efi: Clarify GUID length calculations
[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
99 /*
100  * Length of a GUID string (strlen("aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"))
101  * not including trailing NUL
102  */
103 #define GUID_LEN 36
104
105 /*
106  * The maximum size of VariableName + Data = 1024
107  * Therefore, it's reasonable to save that much
108  * space in each part of the structure,
109  * and we use a page for reading/writing.
110  */
111
112 struct efi_variable {
113         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
114         efi_guid_t    VendorGuid;
115         unsigned long DataSize;
116         __u8          Data[1024];
117         efi_status_t  Status;
118         __u32         Attributes;
119 } __attribute__((packed));
120
121 struct efivar_entry {
122         struct efivars *efivars;
123         struct efi_variable var;
124         struct list_head list;
125         struct kobject kobj;
126 };
127
128 struct efivar_attribute {
129         struct attribute attr;
130         ssize_t (*show) (struct efivar_entry *entry, char *buf);
131         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
132 };
133
134 static struct efivars __efivars;
135 static struct efivar_operations ops;
136
137 #define PSTORE_EFI_ATTRIBUTES \
138         (EFI_VARIABLE_NON_VOLATILE | \
139          EFI_VARIABLE_BOOTSERVICE_ACCESS | \
140          EFI_VARIABLE_RUNTIME_ACCESS)
141
142 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
143 struct efivar_attribute efivar_attr_##_name = { \
144         .attr = {.name = __stringify(_name), .mode = _mode}, \
145         .show = _show, \
146         .store = _store, \
147 };
148
149 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
150 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
151
152 /*
153  * Prototype for sysfs creation function
154  */
155 static int
156 efivar_create_sysfs_entry(struct efivars *efivars,
157                           unsigned long variable_name_size,
158                           efi_char16_t *variable_name,
159                           efi_guid_t *vendor_guid);
160
161 /* Return the number of unicode characters in data */
162 static unsigned long
163 utf16_strnlen(efi_char16_t *s, size_t maxlength)
164 {
165         unsigned long length = 0;
166
167         while (*s++ != 0 && length < maxlength)
168                 length++;
169         return length;
170 }
171
172 static inline unsigned long
173 utf16_strlen(efi_char16_t *s)
174 {
175         return utf16_strnlen(s, ~0UL);
176 }
177
178 /*
179  * Return the number of bytes is the length of this string
180  * Note: this is NOT the same as the number of unicode characters
181  */
182 static inline unsigned long
183 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
184 {
185         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
186 }
187
188 static inline int
189 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
190 {
191         while (1) {
192                 if (len == 0)
193                         return 0;
194                 if (*a < *b)
195                         return -1;
196                 if (*a > *b)
197                         return 1;
198                 if (*a == 0) /* implies *b == 0 */
199                         return 0;
200                 a++;
201                 b++;
202                 len--;
203         }
204 }
205
206 static bool
207 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
208                      unsigned long len)
209 {
210         struct efi_generic_dev_path *node;
211         int offset = 0;
212
213         node = (struct efi_generic_dev_path *)buffer;
214
215         if (len < sizeof(*node))
216                 return false;
217
218         while (offset <= len - sizeof(*node) &&
219                node->length >= sizeof(*node) &&
220                 node->length <= len - offset) {
221                 offset += node->length;
222
223                 if ((node->type == EFI_DEV_END_PATH ||
224                      node->type == EFI_DEV_END_PATH2) &&
225                     node->sub_type == EFI_DEV_END_ENTIRE)
226                         return true;
227
228                 node = (struct efi_generic_dev_path *)(buffer + offset);
229         }
230
231         /*
232          * If we're here then either node->length pointed past the end
233          * of the buffer or we reached the end of the buffer without
234          * finding a device path end node.
235          */
236         return false;
237 }
238
239 static bool
240 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
241                     unsigned long len)
242 {
243         /* An array of 16-bit integers */
244         if ((len % 2) != 0)
245                 return false;
246
247         return true;
248 }
249
250 static bool
251 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
252                      unsigned long len)
253 {
254         u16 filepathlength;
255         int i, desclength = 0, namelen;
256
257         namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
258
259         /* Either "Boot" or "Driver" followed by four digits of hex */
260         for (i = match; i < match+4; i++) {
261                 if (var->VariableName[i] > 127 ||
262                     hex_to_bin(var->VariableName[i] & 0xff) < 0)
263                         return true;
264         }
265
266         /* Reject it if there's 4 digits of hex and then further content */
267         if (namelen > match + 4)
268                 return false;
269
270         /* A valid entry must be at least 8 bytes */
271         if (len < 8)
272                 return false;
273
274         filepathlength = buffer[4] | buffer[5] << 8;
275
276         /*
277          * There's no stored length for the description, so it has to be
278          * found by hand
279          */
280         desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
281
282         /* Each boot entry must have a descriptor */
283         if (!desclength)
284                 return false;
285
286         /*
287          * If the sum of the length of the description, the claimed filepath
288          * length and the original header are greater than the length of the
289          * variable, it's malformed
290          */
291         if ((desclength + filepathlength + 6) > len)
292                 return false;
293
294         /*
295          * And, finally, check the filepath
296          */
297         return validate_device_path(var, match, buffer + desclength + 6,
298                                     filepathlength);
299 }
300
301 static bool
302 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
303                 unsigned long len)
304 {
305         /* A single 16-bit integer */
306         if (len != 2)
307                 return false;
308
309         return true;
310 }
311
312 static bool
313 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
314                       unsigned long len)
315 {
316         int i;
317
318         for (i = 0; i < len; i++) {
319                 if (buffer[i] > 127)
320                         return false;
321
322                 if (buffer[i] == 0)
323                         return true;
324         }
325
326         return false;
327 }
328
329 struct variable_validate {
330         char *name;
331         bool (*validate)(struct efi_variable *var, int match, u8 *data,
332                          unsigned long len);
333 };
334
335 static const struct variable_validate variable_validate[] = {
336         { "BootNext", validate_uint16 },
337         { "BootOrder", validate_boot_order },
338         { "DriverOrder", validate_boot_order },
339         { "Boot*", validate_load_option },
340         { "Driver*", validate_load_option },
341         { "ConIn", validate_device_path },
342         { "ConInDev", validate_device_path },
343         { "ConOut", validate_device_path },
344         { "ConOutDev", validate_device_path },
345         { "ErrOut", validate_device_path },
346         { "ErrOutDev", validate_device_path },
347         { "Timeout", validate_uint16 },
348         { "Lang", validate_ascii_string },
349         { "PlatformLang", validate_ascii_string },
350         { "", NULL },
351 };
352
353 static bool
354 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
355 {
356         int i;
357         u16 *unicode_name = var->VariableName;
358
359         for (i = 0; variable_validate[i].validate != NULL; i++) {
360                 const char *name = variable_validate[i].name;
361                 int match;
362
363                 for (match = 0; ; match++) {
364                         char c = name[match];
365                         u16 u = unicode_name[match];
366
367                         /* All special variables are plain ascii */
368                         if (u > 127)
369                                 return true;
370
371                         /* Wildcard in the matching name means we've matched */
372                         if (c == '*')
373                                 return variable_validate[i].validate(var,
374                                                              match, data, len);
375
376                         /* Case sensitive match */
377                         if (c != u)
378                                 break;
379
380                         /* Reached the end of the string while matching */
381                         if (!c)
382                                 return variable_validate[i].validate(var,
383                                                              match, data, len);
384                 }
385         }
386
387         return true;
388 }
389
390 static efi_status_t
391 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
392 {
393         efi_status_t status;
394
395         var->DataSize = 1024;
396         status = efivars->ops->get_variable(var->VariableName,
397                                             &var->VendorGuid,
398                                             &var->Attributes,
399                                             &var->DataSize,
400                                             var->Data);
401         return status;
402 }
403
404 static efi_status_t
405 get_var_data(struct efivars *efivars, struct efi_variable *var)
406 {
407         efi_status_t status;
408
409         spin_lock(&efivars->lock);
410         status = get_var_data_locked(efivars, var);
411         spin_unlock(&efivars->lock);
412
413         if (status != EFI_SUCCESS) {
414                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
415                         status);
416         }
417         return status;
418 }
419
420 static ssize_t
421 efivar_guid_read(struct efivar_entry *entry, char *buf)
422 {
423         struct efi_variable *var = &entry->var;
424         char *str = buf;
425
426         if (!entry || !buf)
427                 return 0;
428
429         efi_guid_unparse(&var->VendorGuid, str);
430         str += strlen(str);
431         str += sprintf(str, "\n");
432
433         return str - buf;
434 }
435
436 static ssize_t
437 efivar_attr_read(struct efivar_entry *entry, char *buf)
438 {
439         struct efi_variable *var = &entry->var;
440         char *str = buf;
441         efi_status_t status;
442
443         if (!entry || !buf)
444                 return -EINVAL;
445
446         status = get_var_data(entry->efivars, var);
447         if (status != EFI_SUCCESS)
448                 return -EIO;
449
450         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
451                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
452         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
453                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
454         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
455                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
456         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
457                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
458         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
459                 str += sprintf(str,
460                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
461         if (var->Attributes &
462                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
463                 str += sprintf(str,
464                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
465         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
466                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
467         return str - buf;
468 }
469
470 static ssize_t
471 efivar_size_read(struct efivar_entry *entry, char *buf)
472 {
473         struct efi_variable *var = &entry->var;
474         char *str = buf;
475         efi_status_t status;
476
477         if (!entry || !buf)
478                 return -EINVAL;
479
480         status = get_var_data(entry->efivars, var);
481         if (status != EFI_SUCCESS)
482                 return -EIO;
483
484         str += sprintf(str, "0x%lx\n", var->DataSize);
485         return str - buf;
486 }
487
488 static ssize_t
489 efivar_data_read(struct efivar_entry *entry, char *buf)
490 {
491         struct efi_variable *var = &entry->var;
492         efi_status_t status;
493
494         if (!entry || !buf)
495                 return -EINVAL;
496
497         status = get_var_data(entry->efivars, var);
498         if (status != EFI_SUCCESS)
499                 return -EIO;
500
501         memcpy(buf, var->Data, var->DataSize);
502         return var->DataSize;
503 }
504 /*
505  * We allow each variable to be edited via rewriting the
506  * entire efi variable structure.
507  */
508 static ssize_t
509 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
510 {
511         struct efi_variable *new_var, *var = &entry->var;
512         struct efivars *efivars = entry->efivars;
513         efi_status_t status = EFI_NOT_FOUND;
514
515         if (count != sizeof(struct efi_variable))
516                 return -EINVAL;
517
518         new_var = (struct efi_variable *)buf;
519         /*
520          * If only updating the variable data, then the name
521          * and guid should remain the same
522          */
523         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
524                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
525                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
526                 return -EINVAL;
527         }
528
529         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
530                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
531                 return -EINVAL;
532         }
533
534         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
535             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
536                 printk(KERN_ERR "efivars: Malformed variable content\n");
537                 return -EINVAL;
538         }
539
540         spin_lock(&efivars->lock);
541         status = efivars->ops->set_variable(new_var->VariableName,
542                                             &new_var->VendorGuid,
543                                             new_var->Attributes,
544                                             new_var->DataSize,
545                                             new_var->Data);
546
547         spin_unlock(&efivars->lock);
548
549         if (status != EFI_SUCCESS) {
550                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
551                         status);
552                 return -EIO;
553         }
554
555         memcpy(&entry->var, new_var, count);
556         return count;
557 }
558
559 static ssize_t
560 efivar_show_raw(struct efivar_entry *entry, char *buf)
561 {
562         struct efi_variable *var = &entry->var;
563         efi_status_t status;
564
565         if (!entry || !buf)
566                 return 0;
567
568         status = get_var_data(entry->efivars, var);
569         if (status != EFI_SUCCESS)
570                 return -EIO;
571
572         memcpy(buf, var, sizeof(*var));
573         return sizeof(*var);
574 }
575
576 /*
577  * Generic read/write functions that call the specific functions of
578  * the attributes...
579  */
580 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
581                                 char *buf)
582 {
583         struct efivar_entry *var = to_efivar_entry(kobj);
584         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
585         ssize_t ret = -EIO;
586
587         if (!capable(CAP_SYS_ADMIN))
588                 return -EACCES;
589
590         if (efivar_attr->show) {
591                 ret = efivar_attr->show(var, buf);
592         }
593         return ret;
594 }
595
596 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
597                                 const char *buf, size_t count)
598 {
599         struct efivar_entry *var = to_efivar_entry(kobj);
600         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
601         ssize_t ret = -EIO;
602
603         if (!capable(CAP_SYS_ADMIN))
604                 return -EACCES;
605
606         if (efivar_attr->store)
607                 ret = efivar_attr->store(var, buf, count);
608
609         return ret;
610 }
611
612 static const struct sysfs_ops efivar_attr_ops = {
613         .show = efivar_attr_show,
614         .store = efivar_attr_store,
615 };
616
617 static void efivar_release(struct kobject *kobj)
618 {
619         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
620         kfree(var);
621 }
622
623 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
624 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
625 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
626 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
627 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
628
629 static struct attribute *def_attrs[] = {
630         &efivar_attr_guid.attr,
631         &efivar_attr_size.attr,
632         &efivar_attr_attributes.attr,
633         &efivar_attr_data.attr,
634         &efivar_attr_raw_var.attr,
635         NULL,
636 };
637
638 static struct kobj_type efivar_ktype = {
639         .release = efivar_release,
640         .sysfs_ops = &efivar_attr_ops,
641         .default_attrs = def_attrs,
642 };
643
644 static inline void
645 efivar_unregister(struct efivar_entry *var)
646 {
647         kobject_put(&var->kobj);
648 }
649
650 static int efivarfs_file_open(struct inode *inode, struct file *file)
651 {
652         file->private_data = inode->i_private;
653         return 0;
654 }
655
656 static ssize_t efivarfs_file_write(struct file *file,
657                 const char __user *userbuf, size_t count, loff_t *ppos)
658 {
659         struct efivar_entry *var = file->private_data;
660         struct efivars *efivars;
661         efi_status_t status;
662         void *data;
663         u32 attributes;
664         struct inode *inode = file->f_mapping->host;
665         int datasize = count - sizeof(attributes);
666         unsigned long newdatasize;
667
668         if (count < sizeof(attributes))
669                 return -EINVAL;
670
671         data = kmalloc(datasize, GFP_KERNEL);
672
673         if (!data)
674                 return -ENOMEM;
675
676         efivars = var->efivars;
677
678         if (copy_from_user(&attributes, userbuf, sizeof(attributes))) {
679                 count = -EFAULT;
680                 goto out;
681         }
682
683         if (attributes & ~(EFI_VARIABLE_MASK)) {
684                 count = -EINVAL;
685                 goto out;
686         }
687
688         if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
689                 count = -EFAULT;
690                 goto out;
691         }
692
693         if (validate_var(&var->var, data, datasize) == false) {
694                 count = -EINVAL;
695                 goto out;
696         }
697
698         /*
699          * The lock here protects the get_variable call, the conditional
700          * set_variable call, and removal of the variable from the efivars
701          * list (in the case of an authenticated delete).
702          */
703         spin_lock(&efivars->lock);
704
705         status = efivars->ops->set_variable(var->var.VariableName,
706                                             &var->var.VendorGuid,
707                                             attributes, datasize,
708                                             data);
709
710         if (status != EFI_SUCCESS) {
711                 spin_unlock(&efivars->lock);
712                 kfree(data);
713
714                 switch (status) {
715                 case EFI_INVALID_PARAMETER:
716                         count = -EINVAL;
717                         break;
718                 case EFI_OUT_OF_RESOURCES:
719                         count = -ENOSPC;
720                         break;
721                 case EFI_DEVICE_ERROR:
722                         count = -EIO;
723                         break;
724                 case EFI_WRITE_PROTECTED:
725                         count = -EROFS;
726                         break;
727                 case EFI_SECURITY_VIOLATION:
728                         count = -EACCES;
729                         break;
730                 case EFI_NOT_FOUND:
731                         count = -ENOENT;
732                         break;
733                 default:
734                         count = -EINVAL;
735                 }
736                 return count;
737         }
738
739         /*
740          * Writing to the variable may have caused a change in size (which
741          * could either be an append or an overwrite), or the variable to be
742          * deleted. Perform a GetVariable() so we can tell what actually
743          * happened.
744          */
745         newdatasize = 0;
746         status = efivars->ops->get_variable(var->var.VariableName,
747                                             &var->var.VendorGuid,
748                                             NULL, &newdatasize,
749                                             NULL);
750
751         if (status == EFI_BUFFER_TOO_SMALL) {
752                 spin_unlock(&efivars->lock);
753                 mutex_lock(&inode->i_mutex);
754                 i_size_write(inode, newdatasize + sizeof(attributes));
755                 mutex_unlock(&inode->i_mutex);
756
757         } else if (status == EFI_NOT_FOUND) {
758                 list_del(&var->list);
759                 spin_unlock(&efivars->lock);
760                 efivar_unregister(var);
761                 drop_nlink(inode);
762                 dput(file->f_dentry);
763
764         } else {
765                 spin_unlock(&efivars->lock);
766                 pr_warn("efivarfs: inconsistent EFI variable implementation? "
767                                 "status = %lx\n", status);
768         }
769
770 out:
771         kfree(data);
772
773         return count;
774 }
775
776 static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
777                 size_t count, loff_t *ppos)
778 {
779         struct efivar_entry *var = file->private_data;
780         struct efivars *efivars = var->efivars;
781         efi_status_t status;
782         unsigned long datasize = 0;
783         u32 attributes;
784         void *data;
785         ssize_t size = 0;
786
787         spin_lock(&efivars->lock);
788         status = efivars->ops->get_variable(var->var.VariableName,
789                                             &var->var.VendorGuid,
790                                             &attributes, &datasize, NULL);
791         spin_unlock(&efivars->lock);
792
793         if (status != EFI_BUFFER_TOO_SMALL)
794                 return 0;
795
796         data = kmalloc(datasize + 4, GFP_KERNEL);
797
798         if (!data)
799                 return 0;
800
801         spin_lock(&efivars->lock);
802         status = efivars->ops->get_variable(var->var.VariableName,
803                                             &var->var.VendorGuid,
804                                             &attributes, &datasize,
805                                             (data + 4));
806         spin_unlock(&efivars->lock);
807
808         if (status != EFI_SUCCESS)
809                 goto out_free;
810
811         memcpy(data, &attributes, 4);
812         size = simple_read_from_buffer(userbuf, count, ppos,
813                                         data, datasize + 4);
814 out_free:
815         kfree(data);
816
817         return size;
818 }
819
820 static void efivarfs_evict_inode(struct inode *inode)
821 {
822         clear_inode(inode);
823 }
824
825 static const struct super_operations efivarfs_ops = {
826         .statfs = simple_statfs,
827         .drop_inode = generic_delete_inode,
828         .evict_inode = efivarfs_evict_inode,
829         .show_options = generic_show_options,
830 };
831
832 static struct super_block *efivarfs_sb;
833
834 static const struct inode_operations efivarfs_dir_inode_operations;
835
836 static const struct file_operations efivarfs_file_operations = {
837         .open   = efivarfs_file_open,
838         .read   = efivarfs_file_read,
839         .write  = efivarfs_file_write,
840         .llseek = no_llseek,
841 };
842
843 static struct inode *efivarfs_get_inode(struct super_block *sb,
844                                 const struct inode *dir, int mode, dev_t dev)
845 {
846         struct inode *inode = new_inode(sb);
847
848         if (inode) {
849                 inode->i_ino = get_next_ino();
850                 inode->i_uid = inode->i_gid = 0;
851                 inode->i_mode = mode;
852                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
853                 switch (mode & S_IFMT) {
854                 case S_IFREG:
855                         inode->i_fop = &efivarfs_file_operations;
856                         break;
857                 case S_IFDIR:
858                         inode->i_op = &efivarfs_dir_inode_operations;
859                         inode->i_fop = &simple_dir_operations;
860                         inc_nlink(inode);
861                         break;
862                 }
863         }
864         return inode;
865 }
866
867 static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
868 {
869         guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
870         guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
871         guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
872         guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
873         guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
874         guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
875         guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
876         guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
877         guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
878         guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
879         guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
880         guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
881         guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
882         guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
883         guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
884         guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
885 }
886
887 static int efivarfs_create(struct inode *dir, struct dentry *dentry,
888                           umode_t mode, bool excl)
889 {
890         struct inode *inode;
891         struct efivars *efivars = &__efivars;
892         struct efivar_entry *var;
893         int namelen, i = 0, err = 0;
894
895         /*
896          * We need a GUID, plus at least one letter for the variable name,
897          * plus the '-' separator
898          */
899         if (dentry->d_name.len < GUID_LEN + 2)
900                 return -EINVAL;
901
902         inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
903         if (!inode)
904                 return -ENOSPC;
905
906         var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
907         if (!var) {
908                 err = -ENOMEM;
909                 goto out;
910         }
911
912         /* length of the variable name itself: remove GUID and separator */
913         namelen = dentry->d_name.len - GUID_LEN - 1;
914
915         efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
916                         &var->var.VendorGuid);
917
918         for (i = 0; i < namelen; i++)
919                 var->var.VariableName[i] = dentry->d_name.name[i];
920
921         var->var.VariableName[i] = '\0';
922
923         inode->i_private = var;
924         var->efivars = efivars;
925         var->kobj.kset = efivars->kset;
926
927         err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
928                              dentry->d_name.name);
929         if (err)
930                 goto out;
931
932         kobject_uevent(&var->kobj, KOBJ_ADD);
933         spin_lock(&efivars->lock);
934         list_add(&var->list, &efivars->list);
935         spin_unlock(&efivars->lock);
936         d_instantiate(dentry, inode);
937         dget(dentry);
938 out:
939         if (err) {
940                 kfree(var);
941                 iput(inode);
942         }
943         return err;
944 }
945
946 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
947 {
948         struct efivar_entry *var = dentry->d_inode->i_private;
949         struct efivars *efivars = var->efivars;
950         efi_status_t status;
951
952         spin_lock(&efivars->lock);
953
954         status = efivars->ops->set_variable(var->var.VariableName,
955                                             &var->var.VendorGuid,
956                                             0, 0, NULL);
957
958         if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
959                 list_del(&var->list);
960                 spin_unlock(&efivars->lock);
961                 efivar_unregister(var);
962                 drop_nlink(dir);
963                 dput(dentry);
964                 return 0;
965         }
966
967         spin_unlock(&efivars->lock);
968         return -EINVAL;
969 };
970
971 int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
972 {
973         struct inode *inode = NULL;
974         struct dentry *root;
975         struct efivar_entry *entry, *n;
976         struct efivars *efivars = &__efivars;
977         char *name;
978
979         efivarfs_sb = sb;
980
981         sb->s_maxbytes          = MAX_LFS_FILESIZE;
982         sb->s_blocksize         = PAGE_CACHE_SIZE;
983         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
984         sb->s_magic             = PSTOREFS_MAGIC;
985         sb->s_op                = &efivarfs_ops;
986         sb->s_time_gran         = 1;
987
988         inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
989         if (!inode)
990                 return -ENOMEM;
991         inode->i_op = &efivarfs_dir_inode_operations;
992
993         root = d_make_root(inode);
994         sb->s_root = root;
995         if (!root)
996                 return -ENOMEM;
997
998         list_for_each_entry_safe(entry, n, &efivars->list, list) {
999                 struct dentry *dentry, *root = efivarfs_sb->s_root;
1000                 unsigned long size = 0;
1001                 int len, i;
1002
1003                 inode = NULL;
1004
1005                 len = utf16_strlen(entry->var.VariableName);
1006
1007                 /* name, plus '-', plus GUID, plus NUL*/
1008                 name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
1009                 if (!name)
1010                         goto fail;
1011
1012                 for (i = 0; i < len; i++)
1013                         name[i] = entry->var.VariableName[i] & 0xFF;
1014
1015                 name[len] = '-';
1016
1017                 efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
1018
1019                 name[len+GUID_LEN+1] = '\0';
1020
1021                 inode = efivarfs_get_inode(efivarfs_sb, root->d_inode,
1022                                           S_IFREG | 0644, 0);
1023                 if (!inode)
1024                         goto fail_name;
1025
1026                 dentry = d_alloc_name(root, name);
1027                 if (!dentry)
1028                         goto fail_inode;
1029
1030                 /* copied by the above to local storage in the dentry. */
1031                 kfree(name);
1032
1033                 spin_lock(&efivars->lock);
1034                 efivars->ops->get_variable(entry->var.VariableName,
1035                                            &entry->var.VendorGuid,
1036                                            &entry->var.Attributes,
1037                                            &size,
1038                                            NULL);
1039                 spin_unlock(&efivars->lock);
1040
1041                 mutex_lock(&inode->i_mutex);
1042                 inode->i_private = entry;
1043                 i_size_write(inode, size+4);
1044                 mutex_unlock(&inode->i_mutex);
1045                 d_add(dentry, inode);
1046         }
1047
1048         return 0;
1049
1050 fail_inode:
1051         iput(inode);
1052 fail_name:
1053         kfree(name);
1054 fail:
1055         return -ENOMEM;
1056 }
1057
1058 static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
1059                                     int flags, const char *dev_name, void *data)
1060 {
1061         return mount_single(fs_type, flags, data, efivarfs_fill_super);
1062 }
1063
1064 static void efivarfs_kill_sb(struct super_block *sb)
1065 {
1066         kill_litter_super(sb);
1067         efivarfs_sb = NULL;
1068 }
1069
1070 static struct file_system_type efivarfs_type = {
1071         .name    = "efivarfs",
1072         .mount   = efivarfs_mount,
1073         .kill_sb = efivarfs_kill_sb,
1074 };
1075
1076 static const struct inode_operations efivarfs_dir_inode_operations = {
1077         .lookup = simple_lookup,
1078         .unlink = efivarfs_unlink,
1079         .create = efivarfs_create,
1080 };
1081
1082 static struct pstore_info efi_pstore_info;
1083
1084 #ifdef CONFIG_PSTORE
1085
1086 static int efi_pstore_open(struct pstore_info *psi)
1087 {
1088         struct efivars *efivars = psi->data;
1089
1090         spin_lock(&efivars->lock);
1091         efivars->walk_entry = list_first_entry(&efivars->list,
1092                                                struct efivar_entry, list);
1093         return 0;
1094 }
1095
1096 static int efi_pstore_close(struct pstore_info *psi)
1097 {
1098         struct efivars *efivars = psi->data;
1099
1100         spin_unlock(&efivars->lock);
1101         return 0;
1102 }
1103
1104 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1105                                struct timespec *timespec,
1106                                char **buf, struct pstore_info *psi)
1107 {
1108         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1109         struct efivars *efivars = psi->data;
1110         char name[DUMP_NAME_LEN];
1111         int i;
1112         unsigned int part, size;
1113         unsigned long time;
1114
1115         while (&efivars->walk_entry->list != &efivars->list) {
1116                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
1117                                  vendor)) {
1118                         for (i = 0; i < DUMP_NAME_LEN; i++) {
1119                                 name[i] = efivars->walk_entry->var.VariableName[i];
1120                         }
1121                         if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
1122                                 *id = part;
1123                                 timespec->tv_sec = time;
1124                                 timespec->tv_nsec = 0;
1125                                 get_var_data_locked(efivars, &efivars->walk_entry->var);
1126                                 size = efivars->walk_entry->var.DataSize;
1127                                 *buf = kmalloc(size, GFP_KERNEL);
1128                                 if (*buf == NULL)
1129                                         return -ENOMEM;
1130                                 memcpy(*buf, efivars->walk_entry->var.Data,
1131                                        size);
1132                                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1133                                                    struct efivar_entry, list);
1134                                 return size;
1135                         }
1136                 }
1137                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1138                                                  struct efivar_entry, list);
1139         }
1140         return 0;
1141 }
1142
1143 static int efi_pstore_write(enum pstore_type_id type,
1144                 enum kmsg_dump_reason reason, u64 *id,
1145                 unsigned int part, size_t size, struct pstore_info *psi)
1146 {
1147         char name[DUMP_NAME_LEN];
1148         char stub_name[DUMP_NAME_LEN];
1149         efi_char16_t efi_name[DUMP_NAME_LEN];
1150         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1151         struct efivars *efivars = psi->data;
1152         struct efivar_entry *entry, *found = NULL;
1153         int i, ret = 0;
1154
1155         sprintf(stub_name, "dump-type%u-%u-", type, part);
1156         sprintf(name, "%s%lu", stub_name, get_seconds());
1157
1158         spin_lock(&efivars->lock);
1159
1160         for (i = 0; i < DUMP_NAME_LEN; i++)
1161                 efi_name[i] = stub_name[i];
1162
1163         /*
1164          * Clean up any entries with the same name
1165          */
1166
1167         list_for_each_entry(entry, &efivars->list, list) {
1168                 get_var_data_locked(efivars, &entry->var);
1169
1170                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
1171                         continue;
1172                 if (utf16_strncmp(entry->var.VariableName, efi_name,
1173                                   utf16_strlen(efi_name)))
1174                         continue;
1175                 /* Needs to be a prefix */
1176                 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
1177                         continue;
1178
1179                 /* found */
1180                 found = entry;
1181                 efivars->ops->set_variable(entry->var.VariableName,
1182                                            &entry->var.VendorGuid,
1183                                            PSTORE_EFI_ATTRIBUTES,
1184                                            0, NULL);
1185         }
1186
1187         if (found)
1188                 list_del(&found->list);
1189
1190         for (i = 0; i < DUMP_NAME_LEN; i++)
1191                 efi_name[i] = name[i];
1192
1193         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
1194                                    size, psi->buf);
1195
1196         spin_unlock(&efivars->lock);
1197
1198         if (found)
1199                 efivar_unregister(found);
1200
1201         if (size)
1202                 ret = efivar_create_sysfs_entry(efivars,
1203                                           utf16_strsize(efi_name,
1204                                                         DUMP_NAME_LEN * 2),
1205                                           efi_name, &vendor);
1206
1207         *id = part;
1208         return ret;
1209 };
1210
1211 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
1212                             struct pstore_info *psi)
1213 {
1214         efi_pstore_write(type, 0, &id, (unsigned int)id, 0, psi);
1215
1216         return 0;
1217 }
1218 #else
1219 static int efi_pstore_open(struct pstore_info *psi)
1220 {
1221         return 0;
1222 }
1223
1224 static int efi_pstore_close(struct pstore_info *psi)
1225 {
1226         return 0;
1227 }
1228
1229 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1230                                struct timespec *timespec,
1231                                char **buf, struct pstore_info *psi)
1232 {
1233         return -1;
1234 }
1235
1236 static int efi_pstore_write(enum pstore_type_id type,
1237                 enum kmsg_dump_reason reason, u64 *id,
1238                 unsigned int part, size_t size, struct pstore_info *psi)
1239 {
1240         return 0;
1241 }
1242
1243 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
1244                             struct pstore_info *psi)
1245 {
1246         return 0;
1247 }
1248 #endif
1249
1250 static struct pstore_info efi_pstore_info = {
1251         .owner          = THIS_MODULE,
1252         .name           = "efi",
1253         .open           = efi_pstore_open,
1254         .close          = efi_pstore_close,
1255         .read           = efi_pstore_read,
1256         .write          = efi_pstore_write,
1257         .erase          = efi_pstore_erase,
1258 };
1259
1260 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
1261                              struct bin_attribute *bin_attr,
1262                              char *buf, loff_t pos, size_t count)
1263 {
1264         struct efi_variable *new_var = (struct efi_variable *)buf;
1265         struct efivars *efivars = bin_attr->private;
1266         struct efivar_entry *search_efivar, *n;
1267         unsigned long strsize1, strsize2;
1268         efi_status_t status = EFI_NOT_FOUND;
1269         int found = 0;
1270
1271         if (!capable(CAP_SYS_ADMIN))
1272                 return -EACCES;
1273
1274         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
1275             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
1276                 printk(KERN_ERR "efivars: Malformed variable content\n");
1277                 return -EINVAL;
1278         }
1279
1280         spin_lock(&efivars->lock);
1281
1282         /*
1283          * Does this variable already exist?
1284          */
1285         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1286                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1287                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
1288                 if (strsize1 == strsize2 &&
1289                         !memcmp(&(search_efivar->var.VariableName),
1290                                 new_var->VariableName, strsize1) &&
1291                         !efi_guidcmp(search_efivar->var.VendorGuid,
1292                                 new_var->VendorGuid)) {
1293                         found = 1;
1294                         break;
1295                 }
1296         }
1297         if (found) {
1298                 spin_unlock(&efivars->lock);
1299                 return -EINVAL;
1300         }
1301
1302         /* now *really* create the variable via EFI */
1303         status = efivars->ops->set_variable(new_var->VariableName,
1304                                             &new_var->VendorGuid,
1305                                             new_var->Attributes,
1306                                             new_var->DataSize,
1307                                             new_var->Data);
1308
1309         if (status != EFI_SUCCESS) {
1310                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1311                         status);
1312                 spin_unlock(&efivars->lock);
1313                 return -EIO;
1314         }
1315         spin_unlock(&efivars->lock);
1316
1317         /* Create the entry in sysfs.  Locking is not required here */
1318         status = efivar_create_sysfs_entry(efivars,
1319                                            utf16_strsize(new_var->VariableName,
1320                                                          1024),
1321                                            new_var->VariableName,
1322                                            &new_var->VendorGuid);
1323         if (status) {
1324                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
1325         }
1326         return count;
1327 }
1328
1329 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
1330                              struct bin_attribute *bin_attr,
1331                              char *buf, loff_t pos, size_t count)
1332 {
1333         struct efi_variable *del_var = (struct efi_variable *)buf;
1334         struct efivars *efivars = bin_attr->private;
1335         struct efivar_entry *search_efivar, *n;
1336         unsigned long strsize1, strsize2;
1337         efi_status_t status = EFI_NOT_FOUND;
1338         int found = 0;
1339
1340         if (!capable(CAP_SYS_ADMIN))
1341                 return -EACCES;
1342
1343         spin_lock(&efivars->lock);
1344
1345         /*
1346          * Does this variable already exist?
1347          */
1348         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1349                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1350                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
1351                 if (strsize1 == strsize2 &&
1352                         !memcmp(&(search_efivar->var.VariableName),
1353                                 del_var->VariableName, strsize1) &&
1354                         !efi_guidcmp(search_efivar->var.VendorGuid,
1355                                 del_var->VendorGuid)) {
1356                         found = 1;
1357                         break;
1358                 }
1359         }
1360         if (!found) {
1361                 spin_unlock(&efivars->lock);
1362                 return -EINVAL;
1363         }
1364         /* force the Attributes/DataSize to 0 to ensure deletion */
1365         del_var->Attributes = 0;
1366         del_var->DataSize = 0;
1367
1368         status = efivars->ops->set_variable(del_var->VariableName,
1369                                             &del_var->VendorGuid,
1370                                             del_var->Attributes,
1371                                             del_var->DataSize,
1372                                             del_var->Data);
1373
1374         if (status != EFI_SUCCESS) {
1375                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1376                         status);
1377                 spin_unlock(&efivars->lock);
1378                 return -EIO;
1379         }
1380         list_del(&search_efivar->list);
1381         /* We need to release this lock before unregistering. */
1382         spin_unlock(&efivars->lock);
1383         efivar_unregister(search_efivar);
1384
1385         /* It's dead Jim.... */
1386         return count;
1387 }
1388
1389 /*
1390  * Let's not leave out systab information that snuck into
1391  * the efivars driver
1392  */
1393 static ssize_t systab_show(struct kobject *kobj,
1394                            struct kobj_attribute *attr, char *buf)
1395 {
1396         char *str = buf;
1397
1398         if (!kobj || !buf)
1399                 return -EINVAL;
1400
1401         if (efi.mps != EFI_INVALID_TABLE_ADDR)
1402                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1403         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1404                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1405         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1406                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1407         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1408                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1409         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1410                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1411         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1412                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1413         if (efi.uga != EFI_INVALID_TABLE_ADDR)
1414                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1415
1416         return str - buf;
1417 }
1418
1419 static struct kobj_attribute efi_attr_systab =
1420                         __ATTR(systab, 0400, systab_show, NULL);
1421
1422 static struct attribute *efi_subsys_attrs[] = {
1423         &efi_attr_systab.attr,
1424         NULL,   /* maybe more in the future? */
1425 };
1426
1427 static struct attribute_group efi_subsys_attr_group = {
1428         .attrs = efi_subsys_attrs,
1429 };
1430
1431 static struct kobject *efi_kobj;
1432
1433 /*
1434  * efivar_create_sysfs_entry()
1435  * Requires:
1436  *    variable_name_size = number of bytes required to hold
1437  *                         variable_name (not counting the NULL
1438  *                         character at the end.
1439  *    efivars->lock is not held on entry or exit.
1440  * Returns 1 on failure, 0 on success
1441  */
1442 static int
1443 efivar_create_sysfs_entry(struct efivars *efivars,
1444                           unsigned long variable_name_size,
1445                           efi_char16_t *variable_name,
1446                           efi_guid_t *vendor_guid)
1447 {
1448         int i, short_name_size;
1449         char *short_name;
1450         struct efivar_entry *new_efivar;
1451
1452         /*
1453          * Length of the variable bytes in ASCII, plus the '-' separator,
1454          * plus the GUID, plus trailing NUL
1455          */
1456         short_name_size = variable_name_size / sizeof(efi_char16_t)
1457                                 + 1 + GUID_LEN + 1;
1458
1459         short_name = kzalloc(short_name_size, GFP_KERNEL);
1460         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1461
1462         if (!short_name || !new_efivar)  {
1463                 kfree(short_name);
1464                 kfree(new_efivar);
1465                 return 1;
1466         }
1467
1468         new_efivar->efivars = efivars;
1469         memcpy(new_efivar->var.VariableName, variable_name,
1470                 variable_name_size);
1471         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1472
1473         /* Convert Unicode to normal chars (assume top bits are 0),
1474            ala UTF-8 */
1475         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1476                 short_name[i] = variable_name[i] & 0xFF;
1477         }
1478         /* This is ugly, but necessary to separate one vendor's
1479            private variables from another's.         */
1480
1481         *(short_name + strlen(short_name)) = '-';
1482         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1483
1484         new_efivar->kobj.kset = efivars->kset;
1485         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1486                                  "%s", short_name);
1487         if (i) {
1488                 kfree(short_name);
1489                 kfree(new_efivar);
1490                 return 1;
1491         }
1492
1493         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1494         kfree(short_name);
1495         short_name = NULL;
1496
1497         spin_lock(&efivars->lock);
1498         list_add(&new_efivar->list, &efivars->list);
1499         spin_unlock(&efivars->lock);
1500
1501         return 0;
1502 }
1503
1504 static int
1505 create_efivars_bin_attributes(struct efivars *efivars)
1506 {
1507         struct bin_attribute *attr;
1508         int error;
1509
1510         /* new_var */
1511         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1512         if (!attr)
1513                 return -ENOMEM;
1514
1515         attr->attr.name = "new_var";
1516         attr->attr.mode = 0200;
1517         attr->write = efivar_create;
1518         attr->private = efivars;
1519         efivars->new_var = attr;
1520
1521         /* del_var */
1522         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1523         if (!attr) {
1524                 error = -ENOMEM;
1525                 goto out_free;
1526         }
1527         attr->attr.name = "del_var";
1528         attr->attr.mode = 0200;
1529         attr->write = efivar_delete;
1530         attr->private = efivars;
1531         efivars->del_var = attr;
1532
1533         sysfs_bin_attr_init(efivars->new_var);
1534         sysfs_bin_attr_init(efivars->del_var);
1535
1536         /* Register */
1537         error = sysfs_create_bin_file(&efivars->kset->kobj,
1538                                       efivars->new_var);
1539         if (error) {
1540                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1541                         " due to error %d\n", error);
1542                 goto out_free;
1543         }
1544         error = sysfs_create_bin_file(&efivars->kset->kobj,
1545                                       efivars->del_var);
1546         if (error) {
1547                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1548                         " due to error %d\n", error);
1549                 sysfs_remove_bin_file(&efivars->kset->kobj,
1550                                       efivars->new_var);
1551                 goto out_free;
1552         }
1553
1554         return 0;
1555 out_free:
1556         kfree(efivars->del_var);
1557         efivars->del_var = NULL;
1558         kfree(efivars->new_var);
1559         efivars->new_var = NULL;
1560         return error;
1561 }
1562
1563 void unregister_efivars(struct efivars *efivars)
1564 {
1565         struct efivar_entry *entry, *n;
1566
1567         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1568                 spin_lock(&efivars->lock);
1569                 list_del(&entry->list);
1570                 spin_unlock(&efivars->lock);
1571                 efivar_unregister(entry);
1572         }
1573         if (efivars->new_var)
1574                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1575         if (efivars->del_var)
1576                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1577         kfree(efivars->new_var);
1578         kfree(efivars->del_var);
1579         kobject_put(efivars->kobject);
1580         kset_unregister(efivars->kset);
1581 }
1582 EXPORT_SYMBOL_GPL(unregister_efivars);
1583
1584 int register_efivars(struct efivars *efivars,
1585                      const struct efivar_operations *ops,
1586                      struct kobject *parent_kobj)
1587 {
1588         efi_status_t status = EFI_NOT_FOUND;
1589         efi_guid_t vendor_guid;
1590         efi_char16_t *variable_name;
1591         unsigned long variable_name_size = 1024;
1592         int error = 0;
1593
1594         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1595         if (!variable_name) {
1596                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1597                 return -ENOMEM;
1598         }
1599
1600         spin_lock_init(&efivars->lock);
1601         INIT_LIST_HEAD(&efivars->list);
1602         efivars->ops = ops;
1603
1604         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1605         if (!efivars->kset) {
1606                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1607                 error = -ENOMEM;
1608                 goto out;
1609         }
1610
1611         efivars->kobject = kobject_create_and_add("efivars", parent_kobj);
1612         if (!efivars->kobject) {
1613                 pr_err("efivars: Subsystem registration failed.\n");
1614                 error = -ENOMEM;
1615                 kset_unregister(efivars->kset);
1616                 goto out;
1617         }
1618
1619         /*
1620          * Per EFI spec, the maximum storage allocated for both
1621          * the variable name and variable data is 1024 bytes.
1622          */
1623
1624         do {
1625                 variable_name_size = 1024;
1626
1627                 status = ops->get_next_variable(&variable_name_size,
1628                                                 variable_name,
1629                                                 &vendor_guid);
1630                 switch (status) {
1631                 case EFI_SUCCESS:
1632                         efivar_create_sysfs_entry(efivars,
1633                                                   variable_name_size,
1634                                                   variable_name,
1635                                                   &vendor_guid);
1636                         break;
1637                 case EFI_NOT_FOUND:
1638                         break;
1639                 default:
1640                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1641                                 status);
1642                         status = EFI_NOT_FOUND;
1643                         break;
1644                 }
1645         } while (status != EFI_NOT_FOUND);
1646
1647         error = create_efivars_bin_attributes(efivars);
1648         if (error)
1649                 unregister_efivars(efivars);
1650
1651         efivars->efi_pstore_info = efi_pstore_info;
1652
1653         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1654         if (efivars->efi_pstore_info.buf) {
1655                 efivars->efi_pstore_info.bufsize = 1024;
1656                 efivars->efi_pstore_info.data = efivars;
1657                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1658                 pstore_register(&efivars->efi_pstore_info);
1659         }
1660
1661         register_filesystem(&efivarfs_type);
1662
1663 out:
1664         kfree(variable_name);
1665
1666         return error;
1667 }
1668 EXPORT_SYMBOL_GPL(register_efivars);
1669
1670 /*
1671  * For now we register the efi subsystem with the firmware subsystem
1672  * and the vars subsystem with the efi subsystem.  In the future, it
1673  * might make sense to split off the efi subsystem into its own
1674  * driver, but for now only efivars will register with it, so just
1675  * include it here.
1676  */
1677
1678 static int __init
1679 efivars_init(void)
1680 {
1681         int error = 0;
1682
1683         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1684                EFIVARS_DATE);
1685
1686         if (!efi_enabled)
1687                 return 0;
1688
1689         /* For now we'll register the efi directory at /sys/firmware/efi */
1690         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1691         if (!efi_kobj) {
1692                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1693                 return -ENOMEM;
1694         }
1695
1696         ops.get_variable = efi.get_variable;
1697         ops.set_variable = efi.set_variable;
1698         ops.get_next_variable = efi.get_next_variable;
1699         error = register_efivars(&__efivars, &ops, efi_kobj);
1700         if (error)
1701                 goto err_put;
1702
1703         /* Don't forget the systab entry */
1704         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1705         if (error) {
1706                 printk(KERN_ERR
1707                        "efivars: Sysfs attribute export failed with error %d.\n",
1708                        error);
1709                 goto err_unregister;
1710         }
1711
1712         return 0;
1713
1714 err_unregister:
1715         unregister_efivars(&__efivars);
1716 err_put:
1717         kobject_put(efi_kobj);
1718         return error;
1719 }
1720
1721 static void __exit
1722 efivars_exit(void)
1723 {
1724         if (efi_enabled) {
1725                 unregister_efivars(&__efivars);
1726                 kobject_put(efi_kobj);
1727         }
1728 }
1729
1730 module_init(efivars_init);
1731 module_exit(efivars_exit);
1732