Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
a9499fa7 | 2 | * Originally from efivars.c |
1da177e4 LT |
3 | * |
4 | * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com> | |
5 | * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com> | |
6 | * | |
1da177e4 LT |
7 | * This program is free software; you can redistribute it and/or modify |
8 | * it under the terms of the GNU General Public License as published by | |
9 | * the Free Software Foundation; either version 2 of the License, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program; if not, write to the Free Software | |
19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
1da177e4 LT |
20 | */ |
21 | ||
c59ede7b | 22 | #include <linux/capability.h> |
1da177e4 LT |
23 | #include <linux/types.h> |
24 | #include <linux/errno.h> | |
25 | #include <linux/init.h> | |
1da177e4 LT |
26 | #include <linux/mm.h> |
27 | #include <linux/module.h> | |
28 | #include <linux/string.h> | |
29 | #include <linux/smp.h> | |
30 | #include <linux/efi.h> | |
31 | #include <linux/sysfs.h> | |
1da177e4 | 32 | #include <linux/device.h> |
5a0e3ad6 | 33 | #include <linux/slab.h> |
47f531e8 | 34 | #include <linux/ctype.h> |
a614e192 | 35 | #include <linux/ucs2_string.h> |
1da177e4 | 36 | |
4423d779 MF |
37 | /* Private pointer to registered efivars */ |
38 | static struct efivars *__efivars; | |
5d9db883 | 39 | |
e971318b | 40 | static bool efivar_wq_enabled = true; |
a9499fa7 TG |
41 | DECLARE_WORK(efivar_work, NULL); |
42 | EXPORT_SYMBOL_GPL(efivar_work); | |
a93bc0c6 | 43 | |
fec6c20b | 44 | static bool |
a5d92ad3 | 45 | validate_device_path(efi_char16_t *var_name, int match, u8 *buffer, |
54b3a4d3 | 46 | unsigned long len) |
fec6c20b MG |
47 | { |
48 | struct efi_generic_dev_path *node; | |
49 | int offset = 0; | |
50 | ||
51 | node = (struct efi_generic_dev_path *)buffer; | |
52 | ||
54b3a4d3 MG |
53 | if (len < sizeof(*node)) |
54 | return false; | |
fec6c20b | 55 | |
54b3a4d3 MG |
56 | while (offset <= len - sizeof(*node) && |
57 | node->length >= sizeof(*node) && | |
58 | node->length <= len - offset) { | |
59 | offset += node->length; | |
fec6c20b MG |
60 | |
61 | if ((node->type == EFI_DEV_END_PATH || | |
62 | node->type == EFI_DEV_END_PATH2) && | |
63 | node->sub_type == EFI_DEV_END_ENTIRE) | |
64 | return true; | |
65 | ||
66 | node = (struct efi_generic_dev_path *)(buffer + offset); | |
67 | } | |
68 | ||
69 | /* | |
70 | * If we're here then either node->length pointed past the end | |
71 | * of the buffer or we reached the end of the buffer without | |
72 | * finding a device path end node. | |
73 | */ | |
74 | return false; | |
75 | } | |
76 | ||
77 | static bool | |
a5d92ad3 | 78 | validate_boot_order(efi_char16_t *var_name, int match, u8 *buffer, |
54b3a4d3 | 79 | unsigned long len) |
fec6c20b MG |
80 | { |
81 | /* An array of 16-bit integers */ | |
82 | if ((len % 2) != 0) | |
83 | return false; | |
84 | ||
85 | return true; | |
86 | } | |
87 | ||
88 | static bool | |
a5d92ad3 | 89 | validate_load_option(efi_char16_t *var_name, int match, u8 *buffer, |
54b3a4d3 | 90 | unsigned long len) |
fec6c20b MG |
91 | { |
92 | u16 filepathlength; | |
54b3a4d3 MG |
93 | int i, desclength = 0, namelen; |
94 | ||
a5d92ad3 | 95 | namelen = ucs2_strnlen(var_name, EFI_VAR_NAME_LEN); |
fec6c20b MG |
96 | |
97 | /* Either "Boot" or "Driver" followed by four digits of hex */ | |
98 | for (i = match; i < match+4; i++) { | |
a5d92ad3 MF |
99 | if (var_name[i] > 127 || |
100 | hex_to_bin(var_name[i] & 0xff) < 0) | |
fec6c20b MG |
101 | return true; |
102 | } | |
103 | ||
54b3a4d3 MG |
104 | /* Reject it if there's 4 digits of hex and then further content */ |
105 | if (namelen > match + 4) | |
106 | return false; | |
107 | ||
108 | /* A valid entry must be at least 8 bytes */ | |
109 | if (len < 8) | |
fec6c20b MG |
110 | return false; |
111 | ||
112 | filepathlength = buffer[4] | buffer[5] << 8; | |
113 | ||
114 | /* | |
115 | * There's no stored length for the description, so it has to be | |
116 | * found by hand | |
117 | */ | |
a614e192 | 118 | desclength = ucs2_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2; |
fec6c20b MG |
119 | |
120 | /* Each boot entry must have a descriptor */ | |
121 | if (!desclength) | |
122 | return false; | |
123 | ||
124 | /* | |
125 | * If the sum of the length of the description, the claimed filepath | |
126 | * length and the original header are greater than the length of the | |
127 | * variable, it's malformed | |
128 | */ | |
129 | if ((desclength + filepathlength + 6) > len) | |
130 | return false; | |
131 | ||
132 | /* | |
133 | * And, finally, check the filepath | |
134 | */ | |
a5d92ad3 | 135 | return validate_device_path(var_name, match, buffer + desclength + 6, |
fec6c20b MG |
136 | filepathlength); |
137 | } | |
138 | ||
139 | static bool | |
a5d92ad3 | 140 | validate_uint16(efi_char16_t *var_name, int match, u8 *buffer, |
54b3a4d3 | 141 | unsigned long len) |
fec6c20b MG |
142 | { |
143 | /* A single 16-bit integer */ | |
144 | if (len != 2) | |
145 | return false; | |
146 | ||
147 | return true; | |
148 | } | |
149 | ||
150 | static bool | |
a5d92ad3 | 151 | validate_ascii_string(efi_char16_t *var_name, int match, u8 *buffer, |
54b3a4d3 | 152 | unsigned long len) |
fec6c20b MG |
153 | { |
154 | int i; | |
155 | ||
156 | for (i = 0; i < len; i++) { | |
157 | if (buffer[i] > 127) | |
158 | return false; | |
159 | ||
160 | if (buffer[i] == 0) | |
161 | return true; | |
162 | } | |
163 | ||
164 | return false; | |
165 | } | |
166 | ||
167 | struct variable_validate { | |
8282f5d9 | 168 | efi_guid_t vendor; |
fec6c20b | 169 | char *name; |
a5d92ad3 | 170 | bool (*validate)(efi_char16_t *var_name, int match, u8 *data, |
54b3a4d3 | 171 | unsigned long len); |
fec6c20b MG |
172 | }; |
173 | ||
8282f5d9 | 174 | /* |
ed8b0de5 PJ |
175 | * This is the list of variables we need to validate, as well as the |
176 | * whitelist for what we think is safe not to default to immutable. | |
8282f5d9 PJ |
177 | * |
178 | * If it has a validate() method that's not NULL, it'll go into the | |
ed8b0de5 PJ |
179 | * validation routine. If not, it is assumed valid, but still used for |
180 | * whitelisting. | |
8282f5d9 PJ |
181 | * |
182 | * Note that it's sorted by {vendor,name}, but globbed names must come after | |
183 | * any other name with the same prefix. | |
184 | */ | |
fec6c20b | 185 | static const struct variable_validate variable_validate[] = { |
8282f5d9 PJ |
186 | { EFI_GLOBAL_VARIABLE_GUID, "BootNext", validate_uint16 }, |
187 | { EFI_GLOBAL_VARIABLE_GUID, "BootOrder", validate_boot_order }, | |
188 | { EFI_GLOBAL_VARIABLE_GUID, "Boot*", validate_load_option }, | |
189 | { EFI_GLOBAL_VARIABLE_GUID, "DriverOrder", validate_boot_order }, | |
190 | { EFI_GLOBAL_VARIABLE_GUID, "Driver*", validate_load_option }, | |
191 | { EFI_GLOBAL_VARIABLE_GUID, "ConIn", validate_device_path }, | |
192 | { EFI_GLOBAL_VARIABLE_GUID, "ConInDev", validate_device_path }, | |
193 | { EFI_GLOBAL_VARIABLE_GUID, "ConOut", validate_device_path }, | |
194 | { EFI_GLOBAL_VARIABLE_GUID, "ConOutDev", validate_device_path }, | |
195 | { EFI_GLOBAL_VARIABLE_GUID, "ErrOut", validate_device_path }, | |
196 | { EFI_GLOBAL_VARIABLE_GUID, "ErrOutDev", validate_device_path }, | |
197 | { EFI_GLOBAL_VARIABLE_GUID, "Lang", validate_ascii_string }, | |
ed8b0de5 | 198 | { EFI_GLOBAL_VARIABLE_GUID, "OsIndications", NULL }, |
8282f5d9 PJ |
199 | { EFI_GLOBAL_VARIABLE_GUID, "PlatformLang", validate_ascii_string }, |
200 | { EFI_GLOBAL_VARIABLE_GUID, "Timeout", validate_uint16 }, | |
201 | { NULL_GUID, "", NULL }, | |
fec6c20b MG |
202 | }; |
203 | ||
ed8b0de5 PJ |
204 | static bool |
205 | variable_matches(const char *var_name, size_t len, const char *match_name, | |
206 | int *match) | |
207 | { | |
208 | for (*match = 0; ; (*match)++) { | |
209 | char c = match_name[*match]; | |
210 | char u = var_name[*match]; | |
211 | ||
212 | /* Wildcard in the matching name means we've matched */ | |
213 | if (c == '*') | |
214 | return true; | |
215 | ||
216 | /* Case sensitive match */ | |
217 | if (!c && *match == len) | |
218 | return true; | |
219 | ||
220 | if (c != u) | |
221 | return false; | |
222 | ||
223 | if (!c) | |
224 | return true; | |
225 | } | |
226 | return true; | |
227 | } | |
228 | ||
e14ab23d | 229 | bool |
8282f5d9 PJ |
230 | efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data, |
231 | unsigned long data_size) | |
fec6c20b MG |
232 | { |
233 | int i; | |
3dcb1f55 PJ |
234 | unsigned long utf8_size; |
235 | u8 *utf8_name; | |
236 | ||
237 | utf8_size = ucs2_utf8size(var_name); | |
238 | utf8_name = kmalloc(utf8_size + 1, GFP_KERNEL); | |
239 | if (!utf8_name) | |
240 | return false; | |
241 | ||
242 | ucs2_as_utf8(utf8_name, var_name, utf8_size); | |
243 | utf8_name[utf8_size] = '\0'; | |
fec6c20b | 244 | |
8282f5d9 | 245 | for (i = 0; variable_validate[i].name[0] != '\0'; i++) { |
fec6c20b | 246 | const char *name = variable_validate[i].name; |
8282f5d9 PJ |
247 | int match = 0; |
248 | ||
249 | if (efi_guidcmp(vendor, variable_validate[i].vendor)) | |
250 | continue; | |
fec6c20b | 251 | |
ed8b0de5 PJ |
252 | if (variable_matches(utf8_name, utf8_size+1, name, &match)) { |
253 | if (variable_validate[i].validate == NULL) | |
fec6c20b | 254 | break; |
ed8b0de5 PJ |
255 | kfree(utf8_name); |
256 | return variable_validate[i].validate(var_name, match, | |
257 | data, data_size); | |
fec6c20b MG |
258 | } |
259 | } | |
3dcb1f55 | 260 | kfree(utf8_name); |
fec6c20b MG |
261 | return true; |
262 | } | |
e14ab23d | 263 | EXPORT_SYMBOL_GPL(efivar_validate); |
fec6c20b | 264 | |
ed8b0de5 PJ |
265 | bool |
266 | efivar_variable_is_removable(efi_guid_t vendor, const char *var_name, | |
267 | size_t len) | |
268 | { | |
269 | int i; | |
270 | bool found = false; | |
271 | int match = 0; | |
272 | ||
273 | /* | |
274 | * Check if our variable is in the validated variables list | |
275 | */ | |
276 | for (i = 0; variable_validate[i].name[0] != '\0'; i++) { | |
277 | if (efi_guidcmp(variable_validate[i].vendor, vendor)) | |
278 | continue; | |
279 | ||
280 | if (variable_matches(var_name, len, | |
281 | variable_validate[i].name, &match)) { | |
282 | found = true; | |
283 | break; | |
284 | } | |
285 | } | |
286 | ||
287 | /* | |
288 | * If it's in our list, it is removable. | |
289 | */ | |
290 | return found; | |
291 | } | |
292 | EXPORT_SYMBOL_GPL(efivar_variable_is_removable); | |
293 | ||
1da177e4 | 294 | static efi_status_t |
e14ab23d | 295 | check_var_size(u32 attributes, unsigned long size) |
68d92986 | 296 | { |
e14ab23d | 297 | const struct efivar_operations *fops = __efivars->ops; |
68d92986 | 298 | |
a614e192 | 299 | if (!fops->query_variable_store) |
68d92986 MG |
300 | return EFI_UNSUPPORTED; |
301 | ||
a614e192 | 302 | return fops->query_variable_store(attributes, size); |
68d92986 MG |
303 | } |
304 | ||
7253eaba MF |
305 | static int efi_status_to_err(efi_status_t status) |
306 | { | |
307 | int err; | |
308 | ||
309 | switch (status) { | |
e14ab23d MF |
310 | case EFI_SUCCESS: |
311 | err = 0; | |
312 | break; | |
7253eaba MF |
313 | case EFI_INVALID_PARAMETER: |
314 | err = -EINVAL; | |
315 | break; | |
316 | case EFI_OUT_OF_RESOURCES: | |
317 | err = -ENOSPC; | |
318 | break; | |
319 | case EFI_DEVICE_ERROR: | |
320 | err = -EIO; | |
321 | break; | |
322 | case EFI_WRITE_PROTECTED: | |
323 | err = -EROFS; | |
324 | break; | |
325 | case EFI_SECURITY_VIOLATION: | |
326 | err = -EACCES; | |
327 | break; | |
328 | case EFI_NOT_FOUND: | |
e14ab23d | 329 | err = -ENOENT; |
7253eaba MF |
330 | break; |
331 | default: | |
332 | err = -EINVAL; | |
333 | } | |
334 | ||
335 | return err; | |
336 | } | |
337 | ||
e14ab23d MF |
338 | static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor, |
339 | struct list_head *head) | |
a93bc0c6 SA |
340 | { |
341 | struct efivar_entry *entry, *n; | |
a93bc0c6 SA |
342 | unsigned long strsize1, strsize2; |
343 | bool found = false; | |
344 | ||
a614e192 | 345 | strsize1 = ucs2_strsize(variable_name, 1024); |
e14ab23d | 346 | list_for_each_entry_safe(entry, n, head, list) { |
a614e192 | 347 | strsize2 = ucs2_strsize(entry->var.VariableName, 1024); |
a93bc0c6 SA |
348 | if (strsize1 == strsize2 && |
349 | !memcmp(variable_name, &(entry->var.VariableName), | |
350 | strsize2) && | |
351 | !efi_guidcmp(entry->var.VendorGuid, | |
352 | *vendor)) { | |
353 | found = true; | |
354 | break; | |
355 | } | |
356 | } | |
357 | return found; | |
358 | } | |
359 | ||
ec50bd32 MF |
360 | /* |
361 | * Returns the size of variable_name, in bytes, including the | |
362 | * terminating NULL character, or variable_name_size if no NULL | |
363 | * character is found among the first variable_name_size bytes. | |
364 | */ | |
365 | static unsigned long var_name_strnsize(efi_char16_t *variable_name, | |
366 | unsigned long variable_name_size) | |
367 | { | |
368 | unsigned long len; | |
369 | efi_char16_t c; | |
370 | ||
371 | /* | |
372 | * The variable name is, by definition, a NULL-terminated | |
373 | * string, so make absolutely sure that variable_name_size is | |
374 | * the value we expect it to be. If not, return the real size. | |
375 | */ | |
376 | for (len = 2; len <= variable_name_size; len += sizeof(c)) { | |
377 | c = variable_name[(len / sizeof(c)) - 1]; | |
378 | if (!c) | |
379 | break; | |
380 | } | |
381 | ||
382 | return min(len, variable_name_size); | |
383 | } | |
384 | ||
e971318b MF |
385 | /* |
386 | * Print a warning when duplicate EFI variables are encountered and | |
387 | * disable the sysfs workqueue since the firmware is buggy. | |
388 | */ | |
b2fce819 | 389 | static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid, |
e971318b MF |
390 | unsigned long len16) |
391 | { | |
392 | size_t i, len8 = len16 / sizeof(efi_char16_t); | |
b2fce819 | 393 | char *str8; |
e971318b MF |
394 | |
395 | /* | |
396 | * Disable the workqueue since the algorithm it uses for | |
397 | * detecting new variables won't work with this buggy | |
398 | * implementation of GetNextVariableName(). | |
399 | */ | |
400 | efivar_wq_enabled = false; | |
401 | ||
b2fce819 MR |
402 | str8 = kzalloc(len8, GFP_KERNEL); |
403 | if (!str8) | |
e971318b MF |
404 | return; |
405 | ||
406 | for (i = 0; i < len8; i++) | |
b2fce819 | 407 | str8[i] = str16[i]; |
e971318b MF |
408 | |
409 | printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n", | |
b2fce819 MR |
410 | str8, vendor_guid); |
411 | kfree(str8); | |
e971318b MF |
412 | } |
413 | ||
e14ab23d MF |
414 | /** |
415 | * efivar_init - build the initial list of EFI variables | |
416 | * @func: callback function to invoke for every variable | |
417 | * @data: function-specific data to pass to @func | |
418 | * @atomic: do we need to execute the @func-loop atomically? | |
419 | * @duplicates: error if we encounter duplicates on @head? | |
420 | * @head: initialised head of variable list | |
421 | * | |
422 | * Get every EFI variable from the firmware and invoke @func. @func | |
423 | * should call efivar_entry_add() to build the list of variables. | |
424 | * | |
425 | * Returns 0 on success, or a kernel error code on failure. | |
426 | */ | |
427 | int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *), | |
428 | void *data, bool atomic, bool duplicates, | |
429 | struct list_head *head) | |
430 | { | |
431 | const struct efivar_operations *ops = __efivars->ops; | |
432 | unsigned long variable_name_size = 1024; | |
433 | efi_char16_t *variable_name; | |
434 | efi_status_t status; | |
435 | efi_guid_t vendor_guid; | |
436 | int err = 0; | |
437 | ||
438 | variable_name = kzalloc(variable_name_size, GFP_KERNEL); | |
439 | if (!variable_name) { | |
440 | printk(KERN_ERR "efivars: Memory allocation failed.\n"); | |
441 | return -ENOMEM; | |
605e70c7 LCY |
442 | } |
443 | ||
e14ab23d MF |
444 | spin_lock_irq(&__efivars->lock); |
445 | ||
1da177e4 LT |
446 | /* |
447 | * Per EFI spec, the maximum storage allocated for both | |
448 | * the variable name and variable data is 1024 bytes. | |
449 | */ | |
450 | ||
451 | do { | |
452 | variable_name_size = 1024; | |
453 | ||
3295814d | 454 | status = ops->get_next_variable(&variable_name_size, |
1da177e4 LT |
455 | variable_name, |
456 | &vendor_guid); | |
457 | switch (status) { | |
458 | case EFI_SUCCESS: | |
e14ab23d MF |
459 | if (!atomic) |
460 | spin_unlock_irq(&__efivars->lock); | |
461 | ||
ec50bd32 MF |
462 | variable_name_size = var_name_strnsize(variable_name, |
463 | variable_name_size); | |
e971318b MF |
464 | |
465 | /* | |
466 | * Some firmware implementations return the | |
467 | * same variable name on multiple calls to | |
468 | * get_next_variable(). Terminate the loop | |
469 | * immediately as there is no guarantee that | |
470 | * we'll ever see a different variable name, | |
471 | * and may end up looping here forever. | |
472 | */ | |
e14ab23d MF |
473 | if (duplicates && |
474 | variable_is_present(variable_name, &vendor_guid, head)) { | |
e971318b MF |
475 | dup_variable_bug(variable_name, &vendor_guid, |
476 | variable_name_size); | |
e14ab23d MF |
477 | if (!atomic) |
478 | spin_lock_irq(&__efivars->lock); | |
479 | ||
e971318b MF |
480 | status = EFI_NOT_FOUND; |
481 | break; | |
482 | } | |
483 | ||
e14ab23d MF |
484 | err = func(variable_name, vendor_guid, variable_name_size, data); |
485 | if (err) | |
486 | status = EFI_NOT_FOUND; | |
487 | ||
488 | if (!atomic) | |
489 | spin_lock_irq(&__efivars->lock); | |
490 | ||
1da177e4 LT |
491 | break; |
492 | case EFI_NOT_FOUND: | |
493 | break; | |
494 | default: | |
495 | printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n", | |
496 | status); | |
497 | status = EFI_NOT_FOUND; | |
498 | break; | |
499 | } | |
e14ab23d | 500 | |
1da177e4 LT |
501 | } while (status != EFI_NOT_FOUND); |
502 | ||
e14ab23d MF |
503 | spin_unlock_irq(&__efivars->lock); |
504 | ||
505 | kfree(variable_name); | |
506 | ||
507 | return err; | |
508 | } | |
509 | EXPORT_SYMBOL_GPL(efivar_init); | |
510 | ||
511 | /** | |
512 | * efivar_entry_add - add entry to variable list | |
513 | * @entry: entry to add to list | |
514 | * @head: list head | |
515 | */ | |
516 | void efivar_entry_add(struct efivar_entry *entry, struct list_head *head) | |
517 | { | |
518 | spin_lock_irq(&__efivars->lock); | |
519 | list_add(&entry->list, head); | |
520 | spin_unlock_irq(&__efivars->lock); | |
521 | } | |
522 | EXPORT_SYMBOL_GPL(efivar_entry_add); | |
523 | ||
524 | /** | |
525 | * efivar_entry_remove - remove entry from variable list | |
526 | * @entry: entry to remove from list | |
527 | */ | |
528 | void efivar_entry_remove(struct efivar_entry *entry) | |
529 | { | |
530 | spin_lock_irq(&__efivars->lock); | |
531 | list_del(&entry->list); | |
532 | spin_unlock_irq(&__efivars->lock); | |
533 | } | |
534 | EXPORT_SYMBOL_GPL(efivar_entry_remove); | |
535 | ||
536 | /* | |
537 | * efivar_entry_list_del_unlock - remove entry from variable list | |
538 | * @entry: entry to remove | |
539 | * | |
540 | * Remove @entry from the variable list and release the list lock. | |
541 | * | |
542 | * NOTE: slightly weird locking semantics here - we expect to be | |
543 | * called with the efivars lock already held, and we release it before | |
544 | * returning. This is because this function is usually called after | |
545 | * set_variable() while the lock is still held. | |
546 | */ | |
547 | static void efivar_entry_list_del_unlock(struct efivar_entry *entry) | |
548 | { | |
aee530cf | 549 | lockdep_assert_held(&__efivars->lock); |
e14ab23d MF |
550 | |
551 | list_del(&entry->list); | |
552 | spin_unlock_irq(&__efivars->lock); | |
553 | } | |
554 | ||
555 | /** | |
556 | * __efivar_entry_delete - delete an EFI variable | |
557 | * @entry: entry containing EFI variable to delete | |
558 | * | |
a9499fa7 TG |
559 | * Delete the variable from the firmware but leave @entry on the |
560 | * variable list. | |
e14ab23d | 561 | * |
a9499fa7 TG |
562 | * This function differs from efivar_entry_delete() because it does |
563 | * not remove @entry from the variable list. Also, it is safe to be | |
564 | * called from within a efivar_entry_iter_begin() and | |
e14ab23d MF |
565 | * efivar_entry_iter_end() region, unlike efivar_entry_delete(). |
566 | * | |
567 | * Returns 0 on success, or a converted EFI status code if | |
a9499fa7 | 568 | * set_variable() fails. |
e14ab23d MF |
569 | */ |
570 | int __efivar_entry_delete(struct efivar_entry *entry) | |
571 | { | |
572 | const struct efivar_operations *ops = __efivars->ops; | |
573 | efi_status_t status; | |
574 | ||
aee530cf | 575 | lockdep_assert_held(&__efivars->lock); |
e14ab23d MF |
576 | |
577 | status = ops->set_variable(entry->var.VariableName, | |
578 | &entry->var.VendorGuid, | |
579 | 0, 0, NULL); | |
e14ab23d | 580 | |
a9499fa7 | 581 | return efi_status_to_err(status); |
e14ab23d MF |
582 | } |
583 | EXPORT_SYMBOL_GPL(__efivar_entry_delete); | |
584 | ||
585 | /** | |
586 | * efivar_entry_delete - delete variable and remove entry from list | |
587 | * @entry: entry containing variable to delete | |
588 | * | |
589 | * Delete the variable from the firmware and remove @entry from the | |
590 | * variable list. It is the caller's responsibility to free @entry | |
591 | * once we return. | |
592 | * | |
593 | * Returns 0 on success, or a converted EFI status code if | |
594 | * set_variable() fails. | |
595 | */ | |
596 | int efivar_entry_delete(struct efivar_entry *entry) | |
597 | { | |
598 | const struct efivar_operations *ops = __efivars->ops; | |
599 | efi_status_t status; | |
600 | ||
601 | spin_lock_irq(&__efivars->lock); | |
602 | status = ops->set_variable(entry->var.VariableName, | |
603 | &entry->var.VendorGuid, | |
604 | 0, 0, NULL); | |
605 | if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) { | |
606 | spin_unlock_irq(&__efivars->lock); | |
607 | return efi_status_to_err(status); | |
608 | } | |
609 | ||
610 | efivar_entry_list_del_unlock(entry); | |
611 | return 0; | |
612 | } | |
613 | EXPORT_SYMBOL_GPL(efivar_entry_delete); | |
614 | ||
615 | /** | |
616 | * efivar_entry_set - call set_variable() | |
617 | * @entry: entry containing the EFI variable to write | |
618 | * @attributes: variable attributes | |
619 | * @size: size of @data buffer | |
620 | * @data: buffer containing variable data | |
621 | * @head: head of variable list | |
622 | * | |
623 | * Calls set_variable() for an EFI variable. If creating a new EFI | |
624 | * variable, this function is usually followed by efivar_entry_add(). | |
625 | * | |
626 | * Before writing the variable, the remaining EFI variable storage | |
627 | * space is checked to ensure there is enough room available. | |
628 | * | |
629 | * If @head is not NULL a lookup is performed to determine whether | |
630 | * the entry is already on the list. | |
631 | * | |
632 | * Returns 0 on success, -EEXIST if a lookup is performed and the entry | |
633 | * already exists on the list, or a converted EFI status code if | |
634 | * set_variable() fails. | |
635 | */ | |
636 | int efivar_entry_set(struct efivar_entry *entry, u32 attributes, | |
637 | unsigned long size, void *data, struct list_head *head) | |
638 | { | |
639 | const struct efivar_operations *ops = __efivars->ops; | |
640 | efi_status_t status; | |
641 | efi_char16_t *name = entry->var.VariableName; | |
642 | efi_guid_t vendor = entry->var.VendorGuid; | |
643 | ||
644 | spin_lock_irq(&__efivars->lock); | |
645 | ||
646 | if (head && efivar_entry_find(name, vendor, head, false)) { | |
647 | spin_unlock_irq(&__efivars->lock); | |
648 | return -EEXIST; | |
649 | } | |
650 | ||
a614e192 | 651 | status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); |
e14ab23d MF |
652 | if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED) |
653 | status = ops->set_variable(name, &vendor, | |
654 | attributes, size, data); | |
655 | ||
656 | spin_unlock_irq(&__efivars->lock); | |
657 | ||
658 | return efi_status_to_err(status); | |
a9499fa7 | 659 | |
e14ab23d MF |
660 | } |
661 | EXPORT_SYMBOL_GPL(efivar_entry_set); | |
662 | ||
6d80dba1 MF |
663 | /* |
664 | * efivar_entry_set_nonblocking - call set_variable_nonblocking() | |
665 | * | |
666 | * This function is guaranteed to not block and is suitable for calling | |
667 | * from crash/panic handlers. | |
668 | * | |
669 | * Crucially, this function will not block if it cannot acquire | |
670 | * __efivars->lock. Instead, it returns -EBUSY. | |
671 | */ | |
672 | static int | |
673 | efivar_entry_set_nonblocking(efi_char16_t *name, efi_guid_t vendor, | |
674 | u32 attributes, unsigned long size, void *data) | |
675 | { | |
676 | const struct efivar_operations *ops = __efivars->ops; | |
677 | unsigned long flags; | |
678 | efi_status_t status; | |
679 | ||
680 | if (!spin_trylock_irqsave(&__efivars->lock, flags)) | |
681 | return -EBUSY; | |
682 | ||
683 | status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); | |
684 | if (status != EFI_SUCCESS) { | |
685 | spin_unlock_irqrestore(&__efivars->lock, flags); | |
686 | return -ENOSPC; | |
687 | } | |
688 | ||
689 | status = ops->set_variable_nonblocking(name, &vendor, attributes, | |
690 | size, data); | |
691 | ||
692 | spin_unlock_irqrestore(&__efivars->lock, flags); | |
693 | return efi_status_to_err(status); | |
694 | } | |
695 | ||
e14ab23d MF |
696 | /** |
697 | * efivar_entry_set_safe - call set_variable() if enough space in firmware | |
698 | * @name: buffer containing the variable name | |
699 | * @vendor: variable vendor guid | |
700 | * @attributes: variable attributes | |
701 | * @block: can we block in this context? | |
702 | * @size: size of @data buffer | |
703 | * @data: buffer containing variable data | |
704 | * | |
705 | * Ensures there is enough free storage in the firmware for this variable, and | |
706 | * if so, calls set_variable(). If creating a new EFI variable, this function | |
707 | * is usually followed by efivar_entry_add(). | |
708 | * | |
709 | * Returns 0 on success, -ENOSPC if the firmware does not have enough | |
710 | * space for set_variable() to succeed, or a converted EFI status code | |
711 | * if set_variable() fails. | |
712 | */ | |
713 | int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes, | |
714 | bool block, unsigned long size, void *data) | |
715 | { | |
716 | const struct efivar_operations *ops = __efivars->ops; | |
717 | unsigned long flags; | |
718 | efi_status_t status; | |
719 | ||
a614e192 | 720 | if (!ops->query_variable_store) |
e14ab23d MF |
721 | return -ENOSYS; |
722 | ||
6d80dba1 MF |
723 | /* |
724 | * If the EFI variable backend provides a non-blocking | |
725 | * ->set_variable() operation and we're in a context where we | |
726 | * cannot block, then we need to use it to avoid live-locks, | |
727 | * since the implication is that the regular ->set_variable() | |
728 | * will block. | |
729 | * | |
730 | * If no ->set_variable_nonblocking() is provided then | |
731 | * ->set_variable() is assumed to be non-blocking. | |
732 | */ | |
733 | if (!block && ops->set_variable_nonblocking) | |
734 | return efivar_entry_set_nonblocking(name, vendor, attributes, | |
735 | size, data); | |
736 | ||
85c90716 DC |
737 | if (!block) { |
738 | if (!spin_trylock_irqsave(&__efivars->lock, flags)) | |
739 | return -EBUSY; | |
740 | } else { | |
e14ab23d | 741 | spin_lock_irqsave(&__efivars->lock, flags); |
85c90716 | 742 | } |
e14ab23d | 743 | |
a614e192 | 744 | status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); |
e14ab23d MF |
745 | if (status != EFI_SUCCESS) { |
746 | spin_unlock_irqrestore(&__efivars->lock, flags); | |
747 | return -ENOSPC; | |
748 | } | |
749 | ||
750 | status = ops->set_variable(name, &vendor, attributes, size, data); | |
751 | ||
752 | spin_unlock_irqrestore(&__efivars->lock, flags); | |
753 | ||
754 | return efi_status_to_err(status); | |
755 | } | |
756 | EXPORT_SYMBOL_GPL(efivar_entry_set_safe); | |
757 | ||
758 | /** | |
759 | * efivar_entry_find - search for an entry | |
760 | * @name: the EFI variable name | |
761 | * @guid: the EFI variable vendor's guid | |
762 | * @head: head of the variable list | |
763 | * @remove: should we remove the entry from the list? | |
764 | * | |
765 | * Search for an entry on the variable list that has the EFI variable | |
766 | * name @name and vendor guid @guid. If an entry is found on the list | |
767 | * and @remove is true, the entry is removed from the list. | |
768 | * | |
769 | * The caller MUST call efivar_entry_iter_begin() and | |
770 | * efivar_entry_iter_end() before and after the invocation of this | |
771 | * function, respectively. | |
772 | * | |
773 | * Returns the entry if found on the list, %NULL otherwise. | |
774 | */ | |
775 | struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid, | |
776 | struct list_head *head, bool remove) | |
777 | { | |
778 | struct efivar_entry *entry, *n; | |
779 | int strsize1, strsize2; | |
780 | bool found = false; | |
781 | ||
aee530cf | 782 | lockdep_assert_held(&__efivars->lock); |
e14ab23d MF |
783 | |
784 | list_for_each_entry_safe(entry, n, head, list) { | |
a614e192 MF |
785 | strsize1 = ucs2_strsize(name, 1024); |
786 | strsize2 = ucs2_strsize(entry->var.VariableName, 1024); | |
e14ab23d MF |
787 | if (strsize1 == strsize2 && |
788 | !memcmp(name, &(entry->var.VariableName), strsize1) && | |
789 | !efi_guidcmp(guid, entry->var.VendorGuid)) { | |
790 | found = true; | |
791 | break; | |
792 | } | |
793 | } | |
794 | ||
795 | if (!found) | |
796 | return NULL; | |
797 | ||
e0d59733 SA |
798 | if (remove) { |
799 | if (entry->scanning) { | |
800 | /* | |
801 | * The entry will be deleted | |
802 | * after scanning is completed. | |
803 | */ | |
804 | entry->deleting = true; | |
805 | } else | |
806 | list_del(&entry->list); | |
807 | } | |
e14ab23d MF |
808 | |
809 | return entry; | |
810 | } | |
811 | EXPORT_SYMBOL_GPL(efivar_entry_find); | |
812 | ||
813 | /** | |
8a415b8c | 814 | * efivar_entry_size - obtain the size of a variable |
e14ab23d MF |
815 | * @entry: entry for this variable |
816 | * @size: location to store the variable's size | |
e14ab23d | 817 | */ |
8a415b8c | 818 | int efivar_entry_size(struct efivar_entry *entry, unsigned long *size) |
e14ab23d MF |
819 | { |
820 | const struct efivar_operations *ops = __efivars->ops; | |
821 | efi_status_t status; | |
822 | ||
e14ab23d | 823 | *size = 0; |
8a415b8c MF |
824 | |
825 | spin_lock_irq(&__efivars->lock); | |
e14ab23d MF |
826 | status = ops->get_variable(entry->var.VariableName, |
827 | &entry->var.VendorGuid, NULL, size, NULL); | |
8a415b8c MF |
828 | spin_unlock_irq(&__efivars->lock); |
829 | ||
e14ab23d MF |
830 | if (status != EFI_BUFFER_TOO_SMALL) |
831 | return efi_status_to_err(status); | |
832 | ||
833 | return 0; | |
834 | } | |
8a415b8c | 835 | EXPORT_SYMBOL_GPL(efivar_entry_size); |
e14ab23d MF |
836 | |
837 | /** | |
8a415b8c MF |
838 | * __efivar_entry_get - call get_variable() |
839 | * @entry: read data for this variable | |
840 | * @attributes: variable attributes | |
841 | * @size: size of @data buffer | |
842 | * @data: buffer to store variable data | |
843 | * | |
844 | * The caller MUST call efivar_entry_iter_begin() and | |
845 | * efivar_entry_iter_end() before and after the invocation of this | |
846 | * function, respectively. | |
e14ab23d | 847 | */ |
8a415b8c MF |
848 | int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes, |
849 | unsigned long *size, void *data) | |
e14ab23d MF |
850 | { |
851 | const struct efivar_operations *ops = __efivars->ops; | |
852 | efi_status_t status; | |
853 | ||
aee530cf | 854 | lockdep_assert_held(&__efivars->lock); |
e14ab23d | 855 | |
e14ab23d | 856 | status = ops->get_variable(entry->var.VariableName, |
8a415b8c MF |
857 | &entry->var.VendorGuid, |
858 | attributes, size, data); | |
e14ab23d | 859 | |
8a415b8c | 860 | return efi_status_to_err(status); |
e14ab23d | 861 | } |
8a415b8c | 862 | EXPORT_SYMBOL_GPL(__efivar_entry_get); |
e14ab23d MF |
863 | |
864 | /** | |
865 | * efivar_entry_get - call get_variable() | |
866 | * @entry: read data for this variable | |
867 | * @attributes: variable attributes | |
868 | * @size: size of @data buffer | |
869 | * @data: buffer to store variable data | |
870 | */ | |
871 | int efivar_entry_get(struct efivar_entry *entry, u32 *attributes, | |
872 | unsigned long *size, void *data) | |
873 | { | |
874 | const struct efivar_operations *ops = __efivars->ops; | |
875 | efi_status_t status; | |
876 | ||
877 | spin_lock_irq(&__efivars->lock); | |
878 | status = ops->get_variable(entry->var.VariableName, | |
879 | &entry->var.VendorGuid, | |
880 | attributes, size, data); | |
881 | spin_unlock_irq(&__efivars->lock); | |
882 | ||
883 | return efi_status_to_err(status); | |
884 | } | |
885 | EXPORT_SYMBOL_GPL(efivar_entry_get); | |
886 | ||
887 | /** | |
888 | * efivar_entry_set_get_size - call set_variable() and get new size (atomic) | |
889 | * @entry: entry containing variable to set and get | |
890 | * @attributes: attributes of variable to be written | |
891 | * @size: size of data buffer | |
892 | * @data: buffer containing data to write | |
893 | * @set: did the set_variable() call succeed? | |
894 | * | |
895 | * This is a pretty special (complex) function. See efivarfs_file_write(). | |
896 | * | |
897 | * Atomically call set_variable() for @entry and if the call is | |
898 | * successful, return the new size of the variable from get_variable() | |
899 | * in @size. The success of set_variable() is indicated by @set. | |
900 | * | |
901 | * Returns 0 on success, -EINVAL if the variable data is invalid, | |
902 | * -ENOSPC if the firmware does not have enough available space, or a | |
903 | * converted EFI status code if either of set_variable() or | |
904 | * get_variable() fail. | |
905 | * | |
906 | * If the EFI variable does not exist when calling set_variable() | |
907 | * (EFI_NOT_FOUND), @entry is removed from the variable list. | |
908 | */ | |
909 | int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes, | |
910 | unsigned long *size, void *data, bool *set) | |
911 | { | |
912 | const struct efivar_operations *ops = __efivars->ops; | |
913 | efi_char16_t *name = entry->var.VariableName; | |
914 | efi_guid_t *vendor = &entry->var.VendorGuid; | |
915 | efi_status_t status; | |
916 | int err; | |
917 | ||
918 | *set = false; | |
919 | ||
8282f5d9 | 920 | if (efivar_validate(*vendor, name, data, *size) == false) |
e14ab23d MF |
921 | return -EINVAL; |
922 | ||
923 | /* | |
924 | * The lock here protects the get_variable call, the conditional | |
925 | * set_variable call, and removal of the variable from the efivars | |
926 | * list (in the case of an authenticated delete). | |
927 | */ | |
928 | spin_lock_irq(&__efivars->lock); | |
929 | ||
930 | /* | |
931 | * Ensure that the available space hasn't shrunk below the safe level | |
932 | */ | |
a614e192 | 933 | status = check_var_size(attributes, *size + ucs2_strsize(name, 1024)); |
e14ab23d MF |
934 | if (status != EFI_SUCCESS) { |
935 | if (status != EFI_UNSUPPORTED) { | |
936 | err = efi_status_to_err(status); | |
937 | goto out; | |
938 | } | |
939 | ||
940 | if (*size > 65536) { | |
941 | err = -ENOSPC; | |
942 | goto out; | |
943 | } | |
944 | } | |
945 | ||
946 | status = ops->set_variable(name, vendor, attributes, *size, data); | |
947 | if (status != EFI_SUCCESS) { | |
948 | err = efi_status_to_err(status); | |
949 | goto out; | |
950 | } | |
951 | ||
952 | *set = true; | |
953 | ||
954 | /* | |
955 | * Writing to the variable may have caused a change in size (which | |
956 | * could either be an append or an overwrite), or the variable to be | |
957 | * deleted. Perform a GetVariable() so we can tell what actually | |
958 | * happened. | |
959 | */ | |
960 | *size = 0; | |
961 | status = ops->get_variable(entry->var.VariableName, | |
962 | &entry->var.VendorGuid, | |
963 | NULL, size, NULL); | |
964 | ||
965 | if (status == EFI_NOT_FOUND) | |
966 | efivar_entry_list_del_unlock(entry); | |
967 | else | |
968 | spin_unlock_irq(&__efivars->lock); | |
969 | ||
970 | if (status && status != EFI_BUFFER_TOO_SMALL) | |
971 | return efi_status_to_err(status); | |
972 | ||
973 | return 0; | |
974 | ||
975 | out: | |
976 | spin_unlock_irq(&__efivars->lock); | |
977 | return err; | |
978 | ||
979 | } | |
980 | EXPORT_SYMBOL_GPL(efivar_entry_set_get_size); | |
981 | ||
982 | /** | |
983 | * efivar_entry_iter_begin - begin iterating the variable list | |
984 | * | |
985 | * Lock the variable list to prevent entry insertion and removal until | |
986 | * efivar_entry_iter_end() is called. This function is usually used in | |
987 | * conjunction with __efivar_entry_iter() or efivar_entry_iter(). | |
988 | */ | |
989 | void efivar_entry_iter_begin(void) | |
990 | { | |
991 | spin_lock_irq(&__efivars->lock); | |
992 | } | |
993 | EXPORT_SYMBOL_GPL(efivar_entry_iter_begin); | |
994 | ||
995 | /** | |
996 | * efivar_entry_iter_end - finish iterating the variable list | |
997 | * | |
998 | * Unlock the variable list and allow modifications to the list again. | |
999 | */ | |
1000 | void efivar_entry_iter_end(void) | |
1001 | { | |
1002 | spin_unlock_irq(&__efivars->lock); | |
1003 | } | |
1004 | EXPORT_SYMBOL_GPL(efivar_entry_iter_end); | |
1005 | ||
1006 | /** | |
1007 | * __efivar_entry_iter - iterate over variable list | |
1008 | * @func: callback function | |
1009 | * @head: head of the variable list | |
1010 | * @data: function-specific data to pass to callback | |
1011 | * @prev: entry to begin iterating from | |
1012 | * | |
1013 | * Iterate over the list of EFI variables and call @func with every | |
1014 | * entry on the list. It is safe for @func to remove entries in the | |
1015 | * list via efivar_entry_delete(). | |
1016 | * | |
1017 | * You MUST call efivar_enter_iter_begin() before this function, and | |
1018 | * efivar_entry_iter_end() afterwards. | |
1019 | * | |
1020 | * It is possible to begin iteration from an arbitrary entry within | |
1021 | * the list by passing @prev. @prev is updated on return to point to | |
1022 | * the last entry passed to @func. To begin iterating from the | |
1023 | * beginning of the list @prev must be %NULL. | |
1024 | * | |
1025 | * The restrictions for @func are the same as documented for | |
1026 | * efivar_entry_iter(). | |
1027 | */ | |
1028 | int __efivar_entry_iter(int (*func)(struct efivar_entry *, void *), | |
1029 | struct list_head *head, void *data, | |
1030 | struct efivar_entry **prev) | |
1031 | { | |
1032 | struct efivar_entry *entry, *n; | |
1033 | int err = 0; | |
1034 | ||
1035 | if (!prev || !*prev) { | |
1036 | list_for_each_entry_safe(entry, n, head, list) { | |
1037 | err = func(entry, data); | |
1038 | if (err) | |
1039 | break; | |
1040 | } | |
1041 | ||
1042 | if (prev) | |
1043 | *prev = entry; | |
1044 | ||
1045 | return err; | |
1046 | } | |
1047 | ||
1048 | ||
1049 | list_for_each_entry_safe_continue((*prev), n, head, list) { | |
1050 | err = func(*prev, data); | |
1051 | if (err) | |
1052 | break; | |
1053 | } | |
1054 | ||
1055 | return err; | |
1056 | } | |
1057 | EXPORT_SYMBOL_GPL(__efivar_entry_iter); | |
1058 | ||
1059 | /** | |
1060 | * efivar_entry_iter - iterate over variable list | |
1061 | * @func: callback function | |
1062 | * @head: head of variable list | |
1063 | * @data: function-specific data to pass to callback | |
1064 | * | |
1065 | * Iterate over the list of EFI variables and call @func with every | |
1066 | * entry on the list. It is safe for @func to remove entries in the | |
1067 | * list via efivar_entry_delete() while iterating. | |
1068 | * | |
1069 | * Some notes for the callback function: | |
1070 | * - a non-zero return value indicates an error and terminates the loop | |
1071 | * - @func is called from atomic context | |
1072 | */ | |
1073 | int efivar_entry_iter(int (*func)(struct efivar_entry *, void *), | |
1074 | struct list_head *head, void *data) | |
1075 | { | |
1076 | int err = 0; | |
1077 | ||
1078 | efivar_entry_iter_begin(); | |
1079 | err = __efivar_entry_iter(func, head, data, NULL); | |
1080 | efivar_entry_iter_end(); | |
1081 | ||
1082 | return err; | |
1083 | } | |
1084 | EXPORT_SYMBOL_GPL(efivar_entry_iter); | |
1085 | ||
1086 | /** | |
1087 | * efivars_kobject - get the kobject for the registered efivars | |
1088 | * | |
1089 | * If efivars_register() has not been called we return NULL, | |
1090 | * otherwise return the kobject used at registration time. | |
1091 | */ | |
1092 | struct kobject *efivars_kobject(void) | |
1093 | { | |
1094 | if (!__efivars) | |
1095 | return NULL; | |
1096 | ||
1097 | return __efivars->kobject; | |
1098 | } | |
1099 | EXPORT_SYMBOL_GPL(efivars_kobject); | |
1100 | ||
04851772 MF |
1101 | /** |
1102 | * efivar_run_worker - schedule the efivar worker thread | |
1103 | */ | |
1104 | void efivar_run_worker(void) | |
1105 | { | |
1106 | if (efivar_wq_enabled) | |
1107 | schedule_work(&efivar_work); | |
1108 | } | |
1109 | EXPORT_SYMBOL_GPL(efivar_run_worker); | |
1110 | ||
e14ab23d MF |
1111 | /** |
1112 | * efivars_register - register an efivars | |
1113 | * @efivars: efivars to register | |
1114 | * @ops: efivars operations | |
1115 | * @kobject: @efivars-specific kobject | |
1116 | * | |
1117 | * Only a single efivars can be registered at any time. | |
1118 | */ | |
1119 | int efivars_register(struct efivars *efivars, | |
1120 | const struct efivar_operations *ops, | |
1121 | struct kobject *kobject) | |
1122 | { | |
1123 | spin_lock_init(&efivars->lock); | |
1124 | efivars->ops = ops; | |
1125 | efivars->kobject = kobject; | |
1126 | ||
1127 | __efivars = efivars; | |
1da177e4 | 1128 | |
e14ab23d MF |
1129 | return 0; |
1130 | } | |
1131 | EXPORT_SYMBOL_GPL(efivars_register); | |
1da177e4 | 1132 | |
e14ab23d MF |
1133 | /** |
1134 | * efivars_unregister - unregister an efivars | |
1135 | * @efivars: efivars to unregister | |
1136 | * | |
1137 | * The caller must have already removed every entry from the list, | |
1138 | * failure to do so is an error. | |
1139 | */ | |
1140 | int efivars_unregister(struct efivars *efivars) | |
1141 | { | |
1142 | int rv; | |
1143 | ||
1144 | if (!__efivars) { | |
1145 | printk(KERN_ERR "efivars not registered\n"); | |
1146 | rv = -EINVAL; | |
1147 | goto out; | |
1148 | } | |
1149 | ||
1150 | if (__efivars != efivars) { | |
1151 | rv = -EINVAL; | |
1152 | goto out; | |
1153 | } | |
1154 | ||
1155 | __efivars = NULL; | |
1156 | ||
1157 | rv = 0; | |
1158 | out: | |
1159 | return rv; | |
76b53f7c | 1160 | } |
e14ab23d | 1161 | EXPORT_SYMBOL_GPL(efivars_unregister); |