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[deliverable/linux.git] / drivers / firmware / efivars.c
1 /*
2 * EFI Variables - efivars.c
3 *
4 * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
5 * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
6 *
7 * This code takes all variables accessible from EFI runtime and
8 * exports them via sysfs
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 *
24 * Changelog:
25 *
26 * 17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
27 * remove check for efi_enabled in exit
28 * add MODULE_VERSION
29 *
30 * 26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com>
31 * minor bug fixes
32 *
33 * 21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com)
34 * converted driver to export variable information via sysfs
35 * and moved to drivers/firmware directory
36 * bumped revision number to v0.07 to reflect conversion & move
37 *
38 * 10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com>
39 * fix locking per Peter Chubb's findings
40 *
41 * 25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com>
42 * move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_unparse()
43 *
44 * 12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com>
45 * use list_for_each_safe when deleting vars.
46 * remove ifdef CONFIG_SMP around include <linux/smp.h>
47 * v0.04 release to linux-ia64@linuxia64.org
48 *
49 * 20 April 2001 - Matt Domsch <Matt_Domsch@dell.com>
50 * Moved vars from /proc/efi to /proc/efi/vars, and made
51 * efi.c own the /proc/efi directory.
52 * v0.03 release to linux-ia64@linuxia64.org
53 *
54 * 26 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
55 * At the request of Stephane, moved ownership of /proc/efi
56 * to efi.c, and now efivars lives under /proc/efi/vars.
57 *
58 * 12 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
59 * Feedback received from Stephane Eranian incorporated.
60 * efivar_write() checks copy_from_user() return value.
61 * efivar_read/write() returns proper errno.
62 * v0.02 release to linux-ia64@linuxia64.org
63 *
64 * 26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
65 * v0.01 release to linux-ia64@linuxia64.org
66 */
67
68 #include <linux/capability.h>
69 #include <linux/types.h>
70 #include <linux/errno.h>
71 #include <linux/init.h>
72 #include <linux/mm.h>
73 #include <linux/module.h>
74 #include <linux/string.h>
75 #include <linux/smp.h>
76 #include <linux/efi.h>
77 #include <linux/sysfs.h>
78 #include <linux/kobject.h>
79 #include <linux/device.h>
80 #include <linux/slab.h>
81 #include <linux/pstore.h>
82 #include <linux/ctype.h>
83
84 #include <linux/fs.h>
85 #include <linux/ramfs.h>
86 #include <linux/pagemap.h>
87
88 #include <asm/uaccess.h>
89
90 #define EFIVARS_VERSION "0.08"
91 #define EFIVARS_DATE "2004-May-17"
92
93 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
94 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
95 MODULE_LICENSE("GPL");
96 MODULE_VERSION(EFIVARS_VERSION);
97
98 #define DUMP_NAME_LEN 52
99
100 /*
101 * Length of a GUID string (strlen("aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"))
102 * not including trailing NUL
103 */
104 #define GUID_LEN 36
105
106 /*
107 * The maximum size of VariableName + Data = 1024
108 * Therefore, it's reasonable to save that much
109 * space in each part of the structure,
110 * and we use a page for reading/writing.
111 */
112
113 struct efi_variable {
114 efi_char16_t VariableName[1024/sizeof(efi_char16_t)];
115 efi_guid_t VendorGuid;
116 unsigned long DataSize;
117 __u8 Data[1024];
118 efi_status_t Status;
119 __u32 Attributes;
120 } __attribute__((packed));
121
122 struct efivar_entry {
123 struct efivars *efivars;
124 struct efi_variable var;
125 struct list_head list;
126 struct kobject kobj;
127 };
128
129 struct efivar_attribute {
130 struct attribute attr;
131 ssize_t (*show) (struct efivar_entry *entry, char *buf);
132 ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
133 };
134
135 static struct efivars __efivars;
136 static struct efivar_operations ops;
137
138 #define PSTORE_EFI_ATTRIBUTES \
139 (EFI_VARIABLE_NON_VOLATILE | \
140 EFI_VARIABLE_BOOTSERVICE_ACCESS | \
141 EFI_VARIABLE_RUNTIME_ACCESS)
142
143 #define EFIVAR_ATTR(_name, _mode, _show, _store) \
144 struct efivar_attribute efivar_attr_##_name = { \
145 .attr = {.name = __stringify(_name), .mode = _mode}, \
146 .show = _show, \
147 .store = _store, \
148 };
149
150 #define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
151 #define to_efivar_entry(obj) container_of(obj, struct efivar_entry, kobj)
152
153 /*
154 * Prototype for sysfs creation function
155 */
156 static int
157 efivar_create_sysfs_entry(struct efivars *efivars,
158 unsigned long variable_name_size,
159 efi_char16_t *variable_name,
160 efi_guid_t *vendor_guid);
161
162 /*
163 * Prototype for workqueue functions updating sysfs entry
164 */
165
166 static void efivar_update_sysfs_entries(struct work_struct *);
167 static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
168
169 /* Return the number of unicode characters in data */
170 static unsigned long
171 utf16_strnlen(efi_char16_t *s, size_t maxlength)
172 {
173 unsigned long length = 0;
174
175 while (*s++ != 0 && length < maxlength)
176 length++;
177 return length;
178 }
179
180 static inline unsigned long
181 utf16_strlen(efi_char16_t *s)
182 {
183 return utf16_strnlen(s, ~0UL);
184 }
185
186 /*
187 * Return the number of bytes is the length of this string
188 * Note: this is NOT the same as the number of unicode characters
189 */
190 static inline unsigned long
191 utf16_strsize(efi_char16_t *data, unsigned long maxlength)
192 {
193 return utf16_strnlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t);
194 }
195
196 static inline int
197 utf16_strncmp(const efi_char16_t *a, const efi_char16_t *b, size_t len)
198 {
199 while (1) {
200 if (len == 0)
201 return 0;
202 if (*a < *b)
203 return -1;
204 if (*a > *b)
205 return 1;
206 if (*a == 0) /* implies *b == 0 */
207 return 0;
208 a++;
209 b++;
210 len--;
211 }
212 }
213
214 static bool
215 validate_device_path(struct efi_variable *var, int match, u8 *buffer,
216 unsigned long len)
217 {
218 struct efi_generic_dev_path *node;
219 int offset = 0;
220
221 node = (struct efi_generic_dev_path *)buffer;
222
223 if (len < sizeof(*node))
224 return false;
225
226 while (offset <= len - sizeof(*node) &&
227 node->length >= sizeof(*node) &&
228 node->length <= len - offset) {
229 offset += node->length;
230
231 if ((node->type == EFI_DEV_END_PATH ||
232 node->type == EFI_DEV_END_PATH2) &&
233 node->sub_type == EFI_DEV_END_ENTIRE)
234 return true;
235
236 node = (struct efi_generic_dev_path *)(buffer + offset);
237 }
238
239 /*
240 * If we're here then either node->length pointed past the end
241 * of the buffer or we reached the end of the buffer without
242 * finding a device path end node.
243 */
244 return false;
245 }
246
247 static bool
248 validate_boot_order(struct efi_variable *var, int match, u8 *buffer,
249 unsigned long len)
250 {
251 /* An array of 16-bit integers */
252 if ((len % 2) != 0)
253 return false;
254
255 return true;
256 }
257
258 static bool
259 validate_load_option(struct efi_variable *var, int match, u8 *buffer,
260 unsigned long len)
261 {
262 u16 filepathlength;
263 int i, desclength = 0, namelen;
264
265 namelen = utf16_strnlen(var->VariableName, sizeof(var->VariableName));
266
267 /* Either "Boot" or "Driver" followed by four digits of hex */
268 for (i = match; i < match+4; i++) {
269 if (var->VariableName[i] > 127 ||
270 hex_to_bin(var->VariableName[i] & 0xff) < 0)
271 return true;
272 }
273
274 /* Reject it if there's 4 digits of hex and then further content */
275 if (namelen > match + 4)
276 return false;
277
278 /* A valid entry must be at least 8 bytes */
279 if (len < 8)
280 return false;
281
282 filepathlength = buffer[4] | buffer[5] << 8;
283
284 /*
285 * There's no stored length for the description, so it has to be
286 * found by hand
287 */
288 desclength = utf16_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
289
290 /* Each boot entry must have a descriptor */
291 if (!desclength)
292 return false;
293
294 /*
295 * If the sum of the length of the description, the claimed filepath
296 * length and the original header are greater than the length of the
297 * variable, it's malformed
298 */
299 if ((desclength + filepathlength + 6) > len)
300 return false;
301
302 /*
303 * And, finally, check the filepath
304 */
305 return validate_device_path(var, match, buffer + desclength + 6,
306 filepathlength);
307 }
308
309 static bool
310 validate_uint16(struct efi_variable *var, int match, u8 *buffer,
311 unsigned long len)
312 {
313 /* A single 16-bit integer */
314 if (len != 2)
315 return false;
316
317 return true;
318 }
319
320 static bool
321 validate_ascii_string(struct efi_variable *var, int match, u8 *buffer,
322 unsigned long len)
323 {
324 int i;
325
326 for (i = 0; i < len; i++) {
327 if (buffer[i] > 127)
328 return false;
329
330 if (buffer[i] == 0)
331 return true;
332 }
333
334 return false;
335 }
336
337 struct variable_validate {
338 char *name;
339 bool (*validate)(struct efi_variable *var, int match, u8 *data,
340 unsigned long len);
341 };
342
343 static const struct variable_validate variable_validate[] = {
344 { "BootNext", validate_uint16 },
345 { "BootOrder", validate_boot_order },
346 { "DriverOrder", validate_boot_order },
347 { "Boot*", validate_load_option },
348 { "Driver*", validate_load_option },
349 { "ConIn", validate_device_path },
350 { "ConInDev", validate_device_path },
351 { "ConOut", validate_device_path },
352 { "ConOutDev", validate_device_path },
353 { "ErrOut", validate_device_path },
354 { "ErrOutDev", validate_device_path },
355 { "Timeout", validate_uint16 },
356 { "Lang", validate_ascii_string },
357 { "PlatformLang", validate_ascii_string },
358 { "", NULL },
359 };
360
361 static bool
362 validate_var(struct efi_variable *var, u8 *data, unsigned long len)
363 {
364 int i;
365 u16 *unicode_name = var->VariableName;
366
367 for (i = 0; variable_validate[i].validate != NULL; i++) {
368 const char *name = variable_validate[i].name;
369 int match;
370
371 for (match = 0; ; match++) {
372 char c = name[match];
373 u16 u = unicode_name[match];
374
375 /* All special variables are plain ascii */
376 if (u > 127)
377 return true;
378
379 /* Wildcard in the matching name means we've matched */
380 if (c == '*')
381 return variable_validate[i].validate(var,
382 match, data, len);
383
384 /* Case sensitive match */
385 if (c != u)
386 break;
387
388 /* Reached the end of the string while matching */
389 if (!c)
390 return variable_validate[i].validate(var,
391 match, data, len);
392 }
393 }
394
395 return true;
396 }
397
398 static efi_status_t
399 get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
400 {
401 efi_status_t status;
402
403 var->DataSize = 1024;
404 status = efivars->ops->get_variable(var->VariableName,
405 &var->VendorGuid,
406 &var->Attributes,
407 &var->DataSize,
408 var->Data);
409 return status;
410 }
411
412 static efi_status_t
413 get_var_data(struct efivars *efivars, struct efi_variable *var)
414 {
415 efi_status_t status;
416 unsigned long flags;
417
418 spin_lock_irqsave(&efivars->lock, flags);
419 status = get_var_data_locked(efivars, var);
420 spin_unlock_irqrestore(&efivars->lock, flags);
421
422 if (status != EFI_SUCCESS) {
423 printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
424 status);
425 }
426 return status;
427 }
428
429 static efi_status_t
430 check_var_size_locked(struct efivars *efivars, u32 attributes,
431 unsigned long size)
432 {
433 u64 storage_size, remaining_size, max_size;
434 efi_status_t status;
435 const struct efivar_operations *fops = efivars->ops;
436
437 if (!efivars->ops->query_variable_info)
438 return EFI_UNSUPPORTED;
439
440 status = fops->query_variable_info(attributes, &storage_size,
441 &remaining_size, &max_size);
442
443 if (status != EFI_SUCCESS)
444 return status;
445
446 if (!storage_size || size > remaining_size || size > max_size ||
447 (remaining_size - size) < (storage_size / 2))
448 return EFI_OUT_OF_RESOURCES;
449
450 return status;
451 }
452
453
454 static efi_status_t
455 check_var_size(struct efivars *efivars, u32 attributes, unsigned long size)
456 {
457 efi_status_t status;
458 unsigned long flags;
459
460 spin_lock_irqsave(&efivars->lock, flags);
461 status = check_var_size_locked(efivars, attributes, size);
462 spin_unlock_irqrestore(&efivars->lock, flags);
463
464 return status;
465 }
466
467 static ssize_t
468 efivar_guid_read(struct efivar_entry *entry, char *buf)
469 {
470 struct efi_variable *var = &entry->var;
471 char *str = buf;
472
473 if (!entry || !buf)
474 return 0;
475
476 efi_guid_unparse(&var->VendorGuid, str);
477 str += strlen(str);
478 str += sprintf(str, "\n");
479
480 return str - buf;
481 }
482
483 static ssize_t
484 efivar_attr_read(struct efivar_entry *entry, char *buf)
485 {
486 struct efi_variable *var = &entry->var;
487 char *str = buf;
488 efi_status_t status;
489
490 if (!entry || !buf)
491 return -EINVAL;
492
493 status = get_var_data(entry->efivars, var);
494 if (status != EFI_SUCCESS)
495 return -EIO;
496
497 if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
498 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
499 if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
500 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
501 if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
502 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
503 if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
504 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
505 if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
506 str += sprintf(str,
507 "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
508 if (var->Attributes &
509 EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
510 str += sprintf(str,
511 "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
512 if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
513 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
514 return str - buf;
515 }
516
517 static ssize_t
518 efivar_size_read(struct efivar_entry *entry, char *buf)
519 {
520 struct efi_variable *var = &entry->var;
521 char *str = buf;
522 efi_status_t status;
523
524 if (!entry || !buf)
525 return -EINVAL;
526
527 status = get_var_data(entry->efivars, var);
528 if (status != EFI_SUCCESS)
529 return -EIO;
530
531 str += sprintf(str, "0x%lx\n", var->DataSize);
532 return str - buf;
533 }
534
535 static ssize_t
536 efivar_data_read(struct efivar_entry *entry, char *buf)
537 {
538 struct efi_variable *var = &entry->var;
539 efi_status_t status;
540
541 if (!entry || !buf)
542 return -EINVAL;
543
544 status = get_var_data(entry->efivars, var);
545 if (status != EFI_SUCCESS)
546 return -EIO;
547
548 memcpy(buf, var->Data, var->DataSize);
549 return var->DataSize;
550 }
551 /*
552 * We allow each variable to be edited via rewriting the
553 * entire efi variable structure.
554 */
555 static ssize_t
556 efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
557 {
558 struct efi_variable *new_var, *var = &entry->var;
559 struct efivars *efivars = entry->efivars;
560 efi_status_t status = EFI_NOT_FOUND;
561
562 if (count != sizeof(struct efi_variable))
563 return -EINVAL;
564
565 new_var = (struct efi_variable *)buf;
566 /*
567 * If only updating the variable data, then the name
568 * and guid should remain the same
569 */
570 if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) ||
571 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) {
572 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
573 return -EINVAL;
574 }
575
576 if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
577 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
578 return -EINVAL;
579 }
580
581 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
582 validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
583 printk(KERN_ERR "efivars: Malformed variable content\n");
584 return -EINVAL;
585 }
586
587 spin_lock_irq(&efivars->lock);
588
589 status = check_var_size_locked(efivars, new_var->Attributes,
590 new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
591
592 if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
593 status = efivars->ops->set_variable(new_var->VariableName,
594 &new_var->VendorGuid,
595 new_var->Attributes,
596 new_var->DataSize,
597 new_var->Data);
598
599 spin_unlock_irq(&efivars->lock);
600
601 if (status != EFI_SUCCESS) {
602 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
603 status);
604 return -EIO;
605 }
606
607 memcpy(&entry->var, new_var, count);
608 return count;
609 }
610
611 static ssize_t
612 efivar_show_raw(struct efivar_entry *entry, char *buf)
613 {
614 struct efi_variable *var = &entry->var;
615 efi_status_t status;
616
617 if (!entry || !buf)
618 return 0;
619
620 status = get_var_data(entry->efivars, var);
621 if (status != EFI_SUCCESS)
622 return -EIO;
623
624 memcpy(buf, var, sizeof(*var));
625 return sizeof(*var);
626 }
627
628 /*
629 * Generic read/write functions that call the specific functions of
630 * the attributes...
631 */
632 static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
633 char *buf)
634 {
635 struct efivar_entry *var = to_efivar_entry(kobj);
636 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
637 ssize_t ret = -EIO;
638
639 if (!capable(CAP_SYS_ADMIN))
640 return -EACCES;
641
642 if (efivar_attr->show) {
643 ret = efivar_attr->show(var, buf);
644 }
645 return ret;
646 }
647
648 static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
649 const char *buf, size_t count)
650 {
651 struct efivar_entry *var = to_efivar_entry(kobj);
652 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
653 ssize_t ret = -EIO;
654
655 if (!capable(CAP_SYS_ADMIN))
656 return -EACCES;
657
658 if (efivar_attr->store)
659 ret = efivar_attr->store(var, buf, count);
660
661 return ret;
662 }
663
664 static const struct sysfs_ops efivar_attr_ops = {
665 .show = efivar_attr_show,
666 .store = efivar_attr_store,
667 };
668
669 static void efivar_release(struct kobject *kobj)
670 {
671 struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
672 kfree(var);
673 }
674
675 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
676 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
677 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
678 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
679 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
680
681 static struct attribute *def_attrs[] = {
682 &efivar_attr_guid.attr,
683 &efivar_attr_size.attr,
684 &efivar_attr_attributes.attr,
685 &efivar_attr_data.attr,
686 &efivar_attr_raw_var.attr,
687 NULL,
688 };
689
690 static struct kobj_type efivar_ktype = {
691 .release = efivar_release,
692 .sysfs_ops = &efivar_attr_ops,
693 .default_attrs = def_attrs,
694 };
695
696 static inline void
697 efivar_unregister(struct efivar_entry *var)
698 {
699 kobject_put(&var->kobj);
700 }
701
702 static int efivarfs_file_open(struct inode *inode, struct file *file)
703 {
704 file->private_data = inode->i_private;
705 return 0;
706 }
707
708 static int efi_status_to_err(efi_status_t status)
709 {
710 int err;
711
712 switch (status) {
713 case EFI_INVALID_PARAMETER:
714 err = -EINVAL;
715 break;
716 case EFI_OUT_OF_RESOURCES:
717 err = -ENOSPC;
718 break;
719 case EFI_DEVICE_ERROR:
720 err = -EIO;
721 break;
722 case EFI_WRITE_PROTECTED:
723 err = -EROFS;
724 break;
725 case EFI_SECURITY_VIOLATION:
726 err = -EACCES;
727 break;
728 case EFI_NOT_FOUND:
729 err = -EIO;
730 break;
731 default:
732 err = -EINVAL;
733 }
734
735 return err;
736 }
737
738 static ssize_t efivarfs_file_write(struct file *file,
739 const char __user *userbuf, size_t count, loff_t *ppos)
740 {
741 struct efivar_entry *var = file->private_data;
742 struct efivars *efivars;
743 efi_status_t status;
744 void *data;
745 u32 attributes;
746 struct inode *inode = file->f_mapping->host;
747 unsigned long datasize = count - sizeof(attributes);
748 unsigned long newdatasize, varsize;
749 ssize_t bytes = 0;
750
751 if (count < sizeof(attributes))
752 return -EINVAL;
753
754 if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
755 return -EFAULT;
756
757 if (attributes & ~(EFI_VARIABLE_MASK))
758 return -EINVAL;
759
760 efivars = var->efivars;
761
762 /*
763 * Ensure that the user can't allocate arbitrarily large
764 * amounts of memory. Pick a default size of 64K if
765 * QueryVariableInfo() isn't supported by the firmware.
766 */
767
768 varsize = datasize + utf16_strsize(var->var.VariableName, 1024);
769 status = check_var_size(efivars, attributes, varsize);
770
771 if (status != EFI_SUCCESS) {
772 if (status != EFI_UNSUPPORTED)
773 return efi_status_to_err(status);
774
775 if (datasize > 65536)
776 return -ENOSPC;
777 }
778
779 data = kmalloc(datasize, GFP_KERNEL);
780 if (!data)
781 return -ENOMEM;
782
783 if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
784 bytes = -EFAULT;
785 goto out;
786 }
787
788 if (validate_var(&var->var, data, datasize) == false) {
789 bytes = -EINVAL;
790 goto out;
791 }
792
793 /*
794 * The lock here protects the get_variable call, the conditional
795 * set_variable call, and removal of the variable from the efivars
796 * list (in the case of an authenticated delete).
797 */
798 spin_lock_irq(&efivars->lock);
799
800 /*
801 * Ensure that the available space hasn't shrunk below the safe level
802 */
803
804 status = check_var_size_locked(efivars, attributes, varsize);
805
806 if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED) {
807 spin_unlock_irq(&efivars->lock);
808 kfree(data);
809
810 return efi_status_to_err(status);
811 }
812
813 status = efivars->ops->set_variable(var->var.VariableName,
814 &var->var.VendorGuid,
815 attributes, datasize,
816 data);
817
818 if (status != EFI_SUCCESS) {
819 spin_unlock_irq(&efivars->lock);
820 kfree(data);
821
822 return efi_status_to_err(status);
823 }
824
825 bytes = count;
826
827 /*
828 * Writing to the variable may have caused a change in size (which
829 * could either be an append or an overwrite), or the variable to be
830 * deleted. Perform a GetVariable() so we can tell what actually
831 * happened.
832 */
833 newdatasize = 0;
834 status = efivars->ops->get_variable(var->var.VariableName,
835 &var->var.VendorGuid,
836 NULL, &newdatasize,
837 NULL);
838
839 if (status == EFI_BUFFER_TOO_SMALL) {
840 spin_unlock_irq(&efivars->lock);
841 mutex_lock(&inode->i_mutex);
842 i_size_write(inode, newdatasize + sizeof(attributes));
843 mutex_unlock(&inode->i_mutex);
844
845 } else if (status == EFI_NOT_FOUND) {
846 list_del(&var->list);
847 spin_unlock_irq(&efivars->lock);
848 efivar_unregister(var);
849 drop_nlink(inode);
850 d_delete(file->f_dentry);
851 dput(file->f_dentry);
852
853 } else {
854 spin_unlock_irq(&efivars->lock);
855 pr_warn("efivarfs: inconsistent EFI variable implementation? "
856 "status = %lx\n", status);
857 }
858
859 out:
860 kfree(data);
861
862 return bytes;
863 }
864
865 static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
866 size_t count, loff_t *ppos)
867 {
868 struct efivar_entry *var = file->private_data;
869 struct efivars *efivars = var->efivars;
870 efi_status_t status;
871 unsigned long datasize = 0;
872 u32 attributes;
873 void *data;
874 ssize_t size = 0;
875
876 spin_lock_irq(&efivars->lock);
877 status = efivars->ops->get_variable(var->var.VariableName,
878 &var->var.VendorGuid,
879 &attributes, &datasize, NULL);
880 spin_unlock_irq(&efivars->lock);
881
882 if (status != EFI_BUFFER_TOO_SMALL)
883 return efi_status_to_err(status);
884
885 data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
886
887 if (!data)
888 return -ENOMEM;
889
890 spin_lock_irq(&efivars->lock);
891 status = efivars->ops->get_variable(var->var.VariableName,
892 &var->var.VendorGuid,
893 &attributes, &datasize,
894 (data + sizeof(attributes)));
895 spin_unlock_irq(&efivars->lock);
896
897 if (status != EFI_SUCCESS) {
898 size = efi_status_to_err(status);
899 goto out_free;
900 }
901
902 memcpy(data, &attributes, sizeof(attributes));
903 size = simple_read_from_buffer(userbuf, count, ppos,
904 data, datasize + sizeof(attributes));
905 out_free:
906 kfree(data);
907
908 return size;
909 }
910
911 static void efivarfs_evict_inode(struct inode *inode)
912 {
913 clear_inode(inode);
914 }
915
916 static const struct super_operations efivarfs_ops = {
917 .statfs = simple_statfs,
918 .drop_inode = generic_delete_inode,
919 .evict_inode = efivarfs_evict_inode,
920 .show_options = generic_show_options,
921 };
922
923 static struct super_block *efivarfs_sb;
924
925 static const struct inode_operations efivarfs_dir_inode_operations;
926
927 static const struct file_operations efivarfs_file_operations = {
928 .open = efivarfs_file_open,
929 .read = efivarfs_file_read,
930 .write = efivarfs_file_write,
931 .llseek = no_llseek,
932 };
933
934 static struct inode *efivarfs_get_inode(struct super_block *sb,
935 const struct inode *dir, int mode, dev_t dev)
936 {
937 struct inode *inode = new_inode(sb);
938
939 if (inode) {
940 inode->i_ino = get_next_ino();
941 inode->i_mode = mode;
942 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
943 switch (mode & S_IFMT) {
944 case S_IFREG:
945 inode->i_fop = &efivarfs_file_operations;
946 break;
947 case S_IFDIR:
948 inode->i_op = &efivarfs_dir_inode_operations;
949 inode->i_fop = &simple_dir_operations;
950 inc_nlink(inode);
951 break;
952 }
953 }
954 return inode;
955 }
956
957 /*
958 * Return true if 'str' is a valid efivarfs filename of the form,
959 *
960 * VariableName-12345678-1234-1234-1234-1234567891bc
961 */
962 static bool efivarfs_valid_name(const char *str, int len)
963 {
964 static const char dashes[GUID_LEN] = {
965 [8] = 1, [13] = 1, [18] = 1, [23] = 1
966 };
967 const char *s = str + len - GUID_LEN;
968 int i;
969
970 /*
971 * We need a GUID, plus at least one letter for the variable name,
972 * plus the '-' separator
973 */
974 if (len < GUID_LEN + 2)
975 return false;
976
977 /* GUID must be preceded by a '-' */
978 if (*(s - 1) != '-')
979 return false;
980
981 /*
982 * Validate that 's' is of the correct format, e.g.
983 *
984 * 12345678-1234-1234-1234-123456789abc
985 */
986 for (i = 0; i < GUID_LEN; i++) {
987 if (dashes[i]) {
988 if (*s++ != '-')
989 return false;
990 } else {
991 if (!isxdigit(*s++))
992 return false;
993 }
994 }
995
996 return true;
997 }
998
999 static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
1000 {
1001 guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
1002 guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
1003 guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
1004 guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
1005 guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
1006 guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
1007 guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
1008 guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
1009 guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
1010 guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
1011 guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
1012 guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
1013 guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
1014 guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
1015 guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
1016 guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
1017 }
1018
1019 static int efivarfs_create(struct inode *dir, struct dentry *dentry,
1020 umode_t mode, bool excl)
1021 {
1022 struct inode *inode;
1023 struct efivars *efivars = &__efivars;
1024 struct efivar_entry *var;
1025 int namelen, i = 0, err = 0;
1026
1027 if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
1028 return -EINVAL;
1029
1030 inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
1031 if (!inode)
1032 return -ENOMEM;
1033
1034 var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1035 if (!var) {
1036 err = -ENOMEM;
1037 goto out;
1038 }
1039
1040 /* length of the variable name itself: remove GUID and separator */
1041 namelen = dentry->d_name.len - GUID_LEN - 1;
1042
1043 efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
1044 &var->var.VendorGuid);
1045
1046 for (i = 0; i < namelen; i++)
1047 var->var.VariableName[i] = dentry->d_name.name[i];
1048
1049 var->var.VariableName[i] = '\0';
1050
1051 inode->i_private = var;
1052 var->efivars = efivars;
1053 var->kobj.kset = efivars->kset;
1054
1055 err = kobject_init_and_add(&var->kobj, &efivar_ktype, NULL, "%s",
1056 dentry->d_name.name);
1057 if (err)
1058 goto out;
1059
1060 kobject_uevent(&var->kobj, KOBJ_ADD);
1061 spin_lock_irq(&efivars->lock);
1062 list_add(&var->list, &efivars->list);
1063 spin_unlock_irq(&efivars->lock);
1064 d_instantiate(dentry, inode);
1065 dget(dentry);
1066 out:
1067 if (err) {
1068 kfree(var);
1069 iput(inode);
1070 }
1071 return err;
1072 }
1073
1074 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
1075 {
1076 struct efivar_entry *var = dentry->d_inode->i_private;
1077 struct efivars *efivars = var->efivars;
1078 efi_status_t status;
1079
1080 spin_lock_irq(&efivars->lock);
1081
1082 status = efivars->ops->set_variable(var->var.VariableName,
1083 &var->var.VendorGuid,
1084 0, 0, NULL);
1085
1086 if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
1087 list_del(&var->list);
1088 spin_unlock_irq(&efivars->lock);
1089 efivar_unregister(var);
1090 drop_nlink(dentry->d_inode);
1091 dput(dentry);
1092 return 0;
1093 }
1094
1095 spin_unlock_irq(&efivars->lock);
1096 return -EINVAL;
1097 };
1098
1099 /*
1100 * Compare two efivarfs file names.
1101 *
1102 * An efivarfs filename is composed of two parts,
1103 *
1104 * 1. A case-sensitive variable name
1105 * 2. A case-insensitive GUID
1106 *
1107 * So we need to perform a case-sensitive match on part 1 and a
1108 * case-insensitive match on part 2.
1109 */
1110 static int efivarfs_d_compare(const struct dentry *parent, const struct inode *pinode,
1111 const struct dentry *dentry, const struct inode *inode,
1112 unsigned int len, const char *str,
1113 const struct qstr *name)
1114 {
1115 int guid = len - GUID_LEN;
1116
1117 if (name->len != len)
1118 return 1;
1119
1120 /* Case-sensitive compare for the variable name */
1121 if (memcmp(str, name->name, guid))
1122 return 1;
1123
1124 /* Case-insensitive compare for the GUID */
1125 return strncasecmp(name->name + guid, str + guid, GUID_LEN);
1126 }
1127
1128 static int efivarfs_d_hash(const struct dentry *dentry,
1129 const struct inode *inode, struct qstr *qstr)
1130 {
1131 unsigned long hash = init_name_hash();
1132 const unsigned char *s = qstr->name;
1133 unsigned int len = qstr->len;
1134
1135 if (!efivarfs_valid_name(s, len))
1136 return -EINVAL;
1137
1138 while (len-- > GUID_LEN)
1139 hash = partial_name_hash(*s++, hash);
1140
1141 /* GUID is case-insensitive. */
1142 while (len--)
1143 hash = partial_name_hash(tolower(*s++), hash);
1144
1145 qstr->hash = end_name_hash(hash);
1146 return 0;
1147 }
1148
1149 /*
1150 * Retaining negative dentries for an in-memory filesystem just wastes
1151 * memory and lookup time: arrange for them to be deleted immediately.
1152 */
1153 static int efivarfs_delete_dentry(const struct dentry *dentry)
1154 {
1155 return 1;
1156 }
1157
1158 static struct dentry_operations efivarfs_d_ops = {
1159 .d_compare = efivarfs_d_compare,
1160 .d_hash = efivarfs_d_hash,
1161 .d_delete = efivarfs_delete_dentry,
1162 };
1163
1164 static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
1165 {
1166 struct qstr q;
1167
1168 q.name = name;
1169 q.len = strlen(name);
1170
1171 if (efivarfs_d_hash(NULL, NULL, &q))
1172 return NULL;
1173
1174 return d_alloc(parent, &q);
1175 }
1176
1177 static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
1178 {
1179 struct inode *inode = NULL;
1180 struct dentry *root;
1181 struct efivar_entry *entry, *n;
1182 struct efivars *efivars = &__efivars;
1183 char *name;
1184
1185 efivarfs_sb = sb;
1186
1187 sb->s_maxbytes = MAX_LFS_FILESIZE;
1188 sb->s_blocksize = PAGE_CACHE_SIZE;
1189 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1190 sb->s_magic = EFIVARFS_MAGIC;
1191 sb->s_op = &efivarfs_ops;
1192 sb->s_d_op = &efivarfs_d_ops;
1193 sb->s_time_gran = 1;
1194
1195 inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
1196 if (!inode)
1197 return -ENOMEM;
1198 inode->i_op = &efivarfs_dir_inode_operations;
1199
1200 root = d_make_root(inode);
1201 sb->s_root = root;
1202 if (!root)
1203 return -ENOMEM;
1204
1205 list_for_each_entry_safe(entry, n, &efivars->list, list) {
1206 struct dentry *dentry, *root = efivarfs_sb->s_root;
1207 unsigned long size = 0;
1208 int len, i;
1209
1210 inode = NULL;
1211
1212 len = utf16_strlen(entry->var.VariableName);
1213
1214 /* name, plus '-', plus GUID, plus NUL*/
1215 name = kmalloc(len + 1 + GUID_LEN + 1, GFP_ATOMIC);
1216 if (!name)
1217 goto fail;
1218
1219 for (i = 0; i < len; i++)
1220 name[i] = entry->var.VariableName[i] & 0xFF;
1221
1222 name[len] = '-';
1223
1224 efi_guid_unparse(&entry->var.VendorGuid, name + len + 1);
1225
1226 name[len+GUID_LEN+1] = '\0';
1227
1228 inode = efivarfs_get_inode(efivarfs_sb, root->d_inode,
1229 S_IFREG | 0644, 0);
1230 if (!inode)
1231 goto fail_name;
1232
1233 dentry = efivarfs_alloc_dentry(root, name);
1234 if (!dentry)
1235 goto fail_inode;
1236
1237 /* copied by the above to local storage in the dentry. */
1238 kfree(name);
1239
1240 spin_lock_irq(&efivars->lock);
1241 efivars->ops->get_variable(entry->var.VariableName,
1242 &entry->var.VendorGuid,
1243 &entry->var.Attributes,
1244 &size,
1245 NULL);
1246 spin_unlock_irq(&efivars->lock);
1247
1248 mutex_lock(&inode->i_mutex);
1249 inode->i_private = entry;
1250 i_size_write(inode, size + sizeof(entry->var.Attributes));
1251 mutex_unlock(&inode->i_mutex);
1252 d_add(dentry, inode);
1253 }
1254
1255 return 0;
1256
1257 fail_inode:
1258 iput(inode);
1259 fail_name:
1260 kfree(name);
1261 fail:
1262 return -ENOMEM;
1263 }
1264
1265 static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
1266 int flags, const char *dev_name, void *data)
1267 {
1268 return mount_single(fs_type, flags, data, efivarfs_fill_super);
1269 }
1270
1271 static void efivarfs_kill_sb(struct super_block *sb)
1272 {
1273 kill_litter_super(sb);
1274 efivarfs_sb = NULL;
1275 }
1276
1277 static struct file_system_type efivarfs_type = {
1278 .name = "efivarfs",
1279 .mount = efivarfs_mount,
1280 .kill_sb = efivarfs_kill_sb,
1281 };
1282
1283 /*
1284 * Handle negative dentry.
1285 */
1286 static struct dentry *efivarfs_lookup(struct inode *dir, struct dentry *dentry,
1287 unsigned int flags)
1288 {
1289 if (dentry->d_name.len > NAME_MAX)
1290 return ERR_PTR(-ENAMETOOLONG);
1291 d_add(dentry, NULL);
1292 return NULL;
1293 }
1294
1295 static const struct inode_operations efivarfs_dir_inode_operations = {
1296 .lookup = efivarfs_lookup,
1297 .unlink = efivarfs_unlink,
1298 .create = efivarfs_create,
1299 };
1300
1301 static struct pstore_info efi_pstore_info;
1302
1303 #ifdef CONFIG_PSTORE
1304
1305 static int efi_pstore_open(struct pstore_info *psi)
1306 {
1307 struct efivars *efivars = psi->data;
1308
1309 spin_lock_irq(&efivars->lock);
1310 efivars->walk_entry = list_first_entry(&efivars->list,
1311 struct efivar_entry, list);
1312 return 0;
1313 }
1314
1315 static int efi_pstore_close(struct pstore_info *psi)
1316 {
1317 struct efivars *efivars = psi->data;
1318
1319 spin_unlock_irq(&efivars->lock);
1320 return 0;
1321 }
1322
1323 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
1324 int *count, struct timespec *timespec,
1325 char **buf, struct pstore_info *psi)
1326 {
1327 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1328 struct efivars *efivars = psi->data;
1329 char name[DUMP_NAME_LEN];
1330 int i;
1331 int cnt;
1332 unsigned int part, size;
1333 unsigned long time;
1334
1335 while (&efivars->walk_entry->list != &efivars->list) {
1336 if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
1337 vendor)) {
1338 for (i = 0; i < DUMP_NAME_LEN; i++) {
1339 name[i] = efivars->walk_entry->var.VariableName[i];
1340 }
1341 if (sscanf(name, "dump-type%u-%u-%d-%lu",
1342 type, &part, &cnt, &time) == 4) {
1343 *id = part;
1344 *count = cnt;
1345 timespec->tv_sec = time;
1346 timespec->tv_nsec = 0;
1347 } else if (sscanf(name, "dump-type%u-%u-%lu",
1348 type, &part, &time) == 3) {
1349 /*
1350 * Check if an old format,
1351 * which doesn't support holding
1352 * multiple logs, remains.
1353 */
1354 *id = part;
1355 *count = 0;
1356 timespec->tv_sec = time;
1357 timespec->tv_nsec = 0;
1358 } else {
1359 efivars->walk_entry = list_entry(
1360 efivars->walk_entry->list.next,
1361 struct efivar_entry, list);
1362 continue;
1363 }
1364
1365 get_var_data_locked(efivars, &efivars->walk_entry->var);
1366 size = efivars->walk_entry->var.DataSize;
1367 *buf = kmalloc(size, GFP_KERNEL);
1368 if (*buf == NULL)
1369 return -ENOMEM;
1370 memcpy(*buf, efivars->walk_entry->var.Data,
1371 size);
1372 efivars->walk_entry = list_entry(
1373 efivars->walk_entry->list.next,
1374 struct efivar_entry, list);
1375 return size;
1376 }
1377 efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
1378 struct efivar_entry, list);
1379 }
1380 return 0;
1381 }
1382
1383 static int efi_pstore_write(enum pstore_type_id type,
1384 enum kmsg_dump_reason reason, u64 *id,
1385 unsigned int part, int count, size_t size,
1386 struct pstore_info *psi)
1387 {
1388 char name[DUMP_NAME_LEN];
1389 efi_char16_t efi_name[DUMP_NAME_LEN];
1390 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1391 struct efivars *efivars = psi->data;
1392 int i, ret = 0;
1393 efi_status_t status = EFI_NOT_FOUND;
1394 unsigned long flags;
1395
1396 if (pstore_cannot_block_path(reason)) {
1397 /*
1398 * If the lock is taken by another cpu in non-blocking path,
1399 * this driver returns without entering firmware to avoid
1400 * hanging up.
1401 */
1402 if (!spin_trylock_irqsave(&efivars->lock, flags))
1403 return -EBUSY;
1404 } else
1405 spin_lock_irqsave(&efivars->lock, flags);
1406
1407 /*
1408 * Check if there is a space enough to log.
1409 * size: a size of logging data
1410 * DUMP_NAME_LEN * 2: a maximum size of variable name
1411 */
1412
1413 status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
1414 size + DUMP_NAME_LEN * 2);
1415
1416 if (status) {
1417 spin_unlock_irqrestore(&efivars->lock, flags);
1418 *id = part;
1419 return -ENOSPC;
1420 }
1421
1422 sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
1423 get_seconds());
1424
1425 for (i = 0; i < DUMP_NAME_LEN; i++)
1426 efi_name[i] = name[i];
1427
1428 efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
1429 size, psi->buf);
1430
1431 spin_unlock_irqrestore(&efivars->lock, flags);
1432
1433 if (reason == KMSG_DUMP_OOPS)
1434 schedule_work(&efivar_work);
1435
1436 *id = part;
1437 return ret;
1438 };
1439
1440 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1441 struct timespec time, struct pstore_info *psi)
1442 {
1443 char name[DUMP_NAME_LEN];
1444 efi_char16_t efi_name[DUMP_NAME_LEN];
1445 char name_old[DUMP_NAME_LEN];
1446 efi_char16_t efi_name_old[DUMP_NAME_LEN];
1447 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
1448 struct efivars *efivars = psi->data;
1449 struct efivar_entry *entry, *found = NULL;
1450 int i;
1451
1452 sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
1453 time.tv_sec);
1454
1455 spin_lock_irq(&efivars->lock);
1456
1457 for (i = 0; i < DUMP_NAME_LEN; i++)
1458 efi_name[i] = name[i];
1459
1460 /*
1461 * Clean up an entry with the same name
1462 */
1463
1464 list_for_each_entry(entry, &efivars->list, list) {
1465 get_var_data_locked(efivars, &entry->var);
1466
1467 if (efi_guidcmp(entry->var.VendorGuid, vendor))
1468 continue;
1469 if (utf16_strncmp(entry->var.VariableName, efi_name,
1470 utf16_strlen(efi_name))) {
1471 /*
1472 * Check if an old format,
1473 * which doesn't support holding
1474 * multiple logs, remains.
1475 */
1476 sprintf(name_old, "dump-type%u-%u-%lu", type,
1477 (unsigned int)id, time.tv_sec);
1478
1479 for (i = 0; i < DUMP_NAME_LEN; i++)
1480 efi_name_old[i] = name_old[i];
1481
1482 if (utf16_strncmp(entry->var.VariableName, efi_name_old,
1483 utf16_strlen(efi_name_old)))
1484 continue;
1485 }
1486
1487 /* found */
1488 found = entry;
1489 efivars->ops->set_variable(entry->var.VariableName,
1490 &entry->var.VendorGuid,
1491 PSTORE_EFI_ATTRIBUTES,
1492 0, NULL);
1493 break;
1494 }
1495
1496 if (found)
1497 list_del(&found->list);
1498
1499 spin_unlock_irq(&efivars->lock);
1500
1501 if (found)
1502 efivar_unregister(found);
1503
1504 return 0;
1505 }
1506 #else
1507 static int efi_pstore_open(struct pstore_info *psi)
1508 {
1509 return 0;
1510 }
1511
1512 static int efi_pstore_close(struct pstore_info *psi)
1513 {
1514 return 0;
1515 }
1516
1517 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, int *count,
1518 struct timespec *timespec,
1519 char **buf, struct pstore_info *psi)
1520 {
1521 return -1;
1522 }
1523
1524 static int efi_pstore_write(enum pstore_type_id type,
1525 enum kmsg_dump_reason reason, u64 *id,
1526 unsigned int part, int count, size_t size,
1527 struct pstore_info *psi)
1528 {
1529 return 0;
1530 }
1531
1532 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
1533 struct timespec time, struct pstore_info *psi)
1534 {
1535 return 0;
1536 }
1537 #endif
1538
1539 static struct pstore_info efi_pstore_info = {
1540 .owner = THIS_MODULE,
1541 .name = "efi",
1542 .open = efi_pstore_open,
1543 .close = efi_pstore_close,
1544 .read = efi_pstore_read,
1545 .write = efi_pstore_write,
1546 .erase = efi_pstore_erase,
1547 };
1548
1549 static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
1550 struct bin_attribute *bin_attr,
1551 char *buf, loff_t pos, size_t count)
1552 {
1553 struct efi_variable *new_var = (struct efi_variable *)buf;
1554 struct efivars *efivars = bin_attr->private;
1555 struct efivar_entry *search_efivar, *n;
1556 unsigned long strsize1, strsize2;
1557 efi_status_t status = EFI_NOT_FOUND;
1558 int found = 0;
1559
1560 if (!capable(CAP_SYS_ADMIN))
1561 return -EACCES;
1562
1563 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 ||
1564 validate_var(new_var, new_var->Data, new_var->DataSize) == false) {
1565 printk(KERN_ERR "efivars: Malformed variable content\n");
1566 return -EINVAL;
1567 }
1568
1569 spin_lock_irq(&efivars->lock);
1570
1571 /*
1572 * Does this variable already exist?
1573 */
1574 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1575 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1576 strsize2 = utf16_strsize(new_var->VariableName, 1024);
1577 if (strsize1 == strsize2 &&
1578 !memcmp(&(search_efivar->var.VariableName),
1579 new_var->VariableName, strsize1) &&
1580 !efi_guidcmp(search_efivar->var.VendorGuid,
1581 new_var->VendorGuid)) {
1582 found = 1;
1583 break;
1584 }
1585 }
1586 if (found) {
1587 spin_unlock_irq(&efivars->lock);
1588 return -EINVAL;
1589 }
1590
1591 status = check_var_size_locked(efivars, new_var->Attributes,
1592 new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));
1593
1594 if (status && status != EFI_UNSUPPORTED) {
1595 spin_unlock_irq(&efivars->lock);
1596 return efi_status_to_err(status);
1597 }
1598
1599 /* now *really* create the variable via EFI */
1600 status = efivars->ops->set_variable(new_var->VariableName,
1601 &new_var->VendorGuid,
1602 new_var->Attributes,
1603 new_var->DataSize,
1604 new_var->Data);
1605
1606 if (status != EFI_SUCCESS) {
1607 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1608 status);
1609 spin_unlock_irq(&efivars->lock);
1610 return -EIO;
1611 }
1612 spin_unlock_irq(&efivars->lock);
1613
1614 /* Create the entry in sysfs. Locking is not required here */
1615 status = efivar_create_sysfs_entry(efivars,
1616 utf16_strsize(new_var->VariableName,
1617 1024),
1618 new_var->VariableName,
1619 &new_var->VendorGuid);
1620 if (status) {
1621 printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n");
1622 }
1623 return count;
1624 }
1625
1626 static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
1627 struct bin_attribute *bin_attr,
1628 char *buf, loff_t pos, size_t count)
1629 {
1630 struct efi_variable *del_var = (struct efi_variable *)buf;
1631 struct efivars *efivars = bin_attr->private;
1632 struct efivar_entry *search_efivar, *n;
1633 unsigned long strsize1, strsize2;
1634 efi_status_t status = EFI_NOT_FOUND;
1635 int found = 0;
1636
1637 if (!capable(CAP_SYS_ADMIN))
1638 return -EACCES;
1639
1640 spin_lock_irq(&efivars->lock);
1641
1642 /*
1643 * Does this variable already exist?
1644 */
1645 list_for_each_entry_safe(search_efivar, n, &efivars->list, list) {
1646 strsize1 = utf16_strsize(search_efivar->var.VariableName, 1024);
1647 strsize2 = utf16_strsize(del_var->VariableName, 1024);
1648 if (strsize1 == strsize2 &&
1649 !memcmp(&(search_efivar->var.VariableName),
1650 del_var->VariableName, strsize1) &&
1651 !efi_guidcmp(search_efivar->var.VendorGuid,
1652 del_var->VendorGuid)) {
1653 found = 1;
1654 break;
1655 }
1656 }
1657 if (!found) {
1658 spin_unlock_irq(&efivars->lock);
1659 return -EINVAL;
1660 }
1661 /* force the Attributes/DataSize to 0 to ensure deletion */
1662 del_var->Attributes = 0;
1663 del_var->DataSize = 0;
1664
1665 status = efivars->ops->set_variable(del_var->VariableName,
1666 &del_var->VendorGuid,
1667 del_var->Attributes,
1668 del_var->DataSize,
1669 del_var->Data);
1670
1671 if (status != EFI_SUCCESS) {
1672 printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
1673 status);
1674 spin_unlock_irq(&efivars->lock);
1675 return -EIO;
1676 }
1677 list_del(&search_efivar->list);
1678 /* We need to release this lock before unregistering. */
1679 spin_unlock_irq(&efivars->lock);
1680 efivar_unregister(search_efivar);
1681
1682 /* It's dead Jim.... */
1683 return count;
1684 }
1685
1686 static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
1687 {
1688 struct efivar_entry *entry, *n;
1689 struct efivars *efivars = &__efivars;
1690 unsigned long strsize1, strsize2;
1691 bool found = false;
1692
1693 strsize1 = utf16_strsize(variable_name, 1024);
1694 list_for_each_entry_safe(entry, n, &efivars->list, list) {
1695 strsize2 = utf16_strsize(entry->var.VariableName, 1024);
1696 if (strsize1 == strsize2 &&
1697 !memcmp(variable_name, &(entry->var.VariableName),
1698 strsize2) &&
1699 !efi_guidcmp(entry->var.VendorGuid,
1700 *vendor)) {
1701 found = true;
1702 break;
1703 }
1704 }
1705 return found;
1706 }
1707
1708 static void efivar_update_sysfs_entries(struct work_struct *work)
1709 {
1710 struct efivars *efivars = &__efivars;
1711 efi_guid_t vendor;
1712 efi_char16_t *variable_name;
1713 unsigned long variable_name_size = 1024;
1714 efi_status_t status = EFI_NOT_FOUND;
1715 bool found;
1716
1717 /* Add new sysfs entries */
1718 while (1) {
1719 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1720 if (!variable_name) {
1721 pr_err("efivars: Memory allocation failed.\n");
1722 return;
1723 }
1724
1725 spin_lock_irq(&efivars->lock);
1726 found = false;
1727 while (1) {
1728 variable_name_size = 1024;
1729 status = efivars->ops->get_next_variable(
1730 &variable_name_size,
1731 variable_name,
1732 &vendor);
1733 if (status != EFI_SUCCESS) {
1734 break;
1735 } else {
1736 if (!variable_is_present(variable_name,
1737 &vendor)) {
1738 found = true;
1739 break;
1740 }
1741 }
1742 }
1743 spin_unlock_irq(&efivars->lock);
1744
1745 if (!found) {
1746 kfree(variable_name);
1747 break;
1748 } else
1749 efivar_create_sysfs_entry(efivars,
1750 variable_name_size,
1751 variable_name, &vendor);
1752 }
1753 }
1754
1755 /*
1756 * Let's not leave out systab information that snuck into
1757 * the efivars driver
1758 */
1759 static ssize_t systab_show(struct kobject *kobj,
1760 struct kobj_attribute *attr, char *buf)
1761 {
1762 char *str = buf;
1763
1764 if (!kobj || !buf)
1765 return -EINVAL;
1766
1767 if (efi.mps != EFI_INVALID_TABLE_ADDR)
1768 str += sprintf(str, "MPS=0x%lx\n", efi.mps);
1769 if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
1770 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
1771 if (efi.acpi != EFI_INVALID_TABLE_ADDR)
1772 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
1773 if (efi.smbios != EFI_INVALID_TABLE_ADDR)
1774 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
1775 if (efi.hcdp != EFI_INVALID_TABLE_ADDR)
1776 str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp);
1777 if (efi.boot_info != EFI_INVALID_TABLE_ADDR)
1778 str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info);
1779 if (efi.uga != EFI_INVALID_TABLE_ADDR)
1780 str += sprintf(str, "UGA=0x%lx\n", efi.uga);
1781
1782 return str - buf;
1783 }
1784
1785 static struct kobj_attribute efi_attr_systab =
1786 __ATTR(systab, 0400, systab_show, NULL);
1787
1788 static struct attribute *efi_subsys_attrs[] = {
1789 &efi_attr_systab.attr,
1790 NULL, /* maybe more in the future? */
1791 };
1792
1793 static struct attribute_group efi_subsys_attr_group = {
1794 .attrs = efi_subsys_attrs,
1795 };
1796
1797 static struct kobject *efi_kobj;
1798
1799 /*
1800 * efivar_create_sysfs_entry()
1801 * Requires:
1802 * variable_name_size = number of bytes required to hold
1803 * variable_name (not counting the NULL
1804 * character at the end.
1805 * efivars->lock is not held on entry or exit.
1806 * Returns 1 on failure, 0 on success
1807 */
1808 static int
1809 efivar_create_sysfs_entry(struct efivars *efivars,
1810 unsigned long variable_name_size,
1811 efi_char16_t *variable_name,
1812 efi_guid_t *vendor_guid)
1813 {
1814 int i, short_name_size;
1815 char *short_name;
1816 struct efivar_entry *new_efivar;
1817
1818 /*
1819 * Length of the variable bytes in ASCII, plus the '-' separator,
1820 * plus the GUID, plus trailing NUL
1821 */
1822 short_name_size = variable_name_size / sizeof(efi_char16_t)
1823 + 1 + GUID_LEN + 1;
1824
1825 short_name = kzalloc(short_name_size, GFP_KERNEL);
1826 new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
1827
1828 if (!short_name || !new_efivar) {
1829 kfree(short_name);
1830 kfree(new_efivar);
1831 return 1;
1832 }
1833
1834 new_efivar->efivars = efivars;
1835 memcpy(new_efivar->var.VariableName, variable_name,
1836 variable_name_size);
1837 memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
1838
1839 /* Convert Unicode to normal chars (assume top bits are 0),
1840 ala UTF-8 */
1841 for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
1842 short_name[i] = variable_name[i] & 0xFF;
1843 }
1844 /* This is ugly, but necessary to separate one vendor's
1845 private variables from another's. */
1846
1847 *(short_name + strlen(short_name)) = '-';
1848 efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
1849
1850 new_efivar->kobj.kset = efivars->kset;
1851 i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL,
1852 "%s", short_name);
1853 if (i) {
1854 kfree(short_name);
1855 kfree(new_efivar);
1856 return 1;
1857 }
1858
1859 kobject_uevent(&new_efivar->kobj, KOBJ_ADD);
1860 kfree(short_name);
1861 short_name = NULL;
1862
1863 spin_lock_irq(&efivars->lock);
1864 list_add(&new_efivar->list, &efivars->list);
1865 spin_unlock_irq(&efivars->lock);
1866
1867 return 0;
1868 }
1869
1870 static int
1871 create_efivars_bin_attributes(struct efivars *efivars)
1872 {
1873 struct bin_attribute *attr;
1874 int error;
1875
1876 /* new_var */
1877 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1878 if (!attr)
1879 return -ENOMEM;
1880
1881 attr->attr.name = "new_var";
1882 attr->attr.mode = 0200;
1883 attr->write = efivar_create;
1884 attr->private = efivars;
1885 efivars->new_var = attr;
1886
1887 /* del_var */
1888 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1889 if (!attr) {
1890 error = -ENOMEM;
1891 goto out_free;
1892 }
1893 attr->attr.name = "del_var";
1894 attr->attr.mode = 0200;
1895 attr->write = efivar_delete;
1896 attr->private = efivars;
1897 efivars->del_var = attr;
1898
1899 sysfs_bin_attr_init(efivars->new_var);
1900 sysfs_bin_attr_init(efivars->del_var);
1901
1902 /* Register */
1903 error = sysfs_create_bin_file(&efivars->kset->kobj,
1904 efivars->new_var);
1905 if (error) {
1906 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
1907 " due to error %d\n", error);
1908 goto out_free;
1909 }
1910 error = sysfs_create_bin_file(&efivars->kset->kobj,
1911 efivars->del_var);
1912 if (error) {
1913 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
1914 " due to error %d\n", error);
1915 sysfs_remove_bin_file(&efivars->kset->kobj,
1916 efivars->new_var);
1917 goto out_free;
1918 }
1919
1920 return 0;
1921 out_free:
1922 kfree(efivars->del_var);
1923 efivars->del_var = NULL;
1924 kfree(efivars->new_var);
1925 efivars->new_var = NULL;
1926 return error;
1927 }
1928
1929 void unregister_efivars(struct efivars *efivars)
1930 {
1931 struct efivar_entry *entry, *n;
1932
1933 list_for_each_entry_safe(entry, n, &efivars->list, list) {
1934 spin_lock_irq(&efivars->lock);
1935 list_del(&entry->list);
1936 spin_unlock_irq(&efivars->lock);
1937 efivar_unregister(entry);
1938 }
1939 if (efivars->new_var)
1940 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->new_var);
1941 if (efivars->del_var)
1942 sysfs_remove_bin_file(&efivars->kset->kobj, efivars->del_var);
1943 kfree(efivars->new_var);
1944 kfree(efivars->del_var);
1945 kobject_put(efivars->kobject);
1946 kset_unregister(efivars->kset);
1947 }
1948 EXPORT_SYMBOL_GPL(unregister_efivars);
1949
1950 int register_efivars(struct efivars *efivars,
1951 const struct efivar_operations *ops,
1952 struct kobject *parent_kobj)
1953 {
1954 efi_status_t status = EFI_NOT_FOUND;
1955 efi_guid_t vendor_guid;
1956 efi_char16_t *variable_name;
1957 unsigned long variable_name_size = 1024;
1958 int error = 0;
1959
1960 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
1961 if (!variable_name) {
1962 printk(KERN_ERR "efivars: Memory allocation failed.\n");
1963 return -ENOMEM;
1964 }
1965
1966 spin_lock_init(&efivars->lock);
1967 INIT_LIST_HEAD(&efivars->list);
1968 efivars->ops = ops;
1969
1970 efivars->kset = kset_create_and_add("vars", NULL, parent_kobj);
1971 if (!efivars->kset) {
1972 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
1973 error = -ENOMEM;
1974 goto out;
1975 }
1976
1977 efivars->kobject = kobject_create_and_add("efivars", parent_kobj);
1978 if (!efivars->kobject) {
1979 pr_err("efivars: Subsystem registration failed.\n");
1980 error = -ENOMEM;
1981 kset_unregister(efivars->kset);
1982 goto out;
1983 }
1984
1985 /*
1986 * Per EFI spec, the maximum storage allocated for both
1987 * the variable name and variable data is 1024 bytes.
1988 */
1989
1990 do {
1991 variable_name_size = 1024;
1992
1993 status = ops->get_next_variable(&variable_name_size,
1994 variable_name,
1995 &vendor_guid);
1996 switch (status) {
1997 case EFI_SUCCESS:
1998 efivar_create_sysfs_entry(efivars,
1999 variable_name_size,
2000 variable_name,
2001 &vendor_guid);
2002 break;
2003 case EFI_NOT_FOUND:
2004 break;
2005 default:
2006 printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
2007 status);
2008 status = EFI_NOT_FOUND;
2009 break;
2010 }
2011 } while (status != EFI_NOT_FOUND);
2012
2013 error = create_efivars_bin_attributes(efivars);
2014 if (error)
2015 unregister_efivars(efivars);
2016
2017 efivars->efi_pstore_info = efi_pstore_info;
2018
2019 efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
2020 if (efivars->efi_pstore_info.buf) {
2021 efivars->efi_pstore_info.bufsize = 1024;
2022 efivars->efi_pstore_info.data = efivars;
2023 spin_lock_init(&efivars->efi_pstore_info.buf_lock);
2024 pstore_register(&efivars->efi_pstore_info);
2025 }
2026
2027 register_filesystem(&efivarfs_type);
2028
2029 out:
2030 kfree(variable_name);
2031
2032 return error;
2033 }
2034 EXPORT_SYMBOL_GPL(register_efivars);
2035
2036 /*
2037 * For now we register the efi subsystem with the firmware subsystem
2038 * and the vars subsystem with the efi subsystem. In the future, it
2039 * might make sense to split off the efi subsystem into its own
2040 * driver, but for now only efivars will register with it, so just
2041 * include it here.
2042 */
2043
2044 static int __init
2045 efivars_init(void)
2046 {
2047 int error = 0;
2048
2049 printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
2050 EFIVARS_DATE);
2051
2052 if (!efi_enabled(EFI_RUNTIME_SERVICES))
2053 return 0;
2054
2055 /* For now we'll register the efi directory at /sys/firmware/efi */
2056 efi_kobj = kobject_create_and_add("efi", firmware_kobj);
2057 if (!efi_kobj) {
2058 printk(KERN_ERR "efivars: Firmware registration failed.\n");
2059 return -ENOMEM;
2060 }
2061
2062 ops.get_variable = efi.get_variable;
2063 ops.set_variable = efi.set_variable;
2064 ops.get_next_variable = efi.get_next_variable;
2065 ops.query_variable_info = efi.query_variable_info;
2066
2067 error = register_efivars(&__efivars, &ops, efi_kobj);
2068 if (error)
2069 goto err_put;
2070
2071 /* Don't forget the systab entry */
2072 error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
2073 if (error) {
2074 printk(KERN_ERR
2075 "efivars: Sysfs attribute export failed with error %d.\n",
2076 error);
2077 goto err_unregister;
2078 }
2079
2080 return 0;
2081
2082 err_unregister:
2083 unregister_efivars(&__efivars);
2084 err_put:
2085 kobject_put(efi_kobj);
2086 return error;
2087 }
2088
2089 static void __exit
2090 efivars_exit(void)
2091 {
2092 cancel_work_sync(&efivar_work);
2093
2094 if (efi_enabled(EFI_RUNTIME_SERVICES)) {
2095 unregister_efivars(&__efivars);
2096 kobject_put(efi_kobj);
2097 }
2098 }
2099
2100 module_init(efivars_init);
2101 module_exit(efivars_exit);
2102
Linux kernel - Deliverables
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