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/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Copyright (c) 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
*/
#ifndef _EFI_VARIABLE_H
#define _EFI_VARIABLE_H
#include <linux/bitops.h>
#define EFI_VARIABLE_READ_ONLY BIT(31)
/**
* efi_get_variable() - retrieve value of a UEFI variable
*
* @variable_name: name of the variable
* @vendor: vendor GUID
* @attributes: attributes of the variable
* @data_size: size of the buffer to which the variable value is copied
* @data: buffer to which the variable value is copied
* @timep: authentication time (seconds since start of epoch)
* Return: status code
*/
efi_status_t efi_get_variable_int(u16 *variable_name, const efi_guid_t *vendor,
u32 *attributes, efi_uintn_t *data_size,
void *data, u64 *timep);
/**
* efi_set_variable() - set value of a UEFI variable
*
* @variable_name: name of the variable
* @vendor: vendor GUID
* @attributes: attributes of the variable
* @data_size: size of the buffer with the variable value
* @data: buffer with the variable value
* @ro_check: check the read only read only bit in attributes
* Return: status code
*/
efi_status_t efi_set_variable_int(u16 *variable_name, const efi_guid_t *vendor,
u32 attributes, efi_uintn_t data_size,
const void *data, bool ro_check);
/**
* efi_get_next_variable_name_int() - enumerate the current variable names
*
* @variable_name_size: size of variable_name buffer in byte
* @variable_name: name of uefi variable's name in u16
* @vendor: vendor's guid
*
* See the Unified Extensible Firmware Interface (UEFI) specification for
* details.
*
* Return: status code
*/
efi_status_t efi_get_next_variable_name_int(efi_uintn_t *variable_name_size,
u16 *variable_name,
efi_guid_t *vendor);
/**
* efi_query_variable_info_int() - get information about EFI variables
*
* This function implements the QueryVariableInfo() runtime service.
*
* See the Unified Extensible Firmware Interface (UEFI) specification for
* details.
*
* @attributes: bitmask to select variables to be
* queried
* @maximum_variable_storage_size: maximum size of storage area for the
* selected variable types
* @remaining_variable_storage_size: remaining size of storage are for the
* selected variable types
* @maximum_variable_size: maximum size of a variable of the
* selected type
* Returns: status code
*/
efi_status_t efi_query_variable_info_int(u32 attributes,
u64 *maximum_variable_storage_size,
u64 *remaining_variable_storage_size,
u64 *maximum_variable_size);
#define EFI_VAR_FILE_NAME "ubootefi.var"
#define EFI_VAR_BUF_SIZE 0x4000
#define EFI_VAR_FILE_MAGIC 0x0161566966456255 /* UbEfiVa, version 1 */
/**
* struct efi_var_entry - UEFI variable file entry
*
* @length: length of enty, multiple of 8
* @attr: variable attributes
* @time: authentication time (seconds since start of epoch)
* @guid: vendor GUID
* @name: UTF16 variable name
*/
struct efi_var_entry {
u32 length;
u32 attr;
u64 time;
efi_guid_t guid;
u16 name[];
};
/**
* struct efi_var_file - file for storing UEFI variables
*
* @reserved: unused, may be overwritten by memory probing
* @magic: identifies file format
* @length: length including header
* @crc32: CRC32 without header
* @var: variables
*/
struct efi_var_file {
u64 reserved;
u64 magic;
u32 length;
u32 crc32;
struct efi_var_entry var[];
};
/**
* efi_var_to_file() - save non-volatile variables as file
*
* File ubootefi.var is created on the EFI system partion.
*
* Return: status code
*/
efi_status_t efi_var_to_file(void);
/**
* efi_var_from_file() - read variables from file
*
* File ubootefi.var is read from the EFI system partitions and the variables
* stored in the file are created.
*
* In case the file does not exist yet or a variable cannot be set EFI_SUCCESS
* is returned.
*
* Return: status code
*/
efi_status_t efi_var_from_file(void);
#endif
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