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4febfb8d | 1 | // SPDX-License-Identifier: GPL-2.0+ |
1da177e4 | 2 | /* |
a9499fa7 | 3 | * Originally from efivars.c |
1da177e4 LT |
4 | * |
5 | * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com> | |
6 | * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com> | |
1da177e4 LT |
7 | */ |
8 | ||
beeb107c JH |
9 | #define pr_fmt(fmt) "efivars: " fmt |
10 | ||
1da177e4 | 11 | #include <linux/types.h> |
8a254d90 | 12 | #include <linux/sizes.h> |
1da177e4 LT |
13 | #include <linux/errno.h> |
14 | #include <linux/init.h> | |
1da177e4 LT |
15 | #include <linux/module.h> |
16 | #include <linux/string.h> | |
17 | #include <linux/smp.h> | |
18 | #include <linux/efi.h> | |
a614e192 | 19 | #include <linux/ucs2_string.h> |
1da177e4 | 20 | |
4423d779 MF |
21 | /* Private pointer to registered efivars */ |
22 | static struct efivars *__efivars; | |
5d9db883 | 23 | |
48380368 | 24 | static DEFINE_SEMAPHORE(efivars_lock, 1); |
217b27d4 | 25 | |
f11a74b4 AB |
26 | static efi_status_t check_var_size(bool nonblocking, u32 attributes, |
27 | unsigned long size) | |
ca0e30dc | 28 | { |
ab2180a1 | 29 | const struct efivar_operations *fops; |
f11a74b4 | 30 | efi_status_t status; |
ab2180a1 | 31 | |
ab2180a1 | 32 | fops = __efivars->ops; |
ca0e30dc AB |
33 | |
34 | if (!fops->query_variable_store) | |
f11a74b4 AB |
35 | status = EFI_UNSUPPORTED; |
36 | else | |
37 | status = fops->query_variable_store(attributes, size, | |
38 | nonblocking); | |
39 | if (status == EFI_UNSUPPORTED) | |
8a254d90 | 40 | return (size <= SZ_64K) ? EFI_SUCCESS : EFI_OUT_OF_RESOURCES; |
f11a74b4 | 41 | return status; |
68d92986 MG |
42 | } |
43 | ||
e14ab23d | 44 | /** |
ade7fd90 | 45 | * efivar_is_available - check if efivars is available |
e14ab23d | 46 | * |
ade7fd90 | 47 | * @return true iff evivars is currently registered |
e14ab23d | 48 | */ |
ade7fd90 | 49 | bool efivar_is_available(void) |
e14ab23d | 50 | { |
ade7fd90 | 51 | return __efivars != NULL; |
e14ab23d | 52 | } |
ade7fd90 | 53 | EXPORT_SYMBOL_GPL(efivar_is_available); |
e14ab23d MF |
54 | |
55 | /** | |
56 | * efivars_register - register an efivars | |
57 | * @efivars: efivars to register | |
58 | * @ops: efivars operations | |
e14ab23d MF |
59 | * |
60 | * Only a single efivars can be registered at any time. | |
61 | */ | |
62 | int efivars_register(struct efivars *efivars, | |
ade7fd90 | 63 | const struct efivar_operations *ops) |
e14ab23d | 64 | { |
0217a40d | 65 | int rv; |
94f7f618 | 66 | int event; |
0217a40d | 67 | |
21b3ddd3 SC |
68 | if (down_interruptible(&efivars_lock)) |
69 | return -EINTR; | |
70 | ||
0217a40d JH |
71 | if (__efivars) { |
72 | pr_warn("efivars already registered\n"); | |
73 | rv = -EBUSY; | |
74 | goto out; | |
75 | } | |
76 | ||
e14ab23d | 77 | efivars->ops = ops; |
e14ab23d MF |
78 | |
79 | __efivars = efivars; | |
21b3ddd3 | 80 | |
94f7f618 MK |
81 | if (efivar_supports_writes()) |
82 | event = EFIVAR_OPS_RDWR; | |
83 | else | |
84 | event = EFIVAR_OPS_RDONLY; | |
85 | ||
86 | blocking_notifier_call_chain(&efivar_ops_nh, event, NULL); | |
87 | ||
21b3ddd3 | 88 | pr_info("Registered efivars operations\n"); |
0217a40d JH |
89 | rv = 0; |
90 | out: | |
21b3ddd3 | 91 | up(&efivars_lock); |
1da177e4 | 92 | |
0217a40d | 93 | return rv; |
e14ab23d MF |
94 | } |
95 | EXPORT_SYMBOL_GPL(efivars_register); | |
1da177e4 | 96 | |
e14ab23d MF |
97 | /** |
98 | * efivars_unregister - unregister an efivars | |
99 | * @efivars: efivars to unregister | |
100 | * | |
101 | * The caller must have already removed every entry from the list, | |
102 | * failure to do so is an error. | |
103 | */ | |
104 | int efivars_unregister(struct efivars *efivars) | |
105 | { | |
106 | int rv; | |
107 | ||
21b3ddd3 SC |
108 | if (down_interruptible(&efivars_lock)) |
109 | return -EINTR; | |
110 | ||
e14ab23d | 111 | if (!__efivars) { |
beeb107c | 112 | pr_err("efivars not registered\n"); |
e14ab23d MF |
113 | rv = -EINVAL; |
114 | goto out; | |
115 | } | |
116 | ||
117 | if (__efivars != efivars) { | |
118 | rv = -EINVAL; | |
119 | goto out; | |
120 | } | |
121 | ||
21b3ddd3 | 122 | pr_info("Unregistered efivars operations\n"); |
e14ab23d MF |
123 | __efivars = NULL; |
124 | ||
125 | rv = 0; | |
126 | out: | |
21b3ddd3 | 127 | up(&efivars_lock); |
e14ab23d | 128 | return rv; |
76b53f7c | 129 | } |
e14ab23d | 130 | EXPORT_SYMBOL_GPL(efivars_unregister); |
f88814cc | 131 | |
2cf9e278 | 132 | bool efivar_supports_writes(void) |
f88814cc AB |
133 | { |
134 | return __efivars && __efivars->ops->set_variable; | |
135 | } | |
136 | EXPORT_SYMBOL_GPL(efivar_supports_writes); | |
472831d4 AB |
137 | |
138 | /* | |
139 | * efivar_lock() - obtain the efivar lock, wait for it if needed | |
140 | * @return 0 on success, error code on failure | |
141 | */ | |
142 | int efivar_lock(void) | |
143 | { | |
144 | if (down_interruptible(&efivars_lock)) | |
145 | return -EINTR; | |
146 | if (!__efivars->ops) { | |
147 | up(&efivars_lock); | |
148 | return -ENODEV; | |
149 | } | |
150 | return 0; | |
151 | } | |
152 | EXPORT_SYMBOL_NS_GPL(efivar_lock, EFIVAR); | |
153 | ||
154 | /* | |
155 | * efivar_lock() - obtain the efivar lock if it is free | |
156 | * @return 0 on success, error code on failure | |
157 | */ | |
158 | int efivar_trylock(void) | |
159 | { | |
160 | if (down_trylock(&efivars_lock)) | |
161 | return -EBUSY; | |
162 | if (!__efivars->ops) { | |
163 | up(&efivars_lock); | |
164 | return -ENODEV; | |
165 | } | |
166 | return 0; | |
167 | } | |
168 | EXPORT_SYMBOL_NS_GPL(efivar_trylock, EFIVAR); | |
169 | ||
170 | /* | |
171 | * efivar_unlock() - release the efivar lock | |
172 | */ | |
173 | void efivar_unlock(void) | |
174 | { | |
175 | up(&efivars_lock); | |
176 | } | |
177 | EXPORT_SYMBOL_NS_GPL(efivar_unlock, EFIVAR); | |
178 | ||
179 | /* | |
180 | * efivar_get_variable() - retrieve a variable identified by name/vendor | |
181 | * | |
182 | * Must be called with efivars_lock held. | |
183 | */ | |
184 | efi_status_t efivar_get_variable(efi_char16_t *name, efi_guid_t *vendor, | |
185 | u32 *attr, unsigned long *size, void *data) | |
186 | { | |
187 | return __efivars->ops->get_variable(name, vendor, attr, size, data); | |
188 | } | |
189 | EXPORT_SYMBOL_NS_GPL(efivar_get_variable, EFIVAR); | |
190 | ||
191 | /* | |
192 | * efivar_get_next_variable() - enumerate the next name/vendor pair | |
193 | * | |
194 | * Must be called with efivars_lock held. | |
195 | */ | |
196 | efi_status_t efivar_get_next_variable(unsigned long *name_size, | |
197 | efi_char16_t *name, efi_guid_t *vendor) | |
198 | { | |
199 | return __efivars->ops->get_next_variable(name_size, name, vendor); | |
200 | } | |
201 | EXPORT_SYMBOL_NS_GPL(efivar_get_next_variable, EFIVAR); | |
202 | ||
472831d4 AB |
203 | /* |
204 | * efivar_set_variable_locked() - set a variable identified by name/vendor | |
205 | * | |
206 | * Must be called with efivars_lock held. If @nonblocking is set, it will use | |
207 | * non-blocking primitives so it is guaranteed not to sleep. | |
208 | */ | |
209 | efi_status_t efivar_set_variable_locked(efi_char16_t *name, efi_guid_t *vendor, | |
210 | u32 attr, unsigned long data_size, | |
211 | void *data, bool nonblocking) | |
212 | { | |
213 | efi_set_variable_t *setvar; | |
214 | efi_status_t status; | |
215 | ||
f11a74b4 AB |
216 | if (data_size > 0) { |
217 | status = check_var_size(nonblocking, attr, | |
cda30c65 | 218 | data_size + ucs2_strsize(name, EFI_VAR_NAME_LEN)); |
f11a74b4 AB |
219 | if (status != EFI_SUCCESS) |
220 | return status; | |
221 | } | |
472831d4 AB |
222 | |
223 | /* | |
224 | * If no _nonblocking variant exists, the ordinary one | |
225 | * is assumed to be non-blocking. | |
226 | */ | |
f11a74b4 AB |
227 | setvar = __efivars->ops->set_variable_nonblocking; |
228 | if (!setvar || !nonblocking) | |
229 | setvar = __efivars->ops->set_variable; | |
472831d4 | 230 | |
472831d4 AB |
231 | return setvar(name, vendor, attr, data_size, data); |
232 | } | |
233 | EXPORT_SYMBOL_NS_GPL(efivar_set_variable_locked, EFIVAR); | |
234 | ||
235 | /* | |
236 | * efivar_set_variable() - set a variable identified by name/vendor | |
237 | * | |
238 | * Can be called without holding the efivars_lock. Will sleep on obtaining the | |
239 | * lock, or on obtaining other locks that are needed in order to complete the | |
240 | * call. | |
241 | */ | |
242 | efi_status_t efivar_set_variable(efi_char16_t *name, efi_guid_t *vendor, | |
243 | u32 attr, unsigned long data_size, void *data) | |
244 | { | |
245 | efi_status_t status; | |
246 | ||
247 | if (efivar_lock()) | |
248 | return EFI_ABORTED; | |
249 | ||
f11a74b4 AB |
250 | status = efivar_set_variable_locked(name, vendor, attr, data_size, |
251 | data, false); | |
472831d4 AB |
252 | efivar_unlock(); |
253 | return status; | |
254 | } | |
255 | EXPORT_SYMBOL_NS_GPL(efivar_set_variable, EFIVAR); | |
d86ff333 AA |
256 | |
257 | efi_status_t efivar_query_variable_info(u32 attr, | |
258 | u64 *storage_space, | |
259 | u64 *remaining_space, | |
260 | u64 *max_variable_size) | |
261 | { | |
262 | if (!__efivars->ops->query_variable_info) | |
263 | return EFI_UNSUPPORTED; | |
264 | return __efivars->ops->query_variable_info(attr, storage_space, | |
265 | remaining_space, max_variable_size); | |
266 | } | |
267 | EXPORT_SYMBOL_NS_GPL(efivar_query_variable_info, EFIVAR); |