efivars: Disable external interrupt while holding efivars->lock
[pandora-kernel.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 <asm/uaccess.h>
84
85 #define EFIVARS_VERSION "0.08"
86 #define EFIVARS_DATE "2004-May-17"
87
88 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
89 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
90 MODULE_LICENSE("GPL");
91 MODULE_VERSION(EFIVARS_VERSION);
92
93 #define DUMP_NAME_LEN 52
94
95 /*
96  * The maximum size of VariableName + Data = 1024
97  * Therefore, it's reasonable to save that much
98  * space in each part of the structure,
99  * and we use a page for reading/writing.
100  */
101
102 struct efi_variable {
103         efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
104         efi_guid_t    VendorGuid;
105         unsigned long DataSize;
106         __u8          Data[1024];
107         efi_status_t  Status;
108         __u32         Attributes;
109 } __attribute__((packed));
110
111
112 struct efivar_entry {
113         struct efivars *efivars;
114         struct efi_variable var;
115         struct list_head list;
116         struct kobject kobj;
117 };
118
119 struct efivar_attribute {
120         struct attribute attr;
121         ssize_t (*show) (struct efivar_entry *entry, char *buf);
122         ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
123 };
124
125 #define PSTORE_EFI_ATTRIBUTES \
126         (EFI_VARIABLE_NON_VOLATILE | \
127          EFI_VARIABLE_BOOTSERVICE_ACCESS | \
128          EFI_VARIABLE_RUNTIME_ACCESS)
129
130 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
131 struct efivar_attribute efivar_attr_##_name = { \
132         .attr = {.name = __stringify(_name), .mode = _mode}, \
133         .show = _show, \
134         .store = _store, \
135 };
136
137 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
138 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
139
140 /*
141  * Prototype for sysfs creation function
142  */
143 static int
144 efivar_create_sysfs_entry(struct efivars *efivars,
145                           unsigned long variable_name_size,
146                           efi_char16_t *variable_name,
147                           efi_guid_t *vendor_guid);
148
149 /* Return the number of unicode characters in data */
150 static unsigned long
151 utf16_strnlen(efi_char16_t *s, size_t maxlength)
152 {
153         unsigned long length = 0;
154
155         while (*s++ != 0 && length < maxlength)
156                 length++;
157         return length;
158 }
159
160 static inline unsigned long
161 utf16_strlen(efi_char16_t *s)
162 {
163         return utf16_strnlen(s, ~0UL);
164 }
165
166 /*
167  * Return the number of bytes is the length of this string
168  * Note: this is NOT the same as the number of unicode characters
169  */
170 static inline unsigned long
171 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
172 {
173         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
174 }
175
176 static inline int
177 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
178 {
179         while (1) {
180                 if (len == 0)
181                         return 0;
182                 if (*a < *b)
183                         return -1;
184                 if (*a > *b)
185                         return 1;
186                 if (*a == 0) /* implies *b == 0 */
187                         return 0;
188                 a++;
189                 b++;
190                 len--;
191         }
192 }
193
194 static bool
195 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
196                      unsigned long len)
197 {
198         struct efi_generic_dev_path *node;
199         int offset = 0;
200
201         node = (struct efi_generic_dev_path *)buffer;
202
203         if (len < sizeof(*node))
204                 return false;
205
206         while (offset <= len - sizeof(*node) &&
207                node->length >= sizeof(*node) &&
208                 node->length <= len - offset) {
209                 offset += node->length;
210
211                 if ((node->type == EFI_DEV_END_PATH ||
212                      node->type == EFI_DEV_END_PATH2) &&
213                     node->sub_type == EFI_DEV_END_ENTIRE)
214                         return true;
215
216                 node = (struct efi_generic_dev_path *)(buffer + offset);
217         }
218
219         /*
220          * If we're here then either node->length pointed past the end
221          * of the buffer or we reached the end of the buffer without
222          * finding a device path end node.
223          */
224         return false;
225 }
226
227 static bool
228 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
229                     unsigned long len)
230 {
231         /* An array of 16-bit integers */
232         if ((len % 2) != 0)
233                 return false;
234
235         return true;
236 }
237
238 static bool
239 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
240                      unsigned long len)
241 {
242         u16 filepathlength;
243         int i, desclength = 0, namelen;
244
245         namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
246
247         /* Either "Boot" or "Driver" followed by four digits of hex */
248         for (i = match; i < match+4; i++) {
249                 if (var->VariableName[i] > 127 ||
250                     hex_to_bin(var->VariableName[i] & 0xff) < 0)
251                         return true;
252         }
253
254         /* Reject it if there's 4 digits of hex and then further content */
255         if (namelen > match + 4)
256                 return false;
257
258         /* A valid entry must be at least 8 bytes */
259         if (len < 8)
260                 return false;
261
262         filepathlength = buffer[4] | buffer[5] << 8;
263
264         /*
265          * There's no stored length for the description, so it has to be
266          * found by hand
267          */
268         desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
269
270         /* Each boot entry must have a descriptor */
271         if (!desclength)
272                 return false;
273
274         /*
275          * If the sum of the length of the description, the claimed filepath
276          * length and the original header are greater than the length of the
277          * variable, it's malformed
278          */
279         if ((desclength + filepathlength + 6) > len)
280                 return false;
281
282         /*
283          * And, finally, check the filepath
284          */
285         return validate_device_path(var, match, buffer + desclength + 6,
286                                     filepathlength);
287 }
288
289 static bool
290 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
291                 unsigned long len)
292 {
293         /* A single 16-bit integer */
294         if (len != 2)
295                 return false;
296
297         return true;
298 }
299
300 static bool
301 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
302                       unsigned long len)
303 {
304         int i;
305
306         for (i = 0; i < len; i++) {
307                 if (buffer[i] > 127)
308                         return false;
309
310                 if (buffer[i] == 0)
311                         return true;
312         }
313
314         return false;
315 }
316
317 struct variable_validate {
318         char *name;
319         bool (*validate)(struct efi_variable *var, int match, u8 *data,
320                          unsigned long len);
321 };
322
323 static const struct variable_validate variable_validate[] = {
324         { "BootNext", validate_uint16 },
325         { "BootOrder", validate_boot_order },
326         { "DriverOrder", validate_boot_order },
327         { "Boot*", validate_load_option },
328         { "Driver*", validate_load_option },
329         { "ConIn", validate_device_path },
330         { "ConInDev", validate_device_path },
331         { "ConOut", validate_device_path },
332         { "ConOutDev", validate_device_path },
333         { "ErrOut", validate_device_path },
334         { "ErrOutDev", validate_device_path },
335         { "Timeout", validate_uint16 },
336         { "Lang", validate_ascii_string },
337         { "PlatformLang", validate_ascii_string },
338         { "", NULL },
339 };
340
341 static bool
342 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
343 {
344         int i;
345         u16 *unicode_name = var->VariableName;
346
347         for (i = 0; variable_validate[i].validate != NULL; i++) {
348                 const char *name = variable_validate[i].name;
349                 int match;
350
351                 for (match = 0; ; match++) {
352                         char c = name[match];
353                         u16 u = unicode_name[match];
354
355                         /* All special variables are plain ascii */
356                         if (u > 127)
357                                 return true;
358
359                         /* Wildcard in the matching name means we've matched */
360                         if (c == '*')
361                                 return variable_validate[i].validate(var,
362                                                              match, data, len);
363
364                         /* Case sensitive match */
365                         if (c != u)
366                                 break;
367
368                         /* Reached the end of the string while matching */
369                         if (!c)
370                                 return variable_validate[i].validate(var,
371                                                              match, data, len);
372                 }
373         }
374
375         return true;
376 }
377
378 static efi_status_t
379 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
380 {
381         efi_status_t status;
382
383         var->DataSize = 1024;
384         status = efivars->ops->get_variable(var->VariableName,
385                                             &var->VendorGuid,
386                                             &var->Attributes,
387                                             &var->DataSize,
388                                             var->Data);
389         return status;
390 }
391
392 static efi_status_t
393 get_var_data(struct efivars *efivars, struct efi_variable *var)
394 {
395         efi_status_t status;
396         unsigned long flags;
397
398         spin_lock_irqsave(&efivars->lock, flags);
399         status = get_var_data_locked(efivars, var);
400         spin_unlock_irqrestore(&efivars->lock, flags);
401
402         if (status != EFI_SUCCESS) {
403                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
404                         status);
405         }
406         return status;
407 }
408
409 static ssize_t
410 efivar_guid_read(struct efivar_entry *entry, char *buf)
411 {
412         struct efi_variable *var = &entry->var;
413         char *str = buf;
414
415         if (!entry || !buf)
416                 return 0;
417
418         efi_guid_unparse(&var->VendorGuid, str);
419         str += strlen(str);
420         str += sprintf(str, "\n");
421
422         return str - buf;
423 }
424
425 static ssize_t
426 efivar_attr_read(struct efivar_entry *entry, char *buf)
427 {
428         struct efi_variable *var = &entry->var;
429         char *str = buf;
430         efi_status_t status;
431
432         if (!entry || !buf)
433                 return -EINVAL;
434
435         status = get_var_data(entry->efivars, var);
436         if (status != EFI_SUCCESS)
437                 return -EIO;
438
439         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
440                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
441         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
442                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
443         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
444                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
445         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
446                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
447         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
448                 str += sprintf(str,
449                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
450         if (var->Attributes &
451                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
452                 str += sprintf(str,
453                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
454         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
455                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
456         return str - buf;
457 }
458
459 static ssize_t
460 efivar_size_read(struct efivar_entry *entry, char *buf)
461 {
462         struct efi_variable *var = &entry->var;
463         char *str = buf;
464         efi_status_t status;
465
466         if (!entry || !buf)
467                 return -EINVAL;
468
469         status = get_var_data(entry->efivars, var);
470         if (status != EFI_SUCCESS)
471                 return -EIO;
472
473         str += sprintf(str, "0x%lx\n", var->DataSize);
474         return str - buf;
475 }
476
477 static ssize_t
478 efivar_data_read(struct efivar_entry *entry, char *buf)
479 {
480         struct efi_variable *var = &entry->var;
481         efi_status_t status;
482
483         if (!entry || !buf)
484                 return -EINVAL;
485
486         status = get_var_data(entry->efivars, var);
487         if (status != EFI_SUCCESS)
488                 return -EIO;
489
490         memcpy(buf, var->Data, var->DataSize);
491         return var->DataSize;
492 }
493 /*
494  * We allow each variable to be edited via rewriting the
495  * entire efi variable structure.
496  */
497 static ssize_t
498 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
499 {
500         struct efi_variable *new_var, *var = &entry->var;
501         struct efivars *efivars = entry->efivars;
502         efi_status_t status = EFI_NOT_FOUND;
503
504         if (count != sizeof(struct efi_variable))
505                 return -EINVAL;
506
507         new_var = (struct efi_variable *)buf;
508         /*
509          * If only updating the variable data, then the name
510          * and guid should remain the same
511          */
512         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
513                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
514                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
515                 return -EINVAL;
516         }
517
518         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
519                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
520                 return -EINVAL;
521         }
522
523         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
524             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
525                 printk(KERN_ERR "efivars: Malformed variable content\n");
526                 return -EINVAL;
527         }
528
529         spin_lock_irq(&efivars->lock);
530         status = efivars->ops->set_variable(new_var->VariableName,
531                                             &new_var->VendorGuid,
532                                             new_var->Attributes,
533                                             new_var->DataSize,
534                                             new_var->Data);
535
536         spin_unlock_irq(&efivars->lock);
537
538         if (status != EFI_SUCCESS) {
539                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
540                         status);
541                 return -EIO;
542         }
543
544         memcpy(&entry->var, new_var, count);
545         return count;
546 }
547
548 static ssize_t
549 efivar_show_raw(struct efivar_entry *entry, char *buf)
550 {
551         struct efi_variable *var = &entry->var;
552         efi_status_t status;
553
554         if (!entry || !buf)
555                 return 0;
556
557         status = get_var_data(entry->efivars, var);
558         if (status != EFI_SUCCESS)
559                 return -EIO;
560
561         memcpy(buf, var, sizeof(*var));
562         return sizeof(*var);
563 }
564
565 /*
566  * Generic read/write functions that call the specific functions of
567  * the attributes...
568  */
569 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
570                                 char *buf)
571 {
572         struct efivar_entry *var = to_efivar_entry(kobj);
573         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
574         ssize_t ret = -EIO;
575
576         if (!capable(CAP_SYS_ADMIN))
577                 return -EACCES;
578
579         if (efivar_attr->show) {
580                 ret = efivar_attr->show(var, buf);
581         }
582         return ret;
583 }
584
585 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
586                                 const char *buf, size_t count)
587 {
588         struct efivar_entry *var = to_efivar_entry(kobj);
589         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
590         ssize_t ret = -EIO;
591
592         if (!capable(CAP_SYS_ADMIN))
593                 return -EACCES;
594
595         if (efivar_attr->store)
596                 ret = efivar_attr->store(var, buf, count);
597
598         return ret;
599 }
600
601 static const struct sysfs_ops efivar_attr_ops = {
602         .show = efivar_attr_show,
603         .store = efivar_attr_store,
604 };
605
606 static void efivar_release(struct kobject *kobj)
607 {
608         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
609         kfree(var);
610 }
611
612 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
613 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
614 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
615 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
616 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
617
618 static struct attribute *def_attrs[] = {
619         &efivar_attr_guid.attr,
620         &efivar_attr_size.attr,
621         &efivar_attr_attributes.attr,
622         &efivar_attr_data.attr,
623         &efivar_attr_raw_var.attr,
624         NULL,
625 };
626
627 static struct kobj_type efivar_ktype = {
628         .release = efivar_release,
629         .sysfs_ops = &efivar_attr_ops,
630         .default_attrs = def_attrs,
631 };
632
633 static struct pstore_info efi_pstore_info;
634
635 static inline void
636 efivar_unregister(struct efivar_entry *var)
637 {
638         kobject_put(&var->kobj);
639 }
640
641 #ifdef CONFIG_PSTORE
642
643 static int efi_pstore_open(struct pstore_info *psi)
644 {
645         struct efivars *efivars = psi->data;
646
647         spin_lock_irq(&efivars->lock);
648         efivars->walk_entry = list_first_entry(&efivars->list,
649                                                struct efivar_entry, list);
650         return 0;
651 }
652
653 static int efi_pstore_close(struct pstore_info *psi)
654 {
655         struct efivars *efivars = psi->data;
656
657         spin_unlock_irq(&efivars->lock);
658         return 0;
659 }
660
661 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
662                                struct timespec *timespec,
663                                char **buf, struct pstore_info *psi)
664 {
665         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
666         struct efivars *efivars = psi->data;
667         char name[DUMP_NAME_LEN];
668         int i;
669         unsigned int part, size;
670         unsigned long time;
671
672         while (&efivars->walk_entry->list != &efivars->list) {
673                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
674                                  vendor)) {
675                         for (i = 0; i < DUMP_NAME_LEN; i++) {
676                                 name[i] = efivars->walk_entry->var.VariableName[i];
677                         }
678                         if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
679                                 *id = part;
680                                 timespec->tv_sec = time;
681                                 timespec->tv_nsec = 0;
682                                 get_var_data_locked(efivars, &efivars->walk_entry->var);
683                                 size = efivars->walk_entry->var.DataSize;
684                                 *buf = kmalloc(size, GFP_KERNEL);
685                                 if (*buf == NULL)
686                                         return -ENOMEM;
687                                 memcpy(*buf, efivars->walk_entry->var.Data,
688                                        size);
689                                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
690                                                    struct efivar_entry, list);
691                                 return size;
692                         }
693                 }
694                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
695                                                  struct efivar_entry, list);
696         }
697         return 0;
698 }
699
700 static int efi_pstore_write(enum pstore_type_id type, u64 *id,
701                 unsigned int part, size_t size, struct pstore_info *psi)
702 {
703         char name[DUMP_NAME_LEN];
704         char stub_name[DUMP_NAME_LEN];
705         efi_char16_t efi_name[DUMP_NAME_LEN];
706         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
707         struct efivars *efivars = psi->data;
708         struct efivar_entry *entry, *found = NULL;
709         int i, ret = 0;
710         u64 storage_space, remaining_space, max_variable_size;
711         efi_status_t status = EFI_NOT_FOUND;
712         unsigned long flags;
713
714         sprintf(stub_name, "dump-type%u-%u-", type, part);
715         sprintf(name, "%s%lu", stub_name, get_seconds());
716
717         spin_lock_irqsave(&efivars->lock, flags);
718
719         /*
720          * Check if there is a space enough to log.
721          * size: a size of logging data
722          * DUMP_NAME_LEN * 2: a maximum size of variable name
723          */
724         status = efivars->ops->query_variable_info(PSTORE_EFI_ATTRIBUTES,
725                                                    &storage_space,
726                                                    &remaining_space,
727                                                    &max_variable_size);
728         if (status || remaining_space < size + DUMP_NAME_LEN * 2) {
729                 spin_unlock_irqrestore(&efivars->lock, flags);
730                 *id = part;
731                 return -ENOSPC;
732         }
733
734         for (i = 0; i < DUMP_NAME_LEN; i++)
735                 efi_name[i] = stub_name[i];
736
737         /*
738          * Clean up any entries with the same name
739          */
740
741         list_for_each_entry(entry, &efivars->list, list) {
742                 get_var_data_locked(efivars, &entry->var);
743
744                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
745                         continue;
746                 if (utf16_strncmp(entry->var.VariableName, efi_name,
747                                   utf16_strlen(efi_name)))
748                         continue;
749                 /* Needs to be a prefix */
750                 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
751                         continue;
752
753                 /* found */
754                 found = entry;
755                 efivars->ops->set_variable(entry->var.VariableName,
756                                            &entry->var.VendorGuid,
757                                            PSTORE_EFI_ATTRIBUTES,
758                                            0, NULL);
759         }
760
761         if (found)
762                 list_del(&found->list);
763
764         for (i = 0; i < DUMP_NAME_LEN; i++)
765                 efi_name[i] = name[i];
766
767         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
768                                    size, psi->buf);
769
770         spin_unlock_irqrestore(&efivars->lock, flags);
771
772         if (found)
773                 efivar_unregister(found);
774
775         if (size)
776                 ret = efivar_create_sysfs_entry(efivars,
777                                           utf16_strsize(efi_name,
778                                                         DUMP_NAME_LEN * 2),
779                                           efi_name, &vendor);
780
781         *id = part;
782         return ret;
783 };
784
785 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
786                             struct pstore_info *psi)
787 {
788         efi_pstore_write(type, &id, (unsigned int)id, 0, psi);
789
790         return 0;
791 }
792 #else
793 static int efi_pstore_open(struct pstore_info *psi)
794 {
795         return 0;
796 }
797
798 static int efi_pstore_close(struct pstore_info *psi)
799 {
800         return 0;
801 }
802
803 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
804                                struct timespec *timespec,
805                                char **buf, struct pstore_info *psi)
806 {
807         return -1;
808 }
809
810 static int efi_pstore_write(enum pstore_type_id type, u64 *id,
811                 unsigned int part, size_t size, struct pstore_info *psi)
812 {
813         return 0;
814 }
815
816 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
817                             struct pstore_info *psi)
818 {
819         return 0;
820 }
821 #endif
822
823 static struct pstore_info efi_pstore_info = {
824         .owner          = THIS_MODULE,
825         .name           = "efi",
826         .open           = efi_pstore_open,
827         .close          = efi_pstore_close,
828         .read           = efi_pstore_read,
829         .write          = efi_pstore_write,
830         .erase          = efi_pstore_erase,
831 };
832
833 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
834                              struct bin_attribute *bin_attr,
835                              char *buf, loff_t pos, size_t count)
836 {
837         struct efi_variable *new_var = (struct efi_variable *)buf;
838         struct efivars *efivars = bin_attr->private;
839         struct efivar_entry *search_efivar, *n;
840         unsigned long strsize1, strsize2;
841         efi_status_t status = EFI_NOT_FOUND;
842         int found = 0;
843
844         if (!capable(CAP_SYS_ADMIN))
845                 return -EACCES;
846
847         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
848             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
849                 printk(KERN_ERR "efivars: Malformed variable content\n");
850                 return -EINVAL;
851         }
852
853         spin_lock_irq(&efivars->lock);
854
855         /*
856          * Does this variable already exist?
857          */
858         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
859                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
860                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
861                 if (strsize1 == strsize2 &&
862                         !memcmp(&(search_efivar->var.VariableName),
863                                 new_var->VariableName, strsize1) &&
864                         !efi_guidcmp(search_efivar->var.VendorGuid,
865                                 new_var->VendorGuid)) {
866                         found = 1;
867                         break;
868                 }
869         }
870         if (found) {
871                 spin_unlock_irq(&efivars->lock);
872                 return -EINVAL;
873         }
874
875         /* now *really* create the variable via EFI */
876         status = efivars->ops->set_variable(new_var->VariableName,
877                                             &new_var->VendorGuid,
878                                             new_var->Attributes,
879                                             new_var->DataSize,
880                                             new_var->Data);
881
882         if (status != EFI_SUCCESS) {
883                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
884                         status);
885                 spin_unlock_irq(&efivars->lock);
886                 return -EIO;
887         }
888         spin_unlock_irq(&efivars->lock);
889
890         /* Create the entry in sysfs.  Locking is not required here */
891         status = efivar_create_sysfs_entry(efivars,
892                                            utf16_strsize(new_var->VariableName,
893                                                          1024),
894                                            new_var->VariableName,
895                                            &new_var->VendorGuid);
896         if (status) {
897                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
898         }
899         return count;
900 }
901
902 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
903                              struct bin_attribute *bin_attr,
904                              char *buf, loff_t pos, size_t count)
905 {
906         struct efi_variable *del_var = (struct efi_variable *)buf;
907         struct efivars *efivars = bin_attr->private;
908         struct efivar_entry *search_efivar, *n;
909         unsigned long strsize1, strsize2;
910         efi_status_t status = EFI_NOT_FOUND;
911         int found = 0;
912
913         if (!capable(CAP_SYS_ADMIN))
914                 return -EACCES;
915
916         spin_lock_irq(&efivars->lock);
917
918         /*
919          * Does this variable already exist?
920          */
921         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
922                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
923                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
924                 if (strsize1 == strsize2 &&
925                         !memcmp(&(search_efivar->var.VariableName),
926                                 del_var->VariableName, strsize1) &&
927                         !efi_guidcmp(search_efivar->var.VendorGuid,
928                                 del_var->VendorGuid)) {
929                         found = 1;
930                         break;
931                 }
932         }
933         if (!found) {
934                 spin_unlock_irq(&efivars->lock);
935                 return -EINVAL;
936         }
937         /* force the Attributes/DataSize to 0 to ensure deletion */
938         del_var->Attributes = 0;
939         del_var->DataSize = 0;
940
941         status = efivars->ops->set_variable(del_var->VariableName,
942                                             &del_var->VendorGuid,
943                                             del_var->Attributes,
944                                             del_var->DataSize,
945                                             del_var->Data);
946
947         if (status != EFI_SUCCESS) {
948                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
949                         status);
950                 spin_unlock_irq(&efivars->lock);
951                 return -EIO;
952         }
953         list_del(&search_efivar->list);
954         /* We need to release this lock before unregistering. */
955         spin_unlock_irq(&efivars->lock);
956         efivar_unregister(search_efivar);
957
958         /* It's dead Jim.... */
959         return count;
960 }
961
962 /*
963  * Let's not leave out systab information that snuck into
964  * the efivars driver
965  */
966 static ssize_t systab_show(struct kobject *kobj,
967                            struct kobj_attribute *attr, char *buf)
968 {
969         char *str = buf;
970
971         if (!kobj || !buf)
972                 return -EINVAL;
973
974         if (efi.mps != EFI_INVALID_TABLE_ADDR)
975                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
976         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
977                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
978         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
979                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
980         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
981                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
982         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
983                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
984         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
985                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
986         if (efi.uga != EFI_INVALID_TABLE_ADDR)
987                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
988
989         return str - buf;
990 }
991
992 static struct kobj_attribute efi_attr_systab =
993                         __ATTR(systab, 0400, systab_show, NULL);
994
995 static struct attribute *efi_subsys_attrs[] = {
996         &efi_attr_systab.attr,
997         NULL,   /* maybe more in the future? */
998 };
999
1000 static struct attribute_group efi_subsys_attr_group = {
1001         .attrs = efi_subsys_attrs,
1002 };
1003
1004 static struct kobject *efi_kobj;
1005
1006 /*
1007  * efivar_create_sysfs_entry()
1008  * Requires:
1009  *    variable_name_size = number of bytes required to hold
1010  *                         variable_name (not counting the NULL
1011  *                         character at the end.
1012  *    efivars->lock is not held on entry or exit.
1013  * Returns 1 on failure, 0 on success
1014  */
1015 static int
1016 efivar_create_sysfs_entry(struct efivars *efivars,
1017                           unsigned long variable_name_size,
1018                           efi_char16_t *variable_name,
1019                           efi_guid_t *vendor_guid)
1020 {
1021         int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
1022         char *short_name;
1023         struct efivar_entry *new_efivar;
1024
1025         short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
1026         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1027
1028         if (!short_name || !new_efivar)  {
1029                 kfree(short_name);
1030                 kfree(new_efivar);
1031                 return 1;
1032         }
1033
1034         new_efivar->efivars = efivars;
1035         memcpy(new_efivar->var.VariableName, variable_name,
1036                 variable_name_size);
1037         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1038
1039         /* Convert Unicode to normal chars (assume top bits are 0),
1040            ala UTF-8 */
1041         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1042                 short_name[i] = variable_name[i] & 0xFF;
1043         }
1044         /* This is ugly, but necessary to separate one vendor's
1045            private variables from another's.         */
1046
1047         *(short_name + strlen(short_name)) = '-';
1048         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1049
1050         new_efivar->kobj.kset = efivars->kset;
1051         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1052                                  "%s", short_name);
1053         if (i) {
1054                 kfree(short_name);
1055                 kfree(new_efivar);
1056                 return 1;
1057         }
1058
1059         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1060         kfree(short_name);
1061         short_name = NULL;
1062
1063         spin_lock_irq(&efivars->lock);
1064         list_add(&new_efivar->list, &efivars->list);
1065         spin_unlock_irq(&efivars->lock);
1066
1067         return 0;
1068 }
1069
1070 static int
1071 create_efivars_bin_attributes(struct efivars *efivars)
1072 {
1073         struct bin_attribute *attr;
1074         int error;
1075
1076         /* new_var */
1077         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1078         if (!attr)
1079                 return -ENOMEM;
1080
1081         attr->attr.name = "new_var";
1082         attr->attr.mode = 0200;
1083         attr->write = efivar_create;
1084         attr->private = efivars;
1085         efivars->new_var = attr;
1086
1087         /* del_var */
1088         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1089         if (!attr) {
1090                 error = -ENOMEM;
1091                 goto out_free;
1092         }
1093         attr->attr.name = "del_var";
1094         attr->attr.mode = 0200;
1095         attr->write = efivar_delete;
1096         attr->private = efivars;
1097         efivars->del_var = attr;
1098
1099         sysfs_bin_attr_init(efivars->new_var);
1100         sysfs_bin_attr_init(efivars->del_var);
1101
1102         /* Register */
1103         error = sysfs_create_bin_file(&efivars->kset->kobj,
1104                                       efivars->new_var);
1105         if (error) {
1106                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1107                         " due to error %d\n", error);
1108                 goto out_free;
1109         }
1110         error = sysfs_create_bin_file(&efivars->kset->kobj,
1111                                       efivars->del_var);
1112         if (error) {
1113                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1114                         " due to error %d\n", error);
1115                 sysfs_remove_bin_file(&efivars->kset->kobj,
1116                                       efivars->new_var);
1117                 goto out_free;
1118         }
1119
1120         return 0;
1121 out_free:
1122         kfree(efivars->del_var);
1123         efivars->del_var = NULL;
1124         kfree(efivars->new_var);
1125         efivars->new_var = NULL;
1126         return error;
1127 }
1128
1129 void unregister_efivars(struct efivars *efivars)
1130 {
1131         struct efivar_entry *entry, *n;
1132
1133         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1134                 spin_lock_irq(&efivars->lock);
1135                 list_del(&entry->list);
1136                 spin_unlock_irq(&efivars->lock);
1137                 efivar_unregister(entry);
1138         }
1139         if (efivars->new_var)
1140                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1141         if (efivars->del_var)
1142                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1143         kfree(efivars->new_var);
1144         kfree(efivars->del_var);
1145         kset_unregister(efivars->kset);
1146 }
1147 EXPORT_SYMBOL_GPL(unregister_efivars);
1148
1149 int register_efivars(struct efivars *efivars,
1150                      const struct efivar_operations *ops,
1151                      struct kobject *parent_kobj)
1152 {
1153         efi_status_t status = EFI_NOT_FOUND;
1154         efi_guid_t vendor_guid;
1155         efi_char16_t *variable_name;
1156         unsigned long variable_name_size = 1024;
1157         int error = 0;
1158
1159         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1160         if (!variable_name) {
1161                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1162                 return -ENOMEM;
1163         }
1164
1165         spin_lock_init(&efivars->lock);
1166         INIT_LIST_HEAD(&efivars->list);
1167         efivars->ops = ops;
1168
1169         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1170         if (!efivars->kset) {
1171                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1172                 error = -ENOMEM;
1173                 goto out;
1174         }
1175
1176         /*
1177          * Per EFI spec, the maximum storage allocated for both
1178          * the variable name and variable data is 1024 bytes.
1179          */
1180
1181         do {
1182                 variable_name_size = 1024;
1183
1184                 status = ops->get_next_variable(&variable_name_size,
1185                                                 variable_name,
1186                                                 &vendor_guid);
1187                 switch (status) {
1188                 case EFI_SUCCESS:
1189                         efivar_create_sysfs_entry(efivars,
1190                                                   variable_name_size,
1191                                                   variable_name,
1192                                                   &vendor_guid);
1193                         break;
1194                 case EFI_NOT_FOUND:
1195                         break;
1196                 default:
1197                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1198                                 status);
1199                         status = EFI_NOT_FOUND;
1200                         break;
1201                 }
1202         } while (status != EFI_NOT_FOUND);
1203
1204         error = create_efivars_bin_attributes(efivars);
1205         if (error)
1206                 unregister_efivars(efivars);
1207
1208         efivars->efi_pstore_info = efi_pstore_info;
1209
1210         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1211         if (efivars->efi_pstore_info.buf) {
1212                 efivars->efi_pstore_info.bufsize = 1024;
1213                 efivars->efi_pstore_info.data = efivars;
1214                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1215                 pstore_register(&efivars->efi_pstore_info);
1216         }
1217
1218 out:
1219         kfree(variable_name);
1220
1221         return error;
1222 }
1223 EXPORT_SYMBOL_GPL(register_efivars);
1224
1225 static struct efivars __efivars;
1226 static struct efivar_operations ops;
1227
1228 /*
1229  * For now we register the efi subsystem with the firmware subsystem
1230  * and the vars subsystem with the efi subsystem.  In the future, it
1231  * might make sense to split off the efi subsystem into its own
1232  * driver, but for now only efivars will register with it, so just
1233  * include it here.
1234  */
1235
1236 static int __init
1237 efivars_init(void)
1238 {
1239         int error = 0;
1240
1241         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1242                EFIVARS_DATE);
1243
1244         if (!efi_enabled(EFI_RUNTIME_SERVICES))
1245                 return 0;
1246
1247         /* For now we'll register the efi directory at /sys/firmware/efi */
1248         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1249         if (!efi_kobj) {
1250                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1251                 return -ENOMEM;
1252         }
1253
1254         ops.get_variable = efi.get_variable;
1255         ops.set_variable = efi.set_variable;
1256         ops.get_next_variable = efi.get_next_variable;
1257         ops.query_variable_info = efi.query_variable_info;
1258         error = register_efivars(&__efivars, &ops, efi_kobj);
1259         if (error)
1260                 goto err_put;
1261
1262         /* Don't forget the systab entry */
1263         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1264         if (error) {
1265                 printk(KERN_ERR
1266                        "efivars: Sysfs attribute export failed with error %d.\n",
1267                        error);
1268                 goto err_unregister;
1269         }
1270
1271         return 0;
1272
1273 err_unregister:
1274         unregister_efivars(&__efivars);
1275 err_put:
1276         kobject_put(efi_kobj);
1277         return error;
1278 }
1279
1280 static void __exit
1281 efivars_exit(void)
1282 {
1283         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
1284                 unregister_efivars(&__efivars);
1285                 kobject_put(efi_kobj);
1286         }
1287 }
1288
1289 module_init(efivars_init);
1290 module_exit(efivars_exit);
1291