efi_pstore: Add a logic erasing entries to an erase callback
[linux-3.10.git] / drivers / firmware / efivars.c
1 /*
2  * EFI Variables - efivars.c
3  *
4  * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
5  * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
6  *
7  * This code takes all variables accessible from EFI runtime and
8  *  exports them via sysfs
9  *
10  *  This program is free software; you can redistribute it and/or modify
11  *  it under the terms of the GNU General Public License as published by
12  *  the Free Software Foundation; either version 2 of the License, or
13  *  (at your option) any later version.
14  *
15  *  This program is distributed in the hope that it will be useful,
16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  *  GNU General Public License for more details.
19  *
20  *  You should have received a copy of the GNU General Public License
21  *  along with this program; if not, write to the Free Software
22  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
23  *
24  * Changelog:
25  *
26  *  17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
27  *   remove check for efi_enabled in exit
28  *   add MODULE_VERSION
29  *
30  *  26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com>
31  *   minor bug fixes
32  *
33  *  21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com)
34  *   converted driver to export variable information via sysfs
35  *   and moved to drivers/firmware directory
36  *   bumped revision number to v0.07 to reflect conversion & move
37  *
38  *  10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com>
39  *   fix locking per Peter Chubb's findings
40  *
41  *  25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com>
42  *   move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_unparse()
43  *
44  *  12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com>
45  *   use list_for_each_safe when deleting vars.
46  *   remove ifdef CONFIG_SMP around include <linux/smp.h>
47  *   v0.04 release to linux-ia64@linuxia64.org
48  *
49  *  20 April 2001 - Matt Domsch <Matt_Domsch@dell.com>
50  *   Moved vars from /proc/efi to /proc/efi/vars, and made
51  *   efi.c own the /proc/efi directory.
52  *   v0.03 release to linux-ia64@linuxia64.org
53  *
54  *  26 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
55  *   At the request of Stephane, moved ownership of /proc/efi
56  *   to efi.c, and now efivars lives under /proc/efi/vars.
57  *
58  *  12 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
59  *   Feedback received from Stephane Eranian incorporated.
60  *   efivar_write() checks copy_from_user() return value.
61  *   efivar_read/write() returns proper errno.
62  *   v0.02 release to linux-ia64@linuxia64.org
63  *
64  *  26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
65  *   v0.01 release to linux-ia64@linuxia64.org
66  */
67
68 #include <linux/capability.h>
69 #include <linux/types.h>
70 #include <linux/errno.h>
71 #include <linux/init.h>
72 #include <linux/mm.h>
73 #include <linux/module.h>
74 #include <linux/string.h>
75 #include <linux/smp.h>
76 #include <linux/efi.h>
77 #include <linux/sysfs.h>
78 #include <linux/kobject.h>
79 #include <linux/device.h>
80 #include <linux/slab.h>
81 #include <linux/pstore.h>
82
83 #include <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
397         spin_lock(&efivars->lock);
398         status = get_var_data_locked(efivars, var);
399         spin_unlock(&efivars->lock);
400
401         if (status != EFI_SUCCESS) {
402                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
403                         status);
404         }
405         return status;
406 }
407
408 static ssize_t
409 efivar_guid_read(struct efivar_entry *entry, char *buf)
410 {
411         struct efi_variable *var = &entry->var;
412         char *str = buf;
413
414         if (!entry || !buf)
415                 return 0;
416
417         efi_guid_unparse(&var->VendorGuid, str);
418         str += strlen(str);
419         str += sprintf(str, "\n");
420
421         return str - buf;
422 }
423
424 static ssize_t
425 efivar_attr_read(struct efivar_entry *entry, char *buf)
426 {
427         struct efi_variable *var = &entry->var;
428         char *str = buf;
429         efi_status_t status;
430
431         if (!entry || !buf)
432                 return -EINVAL;
433
434         status = get_var_data(entry->efivars, var);
435         if (status != EFI_SUCCESS)
436                 return -EIO;
437
438         if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
439                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
440         if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
441                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
442         if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
443                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
444         if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
445                 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
446         if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
447                 str += sprintf(str,
448                         "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
449         if (var->Attributes &
450                         EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
451                 str += sprintf(str,
452                         "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
453         if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
454                 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
455         return str - buf;
456 }
457
458 static ssize_t
459 efivar_size_read(struct efivar_entry *entry, char *buf)
460 {
461         struct efi_variable *var = &entry->var;
462         char *str = buf;
463         efi_status_t status;
464
465         if (!entry || !buf)
466                 return -EINVAL;
467
468         status = get_var_data(entry->efivars, var);
469         if (status != EFI_SUCCESS)
470                 return -EIO;
471
472         str += sprintf(str, "0x%lx\n", var->DataSize);
473         return str - buf;
474 }
475
476 static ssize_t
477 efivar_data_read(struct efivar_entry *entry, char *buf)
478 {
479         struct efi_variable *var = &entry->var;
480         efi_status_t status;
481
482         if (!entry || !buf)
483                 return -EINVAL;
484
485         status = get_var_data(entry->efivars, var);
486         if (status != EFI_SUCCESS)
487                 return -EIO;
488
489         memcpy(buf, var->Data, var->DataSize);
490         return var->DataSize;
491 }
492 /*
493  * We allow each variable to be edited via rewriting the
494  * entire efi variable structure.
495  */
496 static ssize_t
497 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
498 {
499         struct efi_variable *new_var, *var = &entry->var;
500         struct efivars *efivars = entry->efivars;
501         efi_status_t status = EFI_NOT_FOUND;
502
503         if (count != sizeof(struct efi_variable))
504                 return -EINVAL;
505
506         new_var = (struct efi_variable *)buf;
507         /*
508          * If only updating the variable data, then the name
509          * and guid should remain the same
510          */
511         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
512                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
513                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
514                 return -EINVAL;
515         }
516
517         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
518                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
519                 return -EINVAL;
520         }
521
522         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
523             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
524                 printk(KERN_ERR "efivars: Malformed variable content\n");
525                 return -EINVAL;
526         }
527
528         spin_lock(&efivars->lock);
529         status = efivars->ops->set_variable(new_var->VariableName,
530                                             &new_var->VendorGuid,
531                                             new_var->Attributes,
532                                             new_var->DataSize,
533                                             new_var->Data);
534
535         spin_unlock(&efivars->lock);
536
537         if (status != EFI_SUCCESS) {
538                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
539                         status);
540                 return -EIO;
541         }
542
543         memcpy(&entry->var, new_var, count);
544         return count;
545 }
546
547 static ssize_t
548 efivar_show_raw(struct efivar_entry *entry, char *buf)
549 {
550         struct efi_variable *var = &entry->var;
551         efi_status_t status;
552
553         if (!entry || !buf)
554                 return 0;
555
556         status = get_var_data(entry->efivars, var);
557         if (status != EFI_SUCCESS)
558                 return -EIO;
559
560         memcpy(buf, var, sizeof(*var));
561         return sizeof(*var);
562 }
563
564 /*
565  * Generic read/write functions that call the specific functions of
566  * the attributes...
567  */
568 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
569                                 char *buf)
570 {
571         struct efivar_entry *var = to_efivar_entry(kobj);
572         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
573         ssize_t ret = -EIO;
574
575         if (!capable(CAP_SYS_ADMIN))
576                 return -EACCES;
577
578         if (efivar_attr->show) {
579                 ret = efivar_attr->show(var, buf);
580         }
581         return ret;
582 }
583
584 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
585                                 const char *buf, size_t count)
586 {
587         struct efivar_entry *var = to_efivar_entry(kobj);
588         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
589         ssize_t ret = -EIO;
590
591         if (!capable(CAP_SYS_ADMIN))
592                 return -EACCES;
593
594         if (efivar_attr->store)
595                 ret = efivar_attr->store(var, buf, count);
596
597         return ret;
598 }
599
600 static const struct sysfs_ops efivar_attr_ops = {
601         .show = efivar_attr_show,
602         .store = efivar_attr_store,
603 };
604
605 static void efivar_release(struct kobject *kobj)
606 {
607         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
608         kfree(var);
609 }
610
611 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
612 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
613 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
614 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
615 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
616
617 static struct attribute *def_attrs[] = {
618         &efivar_attr_guid.attr,
619         &efivar_attr_size.attr,
620         &efivar_attr_attributes.attr,
621         &efivar_attr_data.attr,
622         &efivar_attr_raw_var.attr,
623         NULL,
624 };
625
626 static struct kobj_type efivar_ktype = {
627         .release = efivar_release,
628         .sysfs_ops = &efivar_attr_ops,
629         .default_attrs = def_attrs,
630 };
631
632 static struct pstore_info efi_pstore_info;
633
634 static inline void
635 efivar_unregister(struct efivar_entry *var)
636 {
637         kobject_put(&var->kobj);
638 }
639
640 #ifdef CONFIG_PSTORE
641
642 static int efi_pstore_open(struct pstore_info *psi)
643 {
644         struct efivars *efivars = psi->data;
645
646         spin_lock(&efivars->lock);
647         efivars->walk_entry = list_first_entry(&efivars->list,
648                                                struct efivar_entry, list);
649         return 0;
650 }
651
652 static int efi_pstore_close(struct pstore_info *psi)
653 {
654         struct efivars *efivars = psi->data;
655
656         spin_unlock(&efivars->lock);
657         return 0;
658 }
659
660 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
661                                struct timespec *timespec,
662                                char **buf, struct pstore_info *psi)
663 {
664         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
665         struct efivars *efivars = psi->data;
666         char name[DUMP_NAME_LEN];
667         int i;
668         unsigned int part, size;
669         unsigned long time;
670
671         while (&efivars->walk_entry->list != &efivars->list) {
672                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
673                                  vendor)) {
674                         for (i = 0; i < DUMP_NAME_LEN; i++) {
675                                 name[i] = efivars->walk_entry->var.VariableName[i];
676                         }
677                         if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
678                                 *id = part;
679                                 timespec->tv_sec = time;
680                                 timespec->tv_nsec = 0;
681                                 get_var_data_locked(efivars, &efivars->walk_entry->var);
682                                 size = efivars->walk_entry->var.DataSize;
683                                 *buf = kmalloc(size, GFP_KERNEL);
684                                 if (*buf == NULL)
685                                         return -ENOMEM;
686                                 memcpy(*buf, efivars->walk_entry->var.Data,
687                                        size);
688                                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
689                                                    struct efivar_entry, list);
690                                 return size;
691                         }
692                 }
693                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
694                                                  struct efivar_entry, list);
695         }
696         return 0;
697 }
698
699 static int efi_pstore_write(enum pstore_type_id type,
700                 enum kmsg_dump_reason reason, 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
713         sprintf(stub_name, "dump-type%u-%u-", type, part);
714         sprintf(name, "%s%lu", stub_name, get_seconds());
715
716         spin_lock(&efivars->lock);
717
718         /*
719          * Check if there is a space enough to log.
720          * size: a size of logging data
721          * DUMP_NAME_LEN * 2: a maximum size of variable name
722          */
723         status = efivars->ops->query_variable_info(PSTORE_EFI_ATTRIBUTES,
724                                                    &storage_space,
725                                                    &remaining_space,
726                                                    &max_variable_size);
727         if (status || remaining_space < size + DUMP_NAME_LEN * 2) {
728                 spin_unlock(&efivars->lock);
729                 *id = part;
730                 return -ENOSPC;
731         }
732
733         for (i = 0; i < DUMP_NAME_LEN; i++)
734                 efi_name[i] = stub_name[i];
735
736         /*
737          * Clean up any entries with the same name
738          */
739
740         list_for_each_entry(entry, &efivars->list, list) {
741                 get_var_data_locked(efivars, &entry->var);
742
743                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
744                         continue;
745                 if (utf16_strncmp(entry->var.VariableName, efi_name,
746                                   utf16_strlen(efi_name)))
747                         continue;
748                 /* Needs to be a prefix */
749                 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
750                         continue;
751
752                 /* found */
753                 found = entry;
754                 efivars->ops->set_variable(entry->var.VariableName,
755                                            &entry->var.VendorGuid,
756                                            PSTORE_EFI_ATTRIBUTES,
757                                            0, NULL);
758         }
759
760         if (found)
761                 list_del(&found->list);
762
763         for (i = 0; i < DUMP_NAME_LEN; i++)
764                 efi_name[i] = name[i];
765
766         efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
767                                    size, psi->buf);
768
769         spin_unlock(&efivars->lock);
770
771         if (found)
772                 efivar_unregister(found);
773
774         if (size)
775                 ret = efivar_create_sysfs_entry(efivars,
776                                           utf16_strsize(efi_name,
777                                                         DUMP_NAME_LEN * 2),
778                                           efi_name, &vendor);
779
780         *id = part;
781         return ret;
782 };
783
784 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
785                             struct pstore_info *psi)
786 {
787         char stub_name[DUMP_NAME_LEN];
788         efi_char16_t efi_name[DUMP_NAME_LEN];
789         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
790         struct efivars *efivars = psi->data;
791         struct efivar_entry *entry, *found = NULL;
792         int i;
793
794         sprintf(stub_name, "dump-type%u-%u-", type, (unsigned int)id);
795
796         spin_lock(&efivars->lock);
797
798         for (i = 0; i < DUMP_NAME_LEN; i++)
799                 efi_name[i] = stub_name[i];
800
801         /*
802          * Clean up any entries with the same name
803          */
804
805         list_for_each_entry(entry, &efivars->list, list) {
806                 get_var_data_locked(efivars, &entry->var);
807
808                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
809                         continue;
810                 if (utf16_strncmp(entry->var.VariableName, efi_name,
811                                   utf16_strlen(efi_name)))
812                         continue;
813                 /* Needs to be a prefix */
814                 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
815                         continue;
816
817                 /* found */
818                 found = entry;
819                 efivars->ops->set_variable(entry->var.VariableName,
820                                            &entry->var.VendorGuid,
821                                            PSTORE_EFI_ATTRIBUTES,
822                                            0, NULL);
823         }
824
825         if (found)
826                 list_del(&found->list);
827
828         spin_unlock(&efivars->lock);
829
830         if (found)
831                 efivar_unregister(found);
832
833         return 0;
834 }
835 #else
836 static int efi_pstore_open(struct pstore_info *psi)
837 {
838         return 0;
839 }
840
841 static int efi_pstore_close(struct pstore_info *psi)
842 {
843         return 0;
844 }
845
846 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
847                                struct timespec *timespec,
848                                char **buf, struct pstore_info *psi)
849 {
850         return -1;
851 }
852
853 static int efi_pstore_write(enum pstore_type_id type,
854                 enum kmsg_dump_reason reason, u64 *id,
855                 unsigned int part, size_t size, struct pstore_info *psi)
856 {
857         return 0;
858 }
859
860 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
861                             struct pstore_info *psi)
862 {
863         return 0;
864 }
865 #endif
866
867 static struct pstore_info efi_pstore_info = {
868         .owner          = THIS_MODULE,
869         .name           = "efi",
870         .open           = efi_pstore_open,
871         .close          = efi_pstore_close,
872         .read           = efi_pstore_read,
873         .write          = efi_pstore_write,
874         .erase          = efi_pstore_erase,
875 };
876
877 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
878                              struct bin_attribute *bin_attr,
879                              char *buf, loff_t pos, size_t count)
880 {
881         struct efi_variable *new_var = (struct efi_variable *)buf;
882         struct efivars *efivars = bin_attr->private;
883         struct efivar_entry *search_efivar, *n;
884         unsigned long strsize1, strsize2;
885         efi_status_t status = EFI_NOT_FOUND;
886         int found = 0;
887
888         if (!capable(CAP_SYS_ADMIN))
889                 return -EACCES;
890
891         if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
892             validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
893                 printk(KERN_ERR "efivars: Malformed variable content\n");
894                 return -EINVAL;
895         }
896
897         spin_lock(&efivars->lock);
898
899         /*
900          * Does this variable already exist?
901          */
902         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
903                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
904                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
905                 if (strsize1 == strsize2 &&
906                         !memcmp(&(search_efivar->var.VariableName),
907                                 new_var->VariableName, strsize1) &&
908                         !efi_guidcmp(search_efivar->var.VendorGuid,
909                                 new_var->VendorGuid)) {
910                         found = 1;
911                         break;
912                 }
913         }
914         if (found) {
915                 spin_unlock(&efivars->lock);
916                 return -EINVAL;
917         }
918
919         /* now *really* create the variable via EFI */
920         status = efivars->ops->set_variable(new_var->VariableName,
921                                             &new_var->VendorGuid,
922                                             new_var->Attributes,
923                                             new_var->DataSize,
924                                             new_var->Data);
925
926         if (status != EFI_SUCCESS) {
927                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
928                         status);
929                 spin_unlock(&efivars->lock);
930                 return -EIO;
931         }
932         spin_unlock(&efivars->lock);
933
934         /* Create the entry in sysfs.  Locking is not required here */
935         status = efivar_create_sysfs_entry(efivars,
936                                            utf16_strsize(new_var->VariableName,
937                                                          1024),
938                                            new_var->VariableName,
939                                            &new_var->VendorGuid);
940         if (status) {
941                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
942         }
943         return count;
944 }
945
946 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
947                              struct bin_attribute *bin_attr,
948                              char *buf, loff_t pos, size_t count)
949 {
950         struct efi_variable *del_var = (struct efi_variable *)buf;
951         struct efivars *efivars = bin_attr->private;
952         struct efivar_entry *search_efivar, *n;
953         unsigned long strsize1, strsize2;
954         efi_status_t status = EFI_NOT_FOUND;
955         int found = 0;
956
957         if (!capable(CAP_SYS_ADMIN))
958                 return -EACCES;
959
960         spin_lock(&efivars->lock);
961
962         /*
963          * Does this variable already exist?
964          */
965         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
966                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
967                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
968                 if (strsize1 == strsize2 &&
969                         !memcmp(&(search_efivar->var.VariableName),
970                                 del_var->VariableName, strsize1) &&
971                         !efi_guidcmp(search_efivar->var.VendorGuid,
972                                 del_var->VendorGuid)) {
973                         found = 1;
974                         break;
975                 }
976         }
977         if (!found) {
978                 spin_unlock(&efivars->lock);
979                 return -EINVAL;
980         }
981         /* force the Attributes/DataSize to 0 to ensure deletion */
982         del_var->Attributes = 0;
983         del_var->DataSize = 0;
984
985         status = efivars->ops->set_variable(del_var->VariableName,
986                                             &del_var->VendorGuid,
987                                             del_var->Attributes,
988                                             del_var->DataSize,
989                                             del_var->Data);
990
991         if (status != EFI_SUCCESS) {
992                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
993                         status);
994                 spin_unlock(&efivars->lock);
995                 return -EIO;
996         }
997         list_del(&search_efivar->list);
998         /* We need to release this lock before unregistering. */
999         spin_unlock(&efivars->lock);
1000         efivar_unregister(search_efivar);
1001
1002         /* It's dead Jim.... */
1003         return count;
1004 }
1005
1006 /*
1007  * Let's not leave out systab information that snuck into
1008  * the efivars driver
1009  */
1010 static ssize_t systab_show(struct kobject *kobj,
1011                            struct kobj_attribute *attr, char *buf)
1012 {
1013         char *str = buf;
1014
1015         if (!kobj || !buf)
1016                 return -EINVAL;
1017
1018         if (efi.mps != EFI_INVALID_TABLE_ADDR)
1019                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1020         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1021                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1022         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1023                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1024         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1025                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1026         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1027                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1028         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1029                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1030         if (efi.uga != EFI_INVALID_TABLE_ADDR)
1031                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1032
1033         return str - buf;
1034 }
1035
1036 static struct kobj_attribute efi_attr_systab =
1037                         __ATTR(systab, 0400, systab_show, NULL);
1038
1039 static struct attribute *efi_subsys_attrs[] = {
1040         &efi_attr_systab.attr,
1041         NULL,   /* maybe more in the future? */
1042 };
1043
1044 static struct attribute_group efi_subsys_attr_group = {
1045         .attrs = efi_subsys_attrs,
1046 };
1047
1048 static struct kobject *efi_kobj;
1049
1050 /*
1051  * efivar_create_sysfs_entry()
1052  * Requires:
1053  *    variable_name_size = number of bytes required to hold
1054  *                         variable_name (not counting the NULL
1055  *                         character at the end.
1056  *    efivars->lock is not held on entry or exit.
1057  * Returns 1 on failure, 0 on success
1058  */
1059 static int
1060 efivar_create_sysfs_entry(struct efivars *efivars,
1061                           unsigned long variable_name_size,
1062                           efi_char16_t *variable_name,
1063                           efi_guid_t *vendor_guid)
1064 {
1065         int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
1066         char *short_name;
1067         struct efivar_entry *new_efivar;
1068
1069         short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
1070         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1071
1072         if (!short_name || !new_efivar)  {
1073                 kfree(short_name);
1074                 kfree(new_efivar);
1075                 return 1;
1076         }
1077
1078         new_efivar->efivars = efivars;
1079         memcpy(new_efivar->var.VariableName, variable_name,
1080                 variable_name_size);
1081         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1082
1083         /* Convert Unicode to normal chars (assume top bits are 0),
1084            ala UTF-8 */
1085         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1086                 short_name[i] = variable_name[i] & 0xFF;
1087         }
1088         /* This is ugly, but necessary to separate one vendor's
1089            private variables from another's.         */
1090
1091         *(short_name + strlen(short_name)) = '-';
1092         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1093
1094         new_efivar->kobj.kset = efivars->kset;
1095         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1096                                  "%s", short_name);
1097         if (i) {
1098                 kfree(short_name);
1099                 kfree(new_efivar);
1100                 return 1;
1101         }
1102
1103         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1104         kfree(short_name);
1105         short_name = NULL;
1106
1107         spin_lock(&efivars->lock);
1108         list_add(&new_efivar->list, &efivars->list);
1109         spin_unlock(&efivars->lock);
1110
1111         return 0;
1112 }
1113
1114 static int
1115 create_efivars_bin_attributes(struct efivars *efivars)
1116 {
1117         struct bin_attribute *attr;
1118         int error;
1119
1120         /* new_var */
1121         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1122         if (!attr)
1123                 return -ENOMEM;
1124
1125         attr->attr.name = "new_var";
1126         attr->attr.mode = 0200;
1127         attr->write = efivar_create;
1128         attr->private = efivars;
1129         efivars->new_var = attr;
1130
1131         /* del_var */
1132         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1133         if (!attr) {
1134                 error = -ENOMEM;
1135                 goto out_free;
1136         }
1137         attr->attr.name = "del_var";
1138         attr->attr.mode = 0200;
1139         attr->write = efivar_delete;
1140         attr->private = efivars;
1141         efivars->del_var = attr;
1142
1143         sysfs_bin_attr_init(efivars->new_var);
1144         sysfs_bin_attr_init(efivars->del_var);
1145
1146         /* Register */
1147         error = sysfs_create_bin_file(&efivars->kset->kobj,
1148                                       efivars->new_var);
1149         if (error) {
1150                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1151                         " due to error %d\n", error);
1152                 goto out_free;
1153         }
1154         error = sysfs_create_bin_file(&efivars->kset->kobj,
1155                                       efivars->del_var);
1156         if (error) {
1157                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1158                         " due to error %d\n", error);
1159                 sysfs_remove_bin_file(&efivars->kset->kobj,
1160                                       efivars->new_var);
1161                 goto out_free;
1162         }
1163
1164         return 0;
1165 out_free:
1166         kfree(efivars->del_var);
1167         efivars->del_var = NULL;
1168         kfree(efivars->new_var);
1169         efivars->new_var = NULL;
1170         return error;
1171 }
1172
1173 void unregister_efivars(struct efivars *efivars)
1174 {
1175         struct efivar_entry *entry, *n;
1176
1177         list_for_each_entry_safe(entry, n, &efivars->list, list) {
1178                 spin_lock(&efivars->lock);
1179                 list_del(&entry->list);
1180                 spin_unlock(&efivars->lock);
1181                 efivar_unregister(entry);
1182         }
1183         if (efivars->new_var)
1184                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1185         if (efivars->del_var)
1186                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1187         kfree(efivars->new_var);
1188         kfree(efivars->del_var);
1189         kset_unregister(efivars->kset);
1190 }
1191 EXPORT_SYMBOL_GPL(unregister_efivars);
1192
1193 int register_efivars(struct efivars *efivars,
1194                      const struct efivar_operations *ops,
1195                      struct kobject *parent_kobj)
1196 {
1197         efi_status_t status = EFI_NOT_FOUND;
1198         efi_guid_t vendor_guid;
1199         efi_char16_t *variable_name;
1200         unsigned long variable_name_size = 1024;
1201         int error = 0;
1202
1203         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1204         if (!variable_name) {
1205                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1206                 return -ENOMEM;
1207         }
1208
1209         spin_lock_init(&efivars->lock);
1210         INIT_LIST_HEAD(&efivars->list);
1211         efivars->ops = ops;
1212
1213         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1214         if (!efivars->kset) {
1215                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1216                 error = -ENOMEM;
1217                 goto out;
1218         }
1219
1220         /*
1221          * Per EFI spec, the maximum storage allocated for both
1222          * the variable name and variable data is 1024 bytes.
1223          */
1224
1225         do {
1226                 variable_name_size = 1024;
1227
1228                 status = ops->get_next_variable(&variable_name_size,
1229                                                 variable_name,
1230                                                 &vendor_guid);
1231                 switch (status) {
1232                 case EFI_SUCCESS:
1233                         efivar_create_sysfs_entry(efivars,
1234                                                   variable_name_size,
1235                                                   variable_name,
1236                                                   &vendor_guid);
1237                         break;
1238                 case EFI_NOT_FOUND:
1239                         break;
1240                 default:
1241                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
1242                                 status);
1243                         status = EFI_NOT_FOUND;
1244                         break;
1245                 }
1246         } while (status != EFI_NOT_FOUND);
1247
1248         error = create_efivars_bin_attributes(efivars);
1249         if (error)
1250                 unregister_efivars(efivars);
1251
1252         efivars->efi_pstore_info = efi_pstore_info;
1253
1254         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
1255         if (efivars->efi_pstore_info.buf) {
1256                 efivars->efi_pstore_info.bufsize = 1024;
1257                 efivars->efi_pstore_info.data = efivars;
1258                 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
1259                 pstore_register(&efivars->efi_pstore_info);
1260         }
1261
1262 out:
1263         kfree(variable_name);
1264
1265         return error;
1266 }
1267 EXPORT_SYMBOL_GPL(register_efivars);
1268
1269 static struct efivars __efivars;
1270 static struct efivar_operations ops;
1271
1272 /*
1273  * For now we register the efi subsystem with the firmware subsystem
1274  * and the vars subsystem with the efi subsystem.  In the future, it
1275  * might make sense to split off the efi subsystem into its own
1276  * driver, but for now only efivars will register with it, so just
1277  * include it here.
1278  */
1279
1280 static int __init
1281 efivars_init(void)
1282 {
1283         int error = 0;
1284
1285         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1286                EFIVARS_DATE);
1287
1288         if (!efi_enabled)
1289                 return 0;
1290
1291         /* For now we'll register the efi directory at /sys/firmware/efi */
1292         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1293         if (!efi_kobj) {
1294                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1295                 return -ENOMEM;
1296         }
1297
1298         ops.get_variable = efi.get_variable;
1299         ops.set_variable = efi.set_variable;
1300         ops.get_next_variable = efi.get_next_variable;
1301         ops.query_variable_info = efi.query_variable_info;
1302         error = register_efivars(&__efivars, &ops, efi_kobj);
1303         if (error)
1304                 goto err_put;
1305
1306         /* Don't forget the systab entry */
1307         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1308         if (error) {
1309                 printk(KERN_ERR
1310                        "efivars: Sysfs attribute export failed with error %d.\n",
1311                        error);
1312                 goto err_unregister;
1313         }
1314
1315         return 0;
1316
1317 err_unregister:
1318         unregister_efivars(&__efivars);
1319 err_put:
1320         kobject_put(efi_kobj);
1321         return error;
1322 }
1323
1324 static void __exit
1325 efivars_exit(void)
1326 {
1327         if (efi_enabled) {
1328                 unregister_efivars(&__efivars);
1329                 kobject_put(efi_kobj);
1330         }
1331 }
1332
1333 module_init(efivars_init);
1334 module_exit(efivars_exit);
1335