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 { | |
168 | char *name; | |
a5d92ad3 | 169 | bool (*validate)(efi_char16_t *var_name, int match, u8 *data, |
54b3a4d3 | 170 | unsigned long len); |
fec6c20b MG |
171 | }; |
172 | ||
173 | static const struct variable_validate variable_validate[] = { | |
174 | { "BootNext", validate_uint16 }, | |
175 | { "BootOrder", validate_boot_order }, | |
176 | { "DriverOrder", validate_boot_order }, | |
177 | { "Boot*", validate_load_option }, | |
178 | { "Driver*", validate_load_option }, | |
179 | { "ConIn", validate_device_path }, | |
180 | { "ConInDev", validate_device_path }, | |
181 | { "ConOut", validate_device_path }, | |
182 | { "ConOutDev", validate_device_path }, | |
183 | { "ErrOut", validate_device_path }, | |
184 | { "ErrOutDev", validate_device_path }, | |
185 | { "Timeout", validate_uint16 }, | |
186 | { "Lang", validate_ascii_string }, | |
187 | { "PlatformLang", validate_ascii_string }, | |
188 | { "", NULL }, | |
189 | }; | |
190 | ||
e14ab23d | 191 | bool |
3dcb1f55 | 192 | efivar_validate(efi_char16_t *var_name, u8 *data, unsigned long data_size) |
fec6c20b MG |
193 | { |
194 | int i; | |
3dcb1f55 PJ |
195 | unsigned long utf8_size; |
196 | u8 *utf8_name; | |
197 | ||
198 | utf8_size = ucs2_utf8size(var_name); | |
199 | utf8_name = kmalloc(utf8_size + 1, GFP_KERNEL); | |
200 | if (!utf8_name) | |
201 | return false; | |
202 | ||
203 | ucs2_as_utf8(utf8_name, var_name, utf8_size); | |
204 | utf8_name[utf8_size] = '\0'; | |
fec6c20b MG |
205 | |
206 | for (i = 0; variable_validate[i].validate != NULL; i++) { | |
207 | const char *name = variable_validate[i].name; | |
208 | int match; | |
209 | ||
210 | for (match = 0; ; match++) { | |
211 | char c = name[match]; | |
3dcb1f55 | 212 | char u = utf8_name[match]; |
fec6c20b MG |
213 | |
214 | /* Wildcard in the matching name means we've matched */ | |
3dcb1f55 PJ |
215 | if (c == '*') { |
216 | kfree(utf8_name); | |
a5d92ad3 | 217 | return variable_validate[i].validate(var_name, |
3dcb1f55 PJ |
218 | match, data, data_size); |
219 | } | |
fec6c20b MG |
220 | |
221 | /* Case sensitive match */ | |
222 | if (c != u) | |
223 | break; | |
224 | ||
225 | /* Reached the end of the string while matching */ | |
3dcb1f55 PJ |
226 | if (!c) { |
227 | kfree(utf8_name); | |
a5d92ad3 | 228 | return variable_validate[i].validate(var_name, |
3dcb1f55 PJ |
229 | match, data, data_size); |
230 | } | |
fec6c20b MG |
231 | } |
232 | } | |
233 | ||
3dcb1f55 | 234 | kfree(utf8_name); |
fec6c20b MG |
235 | return true; |
236 | } | |
e14ab23d | 237 | EXPORT_SYMBOL_GPL(efivar_validate); |
fec6c20b | 238 | |
1da177e4 | 239 | static efi_status_t |
e14ab23d | 240 | check_var_size(u32 attributes, unsigned long size) |
68d92986 | 241 | { |
e14ab23d | 242 | const struct efivar_operations *fops = __efivars->ops; |
68d92986 | 243 | |
a614e192 | 244 | if (!fops->query_variable_store) |
68d92986 MG |
245 | return EFI_UNSUPPORTED; |
246 | ||
a614e192 | 247 | return fops->query_variable_store(attributes, size); |
68d92986 MG |
248 | } |
249 | ||
7253eaba MF |
250 | static int efi_status_to_err(efi_status_t status) |
251 | { | |
252 | int err; | |
253 | ||
254 | switch (status) { | |
e14ab23d MF |
255 | case EFI_SUCCESS: |
256 | err = 0; | |
257 | break; | |
7253eaba MF |
258 | case EFI_INVALID_PARAMETER: |
259 | err = -EINVAL; | |
260 | break; | |
261 | case EFI_OUT_OF_RESOURCES: | |
262 | err = -ENOSPC; | |
263 | break; | |
264 | case EFI_DEVICE_ERROR: | |
265 | err = -EIO; | |
266 | break; | |
267 | case EFI_WRITE_PROTECTED: | |
268 | err = -EROFS; | |
269 | break; | |
270 | case EFI_SECURITY_VIOLATION: | |
271 | err = -EACCES; | |
272 | break; | |
273 | case EFI_NOT_FOUND: | |
e14ab23d | 274 | err = -ENOENT; |
7253eaba MF |
275 | break; |
276 | default: | |
277 | err = -EINVAL; | |
278 | } | |
279 | ||
280 | return err; | |
281 | } | |
282 | ||
e14ab23d MF |
283 | static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor, |
284 | struct list_head *head) | |
a93bc0c6 SA |
285 | { |
286 | struct efivar_entry *entry, *n; | |
a93bc0c6 SA |
287 | unsigned long strsize1, strsize2; |
288 | bool found = false; | |
289 | ||
a614e192 | 290 | strsize1 = ucs2_strsize(variable_name, 1024); |
e14ab23d | 291 | list_for_each_entry_safe(entry, n, head, list) { |
a614e192 | 292 | strsize2 = ucs2_strsize(entry->var.VariableName, 1024); |
a93bc0c6 SA |
293 | if (strsize1 == strsize2 && |
294 | !memcmp(variable_name, &(entry->var.VariableName), | |
295 | strsize2) && | |
296 | !efi_guidcmp(entry->var.VendorGuid, | |
297 | *vendor)) { | |
298 | found = true; | |
299 | break; | |
300 | } | |
301 | } | |
302 | return found; | |
303 | } | |
304 | ||
ec50bd32 MF |
305 | /* |
306 | * Returns the size of variable_name, in bytes, including the | |
307 | * terminating NULL character, or variable_name_size if no NULL | |
308 | * character is found among the first variable_name_size bytes. | |
309 | */ | |
310 | static unsigned long var_name_strnsize(efi_char16_t *variable_name, | |
311 | unsigned long variable_name_size) | |
312 | { | |
313 | unsigned long len; | |
314 | efi_char16_t c; | |
315 | ||
316 | /* | |
317 | * The variable name is, by definition, a NULL-terminated | |
318 | * string, so make absolutely sure that variable_name_size is | |
319 | * the value we expect it to be. If not, return the real size. | |
320 | */ | |
321 | for (len = 2; len <= variable_name_size; len += sizeof(c)) { | |
322 | c = variable_name[(len / sizeof(c)) - 1]; | |
323 | if (!c) | |
324 | break; | |
325 | } | |
326 | ||
327 | return min(len, variable_name_size); | |
328 | } | |
329 | ||
e971318b MF |
330 | /* |
331 | * Print a warning when duplicate EFI variables are encountered and | |
332 | * disable the sysfs workqueue since the firmware is buggy. | |
333 | */ | |
b2fce819 | 334 | static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid, |
e971318b MF |
335 | unsigned long len16) |
336 | { | |
337 | size_t i, len8 = len16 / sizeof(efi_char16_t); | |
b2fce819 | 338 | char *str8; |
e971318b MF |
339 | |
340 | /* | |
341 | * Disable the workqueue since the algorithm it uses for | |
342 | * detecting new variables won't work with this buggy | |
343 | * implementation of GetNextVariableName(). | |
344 | */ | |
345 | efivar_wq_enabled = false; | |
346 | ||
b2fce819 MR |
347 | str8 = kzalloc(len8, GFP_KERNEL); |
348 | if (!str8) | |
e971318b MF |
349 | return; |
350 | ||
351 | for (i = 0; i < len8; i++) | |
b2fce819 | 352 | str8[i] = str16[i]; |
e971318b MF |
353 | |
354 | printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n", | |
b2fce819 MR |
355 | str8, vendor_guid); |
356 | kfree(str8); | |
e971318b MF |
357 | } |
358 | ||
e14ab23d MF |
359 | /** |
360 | * efivar_init - build the initial list of EFI variables | |
361 | * @func: callback function to invoke for every variable | |
362 | * @data: function-specific data to pass to @func | |
363 | * @atomic: do we need to execute the @func-loop atomically? | |
364 | * @duplicates: error if we encounter duplicates on @head? | |
365 | * @head: initialised head of variable list | |
366 | * | |
367 | * Get every EFI variable from the firmware and invoke @func. @func | |
368 | * should call efivar_entry_add() to build the list of variables. | |
369 | * | |
370 | * Returns 0 on success, or a kernel error code on failure. | |
371 | */ | |
372 | int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *), | |
373 | void *data, bool atomic, bool duplicates, | |
374 | struct list_head *head) | |
375 | { | |
376 | const struct efivar_operations *ops = __efivars->ops; | |
377 | unsigned long variable_name_size = 1024; | |
378 | efi_char16_t *variable_name; | |
379 | efi_status_t status; | |
380 | efi_guid_t vendor_guid; | |
381 | int err = 0; | |
382 | ||
383 | variable_name = kzalloc(variable_name_size, GFP_KERNEL); | |
384 | if (!variable_name) { | |
385 | printk(KERN_ERR "efivars: Memory allocation failed.\n"); | |
386 | return -ENOMEM; | |
605e70c7 LCY |
387 | } |
388 | ||
e14ab23d MF |
389 | spin_lock_irq(&__efivars->lock); |
390 | ||
1da177e4 LT |
391 | /* |
392 | * Per EFI spec, the maximum storage allocated for both | |
393 | * the variable name and variable data is 1024 bytes. | |
394 | */ | |
395 | ||
396 | do { | |
397 | variable_name_size = 1024; | |
398 | ||
3295814d | 399 | status = ops->get_next_variable(&variable_name_size, |
1da177e4 LT |
400 | variable_name, |
401 | &vendor_guid); | |
402 | switch (status) { | |
403 | case EFI_SUCCESS: | |
e14ab23d MF |
404 | if (!atomic) |
405 | spin_unlock_irq(&__efivars->lock); | |
406 | ||
ec50bd32 MF |
407 | variable_name_size = var_name_strnsize(variable_name, |
408 | variable_name_size); | |
e971318b MF |
409 | |
410 | /* | |
411 | * Some firmware implementations return the | |
412 | * same variable name on multiple calls to | |
413 | * get_next_variable(). Terminate the loop | |
414 | * immediately as there is no guarantee that | |
415 | * we'll ever see a different variable name, | |
416 | * and may end up looping here forever. | |
417 | */ | |
e14ab23d MF |
418 | if (duplicates && |
419 | variable_is_present(variable_name, &vendor_guid, head)) { | |
e971318b MF |
420 | dup_variable_bug(variable_name, &vendor_guid, |
421 | variable_name_size); | |
e14ab23d MF |
422 | if (!atomic) |
423 | spin_lock_irq(&__efivars->lock); | |
424 | ||
e971318b MF |
425 | status = EFI_NOT_FOUND; |
426 | break; | |
427 | } | |
428 | ||
e14ab23d MF |
429 | err = func(variable_name, vendor_guid, variable_name_size, data); |
430 | if (err) | |
431 | status = EFI_NOT_FOUND; | |
432 | ||
433 | if (!atomic) | |
434 | spin_lock_irq(&__efivars->lock); | |
435 | ||
1da177e4 LT |
436 | break; |
437 | case EFI_NOT_FOUND: | |
438 | break; | |
439 | default: | |
440 | printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n", | |
441 | status); | |
442 | status = EFI_NOT_FOUND; | |
443 | break; | |
444 | } | |
e14ab23d | 445 | |
1da177e4 LT |
446 | } while (status != EFI_NOT_FOUND); |
447 | ||
e14ab23d MF |
448 | spin_unlock_irq(&__efivars->lock); |
449 | ||
450 | kfree(variable_name); | |
451 | ||
452 | return err; | |
453 | } | |
454 | EXPORT_SYMBOL_GPL(efivar_init); | |
455 | ||
456 | /** | |
457 | * efivar_entry_add - add entry to variable list | |
458 | * @entry: entry to add to list | |
459 | * @head: list head | |
460 | */ | |
461 | void efivar_entry_add(struct efivar_entry *entry, struct list_head *head) | |
462 | { | |
463 | spin_lock_irq(&__efivars->lock); | |
464 | list_add(&entry->list, head); | |
465 | spin_unlock_irq(&__efivars->lock); | |
466 | } | |
467 | EXPORT_SYMBOL_GPL(efivar_entry_add); | |
468 | ||
469 | /** | |
470 | * efivar_entry_remove - remove entry from variable list | |
471 | * @entry: entry to remove from list | |
472 | */ | |
473 | void efivar_entry_remove(struct efivar_entry *entry) | |
474 | { | |
475 | spin_lock_irq(&__efivars->lock); | |
476 | list_del(&entry->list); | |
477 | spin_unlock_irq(&__efivars->lock); | |
478 | } | |
479 | EXPORT_SYMBOL_GPL(efivar_entry_remove); | |
480 | ||
481 | /* | |
482 | * efivar_entry_list_del_unlock - remove entry from variable list | |
483 | * @entry: entry to remove | |
484 | * | |
485 | * Remove @entry from the variable list and release the list lock. | |
486 | * | |
487 | * NOTE: slightly weird locking semantics here - we expect to be | |
488 | * called with the efivars lock already held, and we release it before | |
489 | * returning. This is because this function is usually called after | |
490 | * set_variable() while the lock is still held. | |
491 | */ | |
492 | static void efivar_entry_list_del_unlock(struct efivar_entry *entry) | |
493 | { | |
aee530cf | 494 | lockdep_assert_held(&__efivars->lock); |
e14ab23d MF |
495 | |
496 | list_del(&entry->list); | |
497 | spin_unlock_irq(&__efivars->lock); | |
498 | } | |
499 | ||
500 | /** | |
501 | * __efivar_entry_delete - delete an EFI variable | |
502 | * @entry: entry containing EFI variable to delete | |
503 | * | |
a9499fa7 TG |
504 | * Delete the variable from the firmware but leave @entry on the |
505 | * variable list. | |
e14ab23d | 506 | * |
a9499fa7 TG |
507 | * This function differs from efivar_entry_delete() because it does |
508 | * not remove @entry from the variable list. Also, it is safe to be | |
509 | * called from within a efivar_entry_iter_begin() and | |
e14ab23d MF |
510 | * efivar_entry_iter_end() region, unlike efivar_entry_delete(). |
511 | * | |
512 | * Returns 0 on success, or a converted EFI status code if | |
a9499fa7 | 513 | * set_variable() fails. |
e14ab23d MF |
514 | */ |
515 | int __efivar_entry_delete(struct efivar_entry *entry) | |
516 | { | |
517 | const struct efivar_operations *ops = __efivars->ops; | |
518 | efi_status_t status; | |
519 | ||
aee530cf | 520 | lockdep_assert_held(&__efivars->lock); |
e14ab23d MF |
521 | |
522 | status = ops->set_variable(entry->var.VariableName, | |
523 | &entry->var.VendorGuid, | |
524 | 0, 0, NULL); | |
e14ab23d | 525 | |
a9499fa7 | 526 | return efi_status_to_err(status); |
e14ab23d MF |
527 | } |
528 | EXPORT_SYMBOL_GPL(__efivar_entry_delete); | |
529 | ||
530 | /** | |
531 | * efivar_entry_delete - delete variable and remove entry from list | |
532 | * @entry: entry containing variable to delete | |
533 | * | |
534 | * Delete the variable from the firmware and remove @entry from the | |
535 | * variable list. It is the caller's responsibility to free @entry | |
536 | * once we return. | |
537 | * | |
538 | * Returns 0 on success, or a converted EFI status code if | |
539 | * set_variable() fails. | |
540 | */ | |
541 | int efivar_entry_delete(struct efivar_entry *entry) | |
542 | { | |
543 | const struct efivar_operations *ops = __efivars->ops; | |
544 | efi_status_t status; | |
545 | ||
546 | spin_lock_irq(&__efivars->lock); | |
547 | status = ops->set_variable(entry->var.VariableName, | |
548 | &entry->var.VendorGuid, | |
549 | 0, 0, NULL); | |
550 | if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) { | |
551 | spin_unlock_irq(&__efivars->lock); | |
552 | return efi_status_to_err(status); | |
553 | } | |
554 | ||
555 | efivar_entry_list_del_unlock(entry); | |
556 | return 0; | |
557 | } | |
558 | EXPORT_SYMBOL_GPL(efivar_entry_delete); | |
559 | ||
560 | /** | |
561 | * efivar_entry_set - call set_variable() | |
562 | * @entry: entry containing the EFI variable to write | |
563 | * @attributes: variable attributes | |
564 | * @size: size of @data buffer | |
565 | * @data: buffer containing variable data | |
566 | * @head: head of variable list | |
567 | * | |
568 | * Calls set_variable() for an EFI variable. If creating a new EFI | |
569 | * variable, this function is usually followed by efivar_entry_add(). | |
570 | * | |
571 | * Before writing the variable, the remaining EFI variable storage | |
572 | * space is checked to ensure there is enough room available. | |
573 | * | |
574 | * If @head is not NULL a lookup is performed to determine whether | |
575 | * the entry is already on the list. | |
576 | * | |
577 | * Returns 0 on success, -EEXIST if a lookup is performed and the entry | |
578 | * already exists on the list, or a converted EFI status code if | |
579 | * set_variable() fails. | |
580 | */ | |
581 | int efivar_entry_set(struct efivar_entry *entry, u32 attributes, | |
582 | unsigned long size, void *data, struct list_head *head) | |
583 | { | |
584 | const struct efivar_operations *ops = __efivars->ops; | |
585 | efi_status_t status; | |
586 | efi_char16_t *name = entry->var.VariableName; | |
587 | efi_guid_t vendor = entry->var.VendorGuid; | |
588 | ||
589 | spin_lock_irq(&__efivars->lock); | |
590 | ||
591 | if (head && efivar_entry_find(name, vendor, head, false)) { | |
592 | spin_unlock_irq(&__efivars->lock); | |
593 | return -EEXIST; | |
594 | } | |
595 | ||
a614e192 | 596 | status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); |
e14ab23d MF |
597 | if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED) |
598 | status = ops->set_variable(name, &vendor, | |
599 | attributes, size, data); | |
600 | ||
601 | spin_unlock_irq(&__efivars->lock); | |
602 | ||
603 | return efi_status_to_err(status); | |
a9499fa7 | 604 | |
e14ab23d MF |
605 | } |
606 | EXPORT_SYMBOL_GPL(efivar_entry_set); | |
607 | ||
6d80dba1 MF |
608 | /* |
609 | * efivar_entry_set_nonblocking - call set_variable_nonblocking() | |
610 | * | |
611 | * This function is guaranteed to not block and is suitable for calling | |
612 | * from crash/panic handlers. | |
613 | * | |
614 | * Crucially, this function will not block if it cannot acquire | |
615 | * __efivars->lock. Instead, it returns -EBUSY. | |
616 | */ | |
617 | static int | |
618 | efivar_entry_set_nonblocking(efi_char16_t *name, efi_guid_t vendor, | |
619 | u32 attributes, unsigned long size, void *data) | |
620 | { | |
621 | const struct efivar_operations *ops = __efivars->ops; | |
622 | unsigned long flags; | |
623 | efi_status_t status; | |
624 | ||
625 | if (!spin_trylock_irqsave(&__efivars->lock, flags)) | |
626 | return -EBUSY; | |
627 | ||
628 | status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); | |
629 | if (status != EFI_SUCCESS) { | |
630 | spin_unlock_irqrestore(&__efivars->lock, flags); | |
631 | return -ENOSPC; | |
632 | } | |
633 | ||
634 | status = ops->set_variable_nonblocking(name, &vendor, attributes, | |
635 | size, data); | |
636 | ||
637 | spin_unlock_irqrestore(&__efivars->lock, flags); | |
638 | return efi_status_to_err(status); | |
639 | } | |
640 | ||
e14ab23d MF |
641 | /** |
642 | * efivar_entry_set_safe - call set_variable() if enough space in firmware | |
643 | * @name: buffer containing the variable name | |
644 | * @vendor: variable vendor guid | |
645 | * @attributes: variable attributes | |
646 | * @block: can we block in this context? | |
647 | * @size: size of @data buffer | |
648 | * @data: buffer containing variable data | |
649 | * | |
650 | * Ensures there is enough free storage in the firmware for this variable, and | |
651 | * if so, calls set_variable(). If creating a new EFI variable, this function | |
652 | * is usually followed by efivar_entry_add(). | |
653 | * | |
654 | * Returns 0 on success, -ENOSPC if the firmware does not have enough | |
655 | * space for set_variable() to succeed, or a converted EFI status code | |
656 | * if set_variable() fails. | |
657 | */ | |
658 | int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes, | |
659 | bool block, unsigned long size, void *data) | |
660 | { | |
661 | const struct efivar_operations *ops = __efivars->ops; | |
662 | unsigned long flags; | |
663 | efi_status_t status; | |
664 | ||
a614e192 | 665 | if (!ops->query_variable_store) |
e14ab23d MF |
666 | return -ENOSYS; |
667 | ||
6d80dba1 MF |
668 | /* |
669 | * If the EFI variable backend provides a non-blocking | |
670 | * ->set_variable() operation and we're in a context where we | |
671 | * cannot block, then we need to use it to avoid live-locks, | |
672 | * since the implication is that the regular ->set_variable() | |
673 | * will block. | |
674 | * | |
675 | * If no ->set_variable_nonblocking() is provided then | |
676 | * ->set_variable() is assumed to be non-blocking. | |
677 | */ | |
678 | if (!block && ops->set_variable_nonblocking) | |
679 | return efivar_entry_set_nonblocking(name, vendor, attributes, | |
680 | size, data); | |
681 | ||
85c90716 DC |
682 | if (!block) { |
683 | if (!spin_trylock_irqsave(&__efivars->lock, flags)) | |
684 | return -EBUSY; | |
685 | } else { | |
e14ab23d | 686 | spin_lock_irqsave(&__efivars->lock, flags); |
85c90716 | 687 | } |
e14ab23d | 688 | |
a614e192 | 689 | status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); |
e14ab23d MF |
690 | if (status != EFI_SUCCESS) { |
691 | spin_unlock_irqrestore(&__efivars->lock, flags); | |
692 | return -ENOSPC; | |
693 | } | |
694 | ||
695 | status = ops->set_variable(name, &vendor, attributes, size, data); | |
696 | ||
697 | spin_unlock_irqrestore(&__efivars->lock, flags); | |
698 | ||
699 | return efi_status_to_err(status); | |
700 | } | |
701 | EXPORT_SYMBOL_GPL(efivar_entry_set_safe); | |
702 | ||
703 | /** | |
704 | * efivar_entry_find - search for an entry | |
705 | * @name: the EFI variable name | |
706 | * @guid: the EFI variable vendor's guid | |
707 | * @head: head of the variable list | |
708 | * @remove: should we remove the entry from the list? | |
709 | * | |
710 | * Search for an entry on the variable list that has the EFI variable | |
711 | * name @name and vendor guid @guid. If an entry is found on the list | |
712 | * and @remove is true, the entry is removed from the list. | |
713 | * | |
714 | * The caller MUST call efivar_entry_iter_begin() and | |
715 | * efivar_entry_iter_end() before and after the invocation of this | |
716 | * function, respectively. | |
717 | * | |
718 | * Returns the entry if found on the list, %NULL otherwise. | |
719 | */ | |
720 | struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid, | |
721 | struct list_head *head, bool remove) | |
722 | { | |
723 | struct efivar_entry *entry, *n; | |
724 | int strsize1, strsize2; | |
725 | bool found = false; | |
726 | ||
aee530cf | 727 | lockdep_assert_held(&__efivars->lock); |
e14ab23d MF |
728 | |
729 | list_for_each_entry_safe(entry, n, head, list) { | |
a614e192 MF |
730 | strsize1 = ucs2_strsize(name, 1024); |
731 | strsize2 = ucs2_strsize(entry->var.VariableName, 1024); | |
e14ab23d MF |
732 | if (strsize1 == strsize2 && |
733 | !memcmp(name, &(entry->var.VariableName), strsize1) && | |
734 | !efi_guidcmp(guid, entry->var.VendorGuid)) { | |
735 | found = true; | |
736 | break; | |
737 | } | |
738 | } | |
739 | ||
740 | if (!found) | |
741 | return NULL; | |
742 | ||
e0d59733 SA |
743 | if (remove) { |
744 | if (entry->scanning) { | |
745 | /* | |
746 | * The entry will be deleted | |
747 | * after scanning is completed. | |
748 | */ | |
749 | entry->deleting = true; | |
750 | } else | |
751 | list_del(&entry->list); | |
752 | } | |
e14ab23d MF |
753 | |
754 | return entry; | |
755 | } | |
756 | EXPORT_SYMBOL_GPL(efivar_entry_find); | |
757 | ||
758 | /** | |
8a415b8c | 759 | * efivar_entry_size - obtain the size of a variable |
e14ab23d MF |
760 | * @entry: entry for this variable |
761 | * @size: location to store the variable's size | |
e14ab23d | 762 | */ |
8a415b8c | 763 | int efivar_entry_size(struct efivar_entry *entry, unsigned long *size) |
e14ab23d MF |
764 | { |
765 | const struct efivar_operations *ops = __efivars->ops; | |
766 | efi_status_t status; | |
767 | ||
e14ab23d | 768 | *size = 0; |
8a415b8c MF |
769 | |
770 | spin_lock_irq(&__efivars->lock); | |
e14ab23d MF |
771 | status = ops->get_variable(entry->var.VariableName, |
772 | &entry->var.VendorGuid, NULL, size, NULL); | |
8a415b8c MF |
773 | spin_unlock_irq(&__efivars->lock); |
774 | ||
e14ab23d MF |
775 | if (status != EFI_BUFFER_TOO_SMALL) |
776 | return efi_status_to_err(status); | |
777 | ||
778 | return 0; | |
779 | } | |
8a415b8c | 780 | EXPORT_SYMBOL_GPL(efivar_entry_size); |
e14ab23d MF |
781 | |
782 | /** | |
8a415b8c MF |
783 | * __efivar_entry_get - call get_variable() |
784 | * @entry: read data for this variable | |
785 | * @attributes: variable attributes | |
786 | * @size: size of @data buffer | |
787 | * @data: buffer to store variable data | |
788 | * | |
789 | * The caller MUST call efivar_entry_iter_begin() and | |
790 | * efivar_entry_iter_end() before and after the invocation of this | |
791 | * function, respectively. | |
e14ab23d | 792 | */ |
8a415b8c MF |
793 | int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes, |
794 | unsigned long *size, void *data) | |
e14ab23d MF |
795 | { |
796 | const struct efivar_operations *ops = __efivars->ops; | |
797 | efi_status_t status; | |
798 | ||
aee530cf | 799 | lockdep_assert_held(&__efivars->lock); |
e14ab23d | 800 | |
e14ab23d | 801 | status = ops->get_variable(entry->var.VariableName, |
8a415b8c MF |
802 | &entry->var.VendorGuid, |
803 | attributes, size, data); | |
e14ab23d | 804 | |
8a415b8c | 805 | return efi_status_to_err(status); |
e14ab23d | 806 | } |
8a415b8c | 807 | EXPORT_SYMBOL_GPL(__efivar_entry_get); |
e14ab23d MF |
808 | |
809 | /** | |
810 | * efivar_entry_get - call get_variable() | |
811 | * @entry: read data for this variable | |
812 | * @attributes: variable attributes | |
813 | * @size: size of @data buffer | |
814 | * @data: buffer to store variable data | |
815 | */ | |
816 | int efivar_entry_get(struct efivar_entry *entry, u32 *attributes, | |
817 | unsigned long *size, void *data) | |
818 | { | |
819 | const struct efivar_operations *ops = __efivars->ops; | |
820 | efi_status_t status; | |
821 | ||
822 | spin_lock_irq(&__efivars->lock); | |
823 | status = ops->get_variable(entry->var.VariableName, | |
824 | &entry->var.VendorGuid, | |
825 | attributes, size, data); | |
826 | spin_unlock_irq(&__efivars->lock); | |
827 | ||
828 | return efi_status_to_err(status); | |
829 | } | |
830 | EXPORT_SYMBOL_GPL(efivar_entry_get); | |
831 | ||
832 | /** | |
833 | * efivar_entry_set_get_size - call set_variable() and get new size (atomic) | |
834 | * @entry: entry containing variable to set and get | |
835 | * @attributes: attributes of variable to be written | |
836 | * @size: size of data buffer | |
837 | * @data: buffer containing data to write | |
838 | * @set: did the set_variable() call succeed? | |
839 | * | |
840 | * This is a pretty special (complex) function. See efivarfs_file_write(). | |
841 | * | |
842 | * Atomically call set_variable() for @entry and if the call is | |
843 | * successful, return the new size of the variable from get_variable() | |
844 | * in @size. The success of set_variable() is indicated by @set. | |
845 | * | |
846 | * Returns 0 on success, -EINVAL if the variable data is invalid, | |
847 | * -ENOSPC if the firmware does not have enough available space, or a | |
848 | * converted EFI status code if either of set_variable() or | |
849 | * get_variable() fail. | |
850 | * | |
851 | * If the EFI variable does not exist when calling set_variable() | |
852 | * (EFI_NOT_FOUND), @entry is removed from the variable list. | |
853 | */ | |
854 | int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes, | |
855 | unsigned long *size, void *data, bool *set) | |
856 | { | |
857 | const struct efivar_operations *ops = __efivars->ops; | |
858 | efi_char16_t *name = entry->var.VariableName; | |
859 | efi_guid_t *vendor = &entry->var.VendorGuid; | |
860 | efi_status_t status; | |
861 | int err; | |
862 | ||
863 | *set = false; | |
864 | ||
a5d92ad3 | 865 | if (efivar_validate(name, data, *size) == false) |
e14ab23d MF |
866 | return -EINVAL; |
867 | ||
868 | /* | |
869 | * The lock here protects the get_variable call, the conditional | |
870 | * set_variable call, and removal of the variable from the efivars | |
871 | * list (in the case of an authenticated delete). | |
872 | */ | |
873 | spin_lock_irq(&__efivars->lock); | |
874 | ||
875 | /* | |
876 | * Ensure that the available space hasn't shrunk below the safe level | |
877 | */ | |
a614e192 | 878 | status = check_var_size(attributes, *size + ucs2_strsize(name, 1024)); |
e14ab23d MF |
879 | if (status != EFI_SUCCESS) { |
880 | if (status != EFI_UNSUPPORTED) { | |
881 | err = efi_status_to_err(status); | |
882 | goto out; | |
883 | } | |
884 | ||
885 | if (*size > 65536) { | |
886 | err = -ENOSPC; | |
887 | goto out; | |
888 | } | |
889 | } | |
890 | ||
891 | status = ops->set_variable(name, vendor, attributes, *size, data); | |
892 | if (status != EFI_SUCCESS) { | |
893 | err = efi_status_to_err(status); | |
894 | goto out; | |
895 | } | |
896 | ||
897 | *set = true; | |
898 | ||
899 | /* | |
900 | * Writing to the variable may have caused a change in size (which | |
901 | * could either be an append or an overwrite), or the variable to be | |
902 | * deleted. Perform a GetVariable() so we can tell what actually | |
903 | * happened. | |
904 | */ | |
905 | *size = 0; | |
906 | status = ops->get_variable(entry->var.VariableName, | |
907 | &entry->var.VendorGuid, | |
908 | NULL, size, NULL); | |
909 | ||
910 | if (status == EFI_NOT_FOUND) | |
911 | efivar_entry_list_del_unlock(entry); | |
912 | else | |
913 | spin_unlock_irq(&__efivars->lock); | |
914 | ||
915 | if (status && status != EFI_BUFFER_TOO_SMALL) | |
916 | return efi_status_to_err(status); | |
917 | ||
918 | return 0; | |
919 | ||
920 | out: | |
921 | spin_unlock_irq(&__efivars->lock); | |
922 | return err; | |
923 | ||
924 | } | |
925 | EXPORT_SYMBOL_GPL(efivar_entry_set_get_size); | |
926 | ||
927 | /** | |
928 | * efivar_entry_iter_begin - begin iterating the variable list | |
929 | * | |
930 | * Lock the variable list to prevent entry insertion and removal until | |
931 | * efivar_entry_iter_end() is called. This function is usually used in | |
932 | * conjunction with __efivar_entry_iter() or efivar_entry_iter(). | |
933 | */ | |
934 | void efivar_entry_iter_begin(void) | |
935 | { | |
936 | spin_lock_irq(&__efivars->lock); | |
937 | } | |
938 | EXPORT_SYMBOL_GPL(efivar_entry_iter_begin); | |
939 | ||
940 | /** | |
941 | * efivar_entry_iter_end - finish iterating the variable list | |
942 | * | |
943 | * Unlock the variable list and allow modifications to the list again. | |
944 | */ | |
945 | void efivar_entry_iter_end(void) | |
946 | { | |
947 | spin_unlock_irq(&__efivars->lock); | |
948 | } | |
949 | EXPORT_SYMBOL_GPL(efivar_entry_iter_end); | |
950 | ||
951 | /** | |
952 | * __efivar_entry_iter - iterate over variable list | |
953 | * @func: callback function | |
954 | * @head: head of the variable list | |
955 | * @data: function-specific data to pass to callback | |
956 | * @prev: entry to begin iterating from | |
957 | * | |
958 | * Iterate over the list of EFI variables and call @func with every | |
959 | * entry on the list. It is safe for @func to remove entries in the | |
960 | * list via efivar_entry_delete(). | |
961 | * | |
962 | * You MUST call efivar_enter_iter_begin() before this function, and | |
963 | * efivar_entry_iter_end() afterwards. | |
964 | * | |
965 | * It is possible to begin iteration from an arbitrary entry within | |
966 | * the list by passing @prev. @prev is updated on return to point to | |
967 | * the last entry passed to @func. To begin iterating from the | |
968 | * beginning of the list @prev must be %NULL. | |
969 | * | |
970 | * The restrictions for @func are the same as documented for | |
971 | * efivar_entry_iter(). | |
972 | */ | |
973 | int __efivar_entry_iter(int (*func)(struct efivar_entry *, void *), | |
974 | struct list_head *head, void *data, | |
975 | struct efivar_entry **prev) | |
976 | { | |
977 | struct efivar_entry *entry, *n; | |
978 | int err = 0; | |
979 | ||
980 | if (!prev || !*prev) { | |
981 | list_for_each_entry_safe(entry, n, head, list) { | |
982 | err = func(entry, data); | |
983 | if (err) | |
984 | break; | |
985 | } | |
986 | ||
987 | if (prev) | |
988 | *prev = entry; | |
989 | ||
990 | return err; | |
991 | } | |
992 | ||
993 | ||
994 | list_for_each_entry_safe_continue((*prev), n, head, list) { | |
995 | err = func(*prev, data); | |
996 | if (err) | |
997 | break; | |
998 | } | |
999 | ||
1000 | return err; | |
1001 | } | |
1002 | EXPORT_SYMBOL_GPL(__efivar_entry_iter); | |
1003 | ||
1004 | /** | |
1005 | * efivar_entry_iter - iterate over variable list | |
1006 | * @func: callback function | |
1007 | * @head: head of variable list | |
1008 | * @data: function-specific data to pass to callback | |
1009 | * | |
1010 | * Iterate over the list of EFI variables and call @func with every | |
1011 | * entry on the list. It is safe for @func to remove entries in the | |
1012 | * list via efivar_entry_delete() while iterating. | |
1013 | * | |
1014 | * Some notes for the callback function: | |
1015 | * - a non-zero return value indicates an error and terminates the loop | |
1016 | * - @func is called from atomic context | |
1017 | */ | |
1018 | int efivar_entry_iter(int (*func)(struct efivar_entry *, void *), | |
1019 | struct list_head *head, void *data) | |
1020 | { | |
1021 | int err = 0; | |
1022 | ||
1023 | efivar_entry_iter_begin(); | |
1024 | err = __efivar_entry_iter(func, head, data, NULL); | |
1025 | efivar_entry_iter_end(); | |
1026 | ||
1027 | return err; | |
1028 | } | |
1029 | EXPORT_SYMBOL_GPL(efivar_entry_iter); | |
1030 | ||
1031 | /** | |
1032 | * efivars_kobject - get the kobject for the registered efivars | |
1033 | * | |
1034 | * If efivars_register() has not been called we return NULL, | |
1035 | * otherwise return the kobject used at registration time. | |
1036 | */ | |
1037 | struct kobject *efivars_kobject(void) | |
1038 | { | |
1039 | if (!__efivars) | |
1040 | return NULL; | |
1041 | ||
1042 | return __efivars->kobject; | |
1043 | } | |
1044 | EXPORT_SYMBOL_GPL(efivars_kobject); | |
1045 | ||
04851772 MF |
1046 | /** |
1047 | * efivar_run_worker - schedule the efivar worker thread | |
1048 | */ | |
1049 | void efivar_run_worker(void) | |
1050 | { | |
1051 | if (efivar_wq_enabled) | |
1052 | schedule_work(&efivar_work); | |
1053 | } | |
1054 | EXPORT_SYMBOL_GPL(efivar_run_worker); | |
1055 | ||
e14ab23d MF |
1056 | /** |
1057 | * efivars_register - register an efivars | |
1058 | * @efivars: efivars to register | |
1059 | * @ops: efivars operations | |
1060 | * @kobject: @efivars-specific kobject | |
1061 | * | |
1062 | * Only a single efivars can be registered at any time. | |
1063 | */ | |
1064 | int efivars_register(struct efivars *efivars, | |
1065 | const struct efivar_operations *ops, | |
1066 | struct kobject *kobject) | |
1067 | { | |
1068 | spin_lock_init(&efivars->lock); | |
1069 | efivars->ops = ops; | |
1070 | efivars->kobject = kobject; | |
1071 | ||
1072 | __efivars = efivars; | |
1da177e4 | 1073 | |
e14ab23d MF |
1074 | return 0; |
1075 | } | |
1076 | EXPORT_SYMBOL_GPL(efivars_register); | |
1da177e4 | 1077 | |
e14ab23d MF |
1078 | /** |
1079 | * efivars_unregister - unregister an efivars | |
1080 | * @efivars: efivars to unregister | |
1081 | * | |
1082 | * The caller must have already removed every entry from the list, | |
1083 | * failure to do so is an error. | |
1084 | */ | |
1085 | int efivars_unregister(struct efivars *efivars) | |
1086 | { | |
1087 | int rv; | |
1088 | ||
1089 | if (!__efivars) { | |
1090 | printk(KERN_ERR "efivars not registered\n"); | |
1091 | rv = -EINVAL; | |
1092 | goto out; | |
1093 | } | |
1094 | ||
1095 | if (__efivars != efivars) { | |
1096 | rv = -EINVAL; | |
1097 | goto out; | |
1098 | } | |
1099 | ||
1100 | __efivars = NULL; | |
1101 | ||
1102 | rv = 0; | |
1103 | out: | |
1104 | return rv; | |
76b53f7c | 1105 | } |
e14ab23d | 1106 | EXPORT_SYMBOL_GPL(efivars_unregister); |