Merge branch 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-3.10.git] / drivers / firmware / efivars.c
1 /*
2  * EFI Variables - efivars.c
3  *
4  * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
5  * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
6  *
7  * This code takes all variables accessible from EFI runtime and
8  *  exports them via sysfs
9  *
10  *  This program is free software; you can redistribute it and/or modify
11  *  it under the terms of the GNU General Public License as published by
12  *  the Free Software Foundation; either version 2 of the License, or
13  *  (at your option) any later version.
14  *
15  *  This program is distributed in the hope that it will be useful,
16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  *  GNU General Public License for more details.
19  *
20  *  You should have received a copy of the GNU General Public License
21  *  along with this program; if not, write to the Free Software
22  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
23  *
24  * Changelog:
25  *
26  *  17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
27  *   remove check for efi_enabled in exit
28  *   add MODULE_VERSION
29  *
30  *  26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com>
31  *   minor bug fixes
32  *
33  *  21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com)
34  *   converted driver to export variable information via sysfs
35  *   and moved to drivers/firmware directory
36  *   bumped revision number to v0.07 to reflect conversion & move
37  *
38  *  10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com>
39  *   fix locking per Peter Chubb's findings
40  *
41  *  25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com>
42  *   move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_unparse()
43  *
44  *  12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com>
45  *   use list_for_each_safe when deleting vars.
46  *   remove ifdef CONFIG_SMP around include <linux/smp.h>
47  *   v0.04 release to linux-ia64@linuxia64.org
48  *
49  *  20 April 2001 - Matt Domsch <Matt_Domsch@dell.com>
50  *   Moved vars from /proc/efi to /proc/efi/vars, and made
51  *   efi.c own the /proc/efi directory.
52  *   v0.03 release to linux-ia64@linuxia64.org
53  *
54  *  26 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
55  *   At the request of Stephane, moved ownership of /proc/efi
56  *   to efi.c, and now efivars lives under /proc/efi/vars.
57  *
58  *  12 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
59  *   Feedback received from Stephane Eranian incorporated.
60  *   efivar_write() checks copy_from_user() return value.
61  *   efivar_read/write() returns proper errno.
62  *   v0.02 release to linux-ia64@linuxia64.org
63  *
64  *  26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
65  *   v0.01 release to linux-ia64@linuxia64.org
66  */
67
68 #include <linux/capability.h>
69 #include <linux/types.h>
70 #include <linux/errno.h>
71 #include <linux/init.h>
72 #include <linux/mm.h>
73 #include <linux/module.h>
74 #include <linux/string.h>
75 #include <linux/smp.h>
76 #include <linux/efi.h>
77 #include <linux/sysfs.h>
78 #include <linux/kobject.h>
79 #include <linux/device.h>
80 #include <linux/slab.h>
81 #include <linux/pstore.h>
82 #include <linux/ctype.h>
83
84 #include <linux/fs.h>
85 #include <linux/ramfs.h>
86 #include <linux/pagemap.h>
87
88 #include <asm/uaccess.h>
89
90 #define EFIVARS_VERSION "0.08"
91 #define EFIVARS_DATE "2004-May-17"
92
93 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
94 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
95 MODULE_LICENSE("GPL");
96 MODULE_VERSION(EFIVARS_VERSION);
97
98 #define DUMP_NAME_LEN 52
99
100 /*
101  * Length of a GUID string (strlen("aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"))
102  * not including trailing NUL
103  */
104 #define GUID_LEN 36
105
106 /*
107  * The maximum size of VariableName + Data = 1024
108  * Therefore, it's reasonable to save that much
109  * space in each part of the structure,
110  * and we use a page for reading/writing.
111  */
112
113 struct efi_variable {
114         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
115         efi_guid_t    VendorGuid;
116         unsigned long DataSize;
117         __u8          Data[1024];
118         efi_status_t  Status;
119         __u32         Attributes;
120 } __attribute__((packed));
121
122 struct efivar_entry {
123         struct efivars *efivars;
124         struct efi_variable var;
125         struct list_head list;
126         struct kobject kobj;
127 };
128
129 struct efivar_attribute {
130         struct attribute attr;
131         ssize_t (*show) (struct efivar_entry *entry, char *buf);
132         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
133 };
134
135 static struct efivars __efivars;
136 static struct efivar_operations ops;
137
138 #define PSTORE_EFI_ATTRIBUTES \
139         (EFI_VARIABLE_NON_VOLATILE | \
140          EFI_VARIABLE_BOOTSERVICE_ACCESS | \
141          EFI_VARIABLE_RUNTIME_ACCESS)
142
143 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
144 struct efivar_attribute efivar_attr_##_name = { \
145         .attr = {.name = __stringify(_name), .mode = _mode}, \
146         .show = _show, \
147         .store = _store, \
148 };
149
150 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
151 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
152
153 /*
154  * Prototype for sysfs creation function
155  */
156 static int
157 efivar_create_sysfs_entry(struct efivars *efivars,
158                           unsigned long variable_name_size,
159                           efi_char16_t *variable_name,
160                           efi_guid_t *vendor_guid);
161
162 /*
163  * Prototype for workqueue functions updating sysfs entry
164  */
165
166 static void efivar_update_sysfs_entries(struct work_struct *);
167 static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
168
169 /* Return the number of unicode characters in data */
170 static unsigned long
171 utf16_strnlen(efi_char16_t *s, size_t maxlength)
172 {
173         unsigned long length = 0;
174
175         while (*s++ != 0 && length < maxlength)
176                 length++;
177         return length;
178 }
179
180 static inline unsigned long
181 utf16_strlen(efi_char16_t *s)
182 {
183         return utf16_strnlen(s, ~0UL);
184 }
185
186 /*
187  * Return the number of bytes is the length of this string
188  * Note: this is NOT the same as the number of unicode characters
189  */
190 static inline unsigned long
191 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
192 {
193         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
194 }
195
196 static inline int
197 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
198 {
199         while (1) {
200                 if (len == 0)
201                         return 0;
202                 if (*a < *b)
203                         return -1;
204                 if (*a > *b)
205                         return 1;
206                 if (*a == 0) /* implies *b == 0 */
207                         return 0;
208                 a++;
209                 b++;
210                 len--;
211         }
212 }
213
214 static bool
215 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
216                      unsigned long len)
217 {
218         struct efi_generic_dev_path *node;
219         int offset = 0;
220
221         node = (struct efi_generic_dev_path *)buffer;
222
223         if (len < sizeof(*node))
224                 return false;
225
226         while (offset <= len - sizeof(*node) &&
227                node->length >= sizeof(*node) &&
228                 node->length <= len - offset) {
229                 offset += node->length;
230
231                 if ((node->type == EFI_DEV_END_PATH ||
232                      node->type == EFI_DEV_END_PATH2) &&
233                     node->sub_type == EFI_DEV_END_ENTIRE)
234                         return true;
235
236                 node = (struct efi_generic_dev_path *)(buffer + offset);
237         }
238
239         /*
240          * If we're here then either node->length pointed past the end
241          * of the buffer or we reached the end of the buffer without
242          * finding a device path end node.
243          */
244         return false;
245 }
246
247 static bool
248 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
249                     unsigned long len)
250 {
251         /* An array of 16-bit integers */
252         if ((len % 2) != 0)
253                 return false;
254
255         return true;
256 }
257
258 static bool
259 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
260                      unsigned long len)
261 {
262         u16 filepathlength;
263         int i, desclength = 0, namelen;
264
265         namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
266
267         /* Either "Boot" or "Driver" followed by four digits of hex */
268         for (i = match; i < match+4; i++) {
269                 if (var->VariableName[i] > 127 ||
270                     hex_to_bin(var->VariableName[i] & 0xff) < 0)
271                         return true;
272         }
273
274         /* Reject it if there's 4 digits of hex and then further content */
275         if (namelen > match + 4)
276                 return false;
277
278         /* A valid entry must be at least 8 bytes */
279         if (len < 8)
280                 return false;
281
282         filepathlength = buffer[4] | buffer[5] << 8;
283
284         /*
285          * There's no stored length for the description, so it has to be
286          * found by hand
287          */
288         desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
289
290         /* Each boot entry must have a descriptor */
291         if (!desclength)
292                 return false;
293
294         /*
295          * If the sum of the length of the description, the claimed filepath
296          * length and the original header are greater than the length of the
297          * variable, it's malformed
298          */
299         if ((desclength + filepathlength + 6) > len)
300                 return false;
301
302         /*
303          * And, finally, check the filepath
304          */
305         return validate_device_path(var, match, buffer + desclength + 6,
306                                     filepathlength);
307 }
308
309 static bool
310 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
311                 unsigned long len)
312 {
313         /* A single 16-bit integer */
314         if (len != 2)
315                 return false;
316
317         return true;
318 }
319
320 static bool
321 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
322                       unsigned long len)
323 {
324         int i;
325
326         for (i = 0; i < len; i++) {
327                 if (buffer[i] > 127)
328                         return false;
329
330                 if (buffer[i] == 0)
331                         return true;
332         }
333
334         return false;
335 }
336
337 struct variable_validate {
338         char *name;
339         bool (*validate)(struct efi_variable *var, int match, u8 *data,
340                          unsigned long len);
341 };
342
343 static const struct variable_validate variable_validate[] = {
344         { "BootNext", validate_uint16 },
345         { "BootOrder", validate_boot_order },
346         { "DriverOrder", validate_boot_order },
347         { "Boot*", validate_load_option },
348         { "Driver*", validate_load_option },
349         { "ConIn", validate_device_path },
350         { "ConInDev", validate_device_path },
351         { "ConOut", validate_device_path },
352         { "ConOutDev", validate_device_path },
353         { "ErrOut", validate_device_path },
354         { "ErrOutDev", validate_device_path },
355         { "Timeout", validate_uint16 },
356         { "Lang", validate_ascii_string },
357         { "PlatformLang", validate_ascii_string },
358         { "", NULL },
359 };
360
361 static bool
362 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
363 {
364         int i;
365         u16 *unicode_name = var->VariableName;
366
367         for (i = 0; variable_validate[i].validate != NULL; i++) {
368                 const char *name = variable_validate[i].name;
369                 int match;
370
371                 for (match = 0; ; match++) {
372                         char c = name[match];
373                         u16 u = unicode_name[match];
374
375                         /* All special variables are plain ascii */
376                         if (u > 127)
377                                 return true;
378
379                         /* Wildcard in the matching name means we've matched */
380                         if (c == '*')
381                                 return variable_validate[i].validate(var,
382                                                              match, data, len);
383
384                         /* Case sensitive match */
385                         if (c != u)
386                                 break;
387
388                         /* Reached the end of the string while matching */
389                         if (!c)
390                                 return variable_validate[i].validate(var,
391                                                              match, data, len);
392                 }
393         }
394
395         return true;
396 }
397
398 static efi_status_t
399 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
400 {
401         efi_status_t status;
402
403         var->DataSize = 1024;
404         status = efivars->ops->get_variable(var->VariableName,
405                                             &var->VendorGuid,
406                                             &var->Attributes,
407                                             &var->DataSize,
408                                             var->Data);
409         return status;
410 }
411
412 static efi_status_t
413 get_var_data(struct efivars *efivars, struct efi_variable *var)
414 {
415         efi_status_t status;
416         unsigned long flags;
417
418         spin_lock_irqsave(&efivars->lock, flags);
419         status = get_var_data_locked(efivars, var);
420         spin_unlock_irqrestore(&efivars->lock, flags);
421
422         if (status != EFI_SUCCESS) {
423                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
424                         status);
425         }
426         return status;
427 }
428
429 static ssize_t
430 efivar_guid_read(struct efivar_entry *entry, char *buf)
431 {
432         struct efi_variable *var = &entry->var;
433         char *str = buf;
434
435         if (!entry || !buf)
436                 return 0;
437
438         efi_guid_unparse(&var->VendorGuid, str);
439         str += strlen(str);
440         str += sprintf(str, "\n");
441
442         return str - buf;
443 }
444
445 static ssize_t
446 efivar_attr_read(struct efivar_entry *entry, char *buf)
447 {
448         struct efi_variable *var = &entry->var;
449         char *str = buf;
450         efi_status_t status;
451
452         if (!entry || !buf)
453                 return -EINVAL;
454
455         status = get_var_data(entry->efivars, var);
456         if (status != EFI_SUCCESS)
457                 return -EIO;
458
459         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
460                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
461         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
462                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
463         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
464                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
465         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
466                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
467         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
468                 str += sprintf(str,
469                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
470         if (var->Attributes &
471                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
472                 str += sprintf(str,
473                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
474         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
475                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
476         return str - buf;
477 }
478
479 static ssize_t
480 efivar_size_read(struct efivar_entry *entry, char *buf)
481 {
482         struct efi_variable *var = &entry->var;
483         char *str = buf;
484         efi_status_t status;
485
486         if (!entry || !buf)
487                 return -EINVAL;
488
489         status = get_var_data(entry->efivars, var);
490         if (status != EFI_SUCCESS)
491                 return -EIO;
492
493         str += sprintf(str, "0x%lx\n", var->DataSize);
494         return str - buf;
495 }
496
497 static ssize_t
498 efivar_data_read(struct efivar_entry *entry, char *buf)
499 {
500         struct efi_variable *var = &entry->var;
501         efi_status_t status;
502
503         if (!entry || !buf)
504                 return -EINVAL;
505
506         status = get_var_data(entry->efivars, var);
507         if (status != EFI_SUCCESS)
508                 return -EIO;
509
510         memcpy(buf, var->Data, var->DataSize);
511         return var->DataSize;
512 }
513 /*
514  * We allow each variable to be edited via rewriting the
515  * entire efi variable structure.
516  */
517 static ssize_t
518 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
519 {
520         struct efi_variable *new_var, *var = &entry->var;
521         struct efivars *efivars = entry->efivars;
522         efi_status_t status = EFI_NOT_FOUND;
523
524         if (count != sizeof(struct efi_variable))
525                 return -EINVAL;
526
527         new_var = (struct efi_variable *)buf;
528         /*
529          * If only updating the variable data, then the name
530          * and guid should remain the same
531          */
532         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
533                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
534                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
535                 return -EINVAL;
536         }
537
538         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
539                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
540                 return -EINVAL;
541         }
542
543         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
544             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
545                 printk(KERN_ERR "efivars: Malformed variable content\n");
546                 return -EINVAL;
547         }
548
549         spin_lock_irq(&efivars->lock);
550         status = efivars->ops->set_variable(new_var->VariableName,
551                                             &new_var->VendorGuid,
552                                             new_var->Attributes,
553                                             new_var->DataSize,
554                                             new_var->Data);
555
556         spin_unlock_irq(&efivars->lock);
557
558         if (status != EFI_SUCCESS) {
559                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
560                         status);
561                 return -EIO;
562         }
563
564         memcpy(&entry->var, new_var, count);
565         return count;
566 }
567
568 static ssize_t
569 efivar_show_raw(struct efivar_entry *entry, char *buf)
570 {
571         struct efi_variable *var = &entry->var;
572         efi_status_t status;
573
574         if (!entry || !buf)
575                 return 0;
576
577         status = get_var_data(entry->efivars, var);
578         if (status != EFI_SUCCESS)
579                 return -EIO;
580
581         memcpy(buf, var, sizeof(*var));
582         return sizeof(*var);
583 }
584
585 /*
586  * Generic read/write functions that call the specific functions of
587  * the attributes...
588  */
589 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
590                                 char *buf)
591 {
592         struct efivar_entry *var = to_efivar_entry(kobj);
593         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
594         ssize_t ret = -EIO;
595
596         if (!capable(CAP_SYS_ADMIN))
597                 return -EACCES;
598
599         if (efivar_attr->show) {
600                 ret = efivar_attr->show(var, buf);
601         }
602         return ret;
603 }
604
605 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
606                                 const char *buf, size_t count)
607 {
608         struct efivar_entry *var = to_efivar_entry(kobj);
609         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
610         ssize_t ret = -EIO;
611
612         if (!capable(CAP_SYS_ADMIN))
613                 return -EACCES;
614
615         if (efivar_attr->store)
616                 ret = efivar_attr->store(var, buf, count);
617
618         return ret;
619 }
620
621 static const struct sysfs_ops efivar_attr_ops = {
622         .show = efivar_attr_show,
623         .store = efivar_attr_store,
624 };
625
626 static void efivar_release(struct kobject *kobj)
627 {
628         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
629         kfree(var);
630 }
631
632 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
633 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
634 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
635 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
636 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
637
638 static struct attribute *def_attrs[] = {
639         &efivar_attr_guid.attr,
640         &efivar_attr_size.attr,
641         &efivar_attr_attributes.attr,
642         &efivar_attr_data.attr,
643         &efivar_attr_raw_var.attr,
644         NULL,
645 };
646
647 static struct kobj_type efivar_ktype = {
648         .release = efivar_release,
649         .sysfs_ops = &efivar_attr_ops,
650         .default_attrs = def_attrs,
651 };
652
653 static inline void
654 efivar_unregister(struct efivar_entry *var)
655 {
656         kobject_put(&var->kobj);
657 }
658
659 static int efivarfs_file_open(struct inode *inode, struct file *file)
660 {
661         file->private_data = inode->i_private;
662         return 0;
663 }
664
665 static int efi_status_to_err(efi_status_t status)
666 {
667         int err;
668
669         switch (status) {
670         case EFI_INVALID_PARAMETER:
671                 err = -EINVAL;
672                 break;
673         case EFI_OUT_OF_RESOURCES:
674                 err = -ENOSPC;
675                 break;
676         case EFI_DEVICE_ERROR:
677                 err = -EIO;
678                 break;
679         case EFI_WRITE_PROTECTED:
680                 err = -EROFS;
681                 break;
682         case EFI_SECURITY_VIOLATION:
683                 err = -EACCES;
684                 break;
685         case EFI_NOT_FOUND:
686                 err = -EIO;
687                 break;
688         default:
689                 err = -EINVAL;
690         }
691
692         return err;
693 }
694
695 static ssize_t efivarfs_file_write(struct file *file,
696                 const char __user *userbuf, size_t count, loff_t *ppos)
697 {
698         struct efivar_entry *var = file->private_data;
699         struct efivars *efivars;
700         efi_status_t status;
701         void *data;
702         u32 attributes;
703         struct inode *inode = file->f_mapping->host;
704         unsigned long datasize = count - sizeof(attributes);
705         unsigned long newdatasize;
706         u64 storage_size, remaining_size, max_size;
707         ssize_t bytes = 0;
708
709         if (count < sizeof(attributes))
710                 return -EINVAL;
711
712         if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
713                 return -EFAULT;
714
715         if (attributes & ~(EFI_VARIABLE_MASK))
716                 return -EINVAL;
717
718         efivars = var->efivars;
719
720         /*
721          * Ensure that the user can't allocate arbitrarily large
722          * amounts of memory. Pick a default size of 64K if
723          * QueryVariableInfo() isn't supported by the firmware.
724          */
725         spin_lock_irq(&efivars->lock);
726
727         if (!efivars->ops->query_variable_info)
728                 status = EFI_UNSUPPORTED;
729         else {
730                 const struct efivar_operations *fops = efivars->ops;
731                 status = fops->query_variable_info(attributes, &storage_size,
732                                                    &remaining_size, &max_size);
733         }
734
735         spin_unlock_irq(&efivars->lock);
736
737         if (status != EFI_SUCCESS) {
738                 if (status != EFI_UNSUPPORTED)
739                         return efi_status_to_err(status);
740
741                 remaining_size = 65536;
742         }
743
744         if (datasize > remaining_size)
745                 return -ENOSPC;
746
747         data = kmalloc(datasize, GFP_KERNEL);
748         if (!data)
749                 return -ENOMEM;
750
751         if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
752                 bytes = -EFAULT;
753                 goto out;
754         }
755
756         if (validate_var(&var->var, data, datasize) == false) {
757                 bytes = -EINVAL;
758                 goto out;
759         }
760
761         /*
762          * The lock here protects the get_variable call, the conditional
763          * set_variable call, and removal of the variable from the efivars
764          * list (in the case of an authenticated delete).
765          */
766         spin_lock_irq(&efivars->lock);
767
768         status = efivars->ops->set_variable(var->var.VariableName,
769                                             &var->var.VendorGuid,
770                                             attributes, datasize,
771                                             data);
772
773         if (status != EFI_SUCCESS) {
774                 spin_unlock_irq(&efivars->lock);
775                 kfree(data);
776
777                 return efi_status_to_err(status);
778         }
779
780         bytes = count;
781
782         /*
783          * Writing to the variable may have caused a change in size (which
784          * could either be an append or an overwrite), or the variable to be
785          * deleted. Perform a GetVariable() so we can tell what actually
786          * happened.
787          */
788         newdatasize = 0;
789         status = efivars->ops->get_variable(var->var.VariableName,
790                                             &var->var.VendorGuid,
791                                             NULL, &newdatasize,
792                                             NULL);
793
794         if (status == EFI_BUFFER_TOO_SMALL) {
795                 spin_unlock_irq(&efivars->lock);
796                 mutex_lock(&inode->i_mutex);
797                 i_size_write(inode, newdatasize + sizeof(attributes));
798                 mutex_unlock(&inode->i_mutex);
799
800         } else if (status == EFI_NOT_FOUND) {
801                 list_del(&var->list);
802                 spin_unlock_irq(&efivars->lock);
803                 efivar_unregister(var);
804                 drop_nlink(inode);
805                 d_delete(file->f_dentry);
806                 dput(file->f_dentry);
807
808         } else {
809                 spin_unlock_irq(&efivars->lock);
810                 pr_warn("efivarfs: inconsistent EFI variable implementation? "
811                                 "status = %lx\n", status);
812         }
813
814 out:
815         kfree(data);
816
817         return bytes;
818 }
819
820 static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
821                 size_t count, loff_t *ppos)
822 {
823         struct efivar_entry *var = file->private_data;
824         struct efivars *efivars = var->efivars;
825         efi_status_t status;
826         unsigned long datasize = 0;
827         u32 attributes;
828         void *data;
829         ssize_t size = 0;
830
831         spin_lock_irq(&efivars->lock);
832         status = efivars->ops->get_variable(var->var.VariableName,
833                                             &var->var.VendorGuid,
834                                             &attributes, &datasize, NULL);
835         spin_unlock_irq(&efivars->lock);
836
837         if (status != EFI_BUFFER_TOO_SMALL)
838                 return efi_status_to_err(status);
839
840         data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
841
842         if (!data)
843                 return -ENOMEM;
844
845         spin_lock_irq(&efivars->lock);
846         status = efivars->ops->get_variable(var->var.VariableName,
847                                             &var->var.VendorGuid,
848                                             &attributes, &datasize,
849                                             (data + sizeof(attributes)));
850         spin_unlock_irq(&efivars->lock);
851
852         if (status != EFI_SUCCESS) {
853                 size = efi_status_to_err(status);
854                 goto out_free;
855         }
856
857         memcpy(data, &attributes, sizeof(attributes));
858         size = simple_read_from_buffer(userbuf, count, ppos,
859                                        data, datasize + sizeof(attributes));
860 out_free:
861         kfree(data);
862
863         return size;
864 }
865
866 static void efivarfs_evict_inode(struct inode *inode)
867 {
868         clear_inode(inode);
869 }
870
871 static const struct super_operations efivarfs_ops = {
872         .statfs = simple_statfs,
873         .drop_inode = generic_delete_inode,
874         .evict_inode = efivarfs_evict_inode,
875         .show_options = generic_show_options,
876 };
877
878 static struct super_block *efivarfs_sb;
879
880 static const struct inode_operations efivarfs_dir_inode_operations;
881
882 static const struct file_operations efivarfs_file_operations = {
883         .open   = efivarfs_file_open,
884         .read   = efivarfs_file_read,
885         .write  = efivarfs_file_write,
886         .llseek = no_llseek,
887 };
888
889 static struct inode *efivarfs_get_inode(struct super_block *sb,
890                                 const struct inode *dir, int mode, dev_t dev)
891 {
892         struct inode *inode = new_inode(sb);
893
894         if (inode) {
895                 inode->i_ino = get_next_ino();
896                 inode->i_mode = mode;
897                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
898                 switch (mode & S_IFMT) {
899                 case S_IFREG:
900                         inode->i_fop = &efivarfs_file_operations;
901                         break;
902                 case S_IFDIR:
903                         inode->i_op = &efivarfs_dir_inode_operations;
904                         inode->i_fop = &simple_dir_operations;
905                         inc_nlink(inode);
906                         break;
907                 }
908         }
909         return inode;
910 }
911
912 /*
913  * Return true if 'str' is a valid efivarfs filename of the form,
914  *
915  *      VariableName-12345678-1234-1234-1234-1234567891bc
916  */
917 static bool efivarfs_valid_name(const char *str, int len)
918 {
919         static const char dashes[GUID_LEN] = {
920                 [8] = 1, [13] = 1, [18] = 1, [23] = 1
921         };
922         const char *s = str + len - GUID_LEN;
923         int i;
924
925         /*
926          * We need a GUID, plus at least one letter for the variable name,
927          * plus the '-' separator
928          */
929         if (len < GUID_LEN + 2)
930                 return false;
931
932         /* GUID should be right after the first '-' */
933         if (s - 1 != strchr(str, '-'))
934                 return false;
935
936         /*
937          * Validate that 's' is of the correct format, e.g.
938          *
939          *      12345678-1234-1234-1234-123456789abc
940          */
941         for (i = 0; i < GUID_LEN; i++) {
942                 if (dashes[i]) {
943                         if (*s++ != '-')
944                                 return false;
945                 } else {
946                         if (!isxdigit(*s++))
947                                 return false;
948                 }
949         }
950
951         return true;
952 }
953
954 static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
955 {
956         guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
957         guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
958         guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
959         guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
960         guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
961         guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
962         guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
963         guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
964         guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
965         guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
966         guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
967         guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
968         guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
969         guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
970         guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
971         guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
972 }
973
974 static int efivarfs_create(struct inode *dir, struct dentry *dentry,
975                           umode_t mode, bool excl)
976 {
977         struct inode *inode;
978         struct efivars *efivars = &__efivars;
979         struct efivar_entry *var;
980         int namelen, i = 0, err = 0;
981
982         if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
983                 return -EINVAL;
984
985         inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
986         if (!inode)
987                 return -ENOMEM;
988
989         var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
990         if (!var) {
991                 err = -ENOMEM;
992                 goto out;
993         }
994
995         /* length of the variable name itself: remove GUID and separator */
996         namelen = dentry->d_name.len - GUID_LEN - 1;
997
998         efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
999                         &var->var.VendorGuid);
1000
1001         for (i = 0; i < namelen; i++)
1002                 var->var.VariableName[i] = dentry->d_name.name[i];
1003
1004         var->var.VariableName[i] = '\0';
1005
1006         inode->i_private = var;
1007         var->efivars = efivars;
1008         var->kobj.kset = efivars->kset;
1009
1010         err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
1011                              dentry->d_name.name);
1012         if (err)
1013                 goto out;
1014
1015         kobject_uevent(&var->kobj, KOBJ_ADD);
1016         spin_lock_irq(&efivars->lock);
1017         list_add(&var->list, &efivars->list);
1018         spin_unlock_irq(&efivars->lock);
1019         d_instantiate(dentry, inode);
1020         dget(dentry);
1021 out:
1022         if (err) {
1023                 kfree(var);
1024                 iput(inode);
1025         }
1026         return err;
1027 }
1028
1029 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
1030 {
1031         struct efivar_entry *var = dentry->d_inode->i_private;
1032         struct efivars *efivars = var->efivars;
1033         efi_status_t status;
1034
1035         spin_lock_irq(&efivars->lock);
1036
1037         status = efivars->ops->set_variable(var->var.VariableName,
1038                                             &var->var.VendorGuid,
1039                                             0, 0, NULL);
1040
1041         if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
1042                 list_del(&var->list);
1043                 spin_unlock_irq(&efivars->lock);
1044                 efivar_unregister(var);
1045                 drop_nlink(dentry->d_inode);
1046                 dput(dentry);
1047                 return 0;
1048         }
1049
1050         spin_unlock_irq(&efivars->lock);
1051         return -EINVAL;
1052 };
1053
1054 /*
1055  * Compare two efivarfs file names.
1056  *
1057  * An efivarfs filename is composed of two parts,
1058  *
1059  *      1. A case-sensitive variable name
1060  *      2. A case-insensitive GUID
1061  *
1062  * So we need to perform a case-sensitive match on part 1 and a
1063  * case-insensitive match on part 2.
1064  */
1065 static int efivarfs_d_compare(const struct dentry *parent, const struct inode *pinode,
1066                               const struct dentry *dentry, const struct inode *inode,
1067                               unsigned int len, const char *str,
1068                               const struct qstr *name)
1069 {
1070         int guid = len - GUID_LEN;
1071
1072         if (name->len != len)
1073                 return 1;
1074
1075         /* Case-sensitive compare for the variable name */
1076         if (memcmp(str, name->name, guid))
1077                 return 1;
1078
1079         /* Case-insensitive compare for the GUID */
1080         return strncasecmp(name->name + guid, str + guid, GUID_LEN);
1081 }
1082
1083 static int efivarfs_d_hash(const struct dentry *dentry,
1084                            const struct inode *inode, struct qstr *qstr)
1085 {
1086         unsigned long hash = init_name_hash();
1087         const unsigned char *s = qstr->name;
1088         unsigned int len = qstr->len;
1089
1090         if (!efivarfs_valid_name(s, len))
1091                 return -EINVAL;
1092
1093         while (len-- > GUID_LEN)
1094                 hash = partial_name_hash(*s++, hash);
1095
1096         /* GUID is case-insensitive. */
1097         while (len--)
1098                 hash = partial_name_hash(tolower(*s++), hash);
1099
1100         qstr->hash = end_name_hash(hash);
1101         return 0;
1102 }
1103
1104 /*
1105  * Retaining negative dentries for an in-memory filesystem just wastes
1106  * memory and lookup time: arrange for them to be deleted immediately.
1107  */
1108 static int efivarfs_delete_dentry(const struct dentry *dentry)
1109 {
1110         return 1;
1111 }
1112
1113 static struct dentry_operations efivarfs_d_ops = {
1114         .d_compare = efivarfs_d_compare,
1115         .d_hash = efivarfs_d_hash,
1116         .d_delete = efivarfs_delete_dentry,
1117 };
1118
1119 static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
1120 {
1121         struct qstr q;
1122
1123         q.name = name;
1124         q.len = strlen(name);
1125
1126         if (efivarfs_d_hash(NULL, NULL, &q))
1127                 return NULL;
1128
1129         return d_alloc(parent, &q);
1130 }
1131
1132 static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
1133 {
1134         struct inode *inode = NULL;
1135         struct dentry *root;
1136         struct efivar_entry *entry, *n;
1137         struct efivars *efivars = &__efivars;
1138         char *name;
1139
1140         efivarfs_sb = sb;
1141
1142         sb->s_maxbytes          = MAX_LFS_FILESIZE;
1143         sb->s_blocksize         = PAGE_CACHE_SIZE;
1144         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
1145         sb->s_magic             = EFIVARFS_MAGIC;
1146         sb->s_op                = &efivarfs_ops;
1147         sb->s_d_op              = &efivarfs_d_ops;
1148         sb->s_time_gran         = 1;
1149
1150         inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
1151         if (!inode)
1152                 return -ENOMEM;
1153         inode->i_op = &efivarfs_dir_inode_operations;
1154
1155         root = d_make_root(inode);
1156         sb->s_root = root;
1157         if (!root)
1158                 return -ENOMEM;
1159
1160         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1161                 struct dentry *dentry, *root = efivarfs_sb->s_root;
1162                 unsigned long size = 0;
1163                 int len, i;
1164
1165                 inode = NULL;
1166
1167                 len = utf16_strlen(entry->var.VariableName);
1168
1169                 /* name, plus '-', plus GUID, plus NUL*/
1170                 name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
1171                 if (!name)
1172                         goto fail;
1173
1174                 for (i = 0; i < len; i++)
1175                         name[i] = entry->var.VariableName[i] & 0xFF;
1176
1177                 name[len] = '-';
1178
1179                 efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
1180
1181                 name[len+GUID_LEN+1] = '\0';
1182
1183                 inode = efivarfs_get_inode(efivarfs_sb, root->d_inode,
1184                                           S_IFREG | 0644, 0);
1185                 if (!inode)
1186                         goto fail_name;
1187
1188                 dentry = efivarfs_alloc_dentry(root, name);
1189                 if (!dentry)
1190                         goto fail_inode;
1191
1192                 /* copied by the above to local storage in the dentry. */
1193                 kfree(name);
1194
1195                 spin_lock_irq(&efivars->lock);
1196                 efivars->ops->get_variable(entry->var.VariableName,
1197                                            &entry->var.VendorGuid,
1198                                            &entry->var.Attributes,
1199                                            &size,
1200                                            NULL);
1201                 spin_unlock_irq(&efivars->lock);
1202
1203                 mutex_lock(&inode->i_mutex);
1204                 inode->i_private = entry;
1205                 i_size_write(inode, size + sizeof(entry->var.Attributes));
1206                 mutex_unlock(&inode->i_mutex);
1207                 d_add(dentry, inode);
1208         }
1209
1210         return 0;
1211
1212 fail_inode:
1213         iput(inode);
1214 fail_name:
1215         kfree(name);
1216 fail:
1217         return -ENOMEM;
1218 }
1219
1220 static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
1221                                     int flags, const char *dev_name, void *data)
1222 {
1223         return mount_single(fs_type, flags, data, efivarfs_fill_super);
1224 }
1225
1226 static void efivarfs_kill_sb(struct super_block *sb)
1227 {
1228         kill_litter_super(sb);
1229         efivarfs_sb = NULL;
1230 }
1231
1232 static struct file_system_type efivarfs_type = {
1233         .name    = "efivarfs",
1234         .mount   = efivarfs_mount,
1235         .kill_sb = efivarfs_kill_sb,
1236 };
1237
1238 /*
1239  * Handle negative dentry.
1240  */
1241 static struct dentry *efivarfs_lookup(struct inode *dir, struct dentry *dentry,
1242                                       unsigned int flags)
1243 {
1244         if (dentry->d_name.len > NAME_MAX)
1245                 return ERR_PTR(-ENAMETOOLONG);
1246         d_add(dentry, NULL);
1247         return NULL;
1248 }
1249
1250 static const struct inode_operations efivarfs_dir_inode_operations = {
1251         .lookup = efivarfs_lookup,
1252         .unlink = efivarfs_unlink,
1253         .create = efivarfs_create,
1254 };
1255
1256 static struct pstore_info efi_pstore_info;
1257
1258 #ifdef CONFIG_PSTORE
1259
1260 static int efi_pstore_open(struct pstore_info *psi)
1261 {
1262         struct efivars *efivars = psi->data;
1263
1264         spin_lock_irq(&efivars->lock);
1265         efivars->walk_entry = list_first_entry(&efivars->list,
1266                                                struct efivar_entry, list);
1267         return 0;
1268 }
1269
1270 static int efi_pstore_close(struct pstore_info *psi)
1271 {
1272         struct efivars *efivars = psi->data;
1273
1274         spin_unlock_irq(&efivars->lock);
1275         return 0;
1276 }
1277
1278 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1279                                int *count, struct timespec *timespec,
1280                                char **buf, struct pstore_info *psi)
1281 {
1282         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1283         struct efivars *efivars = psi->data;
1284         char name[DUMP_NAME_LEN];
1285         int i;
1286         int cnt;
1287         unsigned int part, size;
1288         unsigned long time;
1289
1290         while (&efivars->walk_entry->list != &efivars->list) {
1291                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
1292                                  vendor)) {
1293                         for (i = 0; i < DUMP_NAME_LEN; i++) {
1294                                 name[i] = efivars->walk_entry->var.VariableName[i];
1295                         }
1296                         if (sscanf(name, "dump-type%u-%u-%d-%lu",
1297                                    type, &part, &cnt, &time) == 4) {
1298                                 *id = part;
1299                                 *count = cnt;
1300                                 timespec->tv_sec = time;
1301                                 timespec->tv_nsec = 0;
1302                         } else if (sscanf(name, "dump-type%u-%u-%lu",
1303                                    type, &part, &time) == 3) {
1304                                 /*
1305                                  * Check if an old format,
1306                                  * which doesn't support holding
1307                                  * multiple logs, remains.
1308                                  */
1309                                 *id = part;
1310                                 *count = 0;
1311                                 timespec->tv_sec = time;
1312                                 timespec->tv_nsec = 0;
1313                         } else {
1314                                 efivars->walk_entry = list_entry(
1315                                                 efivars->walk_entry->list.next,
1316                                                 struct efivar_entry, list);
1317                                 continue;
1318                         }
1319
1320                         get_var_data_locked(efivars, &efivars->walk_entry->var);
1321                         size = efivars->walk_entry->var.DataSize;
1322                         *buf = kmalloc(size, GFP_KERNEL);
1323                         if (*buf == NULL)
1324                                 return -ENOMEM;
1325                         memcpy(*buf, efivars->walk_entry->var.Data,
1326                                size);
1327                         efivars->walk_entry = list_entry(
1328                                         efivars->walk_entry->list.next,
1329                                         struct efivar_entry, list);
1330                         return size;
1331                 }
1332                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1333                                                  struct efivar_entry, list);
1334         }
1335         return 0;
1336 }
1337
1338 static int efi_pstore_write(enum pstore_type_id type,
1339                 enum kmsg_dump_reason reason, u64 *id,
1340                 unsigned int part, int count, size_t size,
1341                 struct pstore_info *psi)
1342 {
1343         char name[DUMP_NAME_LEN];
1344         efi_char16_t efi_name[DUMP_NAME_LEN];
1345         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1346         struct efivars *efivars = psi->data;
1347         int i, ret = 0;
1348         u64 storage_space, remaining_space, max_variable_size;
1349         efi_status_t status = EFI_NOT_FOUND;
1350         unsigned long flags;
1351
1352         if (pstore_cannot_block_path(reason)) {
1353                 /*
1354                  * If the lock is taken by another cpu in non-blocking path,
1355                  * this driver returns without entering firmware to avoid
1356                  * hanging up.
1357                  */
1358                 if (!spin_trylock_irqsave(&efivars->lock, flags))
1359                         return -EBUSY;
1360         } else
1361                 spin_lock_irqsave(&efivars->lock, flags);
1362
1363         /*
1364          * Check if there is a space enough to log.
1365          * size: a size of logging data
1366          * DUMP_NAME_LEN * 2: a maximum size of variable name
1367          */
1368         status = efivars->ops->query_variable_info(PSTORE_EFI_ATTRIBUTES,
1369                                                    &storage_space,
1370                                                    &remaining_space,
1371                                                    &max_variable_size);
1372         if (status || remaining_space < size + DUMP_NAME_LEN * 2) {
1373                 spin_unlock_irqrestore(&efivars->lock, flags);
1374                 *id = part;
1375                 return -ENOSPC;
1376         }
1377
1378         sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
1379                 get_seconds());
1380
1381         for (i = 0; i < DUMP_NAME_LEN; i++)
1382                 efi_name[i] = name[i];
1383
1384         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
1385                                    size, psi->buf);
1386
1387         spin_unlock_irqrestore(&efivars->lock, flags);
1388
1389         if (reason == KMSG_DUMP_OOPS)
1390                 schedule_work(&efivar_work);
1391
1392         *id = part;
1393         return ret;
1394 };
1395
1396 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1397                             struct timespec time, struct pstore_info *psi)
1398 {
1399         char name[DUMP_NAME_LEN];
1400         efi_char16_t efi_name[DUMP_NAME_LEN];
1401         char name_old[DUMP_NAME_LEN];
1402         efi_char16_t efi_name_old[DUMP_NAME_LEN];
1403         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1404         struct efivars *efivars = psi->data;
1405         struct efivar_entry *entry, *found = NULL;
1406         int i;
1407
1408         sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
1409                 time.tv_sec);
1410
1411         spin_lock_irq(&efivars->lock);
1412
1413         for (i = 0; i < DUMP_NAME_LEN; i++)
1414                 efi_name[i] = name[i];
1415
1416         /*
1417          * Clean up an entry with the same name
1418          */
1419
1420         list_for_each_entry(entry, &efivars->list, list) {
1421                 get_var_data_locked(efivars, &entry->var);
1422
1423                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
1424                         continue;
1425                 if (utf16_strncmp(entry->var.VariableName, efi_name,
1426                                   utf16_strlen(efi_name))) {
1427                         /*
1428                          * Check if an old format,
1429                          * which doesn't support holding
1430                          * multiple logs, remains.
1431                          */
1432                         sprintf(name_old, "dump-type%u-%u-%lu", type,
1433                                 (unsigned int)id, time.tv_sec);
1434
1435                         for (i = 0; i < DUMP_NAME_LEN; i++)
1436                                 efi_name_old[i] = name_old[i];
1437
1438                         if (utf16_strncmp(entry->var.VariableName, efi_name_old,
1439                                           utf16_strlen(efi_name_old)))
1440                                 continue;
1441                 }
1442
1443                 /* found */
1444                 found = entry;
1445                 efivars->ops->set_variable(entry->var.VariableName,
1446                                            &entry->var.VendorGuid,
1447                                            PSTORE_EFI_ATTRIBUTES,
1448                                            0, NULL);
1449                 break;
1450         }
1451
1452         if (found)
1453                 list_del(&found->list);
1454
1455         spin_unlock_irq(&efivars->lock);
1456
1457         if (found)
1458                 efivar_unregister(found);
1459
1460         return 0;
1461 }
1462 #else
1463 static int efi_pstore_open(struct pstore_info *psi)
1464 {
1465         return 0;
1466 }
1467
1468 static int efi_pstore_close(struct pstore_info *psi)
1469 {
1470         return 0;
1471 }
1472
1473 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, int *count,
1474                                struct timespec *timespec,
1475                                char **buf, struct pstore_info *psi)
1476 {
1477         return -1;
1478 }
1479
1480 static int efi_pstore_write(enum pstore_type_id type,
1481                 enum kmsg_dump_reason reason, u64 *id,
1482                 unsigned int part, int count, size_t size,
1483                 struct pstore_info *psi)
1484 {
1485         return 0;
1486 }
1487
1488 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1489                             struct timespec time, struct pstore_info *psi)
1490 {
1491         return 0;
1492 }
1493 #endif
1494
1495 static struct pstore_info efi_pstore_info = {
1496         .owner          = THIS_MODULE,
1497         .name           = "efi",
1498         .open           = efi_pstore_open,
1499         .close          = efi_pstore_close,
1500         .read           = efi_pstore_read,
1501         .write          = efi_pstore_write,
1502         .erase          = efi_pstore_erase,
1503 };
1504
1505 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
1506                              struct bin_attribute *bin_attr,
1507                              char *buf, loff_t pos, size_t count)
1508 {
1509         struct efi_variable *new_var = (struct efi_variable *)buf;
1510         struct efivars *efivars = bin_attr->private;
1511         struct efivar_entry *search_efivar, *n;
1512         unsigned long strsize1, strsize2;
1513         efi_status_t status = EFI_NOT_FOUND;
1514         int found = 0;
1515
1516         if (!capable(CAP_SYS_ADMIN))
1517                 return -EACCES;
1518
1519         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
1520             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
1521                 printk(KERN_ERR "efivars: Malformed variable content\n");
1522                 return -EINVAL;
1523         }
1524
1525         spin_lock_irq(&efivars->lock);
1526
1527         /*
1528          * Does this variable already exist?
1529          */
1530         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1531                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1532                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
1533                 if (strsize1 == strsize2 &&
1534                         !memcmp(&(search_efivar->var.VariableName),
1535                                 new_var->VariableName, strsize1) &&
1536                         !efi_guidcmp(search_efivar->var.VendorGuid,
1537                                 new_var->VendorGuid)) {
1538                         found = 1;
1539                         break;
1540                 }
1541         }
1542         if (found) {
1543                 spin_unlock_irq(&efivars->lock);
1544                 return -EINVAL;
1545         }
1546
1547         /* now *really* create the variable via EFI */
1548         status = efivars->ops->set_variable(new_var->VariableName,
1549                                             &new_var->VendorGuid,
1550                                             new_var->Attributes,
1551                                             new_var->DataSize,
1552                                             new_var->Data);
1553
1554         if (status != EFI_SUCCESS) {
1555                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1556                         status);
1557                 spin_unlock_irq(&efivars->lock);
1558                 return -EIO;
1559         }
1560         spin_unlock_irq(&efivars->lock);
1561
1562         /* Create the entry in sysfs.  Locking is not required here */
1563         status = efivar_create_sysfs_entry(efivars,
1564                                            utf16_strsize(new_var->VariableName,
1565                                                          1024),
1566                                            new_var->VariableName,
1567                                            &new_var->VendorGuid);
1568         if (status) {
1569                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
1570         }
1571         return count;
1572 }
1573
1574 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
1575                              struct bin_attribute *bin_attr,
1576                              char *buf, loff_t pos, size_t count)
1577 {
1578         struct efi_variable *del_var = (struct efi_variable *)buf;
1579         struct efivars *efivars = bin_attr->private;
1580         struct efivar_entry *search_efivar, *n;
1581         unsigned long strsize1, strsize2;
1582         efi_status_t status = EFI_NOT_FOUND;
1583         int found = 0;
1584
1585         if (!capable(CAP_SYS_ADMIN))
1586                 return -EACCES;
1587
1588         spin_lock_irq(&efivars->lock);
1589
1590         /*
1591          * Does this variable already exist?
1592          */
1593         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1594                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1595                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
1596                 if (strsize1 == strsize2 &&
1597                         !memcmp(&(search_efivar->var.VariableName),
1598                                 del_var->VariableName, strsize1) &&
1599                         !efi_guidcmp(search_efivar->var.VendorGuid,
1600                                 del_var->VendorGuid)) {
1601                         found = 1;
1602                         break;
1603                 }
1604         }
1605         if (!found) {
1606                 spin_unlock_irq(&efivars->lock);
1607                 return -EINVAL;
1608         }
1609         /* force the Attributes/DataSize to 0 to ensure deletion */
1610         del_var->Attributes = 0;
1611         del_var->DataSize = 0;
1612
1613         status = efivars->ops->set_variable(del_var->VariableName,
1614                                             &del_var->VendorGuid,
1615                                             del_var->Attributes,
1616                                             del_var->DataSize,
1617                                             del_var->Data);
1618
1619         if (status != EFI_SUCCESS) {
1620                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1621                         status);
1622                 spin_unlock_irq(&efivars->lock);
1623                 return -EIO;
1624         }
1625         list_del(&search_efivar->list);
1626         /* We need to release this lock before unregistering. */
1627         spin_unlock_irq(&efivars->lock);
1628         efivar_unregister(search_efivar);
1629
1630         /* It's dead Jim.... */
1631         return count;
1632 }
1633
1634 static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
1635 {
1636         struct efivar_entry *entry, *n;
1637         struct efivars *efivars = &__efivars;
1638         unsigned long strsize1, strsize2;
1639         bool found = false;
1640
1641         strsize1 = utf16_strsize(variable_name, 1024);
1642         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1643                 strsize2 = utf16_strsize(entry->var.VariableName, 1024);
1644                 if (strsize1 == strsize2 &&
1645                         !memcmp(variable_name, &(entry->var.VariableName),
1646                                 strsize2) &&
1647                         !efi_guidcmp(entry->var.VendorGuid,
1648                                 *vendor)) {
1649                         found = true;
1650                         break;
1651                 }
1652         }
1653         return found;
1654 }
1655
1656 static void efivar_update_sysfs_entries(struct work_struct *work)
1657 {
1658         struct efivars *efivars = &__efivars;
1659         efi_guid_t vendor;
1660         efi_char16_t *variable_name;
1661         unsigned long variable_name_size = 1024;
1662         efi_status_t status = EFI_NOT_FOUND;
1663         bool found;
1664
1665         /* Add new sysfs entries */
1666         while (1) {
1667                 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1668                 if (!variable_name) {
1669                         pr_err("efivars: Memory allocation failed.\n");
1670                         return;
1671                 }
1672
1673                 spin_lock_irq(&efivars->lock);
1674                 found = false;
1675                 while (1) {
1676                         variable_name_size = 1024;
1677                         status = efivars->ops->get_next_variable(
1678                                                         &variable_name_size,
1679                                                         variable_name,
1680                                                         &vendor);
1681                         if (status != EFI_SUCCESS) {
1682                                 break;
1683                         } else {
1684                                 if (!variable_is_present(variable_name,
1685                                     &vendor)) {
1686                                         found = true;
1687                                         break;
1688                                 }
1689                         }
1690                 }
1691                 spin_unlock_irq(&efivars->lock);
1692
1693                 if (!found) {
1694                         kfree(variable_name);
1695                         break;
1696                 } else
1697                         efivar_create_sysfs_entry(efivars,
1698                                                   variable_name_size,
1699                                                   variable_name, &vendor);
1700         }
1701 }
1702
1703 /*
1704  * Let's not leave out systab information that snuck into
1705  * the efivars driver
1706  */
1707 static ssize_t systab_show(struct kobject *kobj,
1708                            struct kobj_attribute *attr, char *buf)
1709 {
1710         char *str = buf;
1711
1712         if (!kobj || !buf)
1713                 return -EINVAL;
1714
1715         if (efi.mps != EFI_INVALID_TABLE_ADDR)
1716                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1717         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1718                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1719         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1720                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1721         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1722                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1723         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1724                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1725         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1726                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1727         if (efi.uga != EFI_INVALID_TABLE_ADDR)
1728                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1729
1730         return str - buf;
1731 }
1732
1733 static struct kobj_attribute efi_attr_systab =
1734                         __ATTR(systab, 0400, systab_show, NULL);
1735
1736 static struct attribute *efi_subsys_attrs[] = {
1737         &efi_attr_systab.attr,
1738         NULL,   /* maybe more in the future? */
1739 };
1740
1741 static struct attribute_group efi_subsys_attr_group = {
1742         .attrs = efi_subsys_attrs,
1743 };
1744
1745 static struct kobject *efi_kobj;
1746
1747 /*
1748  * efivar_create_sysfs_entry()
1749  * Requires:
1750  *    variable_name_size = number of bytes required to hold
1751  *                         variable_name (not counting the NULL
1752  *                         character at the end.
1753  *    efivars->lock is not held on entry or exit.
1754  * Returns 1 on failure, 0 on success
1755  */
1756 static int
1757 efivar_create_sysfs_entry(struct efivars *efivars,
1758                           unsigned long variable_name_size,
1759                           efi_char16_t *variable_name,
1760                           efi_guid_t *vendor_guid)
1761 {
1762         int i, short_name_size;
1763         char *short_name;
1764         struct efivar_entry *new_efivar;
1765
1766         /*
1767          * Length of the variable bytes in ASCII, plus the '-' separator,
1768          * plus the GUID, plus trailing NUL
1769          */
1770         short_name_size = variable_name_size / sizeof(efi_char16_t)
1771                                 + 1 + GUID_LEN + 1;
1772
1773         short_name = kzalloc(short_name_size, GFP_KERNEL);
1774         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1775
1776         if (!short_name || !new_efivar)  {
1777                 kfree(short_name);
1778                 kfree(new_efivar);
1779                 return 1;
1780         }
1781
1782         new_efivar->efivars = efivars;
1783         memcpy(new_efivar->var.VariableName, variable_name,
1784                 variable_name_size);
1785         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1786
1787         /* Convert Unicode to normal chars (assume top bits are 0),
1788            ala UTF-8 */
1789         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1790                 short_name[i] = variable_name[i] & 0xFF;
1791         }
1792         /* This is ugly, but necessary to separate one vendor's
1793            private variables from another's.         */
1794
1795         *(short_name + strlen(short_name)) = '-';
1796         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1797
1798         new_efivar->kobj.kset = efivars->kset;
1799         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1800                                  "%s", short_name);
1801         if (i) {
1802                 kfree(short_name);
1803                 kfree(new_efivar);
1804                 return 1;
1805         }
1806
1807         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1808         kfree(short_name);
1809         short_name = NULL;
1810
1811         spin_lock_irq(&efivars->lock);
1812         list_add(&new_efivar->list, &efivars->list);
1813         spin_unlock_irq(&efivars->lock);
1814
1815         return 0;
1816 }
1817
1818 static int
1819 create_efivars_bin_attributes(struct efivars *efivars)
1820 {
1821         struct bin_attribute *attr;
1822         int error;
1823
1824         /* new_var */
1825         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1826         if (!attr)
1827                 return -ENOMEM;
1828
1829         attr->attr.name = "new_var";
1830         attr->attr.mode = 0200;
1831         attr->write = efivar_create;
1832         attr->private = efivars;
1833         efivars->new_var = attr;
1834
1835         /* del_var */
1836         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1837         if (!attr) {
1838                 error = -ENOMEM;
1839                 goto out_free;
1840         }
1841         attr->attr.name = "del_var";
1842         attr->attr.mode = 0200;
1843         attr->write = efivar_delete;
1844         attr->private = efivars;
1845         efivars->del_var = attr;
1846
1847         sysfs_bin_attr_init(efivars->new_var);
1848         sysfs_bin_attr_init(efivars->del_var);
1849
1850         /* Register */
1851         error = sysfs_create_bin_file(&efivars->kset->kobj,
1852                                       efivars->new_var);
1853         if (error) {
1854                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1855                         " due to error %d\n", error);
1856                 goto out_free;
1857         }
1858         error = sysfs_create_bin_file(&efivars->kset->kobj,
1859                                       efivars->del_var);
1860         if (error) {
1861                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1862                         " due to error %d\n", error);
1863                 sysfs_remove_bin_file(&efivars->kset->kobj,
1864                                       efivars->new_var);
1865                 goto out_free;
1866         }
1867
1868         return 0;
1869 out_free:
1870         kfree(efivars->del_var);
1871         efivars->del_var = NULL;
1872         kfree(efivars->new_var);
1873         efivars->new_var = NULL;
1874         return error;
1875 }
1876
1877 void unregister_efivars(struct efivars *efivars)
1878 {
1879         struct efivar_entry *entry, *n;
1880
1881         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1882                 spin_lock_irq(&efivars->lock);
1883                 list_del(&entry->list);
1884                 spin_unlock_irq(&efivars->lock);
1885                 efivar_unregister(entry);
1886         }
1887         if (efivars->new_var)
1888                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1889         if (efivars->del_var)
1890                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1891         kfree(efivars->new_var);
1892         kfree(efivars->del_var);
1893         kobject_put(efivars->kobject);
1894         kset_unregister(efivars->kset);
1895 }
1896 EXPORT_SYMBOL_GPL(unregister_efivars);
1897
1898 int register_efivars(struct efivars *efivars,
1899                      const struct efivar_operations *ops,
1900                      struct kobject *parent_kobj)
1901 {
1902         efi_status_t status = EFI_NOT_FOUND;
1903         efi_guid_t vendor_guid;
1904         efi_char16_t *variable_name;
1905         unsigned long variable_name_size = 1024;
1906         int error = 0;
1907
1908         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1909         if (!variable_name) {
1910                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1911                 return -ENOMEM;
1912         }
1913
1914         spin_lock_init(&efivars->lock);
1915         INIT_LIST_HEAD(&efivars->list);
1916         efivars->ops = ops;
1917
1918         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1919         if (!efivars->kset) {
1920                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1921                 error = -ENOMEM;
1922                 goto out;
1923         }
1924
1925         efivars->kobject = kobject_create_and_add("efivars", parent_kobj);
1926         if (!efivars->kobject) {
1927                 pr_err("efivars: Subsystem registration failed.\n");
1928                 error = -ENOMEM;
1929                 kset_unregister(efivars->kset);
1930                 goto out;
1931         }
1932
1933         /*
1934          * Per EFI spec, the maximum storage allocated for both
1935          * the variable name and variable data is 1024 bytes.
1936          */
1937
1938         do {
1939                 variable_name_size = 1024;
1940
1941                 status = ops->get_next_variable(&variable_name_size,
1942                                                 variable_name,
1943                                                 &vendor_guid);
1944                 switch (status) {
1945                 case EFI_SUCCESS:
1946                         efivar_create_sysfs_entry(efivars,
1947                                                   variable_name_size,
1948                                                   variable_name,
1949                                                   &vendor_guid);
1950                         break;
1951                 case EFI_NOT_FOUND:
1952                         break;
1953                 default:
1954                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1955                                 status);
1956                         status = EFI_NOT_FOUND;
1957                         break;
1958                 }
1959         } while (status != EFI_NOT_FOUND);
1960
1961         error = create_efivars_bin_attributes(efivars);
1962         if (error)
1963                 unregister_efivars(efivars);
1964
1965         efivars->efi_pstore_info = efi_pstore_info;
1966
1967         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1968         if (efivars->efi_pstore_info.buf) {
1969                 efivars->efi_pstore_info.bufsize = 1024;
1970                 efivars->efi_pstore_info.data = efivars;
1971                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1972                 pstore_register(&efivars->efi_pstore_info);
1973         }
1974
1975         register_filesystem(&efivarfs_type);
1976
1977 out:
1978         kfree(variable_name);
1979
1980         return error;
1981 }
1982 EXPORT_SYMBOL_GPL(register_efivars);
1983
1984 /*
1985  * For now we register the efi subsystem with the firmware subsystem
1986  * and the vars subsystem with the efi subsystem.  In the future, it
1987  * might make sense to split off the efi subsystem into its own
1988  * driver, but for now only efivars will register with it, so just
1989  * include it here.
1990  */
1991
1992 static int __init
1993 efivars_init(void)
1994 {
1995         int error = 0;
1996
1997         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1998                EFIVARS_DATE);
1999
2000         if (!efi_enabled(EFI_RUNTIME_SERVICES))
2001                 return 0;
2002
2003         /* For now we'll register the efi directory at /sys/firmware/efi */
2004         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
2005         if (!efi_kobj) {
2006                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
2007                 return -ENOMEM;
2008         }
2009
2010         ops.get_variable = efi.get_variable;
2011         ops.set_variable = efi.set_variable;
2012         ops.get_next_variable = efi.get_next_variable;
2013         ops.query_variable_info = efi.query_variable_info;
2014
2015         error = register_efivars(&__efivars, &ops, efi_kobj);
2016         if (error)
2017                 goto err_put;
2018
2019         /* Don't forget the systab entry */
2020         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
2021         if (error) {
2022                 printk(KERN_ERR
2023                        "efivars: Sysfs attribute export failed with error %d.\n",
2024                        error);
2025                 goto err_unregister;
2026         }
2027
2028         return 0;
2029
2030 err_unregister:
2031         unregister_efivars(&__efivars);
2032 err_put:
2033         kobject_put(efi_kobj);
2034         return error;
2035 }
2036
2037 static void __exit
2038 efivars_exit(void)
2039 {
2040         cancel_work_sync(&efivar_work);
2041
2042         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
2043                 unregister_efivars(&__efivars);
2044                 kobject_put(efi_kobj);
2045         }
2046 }
2047
2048 module_init(efivars_init);
2049 module_exit(efivars_exit);
2050