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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
88MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
89MODULE_DESCRIPTION("sysfs interface to EFI Variables");
90MODULE_LICENSE("GPL");
91MODULE_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
102struct 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
112struct efivar_entry {
113 struct efivars *efivars;
114 struct efi_variable var;
115 struct list_head list;
116 struct kobject kobj;
117};
118
119struct 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) \
131struct 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 */
143static int
144efivar_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 */
150static unsigned long
151utf16_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
160static inline unsigned long
161utf16_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 */
170static inline unsigned long
171utf16_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
176static inline int
177utf16_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
194static efi_status_t
195get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
196{
197 efi_status_t status;
198
199 var->DataSize = 1024;
200 status = efivars->ops->get_variable(var->VariableName,
201 &var->VendorGuid,
202 &var->Attributes,
203 &var->DataSize,
204 var->Data);
205 return status;
206}
207
208static efi_status_t
209get_var_data(struct efivars *efivars, struct efi_variable *var)
210{
211 efi_status_t status;
212
213 spin_lock(&efivars->lock);
214 status = get_var_data_locked(efivars, var);
215 spin_unlock(&efivars->lock);
216
217 if (status != EFI_SUCCESS) {
218 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
219 status);
220 }
221 return status;
222}
223
224static ssize_t
225efivar_guid_read(struct efivar_entry *entry, char *buf)
226{
227 struct efi_variable *var = &entry->var;
228 char *str = buf;
229
230 if (!entry || !buf)
231 return 0;
232
233 efi_guid_unparse(&var->VendorGuid, str);
234 str += strlen(str);
235 str += sprintf(str, "\n");
236
237 return str - buf;
238}
239
240static ssize_t
241efivar_attr_read(struct efivar_entry *entry, char *buf)
242{
243 struct efi_variable *var = &entry->var;
244 char *str = buf;
245 efi_status_t status;
246
247 if (!entry || !buf)
248 return -EINVAL;
249
250 status = get_var_data(entry->efivars, var);
251 if (status != EFI_SUCCESS)
252 return -EIO;
253
254 if (var->Attributes & 0x1)
255 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
256 if (var->Attributes & 0x2)
257 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
258 if (var->Attributes & 0x4)
259 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
260 return str - buf;
261}
262
263static ssize_t
264efivar_size_read(struct efivar_entry *entry, char *buf)
265{
266 struct efi_variable *var = &entry->var;
267 char *str = buf;
268 efi_status_t status;
269
270 if (!entry || !buf)
271 return -EINVAL;
272
273 status = get_var_data(entry->efivars, var);
274 if (status != EFI_SUCCESS)
275 return -EIO;
276
277 str += sprintf(str, "0x%lx\n", var->DataSize);
278 return str - buf;
279}
280
281static ssize_t
282efivar_data_read(struct efivar_entry *entry, char *buf)
283{
284 struct efi_variable *var = &entry->var;
285 efi_status_t status;
286
287 if (!entry || !buf)
288 return -EINVAL;
289
290 status = get_var_data(entry->efivars, var);
291 if (status != EFI_SUCCESS)
292 return -EIO;
293
294 memcpy(buf, var->Data, var->DataSize);
295 return var->DataSize;
296}
297/*
298 * We allow each variable to be edited via rewriting the
299 * entire efi variable structure.
300 */
301static ssize_t
302efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
303{
304 struct efi_variable *new_var, *var = &entry->var;
305 struct efivars *efivars = entry->efivars;
306 efi_status_t status = EFI_NOT_FOUND;
307
308 if (count != sizeof(struct efi_variable))
309 return -EINVAL;
310
311 new_var = (struct efi_variable *)buf;
312 /*
313 * If only updating the variable data, then the name
314 * and guid should remain the same
315 */
316 if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
317 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
318 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
319 return -EINVAL;
320 }
321
322 if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
323 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
324 return -EINVAL;
325 }
326
327 spin_lock(&efivars->lock);
328 status = efivars->ops->set_variable(new_var->VariableName,
329 &new_var->VendorGuid,
330 new_var->Attributes,
331 new_var->DataSize,
332 new_var->Data);
333
334 spin_unlock(&efivars->lock);
335
336 if (status != EFI_SUCCESS) {
337 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
338 status);
339 return -EIO;
340 }
341
342 memcpy(&entry->var, new_var, count);
343 return count;
344}
345
346static ssize_t
347efivar_show_raw(struct efivar_entry *entry, char *buf)
348{
349 struct efi_variable *var = &entry->var;
350 efi_status_t status;
351
352 if (!entry || !buf)
353 return 0;
354
355 status = get_var_data(entry->efivars, var);
356 if (status != EFI_SUCCESS)
357 return -EIO;
358
359 memcpy(buf, var, sizeof(*var));
360 return sizeof(*var);
361}
362
363/*
364 * Generic read/write functions that call the specific functions of
365 * the attributes...
366 */
367static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
368 char *buf)
369{
370 struct efivar_entry *var = to_efivar_entry(kobj);
371 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
372 ssize_t ret = -EIO;
373
374 if (!capable(CAP_SYS_ADMIN))
375 return -EACCES;
376
377 if (efivar_attr->show) {
378 ret = efivar_attr->show(var, buf);
379 }
380 return ret;
381}
382
383static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
384 const char *buf, size_t count)
385{
386 struct efivar_entry *var = to_efivar_entry(kobj);
387 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
388 ssize_t ret = -EIO;
389
390 if (!capable(CAP_SYS_ADMIN))
391 return -EACCES;
392
393 if (efivar_attr->store)
394 ret = efivar_attr->store(var, buf, count);
395
396 return ret;
397}
398
399static const struct sysfs_ops efivar_attr_ops = {
400 .show = efivar_attr_show,
401 .store = efivar_attr_store,
402};
403
404static void efivar_release(struct kobject *kobj)
405{
406 struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
407 kfree(var);
408}
409
410static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
411static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
412static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
413static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
414static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
415
416static struct attribute *def_attrs[] = {
417 &efivar_attr_guid.attr,
418 &efivar_attr_size.attr,
419 &efivar_attr_attributes.attr,
420 &efivar_attr_data.attr,
421 &efivar_attr_raw_var.attr,
422 NULL,
423};
424
425static struct kobj_type efivar_ktype = {
426 .release = efivar_release,
427 .sysfs_ops = &efivar_attr_ops,
428 .default_attrs = def_attrs,
429};
430
431static struct pstore_info efi_pstore_info;
432
433static inline void
434efivar_unregister(struct efivar_entry *var)
435{
436 kobject_put(&var->kobj);
437}
438
439#ifdef CONFIG_PSTORE
440
441static int efi_pstore_open(struct pstore_info *psi)
442{
443 struct efivars *efivars = psi->data;
444
445 spin_lock(&efivars->lock);
446 efivars->walk_entry = list_first_entry(&efivars->list,
447 struct efivar_entry, list);
448 return 0;
449}
450
451static int efi_pstore_close(struct pstore_info *psi)
452{
453 struct efivars *efivars = psi->data;
454
455 spin_unlock(&efivars->lock);
456 return 0;
457}
458
459static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
460 struct timespec *timespec, struct pstore_info *psi)
461{
462 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
463 struct efivars *efivars = psi->data;
464 char name[DUMP_NAME_LEN];
465 int i;
466 unsigned int part, size;
467 unsigned long time;
468
469 while (&efivars->walk_entry->list != &efivars->list) {
470 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
471 vendor)) {
472 for (i = 0; i < DUMP_NAME_LEN; i++) {
473 name[i] = efivars->walk_entry->var.VariableName[i];
474 }
475 if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
476 *id = part;
477 timespec->tv_sec = time;
478 timespec->tv_nsec = 0;
479 get_var_data_locked(efivars, &efivars->walk_entry->var);
480 size = efivars->walk_entry->var.DataSize;
481 memcpy(psi->buf, efivars->walk_entry->var.Data, size);
482 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
483 struct efivar_entry, list);
484 return size;
485 }
486 }
487 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
488 struct efivar_entry, list);
489 }
490 return 0;
491}
492
493static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
494 size_t size, struct pstore_info *psi)
495{
496 char name[DUMP_NAME_LEN];
497 char stub_name[DUMP_NAME_LEN];
498 efi_char16_t efi_name[DUMP_NAME_LEN];
499 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
500 struct efivars *efivars = psi->data;
501 struct efivar_entry *entry, *found = NULL;
502 int i;
503
504 sprintf(stub_name, "dump-type%u-%u-", type, part);
505 sprintf(name, "%s%lu", stub_name, get_seconds());
506
507 spin_lock(&efivars->lock);
508
509 for (i = 0; i < DUMP_NAME_LEN; i++)
510 efi_name[i] = stub_name[i];
511
512 /*
513 * Clean up any entries with the same name
514 */
515
516 list_for_each_entry(entry, &efivars->list, list) {
517 get_var_data_locked(efivars, &entry->var);
518
519 if (efi_guidcmp(entry->var.VendorGuid, vendor))
520 continue;
521 if (utf16_strncmp(entry->var.VariableName, efi_name,
522 utf16_strlen(efi_name)))
523 continue;
524 /* Needs to be a prefix */
525 if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
526 continue;
527
528 /* found */
529 found = entry;
530 efivars->ops->set_variable(entry->var.VariableName,
531 &entry->var.VendorGuid,
532 PSTORE_EFI_ATTRIBUTES,
533 0, NULL);
534 }
535
536 if (found)
537 list_del(&found->list);
538
539 for (i = 0; i < DUMP_NAME_LEN; i++)
540 efi_name[i] = name[i];
541
542 efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
543 size, psi->buf);
544
545 spin_unlock(&efivars->lock);
546
547 if (found)
548 efivar_unregister(found);
549
550 if (size)
551 efivar_create_sysfs_entry(efivars,
552 utf16_strsize(efi_name,
553 DUMP_NAME_LEN * 2),
554 efi_name, &vendor);
555
556 return part;
557};
558
559static int efi_pstore_erase(enum pstore_type_id type, u64 id,
560 struct pstore_info *psi)
561{
562 efi_pstore_write(type, id, 0, psi);
563
564 return 0;
565}
566#else
567static int efi_pstore_open(struct pstore_info *psi)
568{
569 return 0;
570}
571
572static int efi_pstore_close(struct pstore_info *psi)
573{
574 return 0;
575}
576
577static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
578 struct timespec *time, struct pstore_info *psi)
579{
580 return -1;
581}
582
583static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
584 size_t size, struct pstore_info *psi)
585{
586 return 0;
587}
588
589static int efi_pstore_erase(enum pstore_type_id type, u64 id,
590 struct pstore_info *psi)
591{
592 return 0;
593}
594#endif
595
596static struct pstore_info efi_pstore_info = {
597 .owner = THIS_MODULE,
598 .name = "efi",
599 .open = efi_pstore_open,
600 .close = efi_pstore_close,
601 .read = efi_pstore_read,
602 .write = efi_pstore_write,
603 .erase = efi_pstore_erase,
604};
605
606static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
607 struct bin_attribute *bin_attr,
608 char *buf, loff_t pos, size_t count)
609{
610 struct efi_variable *new_var = (struct efi_variable *)buf;
611 struct efivars *efivars = bin_attr->private;
612 struct efivar_entry *search_efivar, *n;
613 unsigned long strsize1, strsize2;
614 efi_status_t status = EFI_NOT_FOUND;
615 int found = 0;
616
617 if (!capable(CAP_SYS_ADMIN))
618 return -EACCES;
619
620 spin_lock(&efivars->lock);
621
622 /*
623 * Does this variable already exist?
624 */
625 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
626 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
627 strsize2 = utf16_strsize(new_var->VariableName, 1024);
628 if (strsize1 == strsize2 &&
629 !memcmp(&(search_efivar->var.VariableName),
630 new_var->VariableName, strsize1) &&
631 !efi_guidcmp(search_efivar->var.VendorGuid,
632 new_var->VendorGuid)) {
633 found = 1;
634 break;
635 }
636 }
637 if (found) {
638 spin_unlock(&efivars->lock);
639 return -EINVAL;
640 }
641
642 /* now *really* create the variable via EFI */
643 status = efivars->ops->set_variable(new_var->VariableName,
644 &new_var->VendorGuid,
645 new_var->Attributes,
646 new_var->DataSize,
647 new_var->Data);
648
649 if (status != EFI_SUCCESS) {
650 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
651 status);
652 spin_unlock(&efivars->lock);
653 return -EIO;
654 }
655 spin_unlock(&efivars->lock);
656
657 /* Create the entry in sysfs. Locking is not required here */
658 status = efivar_create_sysfs_entry(efivars,
659 utf16_strsize(new_var->VariableName,
660 1024),
661 new_var->VariableName,
662 &new_var->VendorGuid);
663 if (status) {
664 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
665 }
666 return count;
667}
668
669static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
670 struct bin_attribute *bin_attr,
671 char *buf, loff_t pos, size_t count)
672{
673 struct efi_variable *del_var = (struct efi_variable *)buf;
674 struct efivars *efivars = bin_attr->private;
675 struct efivar_entry *search_efivar, *n;
676 unsigned long strsize1, strsize2;
677 efi_status_t status = EFI_NOT_FOUND;
678 int found = 0;
679
680 if (!capable(CAP_SYS_ADMIN))
681 return -EACCES;
682
683 spin_lock(&efivars->lock);
684
685 /*
686 * Does this variable already exist?
687 */
688 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
689 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
690 strsize2 = utf16_strsize(del_var->VariableName, 1024);
691 if (strsize1 == strsize2 &&
692 !memcmp(&(search_efivar->var.VariableName),
693 del_var->VariableName, strsize1) &&
694 !efi_guidcmp(search_efivar->var.VendorGuid,
695 del_var->VendorGuid)) {
696 found = 1;
697 break;
698 }
699 }
700 if (!found) {
701 spin_unlock(&efivars->lock);
702 return -EINVAL;
703 }
704 /* force the Attributes/DataSize to 0 to ensure deletion */
705 del_var->Attributes = 0;
706 del_var->DataSize = 0;
707
708 status = efivars->ops->set_variable(del_var->VariableName,
709 &del_var->VendorGuid,
710 del_var->Attributes,
711 del_var->DataSize,
712 del_var->Data);
713
714 if (status != EFI_SUCCESS) {
715 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
716 status);
717 spin_unlock(&efivars->lock);
718 return -EIO;
719 }
720 list_del(&search_efivar->list);
721 /* We need to release this lock before unregistering. */
722 spin_unlock(&efivars->lock);
723 efivar_unregister(search_efivar);
724
725 /* It's dead Jim.... */
726 return count;
727}
728
729/*
730 * Let's not leave out systab information that snuck into
731 * the efivars driver
732 */
733static ssize_t systab_show(struct kobject *kobj,
734 struct kobj_attribute *attr, char *buf)
735{
736 char *str = buf;
737
738 if (!kobj || !buf)
739 return -EINVAL;
740
741 if (efi.mps != EFI_INVALID_TABLE_ADDR)
742 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
743 if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
744 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
745 if (efi.acpi != EFI_INVALID_TABLE_ADDR)
746 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
747 if (efi.smbios != EFI_INVALID_TABLE_ADDR)
748 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
749 if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
750 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
751 if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
752 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
753 if (efi.uga != EFI_INVALID_TABLE_ADDR)
754 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
755
756 return str - buf;
757}
758
759static struct kobj_attribute efi_attr_systab =
760 __ATTR(systab, 0400, systab_show, NULL);
761
762static struct attribute *efi_subsys_attrs[] = {
763 &efi_attr_systab.attr,
764 NULL, /* maybe more in the future? */
765};
766
767static struct attribute_group efi_subsys_attr_group = {
768 .attrs = efi_subsys_attrs,
769};
770
771static struct kobject *efi_kobj;
772
773/*
774 * efivar_create_sysfs_entry()
775 * Requires:
776 * variable_name_size = number of bytes required to hold
777 * variable_name (not counting the NULL
778 * character at the end.
779 * efivars->lock is not held on entry or exit.
780 * Returns 1 on failure, 0 on success
781 */
782static int
783efivar_create_sysfs_entry(struct efivars *efivars,
784 unsigned long variable_name_size,
785 efi_char16_t *variable_name,
786 efi_guid_t *vendor_guid)
787{
788 int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38;
789 char *short_name;
790 struct efivar_entry *new_efivar;
791
792 short_name = kzalloc(short_name_size + 1, GFP_KERNEL);
793 new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
794
795 if (!short_name || !new_efivar) {
796 kfree(short_name);
797 kfree(new_efivar);
798 return 1;
799 }
800
801 new_efivar->efivars = efivars;
802 memcpy(new_efivar->var.VariableName, variable_name,
803 variable_name_size);
804 memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
805
806 /* Convert Unicode to normal chars (assume top bits are 0),
807 ala UTF-8 */
808 for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
809 short_name[i] = variable_name[i] & 0xFF;
810 }
811 /* This is ugly, but necessary to separate one vendor's
812 private variables from another's. */
813
814 *(short_name + strlen(short_name)) = '-';
815 efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
816
817 new_efivar->kobj.kset = efivars->kset;
818 i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
819 "%s", short_name);
820 if (i) {
821 kfree(short_name);
822 kfree(new_efivar);
823 return 1;
824 }
825
826 kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
827 kfree(short_name);
828 short_name = NULL;
829
830 spin_lock(&efivars->lock);
831 list_add(&new_efivar->list, &efivars->list);
832 spin_unlock(&efivars->lock);
833
834 return 0;
835}
836
837static int
838create_efivars_bin_attributes(struct efivars *efivars)
839{
840 struct bin_attribute *attr;
841 int error;
842
843 /* new_var */
844 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
845 if (!attr)
846 return -ENOMEM;
847
848 attr->attr.name = "new_var";
849 attr->attr.mode = 0200;
850 attr->write = efivar_create;
851 attr->private = efivars;
852 efivars->new_var = attr;
853
854 /* del_var */
855 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
856 if (!attr) {
857 error = -ENOMEM;
858 goto out_free;
859 }
860 attr->attr.name = "del_var";
861 attr->attr.mode = 0200;
862 attr->write = efivar_delete;
863 attr->private = efivars;
864 efivars->del_var = attr;
865
866 sysfs_bin_attr_init(efivars->new_var);
867 sysfs_bin_attr_init(efivars->del_var);
868
869 /* Register */
870 error = sysfs_create_bin_file(&efivars->kset->kobj,
871 efivars->new_var);
872 if (error) {
873 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
874 " due to error %d\n", error);
875 goto out_free;
876 }
877 error = sysfs_create_bin_file(&efivars->kset->kobj,
878 efivars->del_var);
879 if (error) {
880 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
881 " due to error %d\n", error);
882 sysfs_remove_bin_file(&efivars->kset->kobj,
883 efivars->new_var);
884 goto out_free;
885 }
886
887 return 0;
888out_free:
889 kfree(efivars->del_var);
890 efivars->del_var = NULL;
891 kfree(efivars->new_var);
892 efivars->new_var = NULL;
893 return error;
894}
895
896void unregister_efivars(struct efivars *efivars)
897{
898 struct efivar_entry *entry, *n;
899
900 list_for_each_entry_safe(entry, n, &efivars->list, list) {
901 spin_lock(&efivars->lock);
902 list_del(&entry->list);
903 spin_unlock(&efivars->lock);
904 efivar_unregister(entry);
905 }
906 if (efivars->new_var)
907 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
908 if (efivars->del_var)
909 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
910 kfree(efivars->new_var);
911 kfree(efivars->del_var);
912 kset_unregister(efivars->kset);
913}
914EXPORT_SYMBOL_GPL(unregister_efivars);
915
916int register_efivars(struct efivars *efivars,
917 const struct efivar_operations *ops,
918 struct kobject *parent_kobj)
919{
920 efi_status_t status = EFI_NOT_FOUND;
921 efi_guid_t vendor_guid;
922 efi_char16_t *variable_name;
923 unsigned long variable_name_size = 1024;
924 int error = 0;
925
926 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
927 if (!variable_name) {
928 printk(KERN_ERR "efivars: Memory allocation failed.\n");
929 return -ENOMEM;
930 }
931
932 spin_lock_init(&efivars->lock);
933 INIT_LIST_HEAD(&efivars->list);
934 efivars->ops = ops;
935
936 efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
937 if (!efivars->kset) {
938 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
939 error = -ENOMEM;
940 goto out;
941 }
942
943 /*
944 * Per EFI spec, the maximum storage allocated for both
945 * the variable name and variable data is 1024 bytes.
946 */
947
948 do {
949 variable_name_size = 1024;
950
951 status = ops->get_next_variable(&variable_name_size,
952 variable_name,
953 &vendor_guid);
954 switch (status) {
955 case EFI_SUCCESS:
956 efivar_create_sysfs_entry(efivars,
957 variable_name_size,
958 variable_name,
959 &vendor_guid);
960 break;
961 case EFI_NOT_FOUND:
962 break;
963 default:
964 printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
965 status);
966 status = EFI_NOT_FOUND;
967 break;
968 }
969 } while (status != EFI_NOT_FOUND);
970
971 error = create_efivars_bin_attributes(efivars);
972 if (error)
973 unregister_efivars(efivars);
974
975 efivars->efi_pstore_info = efi_pstore_info;
976
977 efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
978 if (efivars->efi_pstore_info.buf) {
979 efivars->efi_pstore_info.bufsize = 1024;
980 efivars->efi_pstore_info.data = efivars;
981 mutex_init(&efivars->efi_pstore_info.buf_mutex);
982 pstore_register(&efivars->efi_pstore_info);
983 }
984
985out:
986 kfree(variable_name);
987
988 return error;
989}
990EXPORT_SYMBOL_GPL(register_efivars);
991
992static struct efivars __efivars;
993static struct efivar_operations ops;
994
995/*
996 * For now we register the efi subsystem with the firmware subsystem
997 * and the vars subsystem with the efi subsystem. In the future, it
998 * might make sense to split off the efi subsystem into its own
999 * driver, but for now only efivars will register with it, so just
1000 * include it here.
1001 */
1002
1003static int __init
1004efivars_init(void)
1005{
1006 int error = 0;
1007
1008 printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
1009 EFIVARS_DATE);
1010
1011 if (!efi_enabled)
1012 return 0;
1013
1014 /* For now we'll register the efi directory at /sys/firmware/efi */
1015 efi_kobj = kobject_create_and_add("efi", firmware_kobj);
1016 if (!efi_kobj) {
1017 printk(KERN_ERR "efivars: Firmware registration failed.\n");
1018 return -ENOMEM;
1019 }
1020
1021 ops.get_variable = efi.get_variable;
1022 ops.set_variable = efi.set_variable;
1023 ops.get_next_variable = efi.get_next_variable;
1024 error = register_efivars(&__efivars, &ops, efi_kobj);
1025 if (error)
1026 goto err_put;
1027
1028 /* Don't forget the systab entry */
1029 error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
1030 if (error) {
1031 printk(KERN_ERR
1032 "efivars: Sysfs attribute export failed with error %d.\n",
1033 error);
1034 goto err_unregister;
1035 }
1036
1037 return 0;
1038
1039err_unregister:
1040 unregister_efivars(&__efivars);
1041err_put:
1042 kobject_put(efi_kobj);
1043 return error;
1044}
1045
1046static void __exit
1047efivars_exit(void)
1048{
1049 if (efi_enabled) {
1050 unregister_efivars(&__efivars);
1051 kobject_put(efi_kobj);
1052 }
1053}
1054
1055module_init(efivars_init);
1056module_exit(efivars_exit);
1057