efivars: Use string functions in pstore_write
[linux-3.10.git] / drivers / firmware / efivars.c
1 /*
2  * EFI Variables - efivars.c
3  *
4  * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
5  * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
6  *
7  * This code takes all variables accessible from EFI runtime and
8  *  exports them via sysfs
9  *
10  *  This program is free software; you can redistribute it and/or modify
11  *  it under the terms of the GNU General Public License as published by
12  *  the Free Software Foundation; either version 2 of the License, or
13  *  (at your option) any later version.
14  *
15  *  This program is distributed in the hope that it will be useful,
16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  *  GNU General Public License for more details.
19  *
20  *  You should have received a copy of the GNU General Public License
21  *  along with this program; if not, write to the Free Software
22  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
23  *
24  * Changelog:
25  *
26  *  17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
27  *   remove check for efi_enabled in exit
28  *   add MODULE_VERSION
29  *
30  *  26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com>
31  *   minor bug fixes
32  *
33  *  21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com)
34  *   converted driver to export variable information via sysfs
35  *   and moved to drivers/firmware directory
36  *   bumped revision number to v0.07 to reflect conversion & move
37  *
38  *  10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com>
39  *   fix locking per Peter Chubb's findings
40  *
41  *  25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com>
42  *   move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_unparse()
43  *
44  *  12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com>
45  *   use list_for_each_safe when deleting vars.
46  *   remove ifdef CONFIG_SMP around include <linux/smp.h>
47  *   v0.04 release to linux-ia64@linuxia64.org
48  *
49  *  20 April 2001 - Matt Domsch <Matt_Domsch@dell.com>
50  *   Moved vars from /proc/efi to /proc/efi/vars, and made
51  *   efi.c own the /proc/efi directory.
52  *   v0.03 release to linux-ia64@linuxia64.org
53  *
54  *  26 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
55  *   At the request of Stephane, moved ownership of /proc/efi
56  *   to efi.c, and now efivars lives under /proc/efi/vars.
57  *
58  *  12 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
59  *   Feedback received from Stephane Eranian incorporated.
60  *   efivar_write() checks copy_from_user() return value.
61  *   efivar_read/write() returns proper errno.
62  *   v0.02 release to linux-ia64@linuxia64.org
63  *
64  *  26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
65  *   v0.01 release to linux-ia64@linuxia64.org
66  */
67
68 #include <linux/capability.h>
69 #include <linux/types.h>
70 #include <linux/errno.h>
71 #include <linux/init.h>
72 #include <linux/mm.h>
73 #include <linux/module.h>
74 #include <linux/string.h>
75 #include <linux/smp.h>
76 #include <linux/efi.h>
77 #include <linux/sysfs.h>
78 #include <linux/kobject.h>
79 #include <linux/device.h>
80 #include <linux/slab.h>
81 #include <linux/pstore.h>
82
83 #include <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
126 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
127 struct efivar_attribute efivar_attr_##_name = { \
128         .attr = {.name = __stringify(_name), .mode = _mode}, \
129         .show = _show, \
130         .store = _store, \
131 };
132
133 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
134 #define to_efivar_entry(obj)  container_of(obj, struct efivar_entry, kobj)
135
136 /*
137  * Prototype for sysfs creation function
138  */
139 static int
140 efivar_create_sysfs_entry(struct efivars *efivars,
141                           unsigned long variable_name_size,
142                           efi_char16_t *variable_name,
143                           efi_guid_t *vendor_guid);
144
145 /* Return the number of unicode characters in data */
146 static unsigned long
147 utf16_strnlen(efi_char16_t *s, size_t maxlength)
148 {
149         unsigned long length = 0;
150
151         while (*s++ != 0 && length < maxlength)
152                 length++;
153         return length;
154 }
155
156 static unsigned long
157 utf16_strlen(efi_char16_t *s)
158 {
159         return utf16_strnlen(s, ~0UL);
160 }
161
162 /*
163  * Return the number of bytes is the length of this string
164  * Note: this is NOT the same as the number of unicode characters
165  */
166 static inline unsigned long
167 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
168 {
169         return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
170 }
171
172 static inline int
173 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
174 {
175         while (1) {
176                 if (len == 0)
177                         return 0;
178                 if (*a < *b)
179                         return -1;
180                 if (*a > *b)
181                         return 1;
182                 if (*a == 0) /* implies *b == 0 */
183                         return 0;
184                 a++;
185                 b++;
186                 len--;
187         }
188 }
189
190 static efi_status_t
191 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
192 {
193         efi_status_t status;
194
195         var->DataSize = 1024;
196         status = efivars->ops->get_variable(var->VariableName,
197                                             &var->VendorGuid,
198                                             &var->Attributes,
199                                             &var->DataSize,
200                                             var->Data);
201         return status;
202 }
203
204 static efi_status_t
205 get_var_data(struct efivars *efivars, struct efi_variable *var)
206 {
207         efi_status_t status;
208
209         spin_lock(&efivars->lock);
210         status = get_var_data_locked(efivars, var);
211         spin_unlock(&efivars->lock);
212
213         if (status != EFI_SUCCESS) {
214                 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
215                         status);
216         }
217         return status;
218 }
219
220 static ssize_t
221 efivar_guid_read(struct efivar_entry *entry, char *buf)
222 {
223         struct efi_variable *var = &entry->var;
224         char *str = buf;
225
226         if (!entry || !buf)
227                 return 0;
228
229         efi_guid_unparse(&var->VendorGuid, str);
230         str += strlen(str);
231         str += sprintf(str, "\n");
232
233         return str - buf;
234 }
235
236 static ssize_t
237 efivar_attr_read(struct efivar_entry *entry, char *buf)
238 {
239         struct efi_variable *var = &entry->var;
240         char *str = buf;
241         efi_status_t status;
242
243         if (!entry || !buf)
244                 return -EINVAL;
245
246         status = get_var_data(entry->efivars, var);
247         if (status != EFI_SUCCESS)
248                 return -EIO;
249
250         if (var->Attributes & 0x1)
251                 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
252         if (var->Attributes & 0x2)
253                 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
254         if (var->Attributes & 0x4)
255                 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
256         return str - buf;
257 }
258
259 static ssize_t
260 efivar_size_read(struct efivar_entry *entry, char *buf)
261 {
262         struct efi_variable *var = &entry->var;
263         char *str = buf;
264         efi_status_t status;
265
266         if (!entry || !buf)
267                 return -EINVAL;
268
269         status = get_var_data(entry->efivars, var);
270         if (status != EFI_SUCCESS)
271                 return -EIO;
272
273         str += sprintf(str, "0x%lx\n", var->DataSize);
274         return str - buf;
275 }
276
277 static ssize_t
278 efivar_data_read(struct efivar_entry *entry, char *buf)
279 {
280         struct efi_variable *var = &entry->var;
281         efi_status_t status;
282
283         if (!entry || !buf)
284                 return -EINVAL;
285
286         status = get_var_data(entry->efivars, var);
287         if (status != EFI_SUCCESS)
288                 return -EIO;
289
290         memcpy(buf, var->Data, var->DataSize);
291         return var->DataSize;
292 }
293 /*
294  * We allow each variable to be edited via rewriting the
295  * entire efi variable structure.
296  */
297 static ssize_t
298 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
299 {
300         struct efi_variable *new_var, *var = &entry->var;
301         struct efivars *efivars = entry->efivars;
302         efi_status_t status = EFI_NOT_FOUND;
303
304         if (count != sizeof(struct efi_variable))
305                 return -EINVAL;
306
307         new_var = (struct efi_variable *)buf;
308         /*
309          * If only updating the variable data, then the name
310          * and guid should remain the same
311          */
312         if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
313                 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
314                 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
315                 return -EINVAL;
316         }
317
318         if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
319                 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
320                 return -EINVAL;
321         }
322
323         spin_lock(&efivars->lock);
324         status = efivars->ops->set_variable(new_var->VariableName,
325                                             &new_var->VendorGuid,
326                                             new_var->Attributes,
327                                             new_var->DataSize,
328                                             new_var->Data);
329
330         spin_unlock(&efivars->lock);
331
332         if (status != EFI_SUCCESS) {
333                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
334                         status);
335                 return -EIO;
336         }
337
338         memcpy(&entry->var, new_var, count);
339         return count;
340 }
341
342 static ssize_t
343 efivar_show_raw(struct efivar_entry *entry, char *buf)
344 {
345         struct efi_variable *var = &entry->var;
346         efi_status_t status;
347
348         if (!entry || !buf)
349                 return 0;
350
351         status = get_var_data(entry->efivars, var);
352         if (status != EFI_SUCCESS)
353                 return -EIO;
354
355         memcpy(buf, var, sizeof(*var));
356         return sizeof(*var);
357 }
358
359 /*
360  * Generic read/write functions that call the specific functions of
361  * the attributes...
362  */
363 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
364                                 char *buf)
365 {
366         struct efivar_entry *var = to_efivar_entry(kobj);
367         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
368         ssize_t ret = -EIO;
369
370         if (!capable(CAP_SYS_ADMIN))
371                 return -EACCES;
372
373         if (efivar_attr->show) {
374                 ret = efivar_attr->show(var, buf);
375         }
376         return ret;
377 }
378
379 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
380                                 const char *buf, size_t count)
381 {
382         struct efivar_entry *var = to_efivar_entry(kobj);
383         struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
384         ssize_t ret = -EIO;
385
386         if (!capable(CAP_SYS_ADMIN))
387                 return -EACCES;
388
389         if (efivar_attr->store)
390                 ret = efivar_attr->store(var, buf, count);
391
392         return ret;
393 }
394
395 static const struct sysfs_ops efivar_attr_ops = {
396         .show = efivar_attr_show,
397         .store = efivar_attr_store,
398 };
399
400 static void efivar_release(struct kobject *kobj)
401 {
402         struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
403         kfree(var);
404 }
405
406 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
407 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
408 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
409 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
410 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
411
412 static struct attribute *def_attrs[] = {
413         &efivar_attr_guid.attr,
414         &efivar_attr_size.attr,
415         &efivar_attr_attributes.attr,
416         &efivar_attr_data.attr,
417         &efivar_attr_raw_var.attr,
418         NULL,
419 };
420
421 static struct kobj_type efivar_ktype = {
422         .release = efivar_release,
423         .sysfs_ops = &efivar_attr_ops,
424         .default_attrs = def_attrs,
425 };
426
427 static struct pstore_info efi_pstore_info;
428
429 static inline void
430 efivar_unregister(struct efivar_entry *var)
431 {
432         kobject_put(&var->kobj);
433 }
434
435 #ifdef CONFIG_PSTORE
436
437 static int efi_pstore_open(struct pstore_info *psi)
438 {
439         struct efivars *efivars = psi->data;
440
441         spin_lock(&efivars->lock);
442         efivars->walk_entry = list_first_entry(&efivars->list,
443                                                struct efivar_entry, list);
444         return 0;
445 }
446
447 static int efi_pstore_close(struct pstore_info *psi)
448 {
449         struct efivars *efivars = psi->data;
450
451         spin_unlock(&efivars->lock);
452         return 0;
453 }
454
455 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
456                                struct timespec *timespec, struct pstore_info *psi)
457 {
458         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
459         struct efivars *efivars = psi->data;
460         char name[DUMP_NAME_LEN];
461         int i;
462         unsigned int part, size;
463         unsigned long time;
464
465         while (&efivars->walk_entry->list != &efivars->list) {
466                 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
467                                  vendor)) {
468                         for (i = 0; i < DUMP_NAME_LEN; i++) {
469                                 name[i] = efivars->walk_entry->var.VariableName[i];
470                         }
471                         if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
472                                 *id = part;
473                                 timespec->tv_sec = time;
474                                 timespec->tv_nsec = 0;
475                                 get_var_data_locked(efivars, &efivars->walk_entry->var);
476                                 size = efivars->walk_entry->var.DataSize;
477                                 memcpy(psi->buf, efivars->walk_entry->var.Data, size);
478                                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
479                                                    struct efivar_entry, list);
480                                 return size;
481                         }
482                 }
483                 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
484                                                  struct efivar_entry, list);
485         }
486         return 0;
487 }
488
489 static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
490                             size_t size, struct pstore_info *psi)
491 {
492         char name[DUMP_NAME_LEN];
493         char stub_name[DUMP_NAME_LEN];
494         efi_char16_t efi_name[DUMP_NAME_LEN];
495         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
496         struct efivars *efivars = psi->data;
497         struct efivar_entry *entry, *found = NULL;
498         int i;
499
500         sprintf(stub_name, "dump-type%u-%u-", type, part);
501         sprintf(name, "%s%lu", stub_name, get_seconds());
502
503         spin_lock(&efivars->lock);
504
505         for (i = 0; i < DUMP_NAME_LEN; i++)
506                 efi_name[i] = stub_name[i];
507
508         /*
509          * Clean up any entries with the same name
510          */
511
512         list_for_each_entry(entry, &efivars->list, list) {
513                 get_var_data_locked(efivars, &entry->var);
514
515                 if (efi_guidcmp(entry->var.VendorGuid, vendor))
516                         continue;
517                 if (utf16_strncmp(entry->var.VariableName, efi_name,
518                                   utf16_strlen(efi_name)))
519                         continue;
520                 /* Needs to be a prefix */
521                 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
522                         continue;
523
524                 /* found */
525                 found = entry;
526                 efivars->ops->set_variable(entry->var.VariableName, &entry->var.VendorGuid,
527                                            EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
528                                            0, NULL);
529         }
530
531         if (found)
532                 list_del(&found->list);
533
534         for (i = 0; i < DUMP_NAME_LEN; i++)
535                 efi_name[i] = name[i];
536
537         efivars->ops->set_variable(efi_name, &vendor,
538                                    EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
539                                    size, psi->buf);
540
541         spin_unlock(&efivars->lock);
542
543         if (found)
544                 efivar_unregister(found);
545
546         if (size)
547                 efivar_create_sysfs_entry(efivars,
548                                           utf16_strsize(efi_name,
549                                                         DUMP_NAME_LEN * 2),
550                                           efi_name, &vendor);
551
552         return part;
553 };
554
555 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
556                             struct pstore_info *psi)
557 {
558         efi_pstore_write(type, id, 0, psi);
559
560         return 0;
561 }
562 #else
563 static int efi_pstore_open(struct pstore_info *psi)
564 {
565         return 0;
566 }
567
568 static int efi_pstore_close(struct pstore_info *psi)
569 {
570         return 0;
571 }
572
573 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
574                                struct timespec *time, struct pstore_info *psi)
575 {
576         return -1;
577 }
578
579 static u64 efi_pstore_write(enum pstore_type_id type, int part, size_t size,
580                             struct pstore_info *psi)
581 {
582         return 0;
583 }
584
585 static int efi_pstore_erase(enum pstore_type_id type, u64 id,
586                             struct pstore_info *psi)
587 {
588         return 0;
589 }
590 #endif
591
592 static struct pstore_info efi_pstore_info = {
593         .owner          = THIS_MODULE,
594         .name           = "efi",
595         .open           = efi_pstore_open,
596         .close          = efi_pstore_close,
597         .read           = efi_pstore_read,
598         .write          = efi_pstore_write,
599         .erase          = efi_pstore_erase,
600 };
601
602 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
603                              struct bin_attribute *bin_attr,
604                              char *buf, loff_t pos, size_t count)
605 {
606         struct efi_variable *new_var = (struct efi_variable *)buf;
607         struct efivars *efivars = bin_attr->private;
608         struct efivar_entry *search_efivar, *n;
609         unsigned long strsize1, strsize2;
610         efi_status_t status = EFI_NOT_FOUND;
611         int found = 0;
612
613         if (!capable(CAP_SYS_ADMIN))
614                 return -EACCES;
615
616         spin_lock(&efivars->lock);
617
618         /*
619          * Does this variable already exist?
620          */
621         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
622                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
623                 strsize2 = utf16_strsize(new_var->VariableName, 1024);
624                 if (strsize1 == strsize2 &&
625                         !memcmp(&(search_efivar->var.VariableName),
626                                 new_var->VariableName, strsize1) &&
627                         !efi_guidcmp(search_efivar->var.VendorGuid,
628                                 new_var->VendorGuid)) {
629                         found = 1;
630                         break;
631                 }
632         }
633         if (found) {
634                 spin_unlock(&efivars->lock);
635                 return -EINVAL;
636         }
637
638         /* now *really* create the variable via EFI */
639         status = efivars->ops->set_variable(new_var->VariableName,
640                                             &new_var->VendorGuid,
641                                             new_var->Attributes,
642                                             new_var->DataSize,
643                                             new_var->Data);
644
645         if (status != EFI_SUCCESS) {
646                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
647                         status);
648                 spin_unlock(&efivars->lock);
649                 return -EIO;
650         }
651         spin_unlock(&efivars->lock);
652
653         /* Create the entry in sysfs.  Locking is not required here */
654         status = efivar_create_sysfs_entry(efivars,
655                                            utf16_strsize(new_var->VariableName,
656                                                          1024),
657                                            new_var->VariableName,
658                                            &new_var->VendorGuid);
659         if (status) {
660                 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
661         }
662         return count;
663 }
664
665 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
666                              struct bin_attribute *bin_attr,
667                              char *buf, loff_t pos, size_t count)
668 {
669         struct efi_variable *del_var = (struct efi_variable *)buf;
670         struct efivars *efivars = bin_attr->private;
671         struct efivar_entry *search_efivar, *n;
672         unsigned long strsize1, strsize2;
673         efi_status_t status = EFI_NOT_FOUND;
674         int found = 0;
675
676         if (!capable(CAP_SYS_ADMIN))
677                 return -EACCES;
678
679         spin_lock(&efivars->lock);
680
681         /*
682          * Does this variable already exist?
683          */
684         list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
685                 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
686                 strsize2 = utf16_strsize(del_var->VariableName, 1024);
687                 if (strsize1 == strsize2 &&
688                         !memcmp(&(search_efivar->var.VariableName),
689                                 del_var->VariableName, strsize1) &&
690                         !efi_guidcmp(search_efivar->var.VendorGuid,
691                                 del_var->VendorGuid)) {
692                         found = 1;
693                         break;
694                 }
695         }
696         if (!found) {
697                 spin_unlock(&efivars->lock);
698                 return -EINVAL;
699         }
700         /* force the Attributes/DataSize to 0 to ensure deletion */
701         del_var->Attributes = 0;
702         del_var->DataSize = 0;
703
704         status = efivars->ops->set_variable(del_var->VariableName,
705                                             &del_var->VendorGuid,
706                                             del_var->Attributes,
707                                             del_var->DataSize,
708                                             del_var->Data);
709
710         if (status != EFI_SUCCESS) {
711                 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
712                         status);
713                 spin_unlock(&efivars->lock);
714                 return -EIO;
715         }
716         list_del(&search_efivar->list);
717         /* We need to release this lock before unregistering. */
718         spin_unlock(&efivars->lock);
719         efivar_unregister(search_efivar);
720
721         /* It's dead Jim.... */
722         return count;
723 }
724
725 /*
726  * Let's not leave out systab information that snuck into
727  * the efivars driver
728  */
729 static ssize_t systab_show(struct kobject *kobj,
730                            struct kobj_attribute *attr, char *buf)
731 {
732         char *str = buf;
733
734         if (!kobj || !buf)
735                 return -EINVAL;
736
737         if (efi.mps != EFI_INVALID_TABLE_ADDR)
738                 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
739         if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
740                 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
741         if (efi.acpi != EFI_INVALID_TABLE_ADDR)
742                 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
743         if (efi.smbios != EFI_INVALID_TABLE_ADDR)
744                 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
745         if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
746                 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
747         if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
748                 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
749         if (efi.uga != EFI_INVALID_TABLE_ADDR)
750                 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
751
752         return str - buf;
753 }
754
755 static struct kobj_attribute efi_attr_systab =
756                         __ATTR(systab, 0400, systab_show, NULL);
757
758 static struct attribute *efi_subsys_attrs[] = {
759         &efi_attr_systab.attr,
760         NULL,   /* maybe more in the future? */
761 };
762
763 static struct attribute_group efi_subsys_attr_group = {
764         .attrs = efi_subsys_attrs,
765 };
766
767 static struct kobject *efi_kobj;
768
769 /*
770  * efivar_create_sysfs_entry()
771  * Requires:
772  *    variable_name_size = number of bytes required to hold
773  *                         variable_name (not counting the NULL
774  *                         character at the end.
775  *    efivars->lock is not held on entry or exit.
776  * Returns 1 on failure, 0 on success
777  */
778 static int
779 efivar_create_sysfs_entry(struct efivars *efivars,
780                           unsigned long variable_name_size,
781                           efi_char16_t *variable_name,
782                           efi_guid_t *vendor_guid)
783 {
784         int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
785         char *short_name;
786         struct efivar_entry *new_efivar;
787
788         short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
789         new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
790
791         if (!short_name || !new_efivar)  {
792                 kfree(short_name);
793                 kfree(new_efivar);
794                 return 1;
795         }
796
797         new_efivar->efivars = efivars;
798         memcpy(new_efivar->var.VariableName, variable_name,
799                 variable_name_size);
800         memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
801
802         /* Convert Unicode to normal chars (assume top bits are 0),
803            ala UTF-8 */
804         for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
805                 short_name[i] = variable_name[i] & 0xFF;
806         }
807         /* This is ugly, but necessary to separate one vendor's
808            private variables from another's.         */
809
810         *(short_name + strlen(short_name)) = '-';
811         efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
812
813         new_efivar->kobj.kset = efivars->kset;
814         i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
815                                  "%s", short_name);
816         if (i) {
817                 kfree(short_name);
818                 kfree(new_efivar);
819                 return 1;
820         }
821
822         kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
823         kfree(short_name);
824         short_name = NULL;
825
826         spin_lock(&efivars->lock);
827         list_add(&new_efivar->list, &efivars->list);
828         spin_unlock(&efivars->lock);
829
830         return 0;
831 }
832
833 static int
834 create_efivars_bin_attributes(struct efivars *efivars)
835 {
836         struct bin_attribute *attr;
837         int error;
838
839         /* new_var */
840         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
841         if (!attr)
842                 return -ENOMEM;
843
844         attr->attr.name = "new_var";
845         attr->attr.mode = 0200;
846         attr->write = efivar_create;
847         attr->private = efivars;
848         efivars->new_var = attr;
849
850         /* del_var */
851         attr = kzalloc(sizeof(*attr), GFP_KERNEL);
852         if (!attr) {
853                 error = -ENOMEM;
854                 goto out_free;
855         }
856         attr->attr.name = "del_var";
857         attr->attr.mode = 0200;
858         attr->write = efivar_delete;
859         attr->private = efivars;
860         efivars->del_var = attr;
861
862         sysfs_bin_attr_init(efivars->new_var);
863         sysfs_bin_attr_init(efivars->del_var);
864
865         /* Register */
866         error = sysfs_create_bin_file(&efivars->kset->kobj,
867                                       efivars->new_var);
868         if (error) {
869                 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
870                         " due to error %d\n", error);
871                 goto out_free;
872         }
873         error = sysfs_create_bin_file(&efivars->kset->kobj,
874                                       efivars->del_var);
875         if (error) {
876                 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
877                         " due to error %d\n", error);
878                 sysfs_remove_bin_file(&efivars->kset->kobj,
879                                       efivars->new_var);
880                 goto out_free;
881         }
882
883         return 0;
884 out_free:
885         kfree(efivars->del_var);
886         efivars->del_var = NULL;
887         kfree(efivars->new_var);
888         efivars->new_var = NULL;
889         return error;
890 }
891
892 void unregister_efivars(struct efivars *efivars)
893 {
894         struct efivar_entry *entry, *n;
895
896         list_for_each_entry_safe(entry, n, &efivars->list, list) {
897                 spin_lock(&efivars->lock);
898                 list_del(&entry->list);
899                 spin_unlock(&efivars->lock);
900                 efivar_unregister(entry);
901         }
902         if (efivars->new_var)
903                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
904         if (efivars->del_var)
905                 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
906         kfree(efivars->new_var);
907         kfree(efivars->del_var);
908         kset_unregister(efivars->kset);
909 }
910 EXPORT_SYMBOL_GPL(unregister_efivars);
911
912 int register_efivars(struct efivars *efivars,
913                      const struct efivar_operations *ops,
914                      struct kobject *parent_kobj)
915 {
916         efi_status_t status = EFI_NOT_FOUND;
917         efi_guid_t vendor_guid;
918         efi_char16_t *variable_name;
919         unsigned long variable_name_size = 1024;
920         int error = 0;
921
922         variable_name = kzalloc(variable_name_size, GFP_KERNEL);
923         if (!variable_name) {
924                 printk(KERN_ERR "efivars: Memory allocation failed.\n");
925                 return -ENOMEM;
926         }
927
928         spin_lock_init(&efivars->lock);
929         INIT_LIST_HEAD(&efivars->list);
930         efivars->ops = ops;
931
932         efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
933         if (!efivars->kset) {
934                 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
935                 error = -ENOMEM;
936                 goto out;
937         }
938
939         /*
940          * Per EFI spec, the maximum storage allocated for both
941          * the variable name and variable data is 1024 bytes.
942          */
943
944         do {
945                 variable_name_size = 1024;
946
947                 status = ops->get_next_variable(&variable_name_size,
948                                                 variable_name,
949                                                 &vendor_guid);
950                 switch (status) {
951                 case EFI_SUCCESS:
952                         efivar_create_sysfs_entry(efivars,
953                                                   variable_name_size,
954                                                   variable_name,
955                                                   &vendor_guid);
956                         break;
957                 case EFI_NOT_FOUND:
958                         break;
959                 default:
960                         printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
961                                 status);
962                         status = EFI_NOT_FOUND;
963                         break;
964                 }
965         } while (status != EFI_NOT_FOUND);
966
967         error = create_efivars_bin_attributes(efivars);
968         if (error)
969                 unregister_efivars(efivars);
970
971         efivars->efi_pstore_info = efi_pstore_info;
972
973         efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
974         if (efivars->efi_pstore_info.buf) {
975                 efivars->efi_pstore_info.bufsize = 1024;
976                 efivars->efi_pstore_info.data = efivars;
977                 mutex_init(&efivars->efi_pstore_info.buf_mutex);
978                 pstore_register(&efivars->efi_pstore_info);
979         }
980
981 out:
982         kfree(variable_name);
983
984         return error;
985 }
986 EXPORT_SYMBOL_GPL(register_efivars);
987
988 static struct efivars __efivars;
989 static struct efivar_operations ops;
990
991 /*
992  * For now we register the efi subsystem with the firmware subsystem
993  * and the vars subsystem with the efi subsystem.  In the future, it
994  * might make sense to split off the efi subsystem into its own
995  * driver, but for now only efivars will register with it, so just
996  * include it here.
997  */
998
999 static int __init
1000 efivars_init(void)
1001 {
1002         int error = 0;
1003
1004         printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1005                EFIVARS_DATE);
1006
1007         if (!efi_enabled)
1008                 return 0;
1009
1010         /* For now we'll register the efi directory at /sys/firmware/efi */
1011         efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1012         if (!efi_kobj) {
1013                 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1014                 return -ENOMEM;
1015         }
1016
1017         ops.get_variable = efi.get_variable;
1018         ops.set_variable = efi.set_variable;
1019         ops.get_next_variable = efi.get_next_variable;
1020         error = register_efivars(&__efivars, &ops, efi_kobj);
1021         if (error)
1022                 goto err_put;
1023
1024         /* Don't forget the systab entry */
1025         error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1026         if (error) {
1027                 printk(KERN_ERR
1028                        "efivars: Sysfs attribute export failed with error %d.\n",
1029                        error);
1030                 goto err_unregister;
1031         }
1032
1033         return 0;
1034
1035 err_unregister:
1036         unregister_efivars(&__efivars);
1037 err_put:
1038         kobject_put(efi_kobj);
1039         return error;
1040 }
1041
1042 static void __exit
1043 efivars_exit(void)
1044 {
1045         if (efi_enabled) {
1046                 unregister_efivars(&__efivars);
1047                 kobject_put(efi_kobj);
1048         }
1049 }
1050
1051 module_init(efivars_init);
1052 module_exit(efivars_exit);
1053