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 }, | |
e246eb56 | 201 | { LINUX_EFI_CRASH_GUID, "*", NULL }, |
8282f5d9 | 202 | { NULL_GUID, "", NULL }, |
fec6c20b MG |
203 | }; |
204 | ||
630ba0cc LE |
205 | /* |
206 | * Check if @var_name matches the pattern given in @match_name. | |
207 | * | |
208 | * @var_name: an array of @len non-NUL characters. | |
209 | * @match_name: a NUL-terminated pattern string, optionally ending in "*". A | |
210 | * final "*" character matches any trailing characters @var_name, | |
211 | * including the case when there are none left in @var_name. | |
212 | * @match: on output, the number of non-wildcard characters in @match_name | |
213 | * that @var_name matches, regardless of the return value. | |
214 | * @return: whether @var_name fully matches @match_name. | |
215 | */ | |
ed8b0de5 PJ |
216 | static bool |
217 | variable_matches(const char *var_name, size_t len, const char *match_name, | |
218 | int *match) | |
219 | { | |
220 | for (*match = 0; ; (*match)++) { | |
221 | char c = match_name[*match]; | |
ed8b0de5 | 222 | |
630ba0cc LE |
223 | switch (c) { |
224 | case '*': | |
225 | /* Wildcard in @match_name means we've matched. */ | |
ed8b0de5 PJ |
226 | return true; |
227 | ||
630ba0cc LE |
228 | case '\0': |
229 | /* @match_name has ended. Has @var_name too? */ | |
230 | return (*match == len); | |
231 | ||
232 | default: | |
233 | /* | |
234 | * We've reached a non-wildcard char in @match_name. | |
235 | * Continue only if there's an identical character in | |
236 | * @var_name. | |
237 | */ | |
238 | if (*match < len && c == var_name[*match]) | |
239 | continue; | |
ed8b0de5 | 240 | return false; |
630ba0cc | 241 | } |
ed8b0de5 | 242 | } |
ed8b0de5 PJ |
243 | } |
244 | ||
e14ab23d | 245 | bool |
8282f5d9 PJ |
246 | efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data, |
247 | unsigned long data_size) | |
fec6c20b MG |
248 | { |
249 | int i; | |
3dcb1f55 PJ |
250 | unsigned long utf8_size; |
251 | u8 *utf8_name; | |
fec6c20b | 252 | |
3dcb1f55 PJ |
253 | utf8_size = ucs2_utf8size(var_name); |
254 | utf8_name = kmalloc(utf8_size + 1, GFP_KERNEL); | |
255 | if (!utf8_name) | |
256 | return false; | |
fec6c20b | 257 | |
3dcb1f55 PJ |
258 | ucs2_as_utf8(utf8_name, var_name, utf8_size); |
259 | utf8_name[utf8_size] = '\0'; | |
fec6c20b | 260 | |
8282f5d9 | 261 | for (i = 0; variable_validate[i].name[0] != '\0'; i++) { |
fec6c20b | 262 | const char *name = variable_validate[i].name; |
8282f5d9 | 263 | int match = 0; |
fec6c20b | 264 | |
8282f5d9 PJ |
265 | if (efi_guidcmp(vendor, variable_validate[i].vendor)) |
266 | continue; | |
fec6c20b | 267 | |
ed8b0de5 PJ |
268 | if (variable_matches(utf8_name, utf8_size+1, name, &match)) { |
269 | if (variable_validate[i].validate == NULL) | |
fec6c20b | 270 | break; |
ed8b0de5 PJ |
271 | kfree(utf8_name); |
272 | return variable_validate[i].validate(var_name, match, | |
273 | data, data_size); | |
fec6c20b MG |
274 | } |
275 | } | |
3dcb1f55 | 276 | kfree(utf8_name); |
fec6c20b MG |
277 | return true; |
278 | } | |
e14ab23d | 279 | EXPORT_SYMBOL_GPL(efivar_validate); |
fec6c20b | 280 | |
ed8b0de5 PJ |
281 | bool |
282 | efivar_variable_is_removable(efi_guid_t vendor, const char *var_name, | |
283 | size_t len) | |
284 | { | |
285 | int i; | |
286 | bool found = false; | |
287 | int match = 0; | |
288 | ||
289 | /* | |
290 | * Check if our variable is in the validated variables list | |
291 | */ | |
292 | for (i = 0; variable_validate[i].name[0] != '\0'; i++) { | |
293 | if (efi_guidcmp(variable_validate[i].vendor, vendor)) | |
294 | continue; | |
295 | ||
296 | if (variable_matches(var_name, len, | |
297 | variable_validate[i].name, &match)) { | |
298 | found = true; | |
299 | break; | |
300 | } | |
301 | } | |
302 | ||
303 | /* | |
304 | * If it's in our list, it is removable. | |
305 | */ | |
306 | return found; | |
307 | } | |
308 | EXPORT_SYMBOL_GPL(efivar_variable_is_removable); | |
309 | ||
1da177e4 | 310 | static efi_status_t |
e14ab23d | 311 | check_var_size(u32 attributes, unsigned long size) |
68d92986 | 312 | { |
e14ab23d | 313 | const struct efivar_operations *fops = __efivars->ops; |
68d92986 | 314 | |
a614e192 | 315 | if (!fops->query_variable_store) |
68d92986 MG |
316 | return EFI_UNSUPPORTED; |
317 | ||
ca0e30dc AB |
318 | return fops->query_variable_store(attributes, size, false); |
319 | } | |
320 | ||
321 | static efi_status_t | |
322 | check_var_size_nonblocking(u32 attributes, unsigned long size) | |
323 | { | |
324 | const struct efivar_operations *fops = __efivars->ops; | |
325 | ||
326 | if (!fops->query_variable_store) | |
327 | return EFI_UNSUPPORTED; | |
328 | ||
329 | return fops->query_variable_store(attributes, size, true); | |
68d92986 MG |
330 | } |
331 | ||
e14ab23d MF |
332 | static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor, |
333 | struct list_head *head) | |
a93bc0c6 SA |
334 | { |
335 | struct efivar_entry *entry, *n; | |
a93bc0c6 SA |
336 | unsigned long strsize1, strsize2; |
337 | bool found = false; | |
338 | ||
a614e192 | 339 | strsize1 = ucs2_strsize(variable_name, 1024); |
e14ab23d | 340 | list_for_each_entry_safe(entry, n, head, list) { |
a614e192 | 341 | strsize2 = ucs2_strsize(entry->var.VariableName, 1024); |
a93bc0c6 SA |
342 | if (strsize1 == strsize2 && |
343 | !memcmp(variable_name, &(entry->var.VariableName), | |
344 | strsize2) && | |
345 | !efi_guidcmp(entry->var.VendorGuid, | |
346 | *vendor)) { | |
347 | found = true; | |
348 | break; | |
349 | } | |
350 | } | |
351 | return found; | |
352 | } | |
353 | ||
ec50bd32 MF |
354 | /* |
355 | * Returns the size of variable_name, in bytes, including the | |
356 | * terminating NULL character, or variable_name_size if no NULL | |
357 | * character is found among the first variable_name_size bytes. | |
358 | */ | |
359 | static unsigned long var_name_strnsize(efi_char16_t *variable_name, | |
360 | unsigned long variable_name_size) | |
361 | { | |
362 | unsigned long len; | |
363 | efi_char16_t c; | |
364 | ||
365 | /* | |
366 | * The variable name is, by definition, a NULL-terminated | |
367 | * string, so make absolutely sure that variable_name_size is | |
368 | * the value we expect it to be. If not, return the real size. | |
369 | */ | |
370 | for (len = 2; len <= variable_name_size; len += sizeof(c)) { | |
371 | c = variable_name[(len / sizeof(c)) - 1]; | |
372 | if (!c) | |
373 | break; | |
374 | } | |
375 | ||
376 | return min(len, variable_name_size); | |
377 | } | |
378 | ||
e971318b MF |
379 | /* |
380 | * Print a warning when duplicate EFI variables are encountered and | |
381 | * disable the sysfs workqueue since the firmware is buggy. | |
382 | */ | |
b2fce819 | 383 | static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid, |
e971318b MF |
384 | unsigned long len16) |
385 | { | |
386 | size_t i, len8 = len16 / sizeof(efi_char16_t); | |
b2fce819 | 387 | char *str8; |
e971318b MF |
388 | |
389 | /* | |
390 | * Disable the workqueue since the algorithm it uses for | |
391 | * detecting new variables won't work with this buggy | |
392 | * implementation of GetNextVariableName(). | |
393 | */ | |
394 | efivar_wq_enabled = false; | |
395 | ||
b2fce819 MR |
396 | str8 = kzalloc(len8, GFP_KERNEL); |
397 | if (!str8) | |
e971318b MF |
398 | return; |
399 | ||
400 | for (i = 0; i < len8; i++) | |
b2fce819 | 401 | str8[i] = str16[i]; |
e971318b MF |
402 | |
403 | printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n", | |
b2fce819 MR |
404 | str8, vendor_guid); |
405 | kfree(str8); | |
e971318b MF |
406 | } |
407 | ||
e14ab23d MF |
408 | /** |
409 | * efivar_init - build the initial list of EFI variables | |
410 | * @func: callback function to invoke for every variable | |
411 | * @data: function-specific data to pass to @func | |
412 | * @atomic: do we need to execute the @func-loop atomically? | |
413 | * @duplicates: error if we encounter duplicates on @head? | |
414 | * @head: initialised head of variable list | |
415 | * | |
416 | * Get every EFI variable from the firmware and invoke @func. @func | |
417 | * should call efivar_entry_add() to build the list of variables. | |
418 | * | |
419 | * Returns 0 on success, or a kernel error code on failure. | |
420 | */ | |
421 | int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *), | |
1cfd6316 | 422 | void *data, bool duplicates, struct list_head *head) |
e14ab23d MF |
423 | { |
424 | const struct efivar_operations *ops = __efivars->ops; | |
425 | unsigned long variable_name_size = 1024; | |
426 | efi_char16_t *variable_name; | |
427 | efi_status_t status; | |
428 | efi_guid_t vendor_guid; | |
429 | int err = 0; | |
430 | ||
431 | variable_name = kzalloc(variable_name_size, GFP_KERNEL); | |
432 | if (!variable_name) { | |
433 | printk(KERN_ERR "efivars: Memory allocation failed.\n"); | |
434 | return -ENOMEM; | |
605e70c7 LCY |
435 | } |
436 | ||
e14ab23d MF |
437 | spin_lock_irq(&__efivars->lock); |
438 | ||
1da177e4 LT |
439 | /* |
440 | * Per EFI spec, the maximum storage allocated for both | |
441 | * the variable name and variable data is 1024 bytes. | |
442 | */ | |
443 | ||
444 | do { | |
445 | variable_name_size = 1024; | |
446 | ||
3295814d | 447 | status = ops->get_next_variable(&variable_name_size, |
1da177e4 LT |
448 | variable_name, |
449 | &vendor_guid); | |
450 | switch (status) { | |
451 | case EFI_SUCCESS: | |
1cfd6316 | 452 | if (duplicates) |
e14ab23d MF |
453 | spin_unlock_irq(&__efivars->lock); |
454 | ||
ec50bd32 MF |
455 | variable_name_size = var_name_strnsize(variable_name, |
456 | variable_name_size); | |
e971318b MF |
457 | |
458 | /* | |
459 | * Some firmware implementations return the | |
460 | * same variable name on multiple calls to | |
461 | * get_next_variable(). Terminate the loop | |
462 | * immediately as there is no guarantee that | |
463 | * we'll ever see a different variable name, | |
464 | * and may end up looping here forever. | |
465 | */ | |
e14ab23d | 466 | if (duplicates && |
1cfd6316 JL |
467 | variable_is_present(variable_name, &vendor_guid, |
468 | head)) { | |
e971318b MF |
469 | dup_variable_bug(variable_name, &vendor_guid, |
470 | variable_name_size); | |
471 | status = EFI_NOT_FOUND; | |
1cfd6316 JL |
472 | } else { |
473 | err = func(variable_name, vendor_guid, | |
474 | variable_name_size, data); | |
475 | if (err) | |
476 | status = EFI_NOT_FOUND; | |
e971318b MF |
477 | } |
478 | ||
1cfd6316 | 479 | if (duplicates) |
e14ab23d MF |
480 | spin_lock_irq(&__efivars->lock); |
481 | ||
1da177e4 LT |
482 | break; |
483 | case EFI_NOT_FOUND: | |
484 | break; | |
485 | default: | |
486 | printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n", | |
487 | status); | |
488 | status = EFI_NOT_FOUND; | |
489 | break; | |
490 | } | |
e14ab23d | 491 | |
1da177e4 LT |
492 | } while (status != EFI_NOT_FOUND); |
493 | ||
e14ab23d MF |
494 | spin_unlock_irq(&__efivars->lock); |
495 | ||
496 | kfree(variable_name); | |
497 | ||
498 | return err; | |
499 | } | |
500 | EXPORT_SYMBOL_GPL(efivar_init); | |
501 | ||
502 | /** | |
503 | * efivar_entry_add - add entry to variable list | |
504 | * @entry: entry to add to list | |
505 | * @head: list head | |
506 | */ | |
507 | void efivar_entry_add(struct efivar_entry *entry, struct list_head *head) | |
508 | { | |
509 | spin_lock_irq(&__efivars->lock); | |
510 | list_add(&entry->list, head); | |
511 | spin_unlock_irq(&__efivars->lock); | |
512 | } | |
513 | EXPORT_SYMBOL_GPL(efivar_entry_add); | |
514 | ||
515 | /** | |
516 | * efivar_entry_remove - remove entry from variable list | |
517 | * @entry: entry to remove from list | |
518 | */ | |
519 | void efivar_entry_remove(struct efivar_entry *entry) | |
520 | { | |
521 | spin_lock_irq(&__efivars->lock); | |
522 | list_del(&entry->list); | |
523 | spin_unlock_irq(&__efivars->lock); | |
524 | } | |
525 | EXPORT_SYMBOL_GPL(efivar_entry_remove); | |
526 | ||
527 | /* | |
528 | * efivar_entry_list_del_unlock - remove entry from variable list | |
529 | * @entry: entry to remove | |
530 | * | |
531 | * Remove @entry from the variable list and release the list lock. | |
532 | * | |
533 | * NOTE: slightly weird locking semantics here - we expect to be | |
534 | * called with the efivars lock already held, and we release it before | |
535 | * returning. This is because this function is usually called after | |
536 | * set_variable() while the lock is still held. | |
537 | */ | |
538 | static void efivar_entry_list_del_unlock(struct efivar_entry *entry) | |
539 | { | |
aee530cf | 540 | lockdep_assert_held(&__efivars->lock); |
e14ab23d MF |
541 | |
542 | list_del(&entry->list); | |
543 | spin_unlock_irq(&__efivars->lock); | |
544 | } | |
545 | ||
546 | /** | |
547 | * __efivar_entry_delete - delete an EFI variable | |
548 | * @entry: entry containing EFI variable to delete | |
549 | * | |
a9499fa7 TG |
550 | * Delete the variable from the firmware but leave @entry on the |
551 | * variable list. | |
e14ab23d | 552 | * |
a9499fa7 TG |
553 | * This function differs from efivar_entry_delete() because it does |
554 | * not remove @entry from the variable list. Also, it is safe to be | |
555 | * called from within a efivar_entry_iter_begin() and | |
e14ab23d MF |
556 | * efivar_entry_iter_end() region, unlike efivar_entry_delete(). |
557 | * | |
558 | * Returns 0 on success, or a converted EFI status code if | |
a9499fa7 | 559 | * set_variable() fails. |
e14ab23d MF |
560 | */ |
561 | int __efivar_entry_delete(struct efivar_entry *entry) | |
562 | { | |
563 | const struct efivar_operations *ops = __efivars->ops; | |
564 | efi_status_t status; | |
565 | ||
aee530cf | 566 | lockdep_assert_held(&__efivars->lock); |
e14ab23d MF |
567 | |
568 | status = ops->set_variable(entry->var.VariableName, | |
569 | &entry->var.VendorGuid, | |
570 | 0, 0, NULL); | |
e14ab23d | 571 | |
a9499fa7 | 572 | return efi_status_to_err(status); |
e14ab23d MF |
573 | } |
574 | EXPORT_SYMBOL_GPL(__efivar_entry_delete); | |
575 | ||
576 | /** | |
577 | * efivar_entry_delete - delete variable and remove entry from list | |
578 | * @entry: entry containing variable to delete | |
579 | * | |
580 | * Delete the variable from the firmware and remove @entry from the | |
581 | * variable list. It is the caller's responsibility to free @entry | |
582 | * once we return. | |
583 | * | |
584 | * Returns 0 on success, or a converted EFI status code if | |
585 | * set_variable() fails. | |
586 | */ | |
587 | int efivar_entry_delete(struct efivar_entry *entry) | |
588 | { | |
589 | const struct efivar_operations *ops = __efivars->ops; | |
590 | efi_status_t status; | |
591 | ||
592 | spin_lock_irq(&__efivars->lock); | |
593 | status = ops->set_variable(entry->var.VariableName, | |
594 | &entry->var.VendorGuid, | |
595 | 0, 0, NULL); | |
596 | if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) { | |
597 | spin_unlock_irq(&__efivars->lock); | |
598 | return efi_status_to_err(status); | |
599 | } | |
600 | ||
601 | efivar_entry_list_del_unlock(entry); | |
602 | return 0; | |
603 | } | |
604 | EXPORT_SYMBOL_GPL(efivar_entry_delete); | |
605 | ||
606 | /** | |
607 | * efivar_entry_set - call set_variable() | |
608 | * @entry: entry containing the EFI variable to write | |
609 | * @attributes: variable attributes | |
610 | * @size: size of @data buffer | |
611 | * @data: buffer containing variable data | |
612 | * @head: head of variable list | |
613 | * | |
614 | * Calls set_variable() for an EFI variable. If creating a new EFI | |
615 | * variable, this function is usually followed by efivar_entry_add(). | |
616 | * | |
617 | * Before writing the variable, the remaining EFI variable storage | |
618 | * space is checked to ensure there is enough room available. | |
619 | * | |
620 | * If @head is not NULL a lookup is performed to determine whether | |
621 | * the entry is already on the list. | |
622 | * | |
623 | * Returns 0 on success, -EEXIST if a lookup is performed and the entry | |
624 | * already exists on the list, or a converted EFI status code if | |
625 | * set_variable() fails. | |
626 | */ | |
627 | int efivar_entry_set(struct efivar_entry *entry, u32 attributes, | |
628 | unsigned long size, void *data, struct list_head *head) | |
629 | { | |
630 | const struct efivar_operations *ops = __efivars->ops; | |
631 | efi_status_t status; | |
632 | efi_char16_t *name = entry->var.VariableName; | |
633 | efi_guid_t vendor = entry->var.VendorGuid; | |
634 | ||
635 | spin_lock_irq(&__efivars->lock); | |
636 | ||
637 | if (head && efivar_entry_find(name, vendor, head, false)) { | |
638 | spin_unlock_irq(&__efivars->lock); | |
639 | return -EEXIST; | |
640 | } | |
641 | ||
a614e192 | 642 | status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); |
e14ab23d MF |
643 | if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED) |
644 | status = ops->set_variable(name, &vendor, | |
645 | attributes, size, data); | |
646 | ||
647 | spin_unlock_irq(&__efivars->lock); | |
648 | ||
649 | return efi_status_to_err(status); | |
a9499fa7 | 650 | |
e14ab23d MF |
651 | } |
652 | EXPORT_SYMBOL_GPL(efivar_entry_set); | |
653 | ||
6d80dba1 MF |
654 | /* |
655 | * efivar_entry_set_nonblocking - call set_variable_nonblocking() | |
656 | * | |
657 | * This function is guaranteed to not block and is suitable for calling | |
658 | * from crash/panic handlers. | |
659 | * | |
660 | * Crucially, this function will not block if it cannot acquire | |
661 | * __efivars->lock. Instead, it returns -EBUSY. | |
662 | */ | |
663 | static int | |
664 | efivar_entry_set_nonblocking(efi_char16_t *name, efi_guid_t vendor, | |
665 | u32 attributes, unsigned long size, void *data) | |
666 | { | |
667 | const struct efivar_operations *ops = __efivars->ops; | |
668 | unsigned long flags; | |
669 | efi_status_t status; | |
670 | ||
671 | if (!spin_trylock_irqsave(&__efivars->lock, flags)) | |
672 | return -EBUSY; | |
673 | ||
ca0e30dc AB |
674 | status = check_var_size_nonblocking(attributes, |
675 | size + ucs2_strsize(name, 1024)); | |
6d80dba1 MF |
676 | if (status != EFI_SUCCESS) { |
677 | spin_unlock_irqrestore(&__efivars->lock, flags); | |
678 | return -ENOSPC; | |
679 | } | |
680 | ||
681 | status = ops->set_variable_nonblocking(name, &vendor, attributes, | |
682 | size, data); | |
683 | ||
684 | spin_unlock_irqrestore(&__efivars->lock, flags); | |
685 | return efi_status_to_err(status); | |
686 | } | |
687 | ||
e14ab23d MF |
688 | /** |
689 | * efivar_entry_set_safe - call set_variable() if enough space in firmware | |
690 | * @name: buffer containing the variable name | |
691 | * @vendor: variable vendor guid | |
692 | * @attributes: variable attributes | |
693 | * @block: can we block in this context? | |
694 | * @size: size of @data buffer | |
695 | * @data: buffer containing variable data | |
696 | * | |
697 | * Ensures there is enough free storage in the firmware for this variable, and | |
698 | * if so, calls set_variable(). If creating a new EFI variable, this function | |
699 | * is usually followed by efivar_entry_add(). | |
700 | * | |
701 | * Returns 0 on success, -ENOSPC if the firmware does not have enough | |
702 | * space for set_variable() to succeed, or a converted EFI status code | |
703 | * if set_variable() fails. | |
704 | */ | |
705 | int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes, | |
706 | bool block, unsigned long size, void *data) | |
707 | { | |
708 | const struct efivar_operations *ops = __efivars->ops; | |
709 | unsigned long flags; | |
710 | efi_status_t status; | |
711 | ||
a614e192 | 712 | if (!ops->query_variable_store) |
e14ab23d MF |
713 | return -ENOSYS; |
714 | ||
6d80dba1 MF |
715 | /* |
716 | * If the EFI variable backend provides a non-blocking | |
717 | * ->set_variable() operation and we're in a context where we | |
718 | * cannot block, then we need to use it to avoid live-locks, | |
719 | * since the implication is that the regular ->set_variable() | |
720 | * will block. | |
721 | * | |
722 | * If no ->set_variable_nonblocking() is provided then | |
723 | * ->set_variable() is assumed to be non-blocking. | |
724 | */ | |
725 | if (!block && ops->set_variable_nonblocking) | |
726 | return efivar_entry_set_nonblocking(name, vendor, attributes, | |
727 | size, data); | |
728 | ||
85c90716 DC |
729 | if (!block) { |
730 | if (!spin_trylock_irqsave(&__efivars->lock, flags)) | |
731 | return -EBUSY; | |
732 | } else { | |
e14ab23d | 733 | spin_lock_irqsave(&__efivars->lock, flags); |
85c90716 | 734 | } |
e14ab23d | 735 | |
a614e192 | 736 | status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); |
e14ab23d MF |
737 | if (status != EFI_SUCCESS) { |
738 | spin_unlock_irqrestore(&__efivars->lock, flags); | |
739 | return -ENOSPC; | |
740 | } | |
741 | ||
742 | status = ops->set_variable(name, &vendor, attributes, size, data); | |
743 | ||
744 | spin_unlock_irqrestore(&__efivars->lock, flags); | |
745 | ||
746 | return efi_status_to_err(status); | |
747 | } | |
748 | EXPORT_SYMBOL_GPL(efivar_entry_set_safe); | |
749 | ||
750 | /** | |
751 | * efivar_entry_find - search for an entry | |
752 | * @name: the EFI variable name | |
753 | * @guid: the EFI variable vendor's guid | |
754 | * @head: head of the variable list | |
755 | * @remove: should we remove the entry from the list? | |
756 | * | |
757 | * Search for an entry on the variable list that has the EFI variable | |
758 | * name @name and vendor guid @guid. If an entry is found on the list | |
759 | * and @remove is true, the entry is removed from the list. | |
760 | * | |
761 | * The caller MUST call efivar_entry_iter_begin() and | |
762 | * efivar_entry_iter_end() before and after the invocation of this | |
763 | * function, respectively. | |
764 | * | |
765 | * Returns the entry if found on the list, %NULL otherwise. | |
766 | */ | |
767 | struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid, | |
768 | struct list_head *head, bool remove) | |
769 | { | |
770 | struct efivar_entry *entry, *n; | |
771 | int strsize1, strsize2; | |
772 | bool found = false; | |
773 | ||
aee530cf | 774 | lockdep_assert_held(&__efivars->lock); |
e14ab23d MF |
775 | |
776 | list_for_each_entry_safe(entry, n, head, list) { | |
a614e192 MF |
777 | strsize1 = ucs2_strsize(name, 1024); |
778 | strsize2 = ucs2_strsize(entry->var.VariableName, 1024); | |
e14ab23d MF |
779 | if (strsize1 == strsize2 && |
780 | !memcmp(name, &(entry->var.VariableName), strsize1) && | |
781 | !efi_guidcmp(guid, entry->var.VendorGuid)) { | |
782 | found = true; | |
783 | break; | |
784 | } | |
785 | } | |
786 | ||
787 | if (!found) | |
788 | return NULL; | |
789 | ||
e0d59733 SA |
790 | if (remove) { |
791 | if (entry->scanning) { | |
792 | /* | |
793 | * The entry will be deleted | |
794 | * after scanning is completed. | |
795 | */ | |
796 | entry->deleting = true; | |
797 | } else | |
798 | list_del(&entry->list); | |
799 | } | |
e14ab23d MF |
800 | |
801 | return entry; | |
802 | } | |
803 | EXPORT_SYMBOL_GPL(efivar_entry_find); | |
804 | ||
805 | /** | |
8a415b8c | 806 | * efivar_entry_size - obtain the size of a variable |
e14ab23d MF |
807 | * @entry: entry for this variable |
808 | * @size: location to store the variable's size | |
e14ab23d | 809 | */ |
8a415b8c | 810 | int efivar_entry_size(struct efivar_entry *entry, unsigned long *size) |
e14ab23d MF |
811 | { |
812 | const struct efivar_operations *ops = __efivars->ops; | |
813 | efi_status_t status; | |
814 | ||
e14ab23d | 815 | *size = 0; |
8a415b8c MF |
816 | |
817 | spin_lock_irq(&__efivars->lock); | |
e14ab23d MF |
818 | status = ops->get_variable(entry->var.VariableName, |
819 | &entry->var.VendorGuid, NULL, size, NULL); | |
8a415b8c MF |
820 | spin_unlock_irq(&__efivars->lock); |
821 | ||
e14ab23d MF |
822 | if (status != EFI_BUFFER_TOO_SMALL) |
823 | return efi_status_to_err(status); | |
824 | ||
825 | return 0; | |
826 | } | |
8a415b8c | 827 | EXPORT_SYMBOL_GPL(efivar_entry_size); |
e14ab23d MF |
828 | |
829 | /** | |
8a415b8c MF |
830 | * __efivar_entry_get - call get_variable() |
831 | * @entry: read data for this variable | |
832 | * @attributes: variable attributes | |
833 | * @size: size of @data buffer | |
834 | * @data: buffer to store variable data | |
835 | * | |
836 | * The caller MUST call efivar_entry_iter_begin() and | |
837 | * efivar_entry_iter_end() before and after the invocation of this | |
838 | * function, respectively. | |
e14ab23d | 839 | */ |
8a415b8c MF |
840 | int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes, |
841 | unsigned long *size, void *data) | |
e14ab23d MF |
842 | { |
843 | const struct efivar_operations *ops = __efivars->ops; | |
844 | efi_status_t status; | |
845 | ||
aee530cf | 846 | lockdep_assert_held(&__efivars->lock); |
e14ab23d | 847 | |
e14ab23d | 848 | status = ops->get_variable(entry->var.VariableName, |
8a415b8c MF |
849 | &entry->var.VendorGuid, |
850 | attributes, size, data); | |
e14ab23d | 851 | |
8a415b8c | 852 | return efi_status_to_err(status); |
e14ab23d | 853 | } |
8a415b8c | 854 | EXPORT_SYMBOL_GPL(__efivar_entry_get); |
e14ab23d MF |
855 | |
856 | /** | |
857 | * efivar_entry_get - call get_variable() | |
858 | * @entry: read data for this variable | |
859 | * @attributes: variable attributes | |
860 | * @size: size of @data buffer | |
861 | * @data: buffer to store variable data | |
862 | */ | |
863 | int efivar_entry_get(struct efivar_entry *entry, u32 *attributes, | |
864 | unsigned long *size, void *data) | |
865 | { | |
866 | const struct efivar_operations *ops = __efivars->ops; | |
867 | efi_status_t status; | |
868 | ||
869 | spin_lock_irq(&__efivars->lock); | |
870 | status = ops->get_variable(entry->var.VariableName, | |
871 | &entry->var.VendorGuid, | |
872 | attributes, size, data); | |
873 | spin_unlock_irq(&__efivars->lock); | |
874 | ||
875 | return efi_status_to_err(status); | |
876 | } | |
877 | EXPORT_SYMBOL_GPL(efivar_entry_get); | |
878 | ||
879 | /** | |
880 | * efivar_entry_set_get_size - call set_variable() and get new size (atomic) | |
881 | * @entry: entry containing variable to set and get | |
882 | * @attributes: attributes of variable to be written | |
883 | * @size: size of data buffer | |
884 | * @data: buffer containing data to write | |
885 | * @set: did the set_variable() call succeed? | |
886 | * | |
887 | * This is a pretty special (complex) function. See efivarfs_file_write(). | |
888 | * | |
889 | * Atomically call set_variable() for @entry and if the call is | |
890 | * successful, return the new size of the variable from get_variable() | |
891 | * in @size. The success of set_variable() is indicated by @set. | |
892 | * | |
893 | * Returns 0 on success, -EINVAL if the variable data is invalid, | |
894 | * -ENOSPC if the firmware does not have enough available space, or a | |
895 | * converted EFI status code if either of set_variable() or | |
896 | * get_variable() fail. | |
897 | * | |
898 | * If the EFI variable does not exist when calling set_variable() | |
899 | * (EFI_NOT_FOUND), @entry is removed from the variable list. | |
900 | */ | |
901 | int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes, | |
902 | unsigned long *size, void *data, bool *set) | |
903 | { | |
904 | const struct efivar_operations *ops = __efivars->ops; | |
905 | efi_char16_t *name = entry->var.VariableName; | |
906 | efi_guid_t *vendor = &entry->var.VendorGuid; | |
907 | efi_status_t status; | |
908 | int err; | |
909 | ||
910 | *set = false; | |
911 | ||
8282f5d9 | 912 | if (efivar_validate(*vendor, name, data, *size) == false) |
e14ab23d MF |
913 | return -EINVAL; |
914 | ||
915 | /* | |
916 | * The lock here protects the get_variable call, the conditional | |
917 | * set_variable call, and removal of the variable from the efivars | |
918 | * list (in the case of an authenticated delete). | |
919 | */ | |
920 | spin_lock_irq(&__efivars->lock); | |
921 | ||
922 | /* | |
923 | * Ensure that the available space hasn't shrunk below the safe level | |
924 | */ | |
a614e192 | 925 | status = check_var_size(attributes, *size + ucs2_strsize(name, 1024)); |
e14ab23d MF |
926 | if (status != EFI_SUCCESS) { |
927 | if (status != EFI_UNSUPPORTED) { | |
928 | err = efi_status_to_err(status); | |
929 | goto out; | |
930 | } | |
931 | ||
932 | if (*size > 65536) { | |
933 | err = -ENOSPC; | |
934 | goto out; | |
935 | } | |
936 | } | |
937 | ||
938 | status = ops->set_variable(name, vendor, attributes, *size, data); | |
939 | if (status != EFI_SUCCESS) { | |
940 | err = efi_status_to_err(status); | |
941 | goto out; | |
942 | } | |
943 | ||
944 | *set = true; | |
945 | ||
946 | /* | |
947 | * Writing to the variable may have caused a change in size (which | |
948 | * could either be an append or an overwrite), or the variable to be | |
949 | * deleted. Perform a GetVariable() so we can tell what actually | |
950 | * happened. | |
951 | */ | |
952 | *size = 0; | |
953 | status = ops->get_variable(entry->var.VariableName, | |
954 | &entry->var.VendorGuid, | |
955 | NULL, size, NULL); | |
956 | ||
957 | if (status == EFI_NOT_FOUND) | |
958 | efivar_entry_list_del_unlock(entry); | |
959 | else | |
960 | spin_unlock_irq(&__efivars->lock); | |
961 | ||
962 | if (status && status != EFI_BUFFER_TOO_SMALL) | |
963 | return efi_status_to_err(status); | |
964 | ||
965 | return 0; | |
966 | ||
967 | out: | |
968 | spin_unlock_irq(&__efivars->lock); | |
969 | return err; | |
970 | ||
971 | } | |
972 | EXPORT_SYMBOL_GPL(efivar_entry_set_get_size); | |
973 | ||
974 | /** | |
975 | * efivar_entry_iter_begin - begin iterating the variable list | |
976 | * | |
977 | * Lock the variable list to prevent entry insertion and removal until | |
978 | * efivar_entry_iter_end() is called. This function is usually used in | |
979 | * conjunction with __efivar_entry_iter() or efivar_entry_iter(). | |
980 | */ | |
981 | void efivar_entry_iter_begin(void) | |
982 | { | |
983 | spin_lock_irq(&__efivars->lock); | |
984 | } | |
985 | EXPORT_SYMBOL_GPL(efivar_entry_iter_begin); | |
986 | ||
987 | /** | |
988 | * efivar_entry_iter_end - finish iterating the variable list | |
989 | * | |
990 | * Unlock the variable list and allow modifications to the list again. | |
991 | */ | |
992 | void efivar_entry_iter_end(void) | |
993 | { | |
994 | spin_unlock_irq(&__efivars->lock); | |
995 | } | |
996 | EXPORT_SYMBOL_GPL(efivar_entry_iter_end); | |
997 | ||
998 | /** | |
999 | * __efivar_entry_iter - iterate over variable list | |
1000 | * @func: callback function | |
1001 | * @head: head of the variable list | |
1002 | * @data: function-specific data to pass to callback | |
1003 | * @prev: entry to begin iterating from | |
1004 | * | |
1005 | * Iterate over the list of EFI variables and call @func with every | |
1006 | * entry on the list. It is safe for @func to remove entries in the | |
1007 | * list via efivar_entry_delete(). | |
1008 | * | |
1009 | * You MUST call efivar_enter_iter_begin() before this function, and | |
1010 | * efivar_entry_iter_end() afterwards. | |
1011 | * | |
1012 | * It is possible to begin iteration from an arbitrary entry within | |
1013 | * the list by passing @prev. @prev is updated on return to point to | |
1014 | * the last entry passed to @func. To begin iterating from the | |
1015 | * beginning of the list @prev must be %NULL. | |
1016 | * | |
1017 | * The restrictions for @func are the same as documented for | |
1018 | * efivar_entry_iter(). | |
1019 | */ | |
1020 | int __efivar_entry_iter(int (*func)(struct efivar_entry *, void *), | |
1021 | struct list_head *head, void *data, | |
1022 | struct efivar_entry **prev) | |
1023 | { | |
1024 | struct efivar_entry *entry, *n; | |
1025 | int err = 0; | |
1026 | ||
1027 | if (!prev || !*prev) { | |
1028 | list_for_each_entry_safe(entry, n, head, list) { | |
1029 | err = func(entry, data); | |
1030 | if (err) | |
1031 | break; | |
1032 | } | |
1033 | ||
1034 | if (prev) | |
1035 | *prev = entry; | |
1036 | ||
1037 | return err; | |
1038 | } | |
1039 | ||
1040 | ||
1041 | list_for_each_entry_safe_continue((*prev), n, head, list) { | |
1042 | err = func(*prev, data); | |
1043 | if (err) | |
1044 | break; | |
1045 | } | |
1046 | ||
1047 | return err; | |
1048 | } | |
1049 | EXPORT_SYMBOL_GPL(__efivar_entry_iter); | |
1050 | ||
1051 | /** | |
1052 | * efivar_entry_iter - iterate over variable list | |
1053 | * @func: callback function | |
1054 | * @head: head of variable list | |
1055 | * @data: function-specific data to pass to callback | |
1056 | * | |
1057 | * Iterate over the list of EFI variables and call @func with every | |
1058 | * entry on the list. It is safe for @func to remove entries in the | |
1059 | * list via efivar_entry_delete() while iterating. | |
1060 | * | |
1061 | * Some notes for the callback function: | |
1062 | * - a non-zero return value indicates an error and terminates the loop | |
1063 | * - @func is called from atomic context | |
1064 | */ | |
1065 | int efivar_entry_iter(int (*func)(struct efivar_entry *, void *), | |
1066 | struct list_head *head, void *data) | |
1067 | { | |
1068 | int err = 0; | |
1069 | ||
1070 | efivar_entry_iter_begin(); | |
1071 | err = __efivar_entry_iter(func, head, data, NULL); | |
1072 | efivar_entry_iter_end(); | |
1073 | ||
1074 | return err; | |
1075 | } | |
1076 | EXPORT_SYMBOL_GPL(efivar_entry_iter); | |
1077 | ||
1078 | /** | |
1079 | * efivars_kobject - get the kobject for the registered efivars | |
1080 | * | |
1081 | * If efivars_register() has not been called we return NULL, | |
1082 | * otherwise return the kobject used at registration time. | |
1083 | */ | |
1084 | struct kobject *efivars_kobject(void) | |
1085 | { | |
1086 | if (!__efivars) | |
1087 | return NULL; | |
1088 | ||
1089 | return __efivars->kobject; | |
1090 | } | |
1091 | EXPORT_SYMBOL_GPL(efivars_kobject); | |
1092 | ||
04851772 MF |
1093 | /** |
1094 | * efivar_run_worker - schedule the efivar worker thread | |
1095 | */ | |
1096 | void efivar_run_worker(void) | |
1097 | { | |
1098 | if (efivar_wq_enabled) | |
1099 | schedule_work(&efivar_work); | |
1100 | } | |
1101 | EXPORT_SYMBOL_GPL(efivar_run_worker); | |
1102 | ||
e14ab23d MF |
1103 | /** |
1104 | * efivars_register - register an efivars | |
1105 | * @efivars: efivars to register | |
1106 | * @ops: efivars operations | |
1107 | * @kobject: @efivars-specific kobject | |
1108 | * | |
1109 | * Only a single efivars can be registered at any time. | |
1110 | */ | |
1111 | int efivars_register(struct efivars *efivars, | |
1112 | const struct efivar_operations *ops, | |
1113 | struct kobject *kobject) | |
1114 | { | |
1115 | spin_lock_init(&efivars->lock); | |
1116 | efivars->ops = ops; | |
1117 | efivars->kobject = kobject; | |
1118 | ||
1119 | __efivars = efivars; | |
1da177e4 | 1120 | |
e14ab23d MF |
1121 | return 0; |
1122 | } | |
1123 | EXPORT_SYMBOL_GPL(efivars_register); | |
1da177e4 | 1124 | |
e14ab23d MF |
1125 | /** |
1126 | * efivars_unregister - unregister an efivars | |
1127 | * @efivars: efivars to unregister | |
1128 | * | |
1129 | * The caller must have already removed every entry from the list, | |
1130 | * failure to do so is an error. | |
1131 | */ | |
1132 | int efivars_unregister(struct efivars *efivars) | |
1133 | { | |
1134 | int rv; | |
1135 | ||
1136 | if (!__efivars) { | |
1137 | printk(KERN_ERR "efivars not registered\n"); | |
1138 | rv = -EINVAL; | |
1139 | goto out; | |
1140 | } | |
1141 | ||
1142 | if (__efivars != efivars) { | |
1143 | rv = -EINVAL; | |
1144 | goto out; | |
1145 | } | |
1146 | ||
1147 | __efivars = NULL; | |
1148 | ||
1149 | rv = 0; | |
1150 | out: | |
1151 | return rv; | |
76b53f7c | 1152 | } |
e14ab23d | 1153 | EXPORT_SYMBOL_GPL(efivars_unregister); |