1 /* SPDX-License-Identifier: GPL-2.0+ */
3 * Copyright (c) 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
6 #ifndef _EFI_VARIABLE_H
7 #define _EFI_VARIABLE_H
9 #include <linux/bitops.h>
11 #define EFI_VARIABLE_READ_ONLY BIT(31)
14 * efi_get_variable() - retrieve value of a UEFI variable
16 * @variable_name: name of the variable
17 * @vendor: vendor GUID
18 * @attributes: attributes of the variable
19 * @data_size: size of the buffer to which the variable value is copied
20 * @data: buffer to which the variable value is copied
21 * @timep: authentication time (seconds since start of epoch)
24 efi_status_t efi_get_variable_int(u16 *variable_name, const efi_guid_t *vendor,
25 u32 *attributes, efi_uintn_t *data_size,
26 void *data, u64 *timep);
29 * efi_set_variable() - set value of a UEFI variable
31 * @variable_name: name of the variable
32 * @vendor: vendor GUID
33 * @attributes: attributes of the variable
34 * @data_size: size of the buffer with the variable value
35 * @data: buffer with the variable value
36 * @ro_check: check the read only read only bit in attributes
39 efi_status_t efi_set_variable_int(u16 *variable_name, const efi_guid_t *vendor,
40 u32 attributes, efi_uintn_t data_size,
41 const void *data, bool ro_check);
44 * efi_get_next_variable_name_int() - enumerate the current variable names
46 * @variable_name_size: size of variable_name buffer in byte
47 * @variable_name: name of uefi variable's name in u16
48 * @vendor: vendor's guid
50 * See the Unified Extensible Firmware Interface (UEFI) specification for
55 efi_status_t efi_get_next_variable_name_int(efi_uintn_t *variable_name_size,
60 * efi_query_variable_info_int() - get information about EFI variables
62 * This function implements the QueryVariableInfo() runtime service.
64 * See the Unified Extensible Firmware Interface (UEFI) specification for
67 * @attributes: bitmask to select variables to be
69 * @maximum_variable_storage_size: maximum size of storage area for the
70 * selected variable types
71 * @remaining_variable_storage_size: remaining size of storage are for the
72 * selected variable types
73 * @maximum_variable_size: maximum size of a variable of the
75 * Returns: status code
77 efi_status_t efi_query_variable_info_int(u32 attributes,
78 u64 *maximum_variable_storage_size,
79 u64 *remaining_variable_storage_size,
80 u64 *maximum_variable_size);
82 #define EFI_VAR_FILE_NAME "ubootefi.var"
84 #define EFI_VAR_BUF_SIZE 0x4000
86 #define EFI_VAR_FILE_MAGIC 0x0161566966456255 /* UbEfiVa, version 1 */
89 * struct efi_var_entry - UEFI variable file entry
91 * @length: length of enty, multiple of 8
92 * @attr: variable attributes
93 * @time: authentication time (seconds since start of epoch)
95 * @name: UTF16 variable name
97 struct efi_var_entry {
106 * struct efi_var_file - file for storing UEFI variables
108 * @reserved: unused, may be overwritten by memory probing
109 * @magic: identifies file format
110 * @length: length including header
111 * @crc32: CRC32 without header
114 struct efi_var_file {
119 struct efi_var_entry var[];
123 * efi_var_to_file() - save non-volatile variables as file
125 * File ubootefi.var is created on the EFI system partion.
127 * Return: status code
129 efi_status_t efi_var_to_file(void);
132 * efi_var_from_file() - read variables from file
134 * File ubootefi.var is read from the EFI system partitions and the variables
135 * stored in the file are created.
137 * In case the file does not exist yet or a variable cannot be set EFI_SUCCESS
140 * Return: status code
142 efi_status_t efi_var_from_file(void);
145 * efi_var_mem_init() - set-up variable list
147 * Return: status code
149 efi_status_t efi_var_mem_init(void);
152 * efi_var_mem_find() - find a variable in the list
154 * @guid: GUID of the variable
155 * @name: name of the variable
156 * @next: on exit pointer to the next variable after the found one
157 * Return: found variable
159 struct efi_var_entry *efi_var_mem_find(const efi_guid_t *guid, const u16 *name,
160 struct efi_var_entry **next);
163 * efi_var_mem_del() - delete a variable from the list of variables
165 * @var: variable to delete
167 void efi_var_mem_del(struct efi_var_entry *var);
170 * efi_var_mem_ins() - append a variable to the list of variables
172 * The variable is appended without checking if a variable of the same name
173 * already exists. The two data buffers are concatenated.
175 * @variable_name: variable name
177 * @attributes: variable attributes
178 * @size1: size of the first data buffer
179 * @data1: first data buffer
180 * @size2: size of the second data field
181 * @data2: second data buffer
182 * @time: time of authentication (as seconds since start of epoch)
183 * Result: status code
185 efi_status_t efi_var_mem_ins(u16 *variable_name,
186 const efi_guid_t *vendor, u32 attributes,
187 const efi_uintn_t size1, const void *data1,
188 const efi_uintn_t size2, const void *data2,
192 * efi_var_mem_free() - determine free memory for variables
194 * Return: maximum data size plus variable name size
196 u64 efi_var_mem_free(void);