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Heinrich Schuchardtf2d2b3a2020-06-22 18:10:27 +02001/* SPDX-License-Identifier: GPL-2.0+ */
2/*
3 * Copyright (c) 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
4 */
5
6#ifndef _EFI_VARIABLE_H
7#define _EFI_VARIABLE_H
8
9#include <linux/bitops.h>
10
11#define EFI_VARIABLE_READ_ONLY BIT(31)
12
Heinrich Schuchardt99bfab82020-07-15 12:40:35 +020013enum efi_auth_var_type {
14 EFI_AUTH_VAR_NONE = 0,
15 EFI_AUTH_VAR_PK,
16 EFI_AUTH_VAR_KEK,
17 EFI_AUTH_VAR_DB,
18 EFI_AUTH_VAR_DBX,
19 EFI_AUTH_VAR_DBT,
20 EFI_AUTH_VAR_DBR,
21};
22
Heinrich Schuchardtf2d2b3a2020-06-22 18:10:27 +020023/**
24 * efi_get_variable() - retrieve value of a UEFI variable
25 *
26 * @variable_name: name of the variable
27 * @vendor: vendor GUID
28 * @attributes: attributes of the variable
29 * @data_size: size of the buffer to which the variable value is copied
30 * @data: buffer to which the variable value is copied
31 * @timep: authentication time (seconds since start of epoch)
32 * Return: status code
33 */
34efi_status_t efi_get_variable_int(u16 *variable_name, const efi_guid_t *vendor,
35 u32 *attributes, efi_uintn_t *data_size,
36 void *data, u64 *timep);
37
38/**
39 * efi_set_variable() - set value of a UEFI variable
40 *
41 * @variable_name: name of the variable
42 * @vendor: vendor GUID
43 * @attributes: attributes of the variable
44 * @data_size: size of the buffer with the variable value
45 * @data: buffer with the variable value
46 * @ro_check: check the read only read only bit in attributes
47 * Return: status code
48 */
49efi_status_t efi_set_variable_int(u16 *variable_name, const efi_guid_t *vendor,
50 u32 attributes, efi_uintn_t data_size,
51 const void *data, bool ro_check);
52
Heinrich Schuchardt01df8cf2020-06-26 17:57:48 +020053/**
54 * efi_get_next_variable_name_int() - enumerate the current variable names
55 *
56 * @variable_name_size: size of variable_name buffer in byte
57 * @variable_name: name of uefi variable's name in u16
58 * @vendor: vendor's guid
59 *
60 * See the Unified Extensible Firmware Interface (UEFI) specification for
61 * details.
62 *
63 * Return: status code
64 */
65efi_status_t efi_get_next_variable_name_int(efi_uintn_t *variable_name_size,
66 u16 *variable_name,
67 efi_guid_t *vendor);
68
69/**
70 * efi_query_variable_info_int() - get information about EFI variables
71 *
72 * This function implements the QueryVariableInfo() runtime service.
73 *
74 * See the Unified Extensible Firmware Interface (UEFI) specification for
75 * details.
76 *
77 * @attributes: bitmask to select variables to be
78 * queried
79 * @maximum_variable_storage_size: maximum size of storage area for the
80 * selected variable types
81 * @remaining_variable_storage_size: remaining size of storage are for the
82 * selected variable types
83 * @maximum_variable_size: maximum size of a variable of the
84 * selected type
85 * Returns: status code
86 */
87efi_status_t efi_query_variable_info_int(u32 attributes,
88 u64 *maximum_variable_storage_size,
89 u64 *remaining_variable_storage_size,
90 u64 *maximum_variable_size);
91
Heinrich Schuchardt5f7dcf02020-03-19 18:21:58 +000092#define EFI_VAR_FILE_NAME "ubootefi.var"
93
94#define EFI_VAR_BUF_SIZE 0x4000
95
Heinrich Schuchardt627ab392020-07-16 07:18:40 +020096/*
97 * This constant identifies the file format for storing UEFI variables in
98 * struct efi_var_file.
99 */
Heinrich Schuchardt5f7dcf02020-03-19 18:21:58 +0000100#define EFI_VAR_FILE_MAGIC 0x0161566966456255 /* UbEfiVa, version 1 */
101
102/**
103 * struct efi_var_entry - UEFI variable file entry
104 *
105 * @length: length of enty, multiple of 8
106 * @attr: variable attributes
107 * @time: authentication time (seconds since start of epoch)
108 * @guid: vendor GUID
109 * @name: UTF16 variable name
110 */
111struct efi_var_entry {
112 u32 length;
113 u32 attr;
114 u64 time;
115 efi_guid_t guid;
116 u16 name[];
117};
118
119/**
120 * struct efi_var_file - file for storing UEFI variables
121 *
122 * @reserved: unused, may be overwritten by memory probing
Heinrich Schuchardt627ab392020-07-16 07:18:40 +0200123 * @magic: identifies file format, takes value %EFI_VAR_FILE_MAGIC
Heinrich Schuchardt5f7dcf02020-03-19 18:21:58 +0000124 * @length: length including header
125 * @crc32: CRC32 without header
126 * @var: variables
127 */
128struct efi_var_file {
129 u64 reserved;
130 u64 magic;
131 u32 length;
132 u32 crc32;
133 struct efi_var_entry var[];
134};
135
136/**
137 * efi_var_to_file() - save non-volatile variables as file
138 *
139 * File ubootefi.var is created on the EFI system partion.
140 *
141 * Return: status code
142 */
143efi_status_t efi_var_to_file(void);
144
145/**
Ilias Apalodimase01aed42020-07-23 15:49:49 +0300146 * efi_var_collect() - collect variables in buffer
147 *
148 * A buffer is allocated and filled with variables in a format ready to be
149 * written to disk.
150 *
151 * @bufp: pointer to pointer of buffer with collected variables
152 * @lenp: pointer to length of buffer
153 * @check_attr_mask: bitmask with required attributes of variables to be collected.
154 * variables are only collected if all of the required
155 * attributes are set.
156 * Return: status code
157 */
158efi_status_t __maybe_unused efi_var_collect(struct efi_var_file **bufp, loff_t *lenp,
159 u32 check_attr_mask);
160
161/**
Heinrich Schuchardt7dda1632020-07-14 21:25:28 +0200162 * efi_var_restore() - restore EFI variables from buffer
163 *
164 * @buf: buffer
165 * Return: status code
166 */
167efi_status_t efi_var_restore(struct efi_var_file *buf);
168
169/**
Heinrich Schuchardt5f7dcf02020-03-19 18:21:58 +0000170 * efi_var_from_file() - read variables from file
171 *
172 * File ubootefi.var is read from the EFI system partitions and the variables
173 * stored in the file are created.
174 *
175 * In case the file does not exist yet or a variable cannot be set EFI_SUCCESS
176 * is returned.
177 *
178 * Return: status code
179 */
180efi_status_t efi_var_from_file(void);
181
Heinrich Schuchardtf1f990a2020-03-22 09:07:50 +0100182/**
183 * efi_var_mem_init() - set-up variable list
184 *
185 * Return: status code
186 */
187efi_status_t efi_var_mem_init(void);
188
189/**
190 * efi_var_mem_find() - find a variable in the list
191 *
192 * @guid: GUID of the variable
193 * @name: name of the variable
194 * @next: on exit pointer to the next variable after the found one
195 * Return: found variable
196 */
197struct efi_var_entry *efi_var_mem_find(const efi_guid_t *guid, const u16 *name,
198 struct efi_var_entry **next);
199
200/**
201 * efi_var_mem_del() - delete a variable from the list of variables
202 *
203 * @var: variable to delete
204 */
205void efi_var_mem_del(struct efi_var_entry *var);
206
207/**
208 * efi_var_mem_ins() - append a variable to the list of variables
209 *
210 * The variable is appended without checking if a variable of the same name
211 * already exists. The two data buffers are concatenated.
212 *
213 * @variable_name: variable name
214 * @vendor: GUID
215 * @attributes: variable attributes
216 * @size1: size of the first data buffer
217 * @data1: first data buffer
218 * @size2: size of the second data field
219 * @data2: second data buffer
220 * @time: time of authentication (as seconds since start of epoch)
221 * Result: status code
222 */
223efi_status_t efi_var_mem_ins(u16 *variable_name,
224 const efi_guid_t *vendor, u32 attributes,
225 const efi_uintn_t size1, const void *data1,
226 const efi_uintn_t size2, const void *data2,
227 const u64 time);
228
229/**
230 * efi_var_mem_free() - determine free memory for variables
231 *
232 * Return: maximum data size plus variable name size
233 */
234u64 efi_var_mem_free(void);
235
Heinrich Schuchardt012c56a2020-07-14 08:04:49 +0200236/**
237 * efi_init_secure_state - initialize secure boot state
238 *
239 * Return: status code
240 */
241efi_status_t efi_init_secure_state(void);
242
Heinrich Schuchardt99bfab82020-07-15 12:40:35 +0200243/**
244 * efi_auth_var_get_type() - convert variable name and guid to enum
245 *
246 * @name: name of UEFI variable
247 * @guid: guid of UEFI variable
248 * Return: identifier for authentication related variables
249 */
250enum efi_auth_var_type efi_auth_var_get_type(u16 *name, const efi_guid_t *guid);
251
Ilias Apalodimase01aed42020-07-23 15:49:49 +0300252/**
253 * efi_get_next_variable_name_mem() - Runtime common code across efi variable
254 * implementations for GetNextVariable()
255 * from the cached memory copy
256 * @variable_name_size: size of variable_name buffer in byte
257 * @variable_name: name of uefi variable's name in u16
258 * @vendor: vendor's guid
259 *
260 * Return: status code
261 */
262efi_status_t __efi_runtime
263efi_get_next_variable_name_mem(efi_uintn_t *variable_name_size, u16 *variable_name,
264 efi_guid_t *vendor);
265/**
266 * efi_get_variable_mem() - Runtime common code across efi variable
267 * implementations for GetVariable() from
268 * the cached memory copy
269 *
270 * @variable_name: name of the variable
271 * @vendor: vendor GUID
272 * @attributes: attributes of the variable
273 * @data_size: size of the buffer to which the variable value is copied
274 * @data: buffer to which the variable value is copied
275 * @timep: authentication time (seconds since start of epoch)
276 * Return: status code
Ilias Apalodimase01aed42020-07-23 15:49:49 +0300277 */
278efi_status_t __efi_runtime
279efi_get_variable_mem(u16 *variable_name, const efi_guid_t *vendor, u32 *attributes,
280 efi_uintn_t *data_size, void *data, u64 *timep);
281
282/**
283 * efi_get_variable_runtime() - runtime implementation of GetVariable()
284 *
285 * @variable_name: name of the variable
286 * @guid: vendor GUID
287 * @attributes: attributes of the variable
288 * @data_size: size of the buffer to which the variable value is copied
289 * @data: buffer to which the variable value is copied
290 * Return: status code
291 */
292efi_status_t __efi_runtime EFIAPI
293efi_get_variable_runtime(u16 *variable_name, const efi_guid_t *guid,
294 u32 *attributes, efi_uintn_t *data_size, void *data);
295
296/**
297 * efi_get_next_variable_name_runtime() - runtime implementation of
298 * GetNextVariable()
299 *
300 * @variable_name_size: size of variable_name buffer in byte
301 * @variable_name: name of uefi variable's name in u16
302 * @guid: vendor's guid
303 * Return: status code
304 */
305efi_status_t __efi_runtime EFIAPI
306efi_get_next_variable_name_runtime(efi_uintn_t *variable_name_size,
307 u16 *variable_name, efi_guid_t *guid);
308
Heinrich Schuchardtf2d2b3a2020-06-22 18:10:27 +0200309#endif