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Commit | Line | Data |
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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 | |
217b27d4 SC |
40 | /* |
41 | * efivars_lock protects three things: | |
42 | * 1) efivarfs_list and efivars_sysfs_list | |
43 | * 2) ->ops calls | |
44 | * 3) (un)registration of __efivars | |
45 | */ | |
21b3ddd3 | 46 | static DEFINE_SEMAPHORE(efivars_lock); |
217b27d4 | 47 | |
e971318b | 48 | static bool efivar_wq_enabled = true; |
a9499fa7 TG |
49 | DECLARE_WORK(efivar_work, NULL); |
50 | EXPORT_SYMBOL_GPL(efivar_work); | |
a93bc0c6 | 51 | |
fec6c20b | 52 | static bool |
a5d92ad3 | 53 | validate_device_path(efi_char16_t *var_name, int match, u8 *buffer, |
54b3a4d3 | 54 | unsigned long len) |
fec6c20b MG |
55 | { |
56 | struct efi_generic_dev_path *node; | |
57 | int offset = 0; | |
58 | ||
59 | node = (struct efi_generic_dev_path *)buffer; | |
60 | ||
54b3a4d3 MG |
61 | if (len < sizeof(*node)) |
62 | return false; | |
fec6c20b | 63 | |
54b3a4d3 MG |
64 | while (offset <= len - sizeof(*node) && |
65 | node->length >= sizeof(*node) && | |
66 | node->length <= len - offset) { | |
67 | offset += node->length; | |
fec6c20b MG |
68 | |
69 | if ((node->type == EFI_DEV_END_PATH || | |
70 | node->type == EFI_DEV_END_PATH2) && | |
71 | node->sub_type == EFI_DEV_END_ENTIRE) | |
72 | return true; | |
73 | ||
74 | node = (struct efi_generic_dev_path *)(buffer + offset); | |
75 | } | |
76 | ||
77 | /* | |
78 | * If we're here then either node->length pointed past the end | |
79 | * of the buffer or we reached the end of the buffer without | |
80 | * finding a device path end node. | |
81 | */ | |
82 | return false; | |
83 | } | |
84 | ||
85 | static bool | |
a5d92ad3 | 86 | validate_boot_order(efi_char16_t *var_name, int match, u8 *buffer, |
54b3a4d3 | 87 | unsigned long len) |
fec6c20b MG |
88 | { |
89 | /* An array of 16-bit integers */ | |
90 | if ((len % 2) != 0) | |
91 | return false; | |
92 | ||
93 | return true; | |
94 | } | |
95 | ||
96 | static bool | |
a5d92ad3 | 97 | validate_load_option(efi_char16_t *var_name, int match, u8 *buffer, |
54b3a4d3 | 98 | unsigned long len) |
fec6c20b MG |
99 | { |
100 | u16 filepathlength; | |
54b3a4d3 MG |
101 | int i, desclength = 0, namelen; |
102 | ||
a5d92ad3 | 103 | namelen = ucs2_strnlen(var_name, EFI_VAR_NAME_LEN); |
fec6c20b MG |
104 | |
105 | /* Either "Boot" or "Driver" followed by four digits of hex */ | |
106 | for (i = match; i < match+4; i++) { | |
a5d92ad3 MF |
107 | if (var_name[i] > 127 || |
108 | hex_to_bin(var_name[i] & 0xff) < 0) | |
fec6c20b MG |
109 | return true; |
110 | } | |
111 | ||
54b3a4d3 MG |
112 | /* Reject it if there's 4 digits of hex and then further content */ |
113 | if (namelen > match + 4) | |
114 | return false; | |
115 | ||
116 | /* A valid entry must be at least 8 bytes */ | |
117 | if (len < 8) | |
fec6c20b MG |
118 | return false; |
119 | ||
120 | filepathlength = buffer[4] | buffer[5] << 8; | |
121 | ||
122 | /* | |
123 | * There's no stored length for the description, so it has to be | |
124 | * found by hand | |
125 | */ | |
a614e192 | 126 | desclength = ucs2_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2; |
fec6c20b MG |
127 | |
128 | /* Each boot entry must have a descriptor */ | |
129 | if (!desclength) | |
130 | return false; | |
131 | ||
132 | /* | |
133 | * If the sum of the length of the description, the claimed filepath | |
134 | * length and the original header are greater than the length of the | |
135 | * variable, it's malformed | |
136 | */ | |
137 | if ((desclength + filepathlength + 6) > len) | |
138 | return false; | |
139 | ||
140 | /* | |
141 | * And, finally, check the filepath | |
142 | */ | |
a5d92ad3 | 143 | return validate_device_path(var_name, match, buffer + desclength + 6, |
fec6c20b MG |
144 | filepathlength); |
145 | } | |
146 | ||
147 | static bool | |
a5d92ad3 | 148 | validate_uint16(efi_char16_t *var_name, int match, u8 *buffer, |
54b3a4d3 | 149 | unsigned long len) |
fec6c20b MG |
150 | { |
151 | /* A single 16-bit integer */ | |
152 | if (len != 2) | |
153 | return false; | |
154 | ||
155 | return true; | |
156 | } | |
157 | ||
158 | static bool | |
a5d92ad3 | 159 | validate_ascii_string(efi_char16_t *var_name, int match, u8 *buffer, |
54b3a4d3 | 160 | unsigned long len) |
fec6c20b MG |
161 | { |
162 | int i; | |
163 | ||
164 | for (i = 0; i < len; i++) { | |
165 | if (buffer[i] > 127) | |
166 | return false; | |
167 | ||
168 | if (buffer[i] == 0) | |
169 | return true; | |
170 | } | |
171 | ||
172 | return false; | |
173 | } | |
174 | ||
175 | struct variable_validate { | |
8282f5d9 | 176 | efi_guid_t vendor; |
fec6c20b | 177 | char *name; |
a5d92ad3 | 178 | bool (*validate)(efi_char16_t *var_name, int match, u8 *data, |
54b3a4d3 | 179 | unsigned long len); |
fec6c20b MG |
180 | }; |
181 | ||
8282f5d9 | 182 | /* |
ed8b0de5 PJ |
183 | * This is the list of variables we need to validate, as well as the |
184 | * whitelist for what we think is safe not to default to immutable. | |
8282f5d9 PJ |
185 | * |
186 | * If it has a validate() method that's not NULL, it'll go into the | |
ed8b0de5 PJ |
187 | * validation routine. If not, it is assumed valid, but still used for |
188 | * whitelisting. | |
8282f5d9 PJ |
189 | * |
190 | * Note that it's sorted by {vendor,name}, but globbed names must come after | |
191 | * any other name with the same prefix. | |
192 | */ | |
fec6c20b | 193 | static const struct variable_validate variable_validate[] = { |
8282f5d9 PJ |
194 | { EFI_GLOBAL_VARIABLE_GUID, "BootNext", validate_uint16 }, |
195 | { EFI_GLOBAL_VARIABLE_GUID, "BootOrder", validate_boot_order }, | |
196 | { EFI_GLOBAL_VARIABLE_GUID, "Boot*", validate_load_option }, | |
197 | { EFI_GLOBAL_VARIABLE_GUID, "DriverOrder", validate_boot_order }, | |
198 | { EFI_GLOBAL_VARIABLE_GUID, "Driver*", validate_load_option }, | |
199 | { EFI_GLOBAL_VARIABLE_GUID, "ConIn", validate_device_path }, | |
200 | { EFI_GLOBAL_VARIABLE_GUID, "ConInDev", validate_device_path }, | |
201 | { EFI_GLOBAL_VARIABLE_GUID, "ConOut", validate_device_path }, | |
202 | { EFI_GLOBAL_VARIABLE_GUID, "ConOutDev", validate_device_path }, | |
203 | { EFI_GLOBAL_VARIABLE_GUID, "ErrOut", validate_device_path }, | |
204 | { EFI_GLOBAL_VARIABLE_GUID, "ErrOutDev", validate_device_path }, | |
205 | { EFI_GLOBAL_VARIABLE_GUID, "Lang", validate_ascii_string }, | |
ed8b0de5 | 206 | { EFI_GLOBAL_VARIABLE_GUID, "OsIndications", NULL }, |
8282f5d9 PJ |
207 | { EFI_GLOBAL_VARIABLE_GUID, "PlatformLang", validate_ascii_string }, |
208 | { EFI_GLOBAL_VARIABLE_GUID, "Timeout", validate_uint16 }, | |
e246eb56 | 209 | { LINUX_EFI_CRASH_GUID, "*", NULL }, |
8282f5d9 | 210 | { NULL_GUID, "", NULL }, |
fec6c20b MG |
211 | }; |
212 | ||
630ba0cc LE |
213 | /* |
214 | * Check if @var_name matches the pattern given in @match_name. | |
215 | * | |
216 | * @var_name: an array of @len non-NUL characters. | |
217 | * @match_name: a NUL-terminated pattern string, optionally ending in "*". A | |
218 | * final "*" character matches any trailing characters @var_name, | |
219 | * including the case when there are none left in @var_name. | |
220 | * @match: on output, the number of non-wildcard characters in @match_name | |
221 | * that @var_name matches, regardless of the return value. | |
222 | * @return: whether @var_name fully matches @match_name. | |
223 | */ | |
ed8b0de5 PJ |
224 | static bool |
225 | variable_matches(const char *var_name, size_t len, const char *match_name, | |
226 | int *match) | |
227 | { | |
228 | for (*match = 0; ; (*match)++) { | |
229 | char c = match_name[*match]; | |
ed8b0de5 | 230 | |
630ba0cc LE |
231 | switch (c) { |
232 | case '*': | |
233 | /* Wildcard in @match_name means we've matched. */ | |
ed8b0de5 PJ |
234 | return true; |
235 | ||
630ba0cc LE |
236 | case '\0': |
237 | /* @match_name has ended. Has @var_name too? */ | |
238 | return (*match == len); | |
239 | ||
240 | default: | |
241 | /* | |
242 | * We've reached a non-wildcard char in @match_name. | |
243 | * Continue only if there's an identical character in | |
244 | * @var_name. | |
245 | */ | |
246 | if (*match < len && c == var_name[*match]) | |
247 | continue; | |
ed8b0de5 | 248 | return false; |
630ba0cc | 249 | } |
ed8b0de5 | 250 | } |
ed8b0de5 PJ |
251 | } |
252 | ||
e14ab23d | 253 | bool |
8282f5d9 PJ |
254 | efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data, |
255 | unsigned long data_size) | |
fec6c20b MG |
256 | { |
257 | int i; | |
3dcb1f55 PJ |
258 | unsigned long utf8_size; |
259 | u8 *utf8_name; | |
fec6c20b | 260 | |
3dcb1f55 PJ |
261 | utf8_size = ucs2_utf8size(var_name); |
262 | utf8_name = kmalloc(utf8_size + 1, GFP_KERNEL); | |
263 | if (!utf8_name) | |
264 | return false; | |
fec6c20b | 265 | |
3dcb1f55 PJ |
266 | ucs2_as_utf8(utf8_name, var_name, utf8_size); |
267 | utf8_name[utf8_size] = '\0'; | |
fec6c20b | 268 | |
8282f5d9 | 269 | for (i = 0; variable_validate[i].name[0] != '\0'; i++) { |
fec6c20b | 270 | const char *name = variable_validate[i].name; |
8282f5d9 | 271 | int match = 0; |
fec6c20b | 272 | |
8282f5d9 PJ |
273 | if (efi_guidcmp(vendor, variable_validate[i].vendor)) |
274 | continue; | |
fec6c20b | 275 | |
ed8b0de5 PJ |
276 | if (variable_matches(utf8_name, utf8_size+1, name, &match)) { |
277 | if (variable_validate[i].validate == NULL) | |
fec6c20b | 278 | break; |
ed8b0de5 PJ |
279 | kfree(utf8_name); |
280 | return variable_validate[i].validate(var_name, match, | |
281 | data, data_size); | |
fec6c20b MG |
282 | } |
283 | } | |
3dcb1f55 | 284 | kfree(utf8_name); |
fec6c20b MG |
285 | return true; |
286 | } | |
e14ab23d | 287 | EXPORT_SYMBOL_GPL(efivar_validate); |
fec6c20b | 288 | |
ed8b0de5 PJ |
289 | bool |
290 | efivar_variable_is_removable(efi_guid_t vendor, const char *var_name, | |
291 | size_t len) | |
292 | { | |
293 | int i; | |
294 | bool found = false; | |
295 | int match = 0; | |
296 | ||
297 | /* | |
298 | * Check if our variable is in the validated variables list | |
299 | */ | |
300 | for (i = 0; variable_validate[i].name[0] != '\0'; i++) { | |
301 | if (efi_guidcmp(variable_validate[i].vendor, vendor)) | |
302 | continue; | |
303 | ||
304 | if (variable_matches(var_name, len, | |
305 | variable_validate[i].name, &match)) { | |
306 | found = true; | |
307 | break; | |
308 | } | |
309 | } | |
310 | ||
311 | /* | |
312 | * If it's in our list, it is removable. | |
313 | */ | |
314 | return found; | |
315 | } | |
316 | EXPORT_SYMBOL_GPL(efivar_variable_is_removable); | |
317 | ||
1da177e4 | 318 | static efi_status_t |
e14ab23d | 319 | check_var_size(u32 attributes, unsigned long size) |
68d92986 | 320 | { |
e14ab23d | 321 | const struct efivar_operations *fops = __efivars->ops; |
68d92986 | 322 | |
a614e192 | 323 | if (!fops->query_variable_store) |
68d92986 MG |
324 | return EFI_UNSUPPORTED; |
325 | ||
ca0e30dc AB |
326 | return fops->query_variable_store(attributes, size, false); |
327 | } | |
328 | ||
329 | static efi_status_t | |
330 | check_var_size_nonblocking(u32 attributes, unsigned long size) | |
331 | { | |
332 | const struct efivar_operations *fops = __efivars->ops; | |
333 | ||
334 | if (!fops->query_variable_store) | |
335 | return EFI_UNSUPPORTED; | |
336 | ||
337 | return fops->query_variable_store(attributes, size, true); | |
68d92986 MG |
338 | } |
339 | ||
e14ab23d MF |
340 | static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor, |
341 | struct list_head *head) | |
a93bc0c6 SA |
342 | { |
343 | struct efivar_entry *entry, *n; | |
a93bc0c6 SA |
344 | unsigned long strsize1, strsize2; |
345 | bool found = false; | |
346 | ||
a614e192 | 347 | strsize1 = ucs2_strsize(variable_name, 1024); |
e14ab23d | 348 | list_for_each_entry_safe(entry, n, head, list) { |
a614e192 | 349 | strsize2 = ucs2_strsize(entry->var.VariableName, 1024); |
a93bc0c6 SA |
350 | if (strsize1 == strsize2 && |
351 | !memcmp(variable_name, &(entry->var.VariableName), | |
352 | strsize2) && | |
353 | !efi_guidcmp(entry->var.VendorGuid, | |
354 | *vendor)) { | |
355 | found = true; | |
356 | break; | |
357 | } | |
358 | } | |
359 | return found; | |
360 | } | |
361 | ||
ec50bd32 MF |
362 | /* |
363 | * Returns the size of variable_name, in bytes, including the | |
364 | * terminating NULL character, or variable_name_size if no NULL | |
365 | * character is found among the first variable_name_size bytes. | |
366 | */ | |
367 | static unsigned long var_name_strnsize(efi_char16_t *variable_name, | |
368 | unsigned long variable_name_size) | |
369 | { | |
370 | unsigned long len; | |
371 | efi_char16_t c; | |
372 | ||
373 | /* | |
374 | * The variable name is, by definition, a NULL-terminated | |
375 | * string, so make absolutely sure that variable_name_size is | |
376 | * the value we expect it to be. If not, return the real size. | |
377 | */ | |
378 | for (len = 2; len <= variable_name_size; len += sizeof(c)) { | |
379 | c = variable_name[(len / sizeof(c)) - 1]; | |
380 | if (!c) | |
381 | break; | |
382 | } | |
383 | ||
384 | return min(len, variable_name_size); | |
385 | } | |
386 | ||
e971318b MF |
387 | /* |
388 | * Print a warning when duplicate EFI variables are encountered and | |
389 | * disable the sysfs workqueue since the firmware is buggy. | |
390 | */ | |
b2fce819 | 391 | static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid, |
e971318b MF |
392 | unsigned long len16) |
393 | { | |
394 | size_t i, len8 = len16 / sizeof(efi_char16_t); | |
b2fce819 | 395 | char *str8; |
e971318b MF |
396 | |
397 | /* | |
398 | * Disable the workqueue since the algorithm it uses for | |
399 | * detecting new variables won't work with this buggy | |
400 | * implementation of GetNextVariableName(). | |
401 | */ | |
402 | efivar_wq_enabled = false; | |
403 | ||
b2fce819 MR |
404 | str8 = kzalloc(len8, GFP_KERNEL); |
405 | if (!str8) | |
e971318b MF |
406 | return; |
407 | ||
408 | for (i = 0; i < len8; i++) | |
b2fce819 | 409 | str8[i] = str16[i]; |
e971318b MF |
410 | |
411 | printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n", | |
b2fce819 MR |
412 | str8, vendor_guid); |
413 | kfree(str8); | |
e971318b MF |
414 | } |
415 | ||
e14ab23d MF |
416 | /** |
417 | * efivar_init - build the initial list of EFI variables | |
418 | * @func: callback function to invoke for every variable | |
419 | * @data: function-specific data to pass to @func | |
420 | * @atomic: do we need to execute the @func-loop atomically? | |
421 | * @duplicates: error if we encounter duplicates on @head? | |
422 | * @head: initialised head of variable list | |
423 | * | |
424 | * Get every EFI variable from the firmware and invoke @func. @func | |
425 | * should call efivar_entry_add() to build the list of variables. | |
426 | * | |
427 | * Returns 0 on success, or a kernel error code on failure. | |
428 | */ | |
429 | int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *), | |
1cfd6316 | 430 | void *data, bool duplicates, struct list_head *head) |
e14ab23d MF |
431 | { |
432 | const struct efivar_operations *ops = __efivars->ops; | |
433 | unsigned long variable_name_size = 1024; | |
434 | efi_char16_t *variable_name; | |
435 | efi_status_t status; | |
436 | efi_guid_t vendor_guid; | |
437 | int err = 0; | |
438 | ||
439 | variable_name = kzalloc(variable_name_size, GFP_KERNEL); | |
440 | if (!variable_name) { | |
441 | printk(KERN_ERR "efivars: Memory allocation failed.\n"); | |
442 | return -ENOMEM; | |
605e70c7 LCY |
443 | } |
444 | ||
21b3ddd3 SC |
445 | if (down_interruptible(&efivars_lock)) { |
446 | err = -EINTR; | |
447 | goto free; | |
448 | } | |
e14ab23d | 449 | |
1da177e4 LT |
450 | /* |
451 | * Per EFI spec, the maximum storage allocated for both | |
452 | * the variable name and variable data is 1024 bytes. | |
453 | */ | |
454 | ||
455 | do { | |
456 | variable_name_size = 1024; | |
457 | ||
3295814d | 458 | status = ops->get_next_variable(&variable_name_size, |
1da177e4 LT |
459 | variable_name, |
460 | &vendor_guid); | |
461 | switch (status) { | |
462 | case EFI_SUCCESS: | |
1cfd6316 | 463 | if (duplicates) |
21b3ddd3 | 464 | up(&efivars_lock); |
e14ab23d | 465 | |
ec50bd32 MF |
466 | variable_name_size = var_name_strnsize(variable_name, |
467 | variable_name_size); | |
e971318b MF |
468 | |
469 | /* | |
470 | * Some firmware implementations return the | |
471 | * same variable name on multiple calls to | |
472 | * get_next_variable(). Terminate the loop | |
473 | * immediately as there is no guarantee that | |
474 | * we'll ever see a different variable name, | |
475 | * and may end up looping here forever. | |
476 | */ | |
e14ab23d | 477 | if (duplicates && |
1cfd6316 JL |
478 | variable_is_present(variable_name, &vendor_guid, |
479 | head)) { | |
e971318b MF |
480 | dup_variable_bug(variable_name, &vendor_guid, |
481 | variable_name_size); | |
482 | status = EFI_NOT_FOUND; | |
1cfd6316 JL |
483 | } else { |
484 | err = func(variable_name, vendor_guid, | |
485 | variable_name_size, data); | |
486 | if (err) | |
487 | status = EFI_NOT_FOUND; | |
e971318b MF |
488 | } |
489 | ||
21b3ddd3 SC |
490 | if (duplicates) { |
491 | if (down_interruptible(&efivars_lock)) { | |
492 | err = -EINTR; | |
493 | goto free; | |
494 | } | |
495 | } | |
e14ab23d | 496 | |
1da177e4 LT |
497 | break; |
498 | case EFI_NOT_FOUND: | |
499 | break; | |
500 | default: | |
501 | printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n", | |
502 | status); | |
503 | status = EFI_NOT_FOUND; | |
504 | break; | |
505 | } | |
e14ab23d | 506 | |
1da177e4 LT |
507 | } while (status != EFI_NOT_FOUND); |
508 | ||
21b3ddd3 SC |
509 | up(&efivars_lock); |
510 | free: | |
e14ab23d MF |
511 | kfree(variable_name); |
512 | ||
513 | return err; | |
514 | } | |
515 | EXPORT_SYMBOL_GPL(efivar_init); | |
516 | ||
517 | /** | |
518 | * efivar_entry_add - add entry to variable list | |
519 | * @entry: entry to add to list | |
520 | * @head: list head | |
21b3ddd3 SC |
521 | * |
522 | * Returns 0 on success, or a kernel error code on failure. | |
e14ab23d | 523 | */ |
21b3ddd3 | 524 | int efivar_entry_add(struct efivar_entry *entry, struct list_head *head) |
e14ab23d | 525 | { |
21b3ddd3 SC |
526 | if (down_interruptible(&efivars_lock)) |
527 | return -EINTR; | |
e14ab23d | 528 | list_add(&entry->list, head); |
21b3ddd3 SC |
529 | up(&efivars_lock); |
530 | ||
531 | return 0; | |
e14ab23d MF |
532 | } |
533 | EXPORT_SYMBOL_GPL(efivar_entry_add); | |
534 | ||
535 | /** | |
536 | * efivar_entry_remove - remove entry from variable list | |
537 | * @entry: entry to remove from list | |
21b3ddd3 SC |
538 | * |
539 | * Returns 0 on success, or a kernel error code on failure. | |
e14ab23d | 540 | */ |
21b3ddd3 | 541 | int efivar_entry_remove(struct efivar_entry *entry) |
e14ab23d | 542 | { |
21b3ddd3 SC |
543 | if (down_interruptible(&efivars_lock)) |
544 | return -EINTR; | |
e14ab23d | 545 | list_del(&entry->list); |
21b3ddd3 SC |
546 | up(&efivars_lock); |
547 | ||
548 | return 0; | |
e14ab23d MF |
549 | } |
550 | EXPORT_SYMBOL_GPL(efivar_entry_remove); | |
551 | ||
552 | /* | |
553 | * efivar_entry_list_del_unlock - remove entry from variable list | |
554 | * @entry: entry to remove | |
555 | * | |
556 | * Remove @entry from the variable list and release the list lock. | |
557 | * | |
558 | * NOTE: slightly weird locking semantics here - we expect to be | |
559 | * called with the efivars lock already held, and we release it before | |
560 | * returning. This is because this function is usually called after | |
561 | * set_variable() while the lock is still held. | |
562 | */ | |
563 | static void efivar_entry_list_del_unlock(struct efivar_entry *entry) | |
564 | { | |
e14ab23d | 565 | list_del(&entry->list); |
21b3ddd3 | 566 | up(&efivars_lock); |
e14ab23d MF |
567 | } |
568 | ||
569 | /** | |
570 | * __efivar_entry_delete - delete an EFI variable | |
571 | * @entry: entry containing EFI variable to delete | |
572 | * | |
a9499fa7 TG |
573 | * Delete the variable from the firmware but leave @entry on the |
574 | * variable list. | |
e14ab23d | 575 | * |
a9499fa7 TG |
576 | * This function differs from efivar_entry_delete() because it does |
577 | * not remove @entry from the variable list. Also, it is safe to be | |
578 | * called from within a efivar_entry_iter_begin() and | |
e14ab23d MF |
579 | * efivar_entry_iter_end() region, unlike efivar_entry_delete(). |
580 | * | |
581 | * Returns 0 on success, or a converted EFI status code if | |
a9499fa7 | 582 | * set_variable() fails. |
e14ab23d MF |
583 | */ |
584 | int __efivar_entry_delete(struct efivar_entry *entry) | |
585 | { | |
586 | const struct efivar_operations *ops = __efivars->ops; | |
587 | efi_status_t status; | |
588 | ||
e14ab23d MF |
589 | status = ops->set_variable(entry->var.VariableName, |
590 | &entry->var.VendorGuid, | |
591 | 0, 0, NULL); | |
e14ab23d | 592 | |
a9499fa7 | 593 | return efi_status_to_err(status); |
e14ab23d MF |
594 | } |
595 | EXPORT_SYMBOL_GPL(__efivar_entry_delete); | |
596 | ||
597 | /** | |
598 | * efivar_entry_delete - delete variable and remove entry from list | |
599 | * @entry: entry containing variable to delete | |
600 | * | |
601 | * Delete the variable from the firmware and remove @entry from the | |
602 | * variable list. It is the caller's responsibility to free @entry | |
603 | * once we return. | |
604 | * | |
21b3ddd3 SC |
605 | * Returns 0 on success, -EINTR if we can't grab the semaphore, |
606 | * converted EFI status code if set_variable() fails. | |
e14ab23d MF |
607 | */ |
608 | int efivar_entry_delete(struct efivar_entry *entry) | |
609 | { | |
610 | const struct efivar_operations *ops = __efivars->ops; | |
611 | efi_status_t status; | |
612 | ||
21b3ddd3 SC |
613 | if (down_interruptible(&efivars_lock)) |
614 | return -EINTR; | |
615 | ||
e14ab23d MF |
616 | status = ops->set_variable(entry->var.VariableName, |
617 | &entry->var.VendorGuid, | |
618 | 0, 0, NULL); | |
619 | if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) { | |
21b3ddd3 | 620 | up(&efivars_lock); |
e14ab23d MF |
621 | return efi_status_to_err(status); |
622 | } | |
623 | ||
624 | efivar_entry_list_del_unlock(entry); | |
625 | return 0; | |
626 | } | |
627 | EXPORT_SYMBOL_GPL(efivar_entry_delete); | |
628 | ||
629 | /** | |
630 | * efivar_entry_set - call set_variable() | |
631 | * @entry: entry containing the EFI variable to write | |
632 | * @attributes: variable attributes | |
633 | * @size: size of @data buffer | |
634 | * @data: buffer containing variable data | |
635 | * @head: head of variable list | |
636 | * | |
637 | * Calls set_variable() for an EFI variable. If creating a new EFI | |
638 | * variable, this function is usually followed by efivar_entry_add(). | |
639 | * | |
640 | * Before writing the variable, the remaining EFI variable storage | |
641 | * space is checked to ensure there is enough room available. | |
642 | * | |
643 | * If @head is not NULL a lookup is performed to determine whether | |
644 | * the entry is already on the list. | |
645 | * | |
21b3ddd3 SC |
646 | * Returns 0 on success, -EINTR if we can't grab the semaphore, |
647 | * -EEXIST if a lookup is performed and the entry already exists on | |
648 | * the list, or a converted EFI status code if set_variable() fails. | |
e14ab23d MF |
649 | */ |
650 | int efivar_entry_set(struct efivar_entry *entry, u32 attributes, | |
651 | unsigned long size, void *data, struct list_head *head) | |
652 | { | |
653 | const struct efivar_operations *ops = __efivars->ops; | |
654 | efi_status_t status; | |
655 | efi_char16_t *name = entry->var.VariableName; | |
656 | efi_guid_t vendor = entry->var.VendorGuid; | |
657 | ||
21b3ddd3 SC |
658 | if (down_interruptible(&efivars_lock)) |
659 | return -EINTR; | |
e14ab23d | 660 | if (head && efivar_entry_find(name, vendor, head, false)) { |
21b3ddd3 | 661 | up(&efivars_lock); |
e14ab23d MF |
662 | return -EEXIST; |
663 | } | |
664 | ||
a614e192 | 665 | status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); |
e14ab23d MF |
666 | if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED) |
667 | status = ops->set_variable(name, &vendor, | |
668 | attributes, size, data); | |
669 | ||
21b3ddd3 | 670 | up(&efivars_lock); |
e14ab23d MF |
671 | |
672 | return efi_status_to_err(status); | |
a9499fa7 | 673 | |
e14ab23d MF |
674 | } |
675 | EXPORT_SYMBOL_GPL(efivar_entry_set); | |
676 | ||
6d80dba1 MF |
677 | /* |
678 | * efivar_entry_set_nonblocking - call set_variable_nonblocking() | |
679 | * | |
680 | * This function is guaranteed to not block and is suitable for calling | |
681 | * from crash/panic handlers. | |
682 | * | |
683 | * Crucially, this function will not block if it cannot acquire | |
217b27d4 | 684 | * efivars_lock. Instead, it returns -EBUSY. |
6d80dba1 MF |
685 | */ |
686 | static int | |
687 | efivar_entry_set_nonblocking(efi_char16_t *name, efi_guid_t vendor, | |
688 | u32 attributes, unsigned long size, void *data) | |
689 | { | |
690 | const struct efivar_operations *ops = __efivars->ops; | |
6d80dba1 MF |
691 | efi_status_t status; |
692 | ||
21b3ddd3 | 693 | if (down_trylock(&efivars_lock)) |
6d80dba1 MF |
694 | return -EBUSY; |
695 | ||
ca0e30dc AB |
696 | status = check_var_size_nonblocking(attributes, |
697 | size + ucs2_strsize(name, 1024)); | |
6d80dba1 | 698 | if (status != EFI_SUCCESS) { |
21b3ddd3 | 699 | up(&efivars_lock); |
6d80dba1 MF |
700 | return -ENOSPC; |
701 | } | |
702 | ||
703 | status = ops->set_variable_nonblocking(name, &vendor, attributes, | |
704 | size, data); | |
705 | ||
21b3ddd3 | 706 | up(&efivars_lock); |
6d80dba1 MF |
707 | return efi_status_to_err(status); |
708 | } | |
709 | ||
e14ab23d MF |
710 | /** |
711 | * efivar_entry_set_safe - call set_variable() if enough space in firmware | |
712 | * @name: buffer containing the variable name | |
713 | * @vendor: variable vendor guid | |
714 | * @attributes: variable attributes | |
715 | * @block: can we block in this context? | |
716 | * @size: size of @data buffer | |
717 | * @data: buffer containing variable data | |
718 | * | |
719 | * Ensures there is enough free storage in the firmware for this variable, and | |
720 | * if so, calls set_variable(). If creating a new EFI variable, this function | |
721 | * is usually followed by efivar_entry_add(). | |
722 | * | |
723 | * Returns 0 on success, -ENOSPC if the firmware does not have enough | |
724 | * space for set_variable() to succeed, or a converted EFI status code | |
725 | * if set_variable() fails. | |
726 | */ | |
727 | int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes, | |
728 | bool block, unsigned long size, void *data) | |
729 | { | |
730 | const struct efivar_operations *ops = __efivars->ops; | |
e14ab23d MF |
731 | efi_status_t status; |
732 | ||
a614e192 | 733 | if (!ops->query_variable_store) |
e14ab23d MF |
734 | return -ENOSYS; |
735 | ||
6d80dba1 MF |
736 | /* |
737 | * If the EFI variable backend provides a non-blocking | |
738 | * ->set_variable() operation and we're in a context where we | |
739 | * cannot block, then we need to use it to avoid live-locks, | |
740 | * since the implication is that the regular ->set_variable() | |
741 | * will block. | |
742 | * | |
743 | * If no ->set_variable_nonblocking() is provided then | |
744 | * ->set_variable() is assumed to be non-blocking. | |
745 | */ | |
746 | if (!block && ops->set_variable_nonblocking) | |
747 | return efivar_entry_set_nonblocking(name, vendor, attributes, | |
748 | size, data); | |
749 | ||
85c90716 | 750 | if (!block) { |
21b3ddd3 | 751 | if (down_trylock(&efivars_lock)) |
85c90716 DC |
752 | return -EBUSY; |
753 | } else { | |
21b3ddd3 SC |
754 | if (down_interruptible(&efivars_lock)) |
755 | return -EINTR; | |
85c90716 | 756 | } |
e14ab23d | 757 | |
a614e192 | 758 | status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); |
e14ab23d | 759 | if (status != EFI_SUCCESS) { |
21b3ddd3 | 760 | up(&efivars_lock); |
e14ab23d MF |
761 | return -ENOSPC; |
762 | } | |
763 | ||
764 | status = ops->set_variable(name, &vendor, attributes, size, data); | |
765 | ||
21b3ddd3 | 766 | up(&efivars_lock); |
e14ab23d MF |
767 | |
768 | return efi_status_to_err(status); | |
769 | } | |
770 | EXPORT_SYMBOL_GPL(efivar_entry_set_safe); | |
771 | ||
772 | /** | |
773 | * efivar_entry_find - search for an entry | |
774 | * @name: the EFI variable name | |
775 | * @guid: the EFI variable vendor's guid | |
776 | * @head: head of the variable list | |
777 | * @remove: should we remove the entry from the list? | |
778 | * | |
779 | * Search for an entry on the variable list that has the EFI variable | |
780 | * name @name and vendor guid @guid. If an entry is found on the list | |
781 | * and @remove is true, the entry is removed from the list. | |
782 | * | |
783 | * The caller MUST call efivar_entry_iter_begin() and | |
784 | * efivar_entry_iter_end() before and after the invocation of this | |
785 | * function, respectively. | |
786 | * | |
787 | * Returns the entry if found on the list, %NULL otherwise. | |
788 | */ | |
789 | struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid, | |
790 | struct list_head *head, bool remove) | |
791 | { | |
792 | struct efivar_entry *entry, *n; | |
793 | int strsize1, strsize2; | |
794 | bool found = false; | |
795 | ||
e14ab23d | 796 | list_for_each_entry_safe(entry, n, head, list) { |
a614e192 MF |
797 | strsize1 = ucs2_strsize(name, 1024); |
798 | strsize2 = ucs2_strsize(entry->var.VariableName, 1024); | |
e14ab23d MF |
799 | if (strsize1 == strsize2 && |
800 | !memcmp(name, &(entry->var.VariableName), strsize1) && | |
801 | !efi_guidcmp(guid, entry->var.VendorGuid)) { | |
802 | found = true; | |
803 | break; | |
804 | } | |
805 | } | |
806 | ||
807 | if (!found) | |
808 | return NULL; | |
809 | ||
e0d59733 SA |
810 | if (remove) { |
811 | if (entry->scanning) { | |
812 | /* | |
813 | * The entry will be deleted | |
814 | * after scanning is completed. | |
815 | */ | |
816 | entry->deleting = true; | |
817 | } else | |
818 | list_del(&entry->list); | |
819 | } | |
e14ab23d MF |
820 | |
821 | return entry; | |
822 | } | |
823 | EXPORT_SYMBOL_GPL(efivar_entry_find); | |
824 | ||
825 | /** | |
8a415b8c | 826 | * efivar_entry_size - obtain the size of a variable |
e14ab23d MF |
827 | * @entry: entry for this variable |
828 | * @size: location to store the variable's size | |
e14ab23d | 829 | */ |
8a415b8c | 830 | int efivar_entry_size(struct efivar_entry *entry, unsigned long *size) |
e14ab23d MF |
831 | { |
832 | const struct efivar_operations *ops = __efivars->ops; | |
833 | efi_status_t status; | |
834 | ||
e14ab23d | 835 | *size = 0; |
8a415b8c | 836 | |
21b3ddd3 SC |
837 | if (down_interruptible(&efivars_lock)) |
838 | return -EINTR; | |
e14ab23d MF |
839 | status = ops->get_variable(entry->var.VariableName, |
840 | &entry->var.VendorGuid, NULL, size, NULL); | |
21b3ddd3 | 841 | up(&efivars_lock); |
8a415b8c | 842 | |
e14ab23d MF |
843 | if (status != EFI_BUFFER_TOO_SMALL) |
844 | return efi_status_to_err(status); | |
845 | ||
846 | return 0; | |
847 | } | |
8a415b8c | 848 | EXPORT_SYMBOL_GPL(efivar_entry_size); |
e14ab23d MF |
849 | |
850 | /** | |
8a415b8c MF |
851 | * __efivar_entry_get - call get_variable() |
852 | * @entry: read data for this variable | |
853 | * @attributes: variable attributes | |
854 | * @size: size of @data buffer | |
855 | * @data: buffer to store variable data | |
856 | * | |
857 | * The caller MUST call efivar_entry_iter_begin() and | |
858 | * efivar_entry_iter_end() before and after the invocation of this | |
859 | * function, respectively. | |
e14ab23d | 860 | */ |
8a415b8c MF |
861 | int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes, |
862 | unsigned long *size, void *data) | |
e14ab23d MF |
863 | { |
864 | const struct efivar_operations *ops = __efivars->ops; | |
865 | efi_status_t status; | |
866 | ||
e14ab23d | 867 | status = ops->get_variable(entry->var.VariableName, |
8a415b8c MF |
868 | &entry->var.VendorGuid, |
869 | attributes, size, data); | |
e14ab23d | 870 | |
8a415b8c | 871 | return efi_status_to_err(status); |
e14ab23d | 872 | } |
8a415b8c | 873 | EXPORT_SYMBOL_GPL(__efivar_entry_get); |
e14ab23d MF |
874 | |
875 | /** | |
876 | * efivar_entry_get - call get_variable() | |
877 | * @entry: read data for this variable | |
878 | * @attributes: variable attributes | |
879 | * @size: size of @data buffer | |
880 | * @data: buffer to store variable data | |
881 | */ | |
882 | int efivar_entry_get(struct efivar_entry *entry, u32 *attributes, | |
883 | unsigned long *size, void *data) | |
884 | { | |
885 | const struct efivar_operations *ops = __efivars->ops; | |
886 | efi_status_t status; | |
887 | ||
21b3ddd3 SC |
888 | if (down_interruptible(&efivars_lock)) |
889 | return -EINTR; | |
e14ab23d MF |
890 | status = ops->get_variable(entry->var.VariableName, |
891 | &entry->var.VendorGuid, | |
892 | attributes, size, data); | |
21b3ddd3 | 893 | up(&efivars_lock); |
e14ab23d MF |
894 | |
895 | return efi_status_to_err(status); | |
896 | } | |
897 | EXPORT_SYMBOL_GPL(efivar_entry_get); | |
898 | ||
899 | /** | |
900 | * efivar_entry_set_get_size - call set_variable() and get new size (atomic) | |
901 | * @entry: entry containing variable to set and get | |
902 | * @attributes: attributes of variable to be written | |
903 | * @size: size of data buffer | |
904 | * @data: buffer containing data to write | |
905 | * @set: did the set_variable() call succeed? | |
906 | * | |
907 | * This is a pretty special (complex) function. See efivarfs_file_write(). | |
908 | * | |
909 | * Atomically call set_variable() for @entry and if the call is | |
910 | * successful, return the new size of the variable from get_variable() | |
911 | * in @size. The success of set_variable() is indicated by @set. | |
912 | * | |
913 | * Returns 0 on success, -EINVAL if the variable data is invalid, | |
914 | * -ENOSPC if the firmware does not have enough available space, or a | |
915 | * converted EFI status code if either of set_variable() or | |
916 | * get_variable() fail. | |
917 | * | |
918 | * If the EFI variable does not exist when calling set_variable() | |
919 | * (EFI_NOT_FOUND), @entry is removed from the variable list. | |
920 | */ | |
921 | int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes, | |
922 | unsigned long *size, void *data, bool *set) | |
923 | { | |
924 | const struct efivar_operations *ops = __efivars->ops; | |
925 | efi_char16_t *name = entry->var.VariableName; | |
926 | efi_guid_t *vendor = &entry->var.VendorGuid; | |
927 | efi_status_t status; | |
928 | int err; | |
929 | ||
930 | *set = false; | |
931 | ||
8282f5d9 | 932 | if (efivar_validate(*vendor, name, data, *size) == false) |
e14ab23d MF |
933 | return -EINVAL; |
934 | ||
935 | /* | |
936 | * The lock here protects the get_variable call, the conditional | |
937 | * set_variable call, and removal of the variable from the efivars | |
938 | * list (in the case of an authenticated delete). | |
939 | */ | |
21b3ddd3 SC |
940 | if (down_interruptible(&efivars_lock)) |
941 | return -EINTR; | |
e14ab23d MF |
942 | |
943 | /* | |
944 | * Ensure that the available space hasn't shrunk below the safe level | |
945 | */ | |
a614e192 | 946 | status = check_var_size(attributes, *size + ucs2_strsize(name, 1024)); |
e14ab23d MF |
947 | if (status != EFI_SUCCESS) { |
948 | if (status != EFI_UNSUPPORTED) { | |
949 | err = efi_status_to_err(status); | |
950 | goto out; | |
951 | } | |
952 | ||
953 | if (*size > 65536) { | |
954 | err = -ENOSPC; | |
955 | goto out; | |
956 | } | |
957 | } | |
958 | ||
959 | status = ops->set_variable(name, vendor, attributes, *size, data); | |
960 | if (status != EFI_SUCCESS) { | |
961 | err = efi_status_to_err(status); | |
962 | goto out; | |
963 | } | |
964 | ||
965 | *set = true; | |
966 | ||
967 | /* | |
968 | * Writing to the variable may have caused a change in size (which | |
969 | * could either be an append or an overwrite), or the variable to be | |
970 | * deleted. Perform a GetVariable() so we can tell what actually | |
971 | * happened. | |
972 | */ | |
973 | *size = 0; | |
974 | status = ops->get_variable(entry->var.VariableName, | |
975 | &entry->var.VendorGuid, | |
976 | NULL, size, NULL); | |
977 | ||
978 | if (status == EFI_NOT_FOUND) | |
979 | efivar_entry_list_del_unlock(entry); | |
980 | else | |
21b3ddd3 | 981 | up(&efivars_lock); |
e14ab23d MF |
982 | |
983 | if (status && status != EFI_BUFFER_TOO_SMALL) | |
984 | return efi_status_to_err(status); | |
985 | ||
986 | return 0; | |
987 | ||
988 | out: | |
21b3ddd3 | 989 | up(&efivars_lock); |
e14ab23d MF |
990 | return err; |
991 | ||
992 | } | |
993 | EXPORT_SYMBOL_GPL(efivar_entry_set_get_size); | |
994 | ||
995 | /** | |
996 | * efivar_entry_iter_begin - begin iterating the variable list | |
997 | * | |
998 | * Lock the variable list to prevent entry insertion and removal until | |
999 | * efivar_entry_iter_end() is called. This function is usually used in | |
1000 | * conjunction with __efivar_entry_iter() or efivar_entry_iter(). | |
1001 | */ | |
21b3ddd3 | 1002 | int efivar_entry_iter_begin(void) |
e14ab23d | 1003 | { |
21b3ddd3 | 1004 | return down_interruptible(&efivars_lock); |
e14ab23d MF |
1005 | } |
1006 | EXPORT_SYMBOL_GPL(efivar_entry_iter_begin); | |
1007 | ||
1008 | /** | |
1009 | * efivar_entry_iter_end - finish iterating the variable list | |
1010 | * | |
1011 | * Unlock the variable list and allow modifications to the list again. | |
1012 | */ | |
1013 | void efivar_entry_iter_end(void) | |
1014 | { | |
21b3ddd3 | 1015 | up(&efivars_lock); |
e14ab23d MF |
1016 | } |
1017 | EXPORT_SYMBOL_GPL(efivar_entry_iter_end); | |
1018 | ||
1019 | /** | |
1020 | * __efivar_entry_iter - iterate over variable list | |
1021 | * @func: callback function | |
1022 | * @head: head of the variable list | |
1023 | * @data: function-specific data to pass to callback | |
1024 | * @prev: entry to begin iterating from | |
1025 | * | |
1026 | * Iterate over the list of EFI variables and call @func with every | |
1027 | * entry on the list. It is safe for @func to remove entries in the | |
1028 | * list via efivar_entry_delete(). | |
1029 | * | |
1030 | * You MUST call efivar_enter_iter_begin() before this function, and | |
1031 | * efivar_entry_iter_end() afterwards. | |
1032 | * | |
1033 | * It is possible to begin iteration from an arbitrary entry within | |
1034 | * the list by passing @prev. @prev is updated on return to point to | |
1035 | * the last entry passed to @func. To begin iterating from the | |
1036 | * beginning of the list @prev must be %NULL. | |
1037 | * | |
1038 | * The restrictions for @func are the same as documented for | |
1039 | * efivar_entry_iter(). | |
1040 | */ | |
1041 | int __efivar_entry_iter(int (*func)(struct efivar_entry *, void *), | |
1042 | struct list_head *head, void *data, | |
1043 | struct efivar_entry **prev) | |
1044 | { | |
1045 | struct efivar_entry *entry, *n; | |
1046 | int err = 0; | |
1047 | ||
1048 | if (!prev || !*prev) { | |
1049 | list_for_each_entry_safe(entry, n, head, list) { | |
1050 | err = func(entry, data); | |
1051 | if (err) | |
1052 | break; | |
1053 | } | |
1054 | ||
1055 | if (prev) | |
1056 | *prev = entry; | |
1057 | ||
1058 | return err; | |
1059 | } | |
1060 | ||
1061 | ||
1062 | list_for_each_entry_safe_continue((*prev), n, head, list) { | |
1063 | err = func(*prev, data); | |
1064 | if (err) | |
1065 | break; | |
1066 | } | |
1067 | ||
1068 | return err; | |
1069 | } | |
1070 | EXPORT_SYMBOL_GPL(__efivar_entry_iter); | |
1071 | ||
1072 | /** | |
1073 | * efivar_entry_iter - iterate over variable list | |
1074 | * @func: callback function | |
1075 | * @head: head of variable list | |
1076 | * @data: function-specific data to pass to callback | |
1077 | * | |
1078 | * Iterate over the list of EFI variables and call @func with every | |
1079 | * entry on the list. It is safe for @func to remove entries in the | |
1080 | * list via efivar_entry_delete() while iterating. | |
1081 | * | |
1082 | * Some notes for the callback function: | |
1083 | * - a non-zero return value indicates an error and terminates the loop | |
1084 | * - @func is called from atomic context | |
1085 | */ | |
1086 | int efivar_entry_iter(int (*func)(struct efivar_entry *, void *), | |
1087 | struct list_head *head, void *data) | |
1088 | { | |
1089 | int err = 0; | |
1090 | ||
21b3ddd3 SC |
1091 | err = efivar_entry_iter_begin(); |
1092 | if (err) | |
1093 | return err; | |
e14ab23d MF |
1094 | err = __efivar_entry_iter(func, head, data, NULL); |
1095 | efivar_entry_iter_end(); | |
1096 | ||
1097 | return err; | |
1098 | } | |
1099 | EXPORT_SYMBOL_GPL(efivar_entry_iter); | |
1100 | ||
1101 | /** | |
1102 | * efivars_kobject - get the kobject for the registered efivars | |
1103 | * | |
1104 | * If efivars_register() has not been called we return NULL, | |
1105 | * otherwise return the kobject used at registration time. | |
1106 | */ | |
1107 | struct kobject *efivars_kobject(void) | |
1108 | { | |
1109 | if (!__efivars) | |
1110 | return NULL; | |
1111 | ||
1112 | return __efivars->kobject; | |
1113 | } | |
1114 | EXPORT_SYMBOL_GPL(efivars_kobject); | |
1115 | ||
04851772 MF |
1116 | /** |
1117 | * efivar_run_worker - schedule the efivar worker thread | |
1118 | */ | |
1119 | void efivar_run_worker(void) | |
1120 | { | |
1121 | if (efivar_wq_enabled) | |
1122 | schedule_work(&efivar_work); | |
1123 | } | |
1124 | EXPORT_SYMBOL_GPL(efivar_run_worker); | |
1125 | ||
e14ab23d MF |
1126 | /** |
1127 | * efivars_register - register an efivars | |
1128 | * @efivars: efivars to register | |
1129 | * @ops: efivars operations | |
1130 | * @kobject: @efivars-specific kobject | |
1131 | * | |
1132 | * Only a single efivars can be registered at any time. | |
1133 | */ | |
1134 | int efivars_register(struct efivars *efivars, | |
1135 | const struct efivar_operations *ops, | |
1136 | struct kobject *kobject) | |
1137 | { | |
21b3ddd3 SC |
1138 | if (down_interruptible(&efivars_lock)) |
1139 | return -EINTR; | |
1140 | ||
e14ab23d MF |
1141 | efivars->ops = ops; |
1142 | efivars->kobject = kobject; | |
1143 | ||
1144 | __efivars = efivars; | |
21b3ddd3 SC |
1145 | |
1146 | pr_info("Registered efivars operations\n"); | |
1147 | ||
1148 | up(&efivars_lock); | |
1da177e4 | 1149 | |
e14ab23d MF |
1150 | return 0; |
1151 | } | |
1152 | EXPORT_SYMBOL_GPL(efivars_register); | |
1da177e4 | 1153 | |
e14ab23d MF |
1154 | /** |
1155 | * efivars_unregister - unregister an efivars | |
1156 | * @efivars: efivars to unregister | |
1157 | * | |
1158 | * The caller must have already removed every entry from the list, | |
1159 | * failure to do so is an error. | |
1160 | */ | |
1161 | int efivars_unregister(struct efivars *efivars) | |
1162 | { | |
1163 | int rv; | |
1164 | ||
21b3ddd3 SC |
1165 | if (down_interruptible(&efivars_lock)) |
1166 | return -EINTR; | |
1167 | ||
e14ab23d MF |
1168 | if (!__efivars) { |
1169 | printk(KERN_ERR "efivars not registered\n"); | |
1170 | rv = -EINVAL; | |
1171 | goto out; | |
1172 | } | |
1173 | ||
1174 | if (__efivars != efivars) { | |
1175 | rv = -EINVAL; | |
1176 | goto out; | |
1177 | } | |
1178 | ||
21b3ddd3 | 1179 | pr_info("Unregistered efivars operations\n"); |
e14ab23d MF |
1180 | __efivars = NULL; |
1181 | ||
1182 | rv = 0; | |
1183 | out: | |
21b3ddd3 | 1184 | up(&efivars_lock); |
e14ab23d | 1185 | return rv; |
76b53f7c | 1186 | } |
e14ab23d | 1187 | EXPORT_SYMBOL_GPL(efivars_unregister); |