efi: add efivars kobject to efi sysfs folder
[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
83 #include <linux/fs.h>
84 #include <linux/ramfs.h>
85 #include <linux/pagemap.h>
86
87 #include <asm/uaccess.h>
88
89 #define EFIVARS_VERSION "0.08"
90 #define EFIVARS_DATE "2004-May-17"
91
92 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
93 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
94 MODULE_LICENSE("GPL");
95 MODULE_VERSION(EFIVARS_VERSION);
96
97 #define DUMP_NAME_LEN 52
98 #define GUID_LEN 37
99
100 /*
101  * The maximum size of VariableName + Data = 1024
102  * Therefore, it's reasonable to save that much
103  * space in each part of the structure,
104  * and we use a page for reading/writing.
105  */
106
107 struct efi_variable {
108         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
109         efi_guid_t    VendorGuid;
110         unsigned long DataSize;
111         __u8          Data[1024];
112         efi_status_t  Status;
113         __u32         Attributes;
114 } __attribute__((packed));
115
116 struct efivar_entry {
117         struct efivars *efivars;
118         struct efi_variable var;
119         struct list_head list;
120         struct kobject kobj;
121 };
122
123 struct efivar_attribute {
124         struct attribute attr;
125         ssize_t (*show) (struct efivar_entry *entry, char *buf);
126         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
127 };
128
129 static struct efivars __efivars;
130 static struct efivar_operations ops;
131
132 #define PSTORE_EFI_ATTRIBUTES \
133         (EFI_VARIABLE_NON_VOLATILE | \
134          EFI_VARIABLE_BOOTSERVICE_ACCESS | \
135          EFI_VARIABLE_RUNTIME_ACCESS)
136
137 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
138 struct efivar_attribute efivar_attr_##_name = { \
139         .attr = {.name = __stringify(_name), .mode = _mode}, \
140         .show = _show, \
141         .store = _store, \
142 };
143
144 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
145 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
146
147 /*
148  * Prototype for sysfs creation function
149  */
150 static int
151 efivar_create_sysfs_entry(struct efivars *efivars,
152                           unsigned long variable_name_size,
153                           efi_char16_t *variable_name,
154                           efi_guid_t *vendor_guid);
155
156 /* Return the number of unicode characters in data */
157 static unsigned long
158 utf16_strnlen(efi_char16_t *s, size_t maxlength)
159 {
160         unsigned long length = 0;
161
162         while (*s++ != 0 && length < maxlength)
163                 length++;
164         return length;
165 }
166
167 static inline unsigned long
168 utf16_strlen(efi_char16_t *s)
169 {
170         return utf16_strnlen(s, ~0UL);
171 }
172
173 /*
174  * Return the number of bytes is the length of this string
175  * Note: this is NOT the same as the number of unicode characters
176  */
177 static inline unsigned long
178 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
179 {
180         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
181 }
182
183 static inline int
184 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
185 {
186         while (1) {
187                 if (len == 0)
188                         return 0;
189                 if (*a < *b)
190                         return -1;
191                 if (*a > *b)
192                         return 1;
193                 if (*a == 0) /* implies *b == 0 */
194                         return 0;
195                 a++;
196                 b++;
197                 len--;
198         }
199 }
200
201 static bool
202 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
203                      unsigned long len)
204 {
205         struct efi_generic_dev_path *node;
206         int offset = 0;
207
208         node = (struct efi_generic_dev_path *)buffer;
209
210         if (len < sizeof(*node))
211                 return false;
212
213         while (offset <= len - sizeof(*node) &&
214                node->length >= sizeof(*node) &&
215                 node->length <= len - offset) {
216                 offset += node->length;
217
218                 if ((node->type == EFI_DEV_END_PATH ||
219                      node->type == EFI_DEV_END_PATH2) &&
220                     node->sub_type == EFI_DEV_END_ENTIRE)
221                         return true;
222
223                 node = (struct efi_generic_dev_path *)(buffer + offset);
224         }
225
226         /*
227          * If we're here then either node->length pointed past the end
228          * of the buffer or we reached the end of the buffer without
229          * finding a device path end node.
230          */
231         return false;
232 }
233
234 static bool
235 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
236                     unsigned long len)
237 {
238         /* An array of 16-bit integers */
239         if ((len % 2) != 0)
240                 return false;
241
242         return true;
243 }
244
245 static bool
246 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
247                      unsigned long len)
248 {
249         u16 filepathlength;
250         int i, desclength = 0, namelen;
251
252         namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
253
254         /* Either "Boot" or "Driver" followed by four digits of hex */
255         for (i = match; i < match+4; i++) {
256                 if (var->VariableName[i] > 127 ||
257                     hex_to_bin(var->VariableName[i] & 0xff) < 0)
258                         return true;
259         }
260
261         /* Reject it if there's 4 digits of hex and then further content */
262         if (namelen > match + 4)
263                 return false;
264
265         /* A valid entry must be at least 8 bytes */
266         if (len < 8)
267                 return false;
268
269         filepathlength = buffer[4] | buffer[5] << 8;
270
271         /*
272          * There's no stored length for the description, so it has to be
273          * found by hand
274          */
275         desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
276
277         /* Each boot entry must have a descriptor */
278         if (!desclength)
279                 return false;
280
281         /*
282          * If the sum of the length of the description, the claimed filepath
283          * length and the original header are greater than the length of the
284          * variable, it's malformed
285          */
286         if ((desclength + filepathlength + 6) > len)
287                 return false;
288
289         /*
290          * And, finally, check the filepath
291          */
292         return validate_device_path(var, match, buffer + desclength + 6,
293                                     filepathlength);
294 }
295
296 static bool
297 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
298                 unsigned long len)
299 {
300         /* A single 16-bit integer */
301         if (len != 2)
302                 return false;
303
304         return true;
305 }
306
307 static bool
308 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
309                       unsigned long len)
310 {
311         int i;
312
313         for (i = 0; i < len; i++) {
314                 if (buffer[i] > 127)
315                         return false;
316
317                 if (buffer[i] == 0)
318                         return true;
319         }
320
321         return false;
322 }
323
324 struct variable_validate {
325         char *name;
326         bool (*validate)(struct efi_variable *var, int match, u8 *data,
327                          unsigned long len);
328 };
329
330 static const struct variable_validate variable_validate[] = {
331         { "BootNext", validate_uint16 },
332         { "BootOrder", validate_boot_order },
333         { "DriverOrder", validate_boot_order },
334         { "Boot*", validate_load_option },
335         { "Driver*", validate_load_option },
336         { "ConIn", validate_device_path },
337         { "ConInDev", validate_device_path },
338         { "ConOut", validate_device_path },
339         { "ConOutDev", validate_device_path },
340         { "ErrOut", validate_device_path },
341         { "ErrOutDev", validate_device_path },
342         { "Timeout", validate_uint16 },
343         { "Lang", validate_ascii_string },
344         { "PlatformLang", validate_ascii_string },
345         { "", NULL },
346 };
347
348 static bool
349 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
350 {
351         int i;
352         u16 *unicode_name = var->VariableName;
353
354         for (i = 0; variable_validate[i].validate != NULL; i++) {
355                 const char *name = variable_validate[i].name;
356                 int match;
357
358                 for (match = 0; ; match++) {
359                         char c = name[match];
360                         u16 u = unicode_name[match];
361
362                         /* All special variables are plain ascii */
363                         if (u > 127)
364                                 return true;
365
366                         /* Wildcard in the matching name means we've matched */
367                         if (c == '*')
368                                 return variable_validate[i].validate(var,
369                                                              match, data, len);
370
371                         /* Case sensitive match */
372                         if (c != u)
373                                 break;
374
375                         /* Reached the end of the string while matching */
376                         if (!c)
377                                 return variable_validate[i].validate(var,
378                                                              match, data, len);
379                 }
380         }
381
382         return true;
383 }
384
385 static efi_status_t
386 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
387 {
388         efi_status_t status;
389
390         var->DataSize = 1024;
391         status = efivars->ops->get_variable(var->VariableName,
392                                             &var->VendorGuid,
393                                             &var->Attributes,
394                                             &var->DataSize,
395                                             var->Data);
396         return status;
397 }
398
399 static efi_status_t
400 get_var_data(struct efivars *efivars, struct efi_variable *var)
401 {
402         efi_status_t status;
403
404         spin_lock(&efivars->lock);
405         status = get_var_data_locked(efivars, var);
406         spin_unlock(&efivars->lock);
407
408         if (status != EFI_SUCCESS) {
409                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
410                         status);
411         }
412         return status;
413 }
414
415 static ssize_t
416 efivar_guid_read(struct efivar_entry *entry, char *buf)
417 {
418         struct efi_variable *var = &entry->var;
419         char *str = buf;
420
421         if (!entry || !buf)
422                 return 0;
423
424         efi_guid_unparse(&var->VendorGuid, str);
425         str += strlen(str);
426         str += sprintf(str, "\n");
427
428         return str - buf;
429 }
430
431 static ssize_t
432 efivar_attr_read(struct efivar_entry *entry, char *buf)
433 {
434         struct efi_variable *var = &entry->var;
435         char *str = buf;
436         efi_status_t status;
437
438         if (!entry || !buf)
439                 return -EINVAL;
440
441         status = get_var_data(entry->efivars, var);
442         if (status != EFI_SUCCESS)
443                 return -EIO;
444
445         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
446                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
447         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
448                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
449         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
450                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
451         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
452                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
453         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
454                 str += sprintf(str,
455                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
456         if (var->Attributes &
457                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
458                 str += sprintf(str,
459                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
460         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
461                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
462         return str - buf;
463 }
464
465 static ssize_t
466 efivar_size_read(struct efivar_entry *entry, char *buf)
467 {
468         struct efi_variable *var = &entry->var;
469         char *str = buf;
470         efi_status_t status;
471
472         if (!entry || !buf)
473                 return -EINVAL;
474
475         status = get_var_data(entry->efivars, var);
476         if (status != EFI_SUCCESS)
477                 return -EIO;
478
479         str += sprintf(str, "0x%lx\n", var->DataSize);
480         return str - buf;
481 }
482
483 static ssize_t
484 efivar_data_read(struct efivar_entry *entry, char *buf)
485 {
486         struct efi_variable *var = &entry->var;
487         efi_status_t status;
488
489         if (!entry || !buf)
490                 return -EINVAL;
491
492         status = get_var_data(entry->efivars, var);
493         if (status != EFI_SUCCESS)
494                 return -EIO;
495
496         memcpy(buf, var->Data, var->DataSize);
497         return var->DataSize;
498 }
499 /*
500  * We allow each variable to be edited via rewriting the
501  * entire efi variable structure.
502  */
503 static ssize_t
504 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
505 {
506         struct efi_variable *new_var, *var = &entry->var;
507         struct efivars *efivars = entry->efivars;
508         efi_status_t status = EFI_NOT_FOUND;
509
510         if (count != sizeof(struct efi_variable))
511                 return -EINVAL;
512
513         new_var = (struct efi_variable *)buf;
514         /*
515          * If only updating the variable data, then the name
516          * and guid should remain the same
517          */
518         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
519                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
520                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
521                 return -EINVAL;
522         }
523
524         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
525                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
526                 return -EINVAL;
527         }
528
529         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
530             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
531                 printk(KERN_ERR "efivars: Malformed variable content\n");
532                 return -EINVAL;
533         }
534
535         spin_lock(&efivars->lock);
536         status = efivars->ops->set_variable(new_var->VariableName,
537                                             &new_var->VendorGuid,
538                                             new_var->Attributes,
539                                             new_var->DataSize,
540                                             new_var->Data);
541
542         spin_unlock(&efivars->lock);
543
544         if (status != EFI_SUCCESS) {
545                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
546                         status);
547                 return -EIO;
548         }
549
550         memcpy(&entry->var, new_var, count);
551         return count;
552 }
553
554 static ssize_t
555 efivar_show_raw(struct efivar_entry *entry, char *buf)
556 {
557         struct efi_variable *var = &entry->var;
558         efi_status_t status;
559
560         if (!entry || !buf)
561                 return 0;
562
563         status = get_var_data(entry->efivars, var);
564         if (status != EFI_SUCCESS)
565                 return -EIO;
566
567         memcpy(buf, var, sizeof(*var));
568         return sizeof(*var);
569 }
570
571 /*
572  * Generic read/write functions that call the specific functions of
573  * the attributes...
574  */
575 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
576                                 char *buf)
577 {
578         struct efivar_entry *var = to_efivar_entry(kobj);
579         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
580         ssize_t ret = -EIO;
581
582         if (!capable(CAP_SYS_ADMIN))
583                 return -EACCES;
584
585         if (efivar_attr->show) {
586                 ret = efivar_attr->show(var, buf);
587         }
588         return ret;
589 }
590
591 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
592                                 const char *buf, size_t count)
593 {
594         struct efivar_entry *var = to_efivar_entry(kobj);
595         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
596         ssize_t ret = -EIO;
597
598         if (!capable(CAP_SYS_ADMIN))
599                 return -EACCES;
600
601         if (efivar_attr->store)
602                 ret = efivar_attr->store(var, buf, count);
603
604         return ret;
605 }
606
607 static const struct sysfs_ops efivar_attr_ops = {
608         .show = efivar_attr_show,
609         .store = efivar_attr_store,
610 };
611
612 static void efivar_release(struct kobject *kobj)
613 {
614         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
615         kfree(var);
616 }
617
618 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
619 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
620 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
621 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
622 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
623
624 static struct attribute *def_attrs[] = {
625         &efivar_attr_guid.attr,
626         &efivar_attr_size.attr,
627         &efivar_attr_attributes.attr,
628         &efivar_attr_data.attr,
629         &efivar_attr_raw_var.attr,
630         NULL,
631 };
632
633 static struct kobj_type efivar_ktype = {
634         .release = efivar_release,
635         .sysfs_ops = &efivar_attr_ops,
636         .default_attrs = def_attrs,
637 };
638
639 static inline void
640 efivar_unregister(struct efivar_entry *var)
641 {
642         kobject_put(&var->kobj);
643 }
644
645 static int efivarfs_file_open(struct inode *inode, struct file *file)
646 {
647         file->private_data = inode->i_private;
648         return 0;
649 }
650
651 static ssize_t efivarfs_file_write(struct file *file,
652                 const char __user *userbuf, size_t count, loff_t *ppos)
653 {
654         struct efivar_entry *var = file->private_data;
655         struct efivars *efivars;
656         efi_status_t status;
657         void *data;
658         u32 attributes;
659         struct inode *inode = file->f_mapping->host;
660         int datasize = count - sizeof(attributes);
661         unsigned long newdatasize;
662
663         if (count < sizeof(attributes))
664                 return -EINVAL;
665
666         data = kmalloc(datasize, GFP_KERNEL);
667
668         if (!data)
669                 return -ENOMEM;
670
671         efivars = var->efivars;
672
673         if (copy_from_user(&attributes, userbuf, sizeof(attributes))) {
674                 count = -EFAULT;
675                 goto out;
676         }
677
678         if (attributes & ~(EFI_VARIABLE_MASK)) {
679                 count = -EINVAL;
680                 goto out;
681         }
682
683         if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
684                 count = -EFAULT;
685                 goto out;
686         }
687
688         if (validate_var(&var->var, data, datasize) == false) {
689                 count = -EINVAL;
690                 goto out;
691         }
692
693         status = efivars->ops->set_variable(var->var.VariableName,
694                                             &var->var.VendorGuid,
695                                             attributes, datasize,
696                                             data);
697
698         switch (status) {
699         case EFI_SUCCESS:
700                 break;
701         case EFI_INVALID_PARAMETER:
702                 count = -EINVAL;
703                 goto out;
704         case EFI_OUT_OF_RESOURCES:
705                 count = -ENOSPC;
706                 goto out;
707         case EFI_DEVICE_ERROR:
708                 count = -EIO;
709                 goto out;
710         case EFI_WRITE_PROTECTED:
711                 count = -EROFS;
712                 goto out;
713         case EFI_SECURITY_VIOLATION:
714                 count = -EACCES;
715                 goto out;
716         case EFI_NOT_FOUND:
717                 count = -ENOENT;
718                 goto out;
719         default:
720                 count = -EINVAL;
721                 goto out;
722         }
723
724         /*
725          * Writing to the variable may have caused a change in size (which
726          * could either be an append or an overwrite), or the variable to be
727          * deleted. Perform a GetVariable() so we can tell what actually
728          * happened.
729          */
730         newdatasize = 0;
731         status = efivars->ops->get_variable(var->var.VariableName,
732                                             &var->var.VendorGuid,
733                                             NULL, &newdatasize,
734                                             NULL);
735
736         if (status == EFI_BUFFER_TOO_SMALL) {
737                 mutex_lock(&inode->i_mutex);
738                 i_size_write(inode, newdatasize + sizeof(attributes));
739                 mutex_unlock(&inode->i_mutex);
740
741         } else if (status == EFI_NOT_FOUND) {
742                 spin_lock(&efivars->lock);
743                 list_del(&var->list);
744                 spin_unlock(&efivars->lock);
745                 efivar_unregister(var);
746                 drop_nlink(inode);
747                 dput(file->f_dentry);
748
749         } else {
750                 pr_warn("efivarfs: inconsistent EFI variable implementation? "
751                                 "status = %lx\n", status);
752         }
753
754 out:
755         kfree(data);
756
757         return count;
758 }
759
760 static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
761                 size_t count, loff_t *ppos)
762 {
763         struct efivar_entry *var = file->private_data;
764         struct efivars *efivars = var->efivars;
765         efi_status_t status;
766         unsigned long datasize = 0;
767         u32 attributes;
768         void *data;
769         ssize_t size;
770
771         status = efivars->ops->get_variable(var->var.VariableName,
772                                             &var->var.VendorGuid,
773                                             &attributes, &datasize, NULL);
774
775         if (status != EFI_BUFFER_TOO_SMALL)
776                 return 0;
777
778         data = kmalloc(datasize + 4, GFP_KERNEL);
779
780         if (!data)
781                 return 0;
782
783         status = efivars->ops->get_variable(var->var.VariableName,
784                                             &var->var.VendorGuid,
785                                             &attributes, &datasize,
786                                             (data + 4));
787
788         if (status != EFI_SUCCESS)
789                 return 0;
790
791         memcpy(data, &attributes, 4);
792         size = simple_read_from_buffer(userbuf, count, ppos,
793                                         data, datasize + 4);
794         kfree(data);
795
796         return size;
797 }
798
799 static void efivarfs_evict_inode(struct inode *inode)
800 {
801         clear_inode(inode);
802 }
803
804 static const struct super_operations efivarfs_ops = {
805         .statfs = simple_statfs,
806         .drop_inode = generic_delete_inode,
807         .evict_inode = efivarfs_evict_inode,
808         .show_options = generic_show_options,
809 };
810
811 static struct super_block *efivarfs_sb;
812
813 static const struct inode_operations efivarfs_dir_inode_operations;
814
815 static const struct file_operations efivarfs_file_operations = {
816         .open   = efivarfs_file_open,
817         .read   = efivarfs_file_read,
818         .write  = efivarfs_file_write,
819         .llseek = no_llseek,
820 };
821
822 static struct inode *efivarfs_get_inode(struct super_block *sb,
823                                 const struct inode *dir, int mode, dev_t dev)
824 {
825         struct inode *inode = new_inode(sb);
826
827         if (inode) {
828                 inode->i_ino = get_next_ino();
829                 inode->i_uid = inode->i_gid = 0;
830                 inode->i_mode = mode;
831                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
832                 switch (mode & S_IFMT) {
833                 case S_IFREG:
834                         inode->i_fop = &efivarfs_file_operations;
835                         break;
836                 case S_IFDIR:
837                         inode->i_op = &efivarfs_dir_inode_operations;
838                         inode->i_fop = &simple_dir_operations;
839                         inc_nlink(inode);
840                         break;
841                 }
842         }
843         return inode;
844 }
845
846 static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
847 {
848         guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
849         guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
850         guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
851         guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
852         guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
853         guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
854         guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
855         guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
856         guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
857         guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
858         guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
859         guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
860         guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
861         guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
862         guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
863         guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
864 }
865
866 static int efivarfs_create(struct inode *dir, struct dentry *dentry,
867                           umode_t mode, bool excl)
868 {
869         struct inode *inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
870         struct efivars *efivars = &__efivars;
871         struct efivar_entry *var;
872         int namelen, i = 0, err = 0;
873
874         if (dentry->d_name.len < 38)
875                 return -EINVAL;
876
877         if (!inode)
878                 return -ENOSPC;
879
880         var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
881
882         if (!var)
883                 return -ENOMEM;
884
885         namelen = dentry->d_name.len - GUID_LEN;
886
887         efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
888                         &var->var.VendorGuid);
889
890         for (i = 0; i < namelen; i++)
891                 var->var.VariableName[i] = dentry->d_name.name[i];
892
893         var->var.VariableName[i] = '\0';
894
895         inode->i_private = var;
896         var->efivars = efivars;
897         var->kobj.kset = efivars->kset;
898
899         err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
900                              dentry->d_name.name);
901         if (err)
902                 goto out;
903
904         kobject_uevent(&var->kobj, KOBJ_ADD);
905         spin_lock(&efivars->lock);
906         list_add(&var->list, &efivars->list);
907         spin_unlock(&efivars->lock);
908         d_instantiate(dentry, inode);
909         dget(dentry);
910 out:
911         if (err)
912                 kfree(var);
913         return err;
914 }
915
916 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
917 {
918         struct efivar_entry *var = dentry->d_inode->i_private;
919         struct efivars *efivars = var->efivars;
920         efi_status_t status;
921
922         spin_lock(&efivars->lock);
923
924         status = efivars->ops->set_variable(var->var.VariableName,
925                                             &var->var.VendorGuid,
926                                             0, 0, NULL);
927
928         if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
929                 list_del(&var->list);
930                 spin_unlock(&efivars->lock);
931                 efivar_unregister(var);
932                 drop_nlink(dir);
933                 dput(dentry);
934                 return 0;
935         }
936
937         spin_unlock(&efivars->lock);
938         return -EINVAL;
939 };
940
941 int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
942 {
943         struct inode *inode = NULL;
944         struct dentry *root;
945         struct efivar_entry *entry, *n;
946         struct efivars *efivars = &__efivars;
947         int err;
948
949         efivarfs_sb = sb;
950
951         sb->s_maxbytes          = MAX_LFS_FILESIZE;
952         sb->s_blocksize         = PAGE_CACHE_SIZE;
953         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
954         sb->s_magic             = PSTOREFS_MAGIC;
955         sb->s_op                = &efivarfs_ops;
956         sb->s_time_gran         = 1;
957
958         inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
959         if (!inode) {
960                 err = -ENOMEM;
961                 goto fail;
962         }
963         inode->i_op = &efivarfs_dir_inode_operations;
964
965         root = d_make_root(inode);
966         sb->s_root = root;
967         if (!root) {
968                 err = -ENOMEM;
969                 goto fail;
970         }
971
972         list_for_each_entry_safe(entry, n, &efivars->list, list) {
973                 struct inode *inode;
974                 struct dentry *dentry, *root = efivarfs_sb->s_root;
975                 char *name;
976                 unsigned long size = 0;
977                 int len, i;
978
979                 len = utf16_strlen(entry->var.VariableName);
980
981                 /* GUID plus trailing NULL */
982                 name = kmalloc(len + 38, GFP_ATOMIC);
983
984                 for (i = 0; i < len; i++)
985                         name[i] = entry->var.VariableName[i] & 0xFF;
986
987                 name[len] = '-';
988
989                 efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
990
991                 name[len+GUID_LEN] = '\0';
992
993                 inode = efivarfs_get_inode(efivarfs_sb, root->d_inode,
994                                           S_IFREG | 0644, 0);
995                 dentry = d_alloc_name(root, name);
996
997                 efivars->ops->get_variable(entry->var.VariableName,
998                                            &entry->var.VendorGuid,
999                                            &entry->var.Attributes,
1000                                            &size,
1001                                            NULL);
1002
1003                 mutex_lock(&inode->i_mutex);
1004                 inode->i_private = entry;
1005                 i_size_write(inode, size+4);
1006                 mutex_unlock(&inode->i_mutex);
1007                 d_add(dentry, inode);
1008         }
1009
1010         return 0;
1011 fail:
1012         iput(inode);
1013         return err;
1014 }
1015
1016 static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
1017                                     int flags, const char *dev_name, void *data)
1018 {
1019         return mount_single(fs_type, flags, data, efivarfs_fill_super);
1020 }
1021
1022 static void efivarfs_kill_sb(struct super_block *sb)
1023 {
1024         kill_litter_super(sb);
1025         efivarfs_sb = NULL;
1026 }
1027
1028 static struct file_system_type efivarfs_type = {
1029         .name    = "efivarfs",
1030         .mount   = efivarfs_mount,
1031         .kill_sb = efivarfs_kill_sb,
1032 };
1033
1034 static const struct inode_operations efivarfs_dir_inode_operations = {
1035         .lookup = simple_lookup,
1036         .unlink = efivarfs_unlink,
1037         .create = efivarfs_create,
1038 };
1039
1040 static struct pstore_info efi_pstore_info;
1041
1042 #ifdef CONFIG_PSTORE
1043
1044 static int efi_pstore_open(struct pstore_info *psi)
1045 {
1046         struct efivars *efivars = psi->data;
1047
1048         spin_lock(&efivars->lock);
1049         efivars->walk_entry = list_first_entry(&efivars->list,
1050                                                struct efivar_entry, list);
1051         return 0;
1052 }
1053
1054 static int efi_pstore_close(struct pstore_info *psi)
1055 {
1056         struct efivars *efivars = psi->data;
1057
1058         spin_unlock(&efivars->lock);
1059         return 0;
1060 }
1061
1062 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1063                                struct timespec *timespec,
1064                                char **buf, struct pstore_info *psi)
1065 {
1066         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1067         struct efivars *efivars = psi->data;
1068         char name[DUMP_NAME_LEN];
1069         int i;
1070         unsigned int part, size;
1071         unsigned long time;
1072
1073         while (&efivars->walk_entry->list != &efivars->list) {
1074                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
1075                                  vendor)) {
1076                         for (i = 0; i < DUMP_NAME_LEN; i++) {
1077                                 name[i] = efivars->walk_entry->var.VariableName[i];
1078                         }
1079                         if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
1080                                 *id = part;
1081                                 timespec->tv_sec = time;
1082                                 timespec->tv_nsec = 0;
1083                                 get_var_data_locked(efivars, &efivars->walk_entry->var);
1084                                 size = efivars->walk_entry->var.DataSize;
1085                                 *buf = kmalloc(size, GFP_KERNEL);
1086                                 if (*buf == NULL)
1087                                         return -ENOMEM;
1088                                 memcpy(*buf, efivars->walk_entry->var.Data,
1089                                        size);
1090                                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1091                                                    struct efivar_entry, list);
1092                                 return size;
1093                         }
1094                 }
1095                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1096                                                  struct efivar_entry, list);
1097         }
1098         return 0;
1099 }
1100
1101 static int efi_pstore_write(enum pstore_type_id type,
1102                 enum kmsg_dump_reason reason, u64 *id,
1103                 unsigned int part, size_t size, struct pstore_info *psi)
1104 {
1105         char name[DUMP_NAME_LEN];
1106         char stub_name[DUMP_NAME_LEN];
1107         efi_char16_t efi_name[DUMP_NAME_LEN];
1108         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1109         struct efivars *efivars = psi->data;
1110         struct efivar_entry *entry, *found = NULL;
1111         int i, ret = 0;
1112
1113         sprintf(stub_name, "dump-type%u-%u-", type, part);
1114         sprintf(name, "%s%lu", stub_name, get_seconds());
1115
1116         spin_lock(&efivars->lock);
1117
1118         for (i = 0; i < DUMP_NAME_LEN; i++)
1119                 efi_name[i] = stub_name[i];
1120
1121         /*
1122          * Clean up any entries with the same name
1123          */
1124
1125         list_for_each_entry(entry, &efivars->list, list) {
1126                 get_var_data_locked(efivars, &entry->var);
1127
1128                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
1129                         continue;
1130                 if (utf16_strncmp(entry->var.VariableName, efi_name,
1131                                   utf16_strlen(efi_name)))
1132                         continue;
1133                 /* Needs to be a prefix */
1134                 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
1135                         continue;
1136
1137                 /* found */
1138                 found = entry;
1139                 efivars->ops->set_variable(entry->var.VariableName,
1140                                            &entry->var.VendorGuid,
1141                                            PSTORE_EFI_ATTRIBUTES,
1142                                            0, NULL);
1143         }
1144
1145         if (found)
1146                 list_del(&found->list);
1147
1148         for (i = 0; i < DUMP_NAME_LEN; i++)
1149                 efi_name[i] = name[i];
1150
1151         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
1152                                    size, psi->buf);
1153
1154         spin_unlock(&efivars->lock);
1155
1156         if (found)
1157                 efivar_unregister(found);
1158
1159         if (size)
1160                 ret = efivar_create_sysfs_entry(efivars,
1161                                           utf16_strsize(efi_name,
1162                                                         DUMP_NAME_LEN * 2),
1163                                           efi_name, &vendor);
1164
1165         *id = part;
1166         return ret;
1167 };
1168
1169 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
1170                             struct pstore_info *psi)
1171 {
1172         efi_pstore_write(type, 0, &id, (unsigned int)id, 0, psi);
1173
1174         return 0;
1175 }
1176 #else
1177 static int efi_pstore_open(struct pstore_info *psi)
1178 {
1179         return 0;
1180 }
1181
1182 static int efi_pstore_close(struct pstore_info *psi)
1183 {
1184         return 0;
1185 }
1186
1187 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1188                                struct timespec *timespec,
1189                                char **buf, struct pstore_info *psi)
1190 {
1191         return -1;
1192 }
1193
1194 static int efi_pstore_write(enum pstore_type_id type,
1195                 enum kmsg_dump_reason reason, u64 *id,
1196                 unsigned int part, size_t size, struct pstore_info *psi)
1197 {
1198         return 0;
1199 }
1200
1201 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
1202                             struct pstore_info *psi)
1203 {
1204         return 0;
1205 }
1206 #endif
1207
1208 static struct pstore_info efi_pstore_info = {
1209         .owner          = THIS_MODULE,
1210         .name           = "efi",
1211         .open           = efi_pstore_open,
1212         .close          = efi_pstore_close,
1213         .read           = efi_pstore_read,
1214         .write          = efi_pstore_write,
1215         .erase          = efi_pstore_erase,
1216 };
1217
1218 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
1219                              struct bin_attribute *bin_attr,
1220                              char *buf, loff_t pos, size_t count)
1221 {
1222         struct efi_variable *new_var = (struct efi_variable *)buf;
1223         struct efivars *efivars = bin_attr->private;
1224         struct efivar_entry *search_efivar, *n;
1225         unsigned long strsize1, strsize2;
1226         efi_status_t status = EFI_NOT_FOUND;
1227         int found = 0;
1228
1229         if (!capable(CAP_SYS_ADMIN))
1230                 return -EACCES;
1231
1232         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
1233             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
1234                 printk(KERN_ERR "efivars: Malformed variable content\n");
1235                 return -EINVAL;
1236         }
1237
1238         spin_lock(&efivars->lock);
1239
1240         /*
1241          * Does this variable already exist?
1242          */
1243         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1244                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1245                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
1246                 if (strsize1 == strsize2 &&
1247                         !memcmp(&(search_efivar->var.VariableName),
1248                                 new_var->VariableName, strsize1) &&
1249                         !efi_guidcmp(search_efivar->var.VendorGuid,
1250                                 new_var->VendorGuid)) {
1251                         found = 1;
1252                         break;
1253                 }
1254         }
1255         if (found) {
1256                 spin_unlock(&efivars->lock);
1257                 return -EINVAL;
1258         }
1259
1260         /* now *really* create the variable via EFI */
1261         status = efivars->ops->set_variable(new_var->VariableName,
1262                                             &new_var->VendorGuid,
1263                                             new_var->Attributes,
1264                                             new_var->DataSize,
1265                                             new_var->Data);
1266
1267         if (status != EFI_SUCCESS) {
1268                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1269                         status);
1270                 spin_unlock(&efivars->lock);
1271                 return -EIO;
1272         }
1273         spin_unlock(&efivars->lock);
1274
1275         /* Create the entry in sysfs.  Locking is not required here */
1276         status = efivar_create_sysfs_entry(efivars,
1277                                            utf16_strsize(new_var->VariableName,
1278                                                          1024),
1279                                            new_var->VariableName,
1280                                            &new_var->VendorGuid);
1281         if (status) {
1282                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
1283         }
1284         return count;
1285 }
1286
1287 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
1288                              struct bin_attribute *bin_attr,
1289                              char *buf, loff_t pos, size_t count)
1290 {
1291         struct efi_variable *del_var = (struct efi_variable *)buf;
1292         struct efivars *efivars = bin_attr->private;
1293         struct efivar_entry *search_efivar, *n;
1294         unsigned long strsize1, strsize2;
1295         efi_status_t status = EFI_NOT_FOUND;
1296         int found = 0;
1297
1298         if (!capable(CAP_SYS_ADMIN))
1299                 return -EACCES;
1300
1301         spin_lock(&efivars->lock);
1302
1303         /*
1304          * Does this variable already exist?
1305          */
1306         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1307                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1308                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
1309                 if (strsize1 == strsize2 &&
1310                         !memcmp(&(search_efivar->var.VariableName),
1311                                 del_var->VariableName, strsize1) &&
1312                         !efi_guidcmp(search_efivar->var.VendorGuid,
1313                                 del_var->VendorGuid)) {
1314                         found = 1;
1315                         break;
1316                 }
1317         }
1318         if (!found) {
1319                 spin_unlock(&efivars->lock);
1320                 return -EINVAL;
1321         }
1322         /* force the Attributes/DataSize to 0 to ensure deletion */
1323         del_var->Attributes = 0;
1324         del_var->DataSize = 0;
1325
1326         status = efivars->ops->set_variable(del_var->VariableName,
1327                                             &del_var->VendorGuid,
1328                                             del_var->Attributes,
1329                                             del_var->DataSize,
1330                                             del_var->Data);
1331
1332         if (status != EFI_SUCCESS) {
1333                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1334                         status);
1335                 spin_unlock(&efivars->lock);
1336                 return -EIO;
1337         }
1338         list_del(&search_efivar->list);
1339         /* We need to release this lock before unregistering. */
1340         spin_unlock(&efivars->lock);
1341         efivar_unregister(search_efivar);
1342
1343         /* It's dead Jim.... */
1344         return count;
1345 }
1346
1347 /*
1348  * Let's not leave out systab information that snuck into
1349  * the efivars driver
1350  */
1351 static ssize_t systab_show(struct kobject *kobj,
1352                            struct kobj_attribute *attr, char *buf)
1353 {
1354         char *str = buf;
1355
1356         if (!kobj || !buf)
1357                 return -EINVAL;
1358
1359         if (efi.mps != EFI_INVALID_TABLE_ADDR)
1360                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1361         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1362                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1363         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1364                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1365         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1366                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1367         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1368                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1369         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1370                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1371         if (efi.uga != EFI_INVALID_TABLE_ADDR)
1372                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1373
1374         return str - buf;
1375 }
1376
1377 static struct kobj_attribute efi_attr_systab =
1378                         __ATTR(systab, 0400, systab_show, NULL);
1379
1380 static struct attribute *efi_subsys_attrs[] = {
1381         &efi_attr_systab.attr,
1382         NULL,   /* maybe more in the future? */
1383 };
1384
1385 static struct attribute_group efi_subsys_attr_group = {
1386         .attrs = efi_subsys_attrs,
1387 };
1388
1389 static struct kobject *efi_kobj;
1390
1391 /*
1392  * efivar_create_sysfs_entry()
1393  * Requires:
1394  *    variable_name_size = number of bytes required to hold
1395  *                         variable_name (not counting the NULL
1396  *                         character at the end.
1397  *    efivars->lock is not held on entry or exit.
1398  * Returns 1 on failure, 0 on success
1399  */
1400 static int
1401 efivar_create_sysfs_entry(struct efivars *efivars,
1402                           unsigned long variable_name_size,
1403                           efi_char16_t *variable_name,
1404                           efi_guid_t *vendor_guid)
1405 {
1406         int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
1407         char *short_name;
1408         struct efivar_entry *new_efivar;
1409
1410         short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
1411         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1412
1413         if (!short_name || !new_efivar)  {
1414                 kfree(short_name);
1415                 kfree(new_efivar);
1416                 return 1;
1417         }
1418
1419         new_efivar->efivars = efivars;
1420         memcpy(new_efivar->var.VariableName, variable_name,
1421                 variable_name_size);
1422         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1423
1424         /* Convert Unicode to normal chars (assume top bits are 0),
1425            ala UTF-8 */
1426         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1427                 short_name[i] = variable_name[i] & 0xFF;
1428         }
1429         /* This is ugly, but necessary to separate one vendor's
1430            private variables from another's.         */
1431
1432         *(short_name + strlen(short_name)) = '-';
1433         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1434
1435         new_efivar->kobj.kset = efivars->kset;
1436         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1437                                  "%s", short_name);
1438         if (i) {
1439                 kfree(short_name);
1440                 kfree(new_efivar);
1441                 return 1;
1442         }
1443
1444         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1445         kfree(short_name);
1446         short_name = NULL;
1447
1448         spin_lock(&efivars->lock);
1449         list_add(&new_efivar->list, &efivars->list);
1450         spin_unlock(&efivars->lock);
1451
1452         return 0;
1453 }
1454
1455 static int
1456 create_efivars_bin_attributes(struct efivars *efivars)
1457 {
1458         struct bin_attribute *attr;
1459         int error;
1460
1461         /* new_var */
1462         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1463         if (!attr)
1464                 return -ENOMEM;
1465
1466         attr->attr.name = "new_var";
1467         attr->attr.mode = 0200;
1468         attr->write = efivar_create;
1469         attr->private = efivars;
1470         efivars->new_var = attr;
1471
1472         /* del_var */
1473         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1474         if (!attr) {
1475                 error = -ENOMEM;
1476                 goto out_free;
1477         }
1478         attr->attr.name = "del_var";
1479         attr->attr.mode = 0200;
1480         attr->write = efivar_delete;
1481         attr->private = efivars;
1482         efivars->del_var = attr;
1483
1484         sysfs_bin_attr_init(efivars->new_var);
1485         sysfs_bin_attr_init(efivars->del_var);
1486
1487         /* Register */
1488         error = sysfs_create_bin_file(&efivars->kset->kobj,
1489                                       efivars->new_var);
1490         if (error) {
1491                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1492                         " due to error %d\n", error);
1493                 goto out_free;
1494         }
1495         error = sysfs_create_bin_file(&efivars->kset->kobj,
1496                                       efivars->del_var);
1497         if (error) {
1498                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1499                         " due to error %d\n", error);
1500                 sysfs_remove_bin_file(&efivars->kset->kobj,
1501                                       efivars->new_var);
1502                 goto out_free;
1503         }
1504
1505         return 0;
1506 out_free:
1507         kfree(efivars->del_var);
1508         efivars->del_var = NULL;
1509         kfree(efivars->new_var);
1510         efivars->new_var = NULL;
1511         return error;
1512 }
1513
1514 void unregister_efivars(struct efivars *efivars)
1515 {
1516         struct efivar_entry *entry, *n;
1517
1518         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1519                 spin_lock(&efivars->lock);
1520                 list_del(&entry->list);
1521                 spin_unlock(&efivars->lock);
1522                 efivar_unregister(entry);
1523         }
1524         if (efivars->new_var)
1525                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1526         if (efivars->del_var)
1527                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1528         kfree(efivars->new_var);
1529         kfree(efivars->del_var);
1530         kobject_put(efivars->kobject);
1531         kset_unregister(efivars->kset);
1532 }
1533 EXPORT_SYMBOL_GPL(unregister_efivars);
1534
1535 int register_efivars(struct efivars *efivars,
1536                      const struct efivar_operations *ops,
1537                      struct kobject *parent_kobj)
1538 {
1539         efi_status_t status = EFI_NOT_FOUND;
1540         efi_guid_t vendor_guid;
1541         efi_char16_t *variable_name;
1542         unsigned long variable_name_size = 1024;
1543         int error = 0;
1544
1545         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1546         if (!variable_name) {
1547                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1548                 return -ENOMEM;
1549         }
1550
1551         spin_lock_init(&efivars->lock);
1552         INIT_LIST_HEAD(&efivars->list);
1553         efivars->ops = ops;
1554
1555         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1556         if (!efivars->kset) {
1557                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1558                 error = -ENOMEM;
1559                 goto out;
1560         }
1561
1562         efivars->kobject = kobject_create_and_add("efivars", parent_kobj);
1563         if (!efivars->kobject) {
1564                 pr_err("efivars: Subsystem registration failed.\n");
1565                 error = -ENOMEM;
1566                 kset_unregister(efivars->kset);
1567                 goto out;
1568         }
1569
1570         /*
1571          * Per EFI spec, the maximum storage allocated for both
1572          * the variable name and variable data is 1024 bytes.
1573          */
1574
1575         do {
1576                 variable_name_size = 1024;
1577
1578                 status = ops->get_next_variable(&variable_name_size,
1579                                                 variable_name,
1580                                                 &vendor_guid);
1581                 switch (status) {
1582                 case EFI_SUCCESS:
1583                         efivar_create_sysfs_entry(efivars,
1584                                                   variable_name_size,
1585                                                   variable_name,
1586                                                   &vendor_guid);
1587                         break;
1588                 case EFI_NOT_FOUND:
1589                         break;
1590                 default:
1591                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1592                                 status);
1593                         status = EFI_NOT_FOUND;
1594                         break;
1595                 }
1596         } while (status != EFI_NOT_FOUND);
1597
1598         error = create_efivars_bin_attributes(efivars);
1599         if (error)
1600                 unregister_efivars(efivars);
1601
1602         efivars->efi_pstore_info = efi_pstore_info;
1603
1604         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1605         if (efivars->efi_pstore_info.buf) {
1606                 efivars->efi_pstore_info.bufsize = 1024;
1607                 efivars->efi_pstore_info.data = efivars;
1608                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1609                 pstore_register(&efivars->efi_pstore_info);
1610         }
1611
1612         register_filesystem(&efivarfs_type);
1613
1614 out:
1615         kfree(variable_name);
1616
1617         return error;
1618 }
1619 EXPORT_SYMBOL_GPL(register_efivars);
1620
1621 /*
1622  * For now we register the efi subsystem with the firmware subsystem
1623  * and the vars subsystem with the efi subsystem.  In the future, it
1624  * might make sense to split off the efi subsystem into its own
1625  * driver, but for now only efivars will register with it, so just
1626  * include it here.
1627  */
1628
1629 static int __init
1630 efivars_init(void)
1631 {
1632         int error = 0;
1633
1634         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1635                EFIVARS_DATE);
1636
1637         if (!efi_enabled)
1638                 return 0;
1639
1640         /* For now we'll register the efi directory at /sys/firmware/efi */
1641         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1642         if (!efi_kobj) {
1643                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1644                 return -ENOMEM;
1645         }
1646
1647         ops.get_variable = efi.get_variable;
1648         ops.set_variable = efi.set_variable;
1649         ops.get_next_variable = efi.get_next_variable;
1650         error = register_efivars(&__efivars, &ops, efi_kobj);
1651         if (error)
1652                 goto err_put;
1653
1654         /* Don't forget the systab entry */
1655         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1656         if (error) {
1657                 printk(KERN_ERR
1658                        "efivars: Sysfs attribute export failed with error %d.\n",
1659                        error);
1660                 goto err_unregister;
1661         }
1662
1663         return 0;
1664
1665 err_unregister:
1666         unregister_efivars(&__efivars);
1667 err_put:
1668         kobject_put(efi_kobj);
1669         return error;
1670 }
1671
1672 static void __exit
1673 efivars_exit(void)
1674 {
1675         if (efi_enabled) {
1676                 unregister_efivars(&__efivars);
1677                 kobject_put(efi_kobj);
1678         }
1679 }
1680
1681 module_init(efivars_init);
1682 module_exit(efivars_exit);
1683