efivarfs: Delete dentry from dcache in efivarfs_file_write()
[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 int efi_status_to_err(efi_status_t status)
657 {
658         int err;
659
660         switch (status) {
661         case EFI_INVALID_PARAMETER:
662                 err = -EINVAL;
663                 break;
664         case EFI_OUT_OF_RESOURCES:
665                 err = -ENOSPC;
666                 break;
667         case EFI_DEVICE_ERROR:
668                 err = -EIO;
669                 break;
670         case EFI_WRITE_PROTECTED:
671                 err = -EROFS;
672                 break;
673         case EFI_SECURITY_VIOLATION:
674                 err = -EACCES;
675                 break;
676         case EFI_NOT_FOUND:
677                 err = -EIO;
678                 break;
679         default:
680                 err = -EINVAL;
681         }
682
683         return err;
684 }
685
686 static ssize_t efivarfs_file_write(struct file *file,
687                 const char __user *userbuf, size_t count, loff_t *ppos)
688 {
689         struct efivar_entry *var = file->private_data;
690         struct efivars *efivars;
691         efi_status_t status;
692         void *data;
693         u32 attributes;
694         struct inode *inode = file->f_mapping->host;
695         unsigned long datasize = count - sizeof(attributes);
696         unsigned long newdatasize;
697         u64 storage_size, remaining_size, max_size;
698         ssize_t bytes = 0;
699
700         if (count < sizeof(attributes))
701                 return -EINVAL;
702
703         if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
704                 return -EFAULT;
705
706         if (attributes & ~(EFI_VARIABLE_MASK))
707                 return -EINVAL;
708
709         efivars = var->efivars;
710
711         /*
712          * Ensure that the user can't allocate arbitrarily large
713          * amounts of memory. Pick a default size of 64K if
714          * QueryVariableInfo() isn't supported by the firmware.
715          */
716         spin_lock(&efivars->lock);
717
718         if (!efivars->ops->query_variable_info)
719                 status = EFI_UNSUPPORTED;
720         else {
721                 const struct efivar_operations *fops = efivars->ops;
722                 status = fops->query_variable_info(attributes, &storage_size,
723                                                    &remaining_size, &max_size);
724         }
725
726         spin_unlock(&efivars->lock);
727
728         if (status != EFI_SUCCESS) {
729                 if (status != EFI_UNSUPPORTED)
730                         return efi_status_to_err(status);
731
732                 remaining_size = 65536;
733         }
734
735         if (datasize > remaining_size)
736                 return -ENOSPC;
737
738         data = kmalloc(datasize, GFP_KERNEL);
739         if (!data)
740                 return -ENOMEM;
741
742         if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
743                 bytes = -EFAULT;
744                 goto out;
745         }
746
747         if (validate_var(&var->var, data, datasize) == false) {
748                 bytes = -EINVAL;
749                 goto out;
750         }
751
752         /*
753          * The lock here protects the get_variable call, the conditional
754          * set_variable call, and removal of the variable from the efivars
755          * list (in the case of an authenticated delete).
756          */
757         spin_lock(&efivars->lock);
758
759         status = efivars->ops->set_variable(var->var.VariableName,
760                                             &var->var.VendorGuid,
761                                             attributes, datasize,
762                                             data);
763
764         if (status != EFI_SUCCESS) {
765                 spin_unlock(&efivars->lock);
766                 kfree(data);
767
768                 return efi_status_to_err(status);
769         }
770
771         bytes = count;
772
773         /*
774          * Writing to the variable may have caused a change in size (which
775          * could either be an append or an overwrite), or the variable to be
776          * deleted. Perform a GetVariable() so we can tell what actually
777          * happened.
778          */
779         newdatasize = 0;
780         status = efivars->ops->get_variable(var->var.VariableName,
781                                             &var->var.VendorGuid,
782                                             NULL, &newdatasize,
783                                             NULL);
784
785         if (status == EFI_BUFFER_TOO_SMALL) {
786                 spin_unlock(&efivars->lock);
787                 mutex_lock(&inode->i_mutex);
788                 i_size_write(inode, newdatasize + sizeof(attributes));
789                 mutex_unlock(&inode->i_mutex);
790
791         } else if (status == EFI_NOT_FOUND) {
792                 list_del(&var->list);
793                 spin_unlock(&efivars->lock);
794                 efivar_unregister(var);
795                 drop_nlink(inode);
796                 d_delete(file->f_dentry);
797                 dput(file->f_dentry);
798
799         } else {
800                 spin_unlock(&efivars->lock);
801                 pr_warn("efivarfs: inconsistent EFI variable implementation? "
802                                 "status = %lx\n", status);
803         }
804
805 out:
806         kfree(data);
807
808         return bytes;
809 }
810
811 static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
812                 size_t count, loff_t *ppos)
813 {
814         struct efivar_entry *var = file->private_data;
815         struct efivars *efivars = var->efivars;
816         efi_status_t status;
817         unsigned long datasize = 0;
818         u32 attributes;
819         void *data;
820         ssize_t size = 0;
821
822         spin_lock(&efivars->lock);
823         status = efivars->ops->get_variable(var->var.VariableName,
824                                             &var->var.VendorGuid,
825                                             &attributes, &datasize, NULL);
826         spin_unlock(&efivars->lock);
827
828         if (status != EFI_BUFFER_TOO_SMALL)
829                 return efi_status_to_err(status);
830
831         data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
832
833         if (!data)
834                 return -ENOMEM;
835
836         spin_lock(&efivars->lock);
837         status = efivars->ops->get_variable(var->var.VariableName,
838                                             &var->var.VendorGuid,
839                                             &attributes, &datasize,
840                                             (data + sizeof(attributes)));
841         spin_unlock(&efivars->lock);
842
843         if (status != EFI_SUCCESS) {
844                 size = efi_status_to_err(status);
845                 goto out_free;
846         }
847
848         memcpy(data, &attributes, sizeof(attributes));
849         size = simple_read_from_buffer(userbuf, count, ppos,
850                                        data, datasize + sizeof(attributes));
851 out_free:
852         kfree(data);
853
854         return size;
855 }
856
857 static void efivarfs_evict_inode(struct inode *inode)
858 {
859         clear_inode(inode);
860 }
861
862 static const struct super_operations efivarfs_ops = {
863         .statfs = simple_statfs,
864         .drop_inode = generic_delete_inode,
865         .evict_inode = efivarfs_evict_inode,
866         .show_options = generic_show_options,
867 };
868
869 static struct super_block *efivarfs_sb;
870
871 static const struct inode_operations efivarfs_dir_inode_operations;
872
873 static const struct file_operations efivarfs_file_operations = {
874         .open   = efivarfs_file_open,
875         .read   = efivarfs_file_read,
876         .write  = efivarfs_file_write,
877         .llseek = no_llseek,
878 };
879
880 static struct inode *efivarfs_get_inode(struct super_block *sb,
881                                 const struct inode *dir, int mode, dev_t dev)
882 {
883         struct inode *inode = new_inode(sb);
884
885         if (inode) {
886                 inode->i_ino = get_next_ino();
887                 inode->i_mode = mode;
888                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
889                 switch (mode & S_IFMT) {
890                 case S_IFREG:
891                         inode->i_fop = &efivarfs_file_operations;
892                         break;
893                 case S_IFDIR:
894                         inode->i_op = &efivarfs_dir_inode_operations;
895                         inode->i_fop = &simple_dir_operations;
896                         inc_nlink(inode);
897                         break;
898                 }
899         }
900         return inode;
901 }
902
903 static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
904 {
905         guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
906         guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
907         guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
908         guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
909         guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
910         guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
911         guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
912         guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
913         guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
914         guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
915         guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
916         guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
917         guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
918         guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
919         guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
920         guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
921 }
922
923 static int efivarfs_create(struct inode *dir, struct dentry *dentry,
924                           umode_t mode, bool excl)
925 {
926         struct inode *inode;
927         struct efivars *efivars = &__efivars;
928         struct efivar_entry *var;
929         int namelen, i = 0, err = 0;
930
931         /*
932          * We need a GUID, plus at least one letter for the variable name,
933          * plus the '-' separator
934          */
935         if (dentry->d_name.len < GUID_LEN + 2)
936                 return -EINVAL;
937
938         inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
939         if (!inode)
940                 return -ENOMEM;
941
942         var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
943         if (!var) {
944                 err = -ENOMEM;
945                 goto out;
946         }
947
948         /* length of the variable name itself: remove GUID and separator */
949         namelen = dentry->d_name.len - GUID_LEN - 1;
950
951         efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
952                         &var->var.VendorGuid);
953
954         for (i = 0; i < namelen; i++)
955                 var->var.VariableName[i] = dentry->d_name.name[i];
956
957         var->var.VariableName[i] = '\0';
958
959         inode->i_private = var;
960         var->efivars = efivars;
961         var->kobj.kset = efivars->kset;
962
963         err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
964                              dentry->d_name.name);
965         if (err)
966                 goto out;
967
968         kobject_uevent(&var->kobj, KOBJ_ADD);
969         spin_lock(&efivars->lock);
970         list_add(&var->list, &efivars->list);
971         spin_unlock(&efivars->lock);
972         d_instantiate(dentry, inode);
973         dget(dentry);
974 out:
975         if (err) {
976                 kfree(var);
977                 iput(inode);
978         }
979         return err;
980 }
981
982 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
983 {
984         struct efivar_entry *var = dentry->d_inode->i_private;
985         struct efivars *efivars = var->efivars;
986         efi_status_t status;
987
988         spin_lock(&efivars->lock);
989
990         status = efivars->ops->set_variable(var->var.VariableName,
991                                             &var->var.VendorGuid,
992                                             0, 0, NULL);
993
994         if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
995                 list_del(&var->list);
996                 spin_unlock(&efivars->lock);
997                 efivar_unregister(var);
998                 drop_nlink(dentry->d_inode);
999                 dput(dentry);
1000                 return 0;
1001         }
1002
1003         spin_unlock(&efivars->lock);
1004         return -EINVAL;
1005 };
1006
1007 static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
1008 {
1009         struct inode *inode = NULL;
1010         struct dentry *root;
1011         struct efivar_entry *entry, *n;
1012         struct efivars *efivars = &__efivars;
1013         char *name;
1014
1015         efivarfs_sb = sb;
1016
1017         sb->s_maxbytes          = MAX_LFS_FILESIZE;
1018         sb->s_blocksize         = PAGE_CACHE_SIZE;
1019         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
1020         sb->s_magic             = EFIVARFS_MAGIC;
1021         sb->s_op                = &efivarfs_ops;
1022         sb->s_time_gran         = 1;
1023
1024         inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
1025         if (!inode)
1026                 return -ENOMEM;
1027         inode->i_op = &efivarfs_dir_inode_operations;
1028
1029         root = d_make_root(inode);
1030         sb->s_root = root;
1031         if (!root)
1032                 return -ENOMEM;
1033
1034         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1035                 struct dentry *dentry, *root = efivarfs_sb->s_root;
1036                 unsigned long size = 0;
1037                 int len, i;
1038
1039                 inode = NULL;
1040
1041                 len = utf16_strlen(entry->var.VariableName);
1042
1043                 /* name, plus '-', plus GUID, plus NUL*/
1044                 name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
1045                 if (!name)
1046                         goto fail;
1047
1048                 for (i = 0; i < len; i++)
1049                         name[i] = entry->var.VariableName[i] & 0xFF;
1050
1051                 name[len] = '-';
1052
1053                 efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
1054
1055                 name[len+GUID_LEN+1] = '\0';
1056
1057                 inode = efivarfs_get_inode(efivarfs_sb, root->d_inode,
1058                                           S_IFREG | 0644, 0);
1059                 if (!inode)
1060                         goto fail_name;
1061
1062                 dentry = d_alloc_name(root, name);
1063                 if (!dentry)
1064                         goto fail_inode;
1065
1066                 /* copied by the above to local storage in the dentry. */
1067                 kfree(name);
1068
1069                 spin_lock(&efivars->lock);
1070                 efivars->ops->get_variable(entry->var.VariableName,
1071                                            &entry->var.VendorGuid,
1072                                            &entry->var.Attributes,
1073                                            &size,
1074                                            NULL);
1075                 spin_unlock(&efivars->lock);
1076
1077                 mutex_lock(&inode->i_mutex);
1078                 inode->i_private = entry;
1079                 i_size_write(inode, size+4);
1080                 mutex_unlock(&inode->i_mutex);
1081                 d_add(dentry, inode);
1082         }
1083
1084         return 0;
1085
1086 fail_inode:
1087         iput(inode);
1088 fail_name:
1089         kfree(name);
1090 fail:
1091         return -ENOMEM;
1092 }
1093
1094 static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
1095                                     int flags, const char *dev_name, void *data)
1096 {
1097         return mount_single(fs_type, flags, data, efivarfs_fill_super);
1098 }
1099
1100 static void efivarfs_kill_sb(struct super_block *sb)
1101 {
1102         kill_litter_super(sb);
1103         efivarfs_sb = NULL;
1104 }
1105
1106 static struct file_system_type efivarfs_type = {
1107         .name    = "efivarfs",
1108         .mount   = efivarfs_mount,
1109         .kill_sb = efivarfs_kill_sb,
1110 };
1111
1112 static const struct inode_operations efivarfs_dir_inode_operations = {
1113         .lookup = simple_lookup,
1114         .unlink = efivarfs_unlink,
1115         .create = efivarfs_create,
1116 };
1117
1118 static struct pstore_info efi_pstore_info;
1119
1120 #ifdef CONFIG_PSTORE
1121
1122 static int efi_pstore_open(struct pstore_info *psi)
1123 {
1124         struct efivars *efivars = psi->data;
1125
1126         spin_lock(&efivars->lock);
1127         efivars->walk_entry = list_first_entry(&efivars->list,
1128                                                struct efivar_entry, list);
1129         return 0;
1130 }
1131
1132 static int efi_pstore_close(struct pstore_info *psi)
1133 {
1134         struct efivars *efivars = psi->data;
1135
1136         spin_unlock(&efivars->lock);
1137         return 0;
1138 }
1139
1140 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1141                                int *count, struct timespec *timespec,
1142                                char **buf, struct pstore_info *psi)
1143 {
1144         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1145         struct efivars *efivars = psi->data;
1146         char name[DUMP_NAME_LEN];
1147         int i;
1148         int cnt;
1149         unsigned int part, size;
1150         unsigned long time;
1151
1152         while (&efivars->walk_entry->list != &efivars->list) {
1153                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
1154                                  vendor)) {
1155                         for (i = 0; i < DUMP_NAME_LEN; i++) {
1156                                 name[i] = efivars->walk_entry->var.VariableName[i];
1157                         }
1158                         if (sscanf(name, "dump-type%u-%u-%d-%lu",
1159                                    type, &part, &cnt, &time) == 4) {
1160                                 *id = part;
1161                                 *count = cnt;
1162                                 timespec->tv_sec = time;
1163                                 timespec->tv_nsec = 0;
1164                         } else if (sscanf(name, "dump-type%u-%u-%lu",
1165                                    type, &part, &time) == 3) {
1166                                 /*
1167                                  * Check if an old format,
1168                                  * which doesn't support holding
1169                                  * multiple logs, remains.
1170                                  */
1171                                 *id = part;
1172                                 *count = 0;
1173                                 timespec->tv_sec = time;
1174                                 timespec->tv_nsec = 0;
1175                         } else {
1176                                 efivars->walk_entry = list_entry(
1177                                                 efivars->walk_entry->list.next,
1178                                                 struct efivar_entry, list);
1179                                 continue;
1180                         }
1181
1182                         get_var_data_locked(efivars, &efivars->walk_entry->var);
1183                         size = efivars->walk_entry->var.DataSize;
1184                         *buf = kmalloc(size, GFP_KERNEL);
1185                         if (*buf == NULL)
1186                                 return -ENOMEM;
1187                         memcpy(*buf, efivars->walk_entry->var.Data,
1188                                size);
1189                         efivars->walk_entry = list_entry(
1190                                         efivars->walk_entry->list.next,
1191                                         struct efivar_entry, list);
1192                         return size;
1193                 }
1194                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1195                                                  struct efivar_entry, list);
1196         }
1197         return 0;
1198 }
1199
1200 static int efi_pstore_write(enum pstore_type_id type,
1201                 enum kmsg_dump_reason reason, u64 *id,
1202                 unsigned int part, int count, size_t size,
1203                 struct pstore_info *psi)
1204 {
1205         char name[DUMP_NAME_LEN];
1206         efi_char16_t efi_name[DUMP_NAME_LEN];
1207         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1208         struct efivars *efivars = psi->data;
1209         int i, ret = 0;
1210         u64 storage_space, remaining_space, max_variable_size;
1211         efi_status_t status = EFI_NOT_FOUND;
1212
1213         spin_lock(&efivars->lock);
1214
1215         /*
1216          * Check if there is a space enough to log.
1217          * size: a size of logging data
1218          * DUMP_NAME_LEN * 2: a maximum size of variable name
1219          */
1220         status = efivars->ops->query_variable_info(PSTORE_EFI_ATTRIBUTES,
1221                                                    &storage_space,
1222                                                    &remaining_space,
1223                                                    &max_variable_size);
1224         if (status || remaining_space < size + DUMP_NAME_LEN * 2) {
1225                 spin_unlock(&efivars->lock);
1226                 *id = part;
1227                 return -ENOSPC;
1228         }
1229
1230         sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
1231                 get_seconds());
1232
1233         for (i = 0; i < DUMP_NAME_LEN; i++)
1234                 efi_name[i] = name[i];
1235
1236         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
1237                                    size, psi->buf);
1238
1239         spin_unlock(&efivars->lock);
1240
1241         if (size)
1242                 ret = efivar_create_sysfs_entry(efivars,
1243                                           utf16_strsize(efi_name,
1244                                                         DUMP_NAME_LEN * 2),
1245                                           efi_name, &vendor);
1246
1247         *id = part;
1248         return ret;
1249 };
1250
1251 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1252                             struct timespec time, struct pstore_info *psi)
1253 {
1254         char name[DUMP_NAME_LEN];
1255         efi_char16_t efi_name[DUMP_NAME_LEN];
1256         char name_old[DUMP_NAME_LEN];
1257         efi_char16_t efi_name_old[DUMP_NAME_LEN];
1258         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1259         struct efivars *efivars = psi->data;
1260         struct efivar_entry *entry, *found = NULL;
1261         int i;
1262
1263         sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
1264                 time.tv_sec);
1265
1266         spin_lock(&efivars->lock);
1267
1268         for (i = 0; i < DUMP_NAME_LEN; i++)
1269                 efi_name[i] = name[i];
1270
1271         /*
1272          * Clean up an entry with the same name
1273          */
1274
1275         list_for_each_entry(entry, &efivars->list, list) {
1276                 get_var_data_locked(efivars, &entry->var);
1277
1278                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
1279                         continue;
1280                 if (utf16_strncmp(entry->var.VariableName, efi_name,
1281                                   utf16_strlen(efi_name))) {
1282                         /*
1283                          * Check if an old format,
1284                          * which doesn't support holding
1285                          * multiple logs, remains.
1286                          */
1287                         sprintf(name_old, "dump-type%u-%u-%lu", type,
1288                                 (unsigned int)id, time.tv_sec);
1289
1290                         for (i = 0; i < DUMP_NAME_LEN; i++)
1291                                 efi_name_old[i] = name_old[i];
1292
1293                         if (utf16_strncmp(entry->var.VariableName, efi_name_old,
1294                                           utf16_strlen(efi_name_old)))
1295                                 continue;
1296                 }
1297
1298                 /* found */
1299                 found = entry;
1300                 efivars->ops->set_variable(entry->var.VariableName,
1301                                            &entry->var.VendorGuid,
1302                                            PSTORE_EFI_ATTRIBUTES,
1303                                            0, NULL);
1304                 break;
1305         }
1306
1307         if (found)
1308                 list_del(&found->list);
1309
1310         spin_unlock(&efivars->lock);
1311
1312         if (found)
1313                 efivar_unregister(found);
1314
1315         return 0;
1316 }
1317 #else
1318 static int efi_pstore_open(struct pstore_info *psi)
1319 {
1320         return 0;
1321 }
1322
1323 static int efi_pstore_close(struct pstore_info *psi)
1324 {
1325         return 0;
1326 }
1327
1328 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, int *count,
1329                                struct timespec *timespec,
1330                                char **buf, struct pstore_info *psi)
1331 {
1332         return -1;
1333 }
1334
1335 static int efi_pstore_write(enum pstore_type_id type,
1336                 enum kmsg_dump_reason reason, u64 *id,
1337                 unsigned int part, int count, size_t size,
1338                 struct pstore_info *psi)
1339 {
1340         return 0;
1341 }
1342
1343 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1344                             struct timespec time, struct pstore_info *psi)
1345 {
1346         return 0;
1347 }
1348 #endif
1349
1350 static struct pstore_info efi_pstore_info = {
1351         .owner          = THIS_MODULE,
1352         .name           = "efi",
1353         .open           = efi_pstore_open,
1354         .close          = efi_pstore_close,
1355         .read           = efi_pstore_read,
1356         .write          = efi_pstore_write,
1357         .erase          = efi_pstore_erase,
1358 };
1359
1360 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
1361                              struct bin_attribute *bin_attr,
1362                              char *buf, loff_t pos, size_t count)
1363 {
1364         struct efi_variable *new_var = (struct efi_variable *)buf;
1365         struct efivars *efivars = bin_attr->private;
1366         struct efivar_entry *search_efivar, *n;
1367         unsigned long strsize1, strsize2;
1368         efi_status_t status = EFI_NOT_FOUND;
1369         int found = 0;
1370
1371         if (!capable(CAP_SYS_ADMIN))
1372                 return -EACCES;
1373
1374         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
1375             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
1376                 printk(KERN_ERR "efivars: Malformed variable content\n");
1377                 return -EINVAL;
1378         }
1379
1380         spin_lock(&efivars->lock);
1381
1382         /*
1383          * Does this variable already exist?
1384          */
1385         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1386                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1387                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
1388                 if (strsize1 == strsize2 &&
1389                         !memcmp(&(search_efivar->var.VariableName),
1390                                 new_var->VariableName, strsize1) &&
1391                         !efi_guidcmp(search_efivar->var.VendorGuid,
1392                                 new_var->VendorGuid)) {
1393                         found = 1;
1394                         break;
1395                 }
1396         }
1397         if (found) {
1398                 spin_unlock(&efivars->lock);
1399                 return -EINVAL;
1400         }
1401
1402         /* now *really* create the variable via EFI */
1403         status = efivars->ops->set_variable(new_var->VariableName,
1404                                             &new_var->VendorGuid,
1405                                             new_var->Attributes,
1406                                             new_var->DataSize,
1407                                             new_var->Data);
1408
1409         if (status != EFI_SUCCESS) {
1410                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1411                         status);
1412                 spin_unlock(&efivars->lock);
1413                 return -EIO;
1414         }
1415         spin_unlock(&efivars->lock);
1416
1417         /* Create the entry in sysfs.  Locking is not required here */
1418         status = efivar_create_sysfs_entry(efivars,
1419                                            utf16_strsize(new_var->VariableName,
1420                                                          1024),
1421                                            new_var->VariableName,
1422                                            &new_var->VendorGuid);
1423         if (status) {
1424                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
1425         }
1426         return count;
1427 }
1428
1429 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
1430                              struct bin_attribute *bin_attr,
1431                              char *buf, loff_t pos, size_t count)
1432 {
1433         struct efi_variable *del_var = (struct efi_variable *)buf;
1434         struct efivars *efivars = bin_attr->private;
1435         struct efivar_entry *search_efivar, *n;
1436         unsigned long strsize1, strsize2;
1437         efi_status_t status = EFI_NOT_FOUND;
1438         int found = 0;
1439
1440         if (!capable(CAP_SYS_ADMIN))
1441                 return -EACCES;
1442
1443         spin_lock(&efivars->lock);
1444
1445         /*
1446          * Does this variable already exist?
1447          */
1448         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1449                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1450                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
1451                 if (strsize1 == strsize2 &&
1452                         !memcmp(&(search_efivar->var.VariableName),
1453                                 del_var->VariableName, strsize1) &&
1454                         !efi_guidcmp(search_efivar->var.VendorGuid,
1455                                 del_var->VendorGuid)) {
1456                         found = 1;
1457                         break;
1458                 }
1459         }
1460         if (!found) {
1461                 spin_unlock(&efivars->lock);
1462                 return -EINVAL;
1463         }
1464         /* force the Attributes/DataSize to 0 to ensure deletion */
1465         del_var->Attributes = 0;
1466         del_var->DataSize = 0;
1467
1468         status = efivars->ops->set_variable(del_var->VariableName,
1469                                             &del_var->VendorGuid,
1470                                             del_var->Attributes,
1471                                             del_var->DataSize,
1472                                             del_var->Data);
1473
1474         if (status != EFI_SUCCESS) {
1475                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1476                         status);
1477                 spin_unlock(&efivars->lock);
1478                 return -EIO;
1479         }
1480         list_del(&search_efivar->list);
1481         /* We need to release this lock before unregistering. */
1482         spin_unlock(&efivars->lock);
1483         efivar_unregister(search_efivar);
1484
1485         /* It's dead Jim.... */
1486         return count;
1487 }
1488
1489 /*
1490  * Let's not leave out systab information that snuck into
1491  * the efivars driver
1492  */
1493 static ssize_t systab_show(struct kobject *kobj,
1494                            struct kobj_attribute *attr, char *buf)
1495 {
1496         char *str = buf;
1497
1498         if (!kobj || !buf)
1499                 return -EINVAL;
1500
1501         if (efi.mps != EFI_INVALID_TABLE_ADDR)
1502                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1503         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1504                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1505         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1506                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1507         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1508                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1509         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1510                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1511         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1512                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1513         if (efi.uga != EFI_INVALID_TABLE_ADDR)
1514                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1515
1516         return str - buf;
1517 }
1518
1519 static struct kobj_attribute efi_attr_systab =
1520                         __ATTR(systab, 0400, systab_show, NULL);
1521
1522 static struct attribute *efi_subsys_attrs[] = {
1523         &efi_attr_systab.attr,
1524         NULL,   /* maybe more in the future? */
1525 };
1526
1527 static struct attribute_group efi_subsys_attr_group = {
1528         .attrs = efi_subsys_attrs,
1529 };
1530
1531 static struct kobject *efi_kobj;
1532
1533 /*
1534  * efivar_create_sysfs_entry()
1535  * Requires:
1536  *    variable_name_size = number of bytes required to hold
1537  *                         variable_name (not counting the NULL
1538  *                         character at the end.
1539  *    efivars->lock is not held on entry or exit.
1540  * Returns 1 on failure, 0 on success
1541  */
1542 static int
1543 efivar_create_sysfs_entry(struct efivars *efivars,
1544                           unsigned long variable_name_size,
1545                           efi_char16_t *variable_name,
1546                           efi_guid_t *vendor_guid)
1547 {
1548         int i, short_name_size;
1549         char *short_name;
1550         struct efivar_entry *new_efivar;
1551
1552         /*
1553          * Length of the variable bytes in ASCII, plus the '-' separator,
1554          * plus the GUID, plus trailing NUL
1555          */
1556         short_name_size = variable_name_size / sizeof(efi_char16_t)
1557                                 + 1 + GUID_LEN + 1;
1558
1559         short_name = kzalloc(short_name_size, GFP_KERNEL);
1560         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1561
1562         if (!short_name || !new_efivar)  {
1563                 kfree(short_name);
1564                 kfree(new_efivar);
1565                 return 1;
1566         }
1567
1568         new_efivar->efivars = efivars;
1569         memcpy(new_efivar->var.VariableName, variable_name,
1570                 variable_name_size);
1571         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1572
1573         /* Convert Unicode to normal chars (assume top bits are 0),
1574            ala UTF-8 */
1575         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1576                 short_name[i] = variable_name[i] & 0xFF;
1577         }
1578         /* This is ugly, but necessary to separate one vendor's
1579            private variables from another's.         */
1580
1581         *(short_name + strlen(short_name)) = '-';
1582         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1583
1584         new_efivar->kobj.kset = efivars->kset;
1585         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1586                                  "%s", short_name);
1587         if (i) {
1588                 kfree(short_name);
1589                 kfree(new_efivar);
1590                 return 1;
1591         }
1592
1593         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1594         kfree(short_name);
1595         short_name = NULL;
1596
1597         spin_lock(&efivars->lock);
1598         list_add(&new_efivar->list, &efivars->list);
1599         spin_unlock(&efivars->lock);
1600
1601         return 0;
1602 }
1603
1604 static int
1605 create_efivars_bin_attributes(struct efivars *efivars)
1606 {
1607         struct bin_attribute *attr;
1608         int error;
1609
1610         /* new_var */
1611         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1612         if (!attr)
1613                 return -ENOMEM;
1614
1615         attr->attr.name = "new_var";
1616         attr->attr.mode = 0200;
1617         attr->write = efivar_create;
1618         attr->private = efivars;
1619         efivars->new_var = attr;
1620
1621         /* del_var */
1622         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1623         if (!attr) {
1624                 error = -ENOMEM;
1625                 goto out_free;
1626         }
1627         attr->attr.name = "del_var";
1628         attr->attr.mode = 0200;
1629         attr->write = efivar_delete;
1630         attr->private = efivars;
1631         efivars->del_var = attr;
1632
1633         sysfs_bin_attr_init(efivars->new_var);
1634         sysfs_bin_attr_init(efivars->del_var);
1635
1636         /* Register */
1637         error = sysfs_create_bin_file(&efivars->kset->kobj,
1638                                       efivars->new_var);
1639         if (error) {
1640                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1641                         " due to error %d\n", error);
1642                 goto out_free;
1643         }
1644         error = sysfs_create_bin_file(&efivars->kset->kobj,
1645                                       efivars->del_var);
1646         if (error) {
1647                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1648                         " due to error %d\n", error);
1649                 sysfs_remove_bin_file(&efivars->kset->kobj,
1650                                       efivars->new_var);
1651                 goto out_free;
1652         }
1653
1654         return 0;
1655 out_free:
1656         kfree(efivars->del_var);
1657         efivars->del_var = NULL;
1658         kfree(efivars->new_var);
1659         efivars->new_var = NULL;
1660         return error;
1661 }
1662
1663 void unregister_efivars(struct efivars *efivars)
1664 {
1665         struct efivar_entry *entry, *n;
1666
1667         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1668                 spin_lock(&efivars->lock);
1669                 list_del(&entry->list);
1670                 spin_unlock(&efivars->lock);
1671                 efivar_unregister(entry);
1672         }
1673         if (efivars->new_var)
1674                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1675         if (efivars->del_var)
1676                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1677         kfree(efivars->new_var);
1678         kfree(efivars->del_var);
1679         kobject_put(efivars->kobject);
1680         kset_unregister(efivars->kset);
1681 }
1682 EXPORT_SYMBOL_GPL(unregister_efivars);
1683
1684 int register_efivars(struct efivars *efivars,
1685                      const struct efivar_operations *ops,
1686                      struct kobject *parent_kobj)
1687 {
1688         efi_status_t status = EFI_NOT_FOUND;
1689         efi_guid_t vendor_guid;
1690         efi_char16_t *variable_name;
1691         unsigned long variable_name_size = 1024;
1692         int error = 0;
1693
1694         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1695         if (!variable_name) {
1696                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1697                 return -ENOMEM;
1698         }
1699
1700         spin_lock_init(&efivars->lock);
1701         INIT_LIST_HEAD(&efivars->list);
1702         efivars->ops = ops;
1703
1704         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1705         if (!efivars->kset) {
1706                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1707                 error = -ENOMEM;
1708                 goto out;
1709         }
1710
1711         efivars->kobject = kobject_create_and_add("efivars", parent_kobj);
1712         if (!efivars->kobject) {
1713                 pr_err("efivars: Subsystem registration failed.\n");
1714                 error = -ENOMEM;
1715                 kset_unregister(efivars->kset);
1716                 goto out;
1717         }
1718
1719         /*
1720          * Per EFI spec, the maximum storage allocated for both
1721          * the variable name and variable data is 1024 bytes.
1722          */
1723
1724         do {
1725                 variable_name_size = 1024;
1726
1727                 status = ops->get_next_variable(&variable_name_size,
1728                                                 variable_name,
1729                                                 &vendor_guid);
1730                 switch (status) {
1731                 case EFI_SUCCESS:
1732                         efivar_create_sysfs_entry(efivars,
1733                                                   variable_name_size,
1734                                                   variable_name,
1735                                                   &vendor_guid);
1736                         break;
1737                 case EFI_NOT_FOUND:
1738                         break;
1739                 default:
1740                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1741                                 status);
1742                         status = EFI_NOT_FOUND;
1743                         break;
1744                 }
1745         } while (status != EFI_NOT_FOUND);
1746
1747         error = create_efivars_bin_attributes(efivars);
1748         if (error)
1749                 unregister_efivars(efivars);
1750
1751         efivars->efi_pstore_info = efi_pstore_info;
1752
1753         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1754         if (efivars->efi_pstore_info.buf) {
1755                 efivars->efi_pstore_info.bufsize = 1024;
1756                 efivars->efi_pstore_info.data = efivars;
1757                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1758                 pstore_register(&efivars->efi_pstore_info);
1759         }
1760
1761         register_filesystem(&efivarfs_type);
1762
1763 out:
1764         kfree(variable_name);
1765
1766         return error;
1767 }
1768 EXPORT_SYMBOL_GPL(register_efivars);
1769
1770 /*
1771  * For now we register the efi subsystem with the firmware subsystem
1772  * and the vars subsystem with the efi subsystem.  In the future, it
1773  * might make sense to split off the efi subsystem into its own
1774  * driver, but for now only efivars will register with it, so just
1775  * include it here.
1776  */
1777
1778 static int __init
1779 efivars_init(void)
1780 {
1781         int error = 0;
1782
1783         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1784                EFIVARS_DATE);
1785
1786         if (!efi_enabled)
1787                 return 0;
1788
1789         /* For now we'll register the efi directory at /sys/firmware/efi */
1790         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1791         if (!efi_kobj) {
1792                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1793                 return -ENOMEM;
1794         }
1795
1796         ops.get_variable = efi.get_variable;
1797         ops.set_variable = efi.set_variable;
1798         ops.get_next_variable = efi.get_next_variable;
1799         ops.query_variable_info = efi.query_variable_info;
1800
1801         error = register_efivars(&__efivars, &ops, efi_kobj);
1802         if (error)
1803                 goto err_put;
1804
1805         /* Don't forget the systab entry */
1806         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1807         if (error) {
1808                 printk(KERN_ERR
1809                        "efivars: Sysfs attribute export failed with error %d.\n",
1810                        error);
1811                 goto err_unregister;
1812         }
1813
1814         return 0;
1815
1816 err_unregister:
1817         unregister_efivars(&__efivars);
1818 err_put:
1819         kobject_put(efi_kobj);
1820         return error;
1821 }
1822
1823 static void __exit
1824 efivars_exit(void)
1825 {
1826         if (efi_enabled) {
1827                 unregister_efivars(&__efivars);
1828                 kobject_put(efi_kobj);
1829         }
1830 }
1831
1832 module_init(efivars_init);
1833 module_exit(efivars_exit);
1834