->new_var)
1952                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1953         if (efivars->del_var)
1954                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1955         kfree(efivars->new_var);
1956         kfree(efivars->del_var);
1957         kobject_put(efivars->kobject);
1958         kset_unregister(efivars->kset);
1959 }
1960 EXPORT_SYMBOL_GPL(unregister_efivars);
1961
1962 /*
1963  * Print a warning when duplicate EFI variables are encountered and
1964  * disable the sysfs workqueue since the firmware is buggy.
1965  */
1966 static void dup_variable_bug(efi_char16_t *s16, efi_guid_t *vendor_guid,
1967                              unsigned long len16)
1968 {
1969         size_t i, len8 = len16 / sizeof(efi_char16_t);
1970         char *s8;
1971
1972         /*
1973          * Disable the workqueue since the algorithm it uses for
1974          * detecting new variables won't work with this buggy
1975          * implementation of GetNextVariableName().
1976          */
1977         efivar_wq_enabled = false;
1978
1979         s8 = kzalloc(len8, GFP_KERNEL);
1980         if (!s8)
1981                 return;
1982
1983         for (i = 0; i < len8; i++)
1984                 s8[i] = s16[i];
1985
1986         printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n",
1987                s8, vendor_guid);
1988         kfree(s8);
1989 }
1990
1991 int register_efivars(struct efivars *efivars,
1992                      const struct efivar_operations *ops,
1993                      struct kobject *parent_kobj)
1994 {
1995         efi_status_t status = EFI_NOT_FOUND;
1996         efi_guid_t vendor_guid;
1997         efi_char16_t *variable_name;
1998         unsigned long variable_name_size = 1024;
1999         int error = 0;
2000
2001         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
2002         if (!variable_name) {
2003                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
2004                 return -ENOMEM;
2005         }
2006
2007         spin_lock_init(&efivars->lock);
2008         INIT_LIST_HEAD(&efivars->list);
2009         efivars->ops = ops;
2010
2011         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
2012         if (!efivars->kset) {
2013                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
2014                 error = -ENOMEM;
2015                 goto out;
2016         }
2017
2018         efivars->kobject = kobject_create_and_add("efivars", parent_kobj);
2019         if (!efivars->kobject) {
2020                 pr_err("efivars: Subsystem registration failed.\n");
2021                 error = -ENOMEM;
2022                 kset_unregister(efivars->kset);
2023                 goto out;
2024         }
2025
2026         /*
2027          * Per EFI spec, the maximum storage allocated for both
2028          * the variable name and variable data is 1024 bytes.
2029          */
2030
2031         do {
2032                 variable_name_size = 1024;
2033
2034                 status = ops->get_next_variable(&variable_name_size,
2035                                                 variable_name,
2036                                                 &vendor_guid);
2037                 switch (status) {
2038                 case EFI_SUCCESS:
2039                         variable_name_size = var_name_strnsize(variable_name,
2040                                                                variable_name_size);
2041
2042                         /*
2043                          * Some firmware implementations return the
2044                          * same variable name on multiple calls to
2045                          * get_next_variable(). Terminate the loop
2046                          * immediately as there is no guarantee that
2047                          * we'll ever see a different variable name,
2048                          * and may end up looping here forever.
2049                          */
2050                         if (variable_is_present(variable_name, &vendor_guid)) {
2051                                 dup_variable_bug(variable_name, &vendor_guid,
2052                                                  variable_name_size);
2053                                 status = EFI_NOT_FOUND;
2054                                 break;
2055                         }
2056
2057                         efivar_create_sysfs_entry(efivars,
2058                                                   variable_name_size,
2059                                                   variable_name,
2060                                                   &vendor_guid);
2061                         break;
2062                 case EFI_NOT_FOUND:
2063                         break;
2064                 default:
2065                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
2066                                 status);
2067                         status = EFI_NOT_FOUND;
2068                         break;
2069                 }
2070         } while (status != EFI_NOT_FOUND);
2071
2072         error = create_efivars_bin_attributes(efivars);
2073         if (error)
2074                 unregister_efivars(efivars);
2075
2076         if (!efivars_pstore_disable)
2077                 efivar_pstore_register(efivars);
2078
2079         register_filesystem(&efivarfs_type);
2080
2081 out:
2082         kfree(variable_name);
2083
2084         return error;
2085 }
2086 EXPORT_SYMBOL_GPL(register_efivars);
2087
2088 /*
2089  * For now we register the efi subsystem with the firmware subsystem
2090  * and the vars subsystem with the efi subsystem.  In the future, it
2091  * might make sense to split off the efi subsystem into its own
2092  * driver, but for now only efivars will register with it, so just
2093  * include it here.
2094  */
2095
2096 static int __init
2097 efivars_init(void)
2098 {
2099         int error = 0;
2100
2101         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
2102                EFIVARS_DATE);
2103
2104         if (!efi_enabled(EFI_RUNTIME_SERVICES))
2105                 return 0;
2106
2107         /* For now we'll register the efi directory at /sys/firmware/efi */
2108         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
2109         if (!efi_kobj) {
2110                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
2111                 return -ENOMEM;
2112         }
2113
2114         ops.get_variable = efi.get_variable;
2115         ops.set_variable = efi.set_variable;
2116         ops.get_next_variable = efi.get_next_variable;
2117         ops.query_variable_info = efi.query_variable_info;
2118
2119         error = register_efivars(&__efivars, &ops, efi_kobj);
2120         if (error)
2121                 goto err_put;
2122
2123         /* Don't forget the systab entry */
2124         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
2125         if (error) {
2126                 printk(KERN_ERR
2127                        "efivars: Sysfs attribute export failed with error %d.\n",
2128                        error);
2129                 goto err_unregister;
2130         }
2131
2132         return 0;
2133
2134 err_unregister:
2135         unregister_efivars(&__efivars);
2136 err_put:
2137         kobject_put(efi_kobj);
2138         return error;
2139 }
2140
2141 static void __exit
2142 efivars_exit(void)
2143 {
2144         cancel_work_sync(&efivar_work);
2145
2146         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
2147                 unregister_efivars(&__efivars);
2148                 kobject_put(efi_kobj);
2149         }
2150 }
2151
2152 module_init(efivars_init);
2153 module_exit(efivars_exit);
2154