321 lines
9.3 KiB
C
321 lines
9.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* Copyright (c) 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
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*/
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#ifndef _EFI_VARIABLE_H
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#define _EFI_VARIABLE_H
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#include <linux/bitops.h>
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#define EFI_VARIABLE_READ_ONLY BIT(31)
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enum efi_auth_var_type {
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EFI_AUTH_VAR_NONE = 0,
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EFI_AUTH_VAR_PK,
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EFI_AUTH_VAR_KEK,
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EFI_AUTH_VAR_DB,
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EFI_AUTH_VAR_DBX,
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EFI_AUTH_VAR_DBT,
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EFI_AUTH_VAR_DBR,
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};
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/**
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* efi_get_variable() - retrieve value of a UEFI variable
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*
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* @variable_name: name of the variable
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* @vendor: vendor GUID
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* @attributes: attributes of the variable
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* @data_size: size of the buffer to which the variable value is copied
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* @data: buffer to which the variable value is copied
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* @timep: authentication time (seconds since start of epoch)
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* Return: status code
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*/
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efi_status_t efi_get_variable_int(u16 *variable_name, const efi_guid_t *vendor,
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u32 *attributes, efi_uintn_t *data_size,
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void *data, u64 *timep);
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/**
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* efi_set_variable() - set value of a UEFI variable
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*
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* @variable_name: name of the variable
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* @vendor: vendor GUID
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* @attributes: attributes of the variable
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* @data_size: size of the buffer with the variable value
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* @data: buffer with the variable value
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* @ro_check: check the read only read only bit in attributes
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* Return: status code
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*/
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efi_status_t efi_set_variable_int(u16 *variable_name, const efi_guid_t *vendor,
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u32 attributes, efi_uintn_t data_size,
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const void *data, bool ro_check);
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/**
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* efi_get_next_variable_name_int() - enumerate the current variable names
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*
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* @variable_name_size: size of variable_name buffer in byte
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* @variable_name: name of uefi variable's name in u16
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* @vendor: vendor's guid
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*
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* See the Unified Extensible Firmware Interface (UEFI) specification for
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* details.
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*
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* Return: status code
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*/
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efi_status_t efi_get_next_variable_name_int(efi_uintn_t *variable_name_size,
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u16 *variable_name,
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efi_guid_t *vendor);
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/**
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* efi_query_variable_info_int() - get information about EFI variables
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*
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* This function implements the QueryVariableInfo() runtime service.
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*
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* See the Unified Extensible Firmware Interface (UEFI) specification for
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* details.
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*
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* @attributes: bitmask to select variables to be
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* queried
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* @maximum_variable_storage_size: maximum size of storage area for the
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* selected variable types
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* @remaining_variable_storage_size: remaining size of storage are for the
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* selected variable types
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* @maximum_variable_size: maximum size of a variable of the
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* selected type
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* Returns: status code
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*/
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efi_status_t efi_query_variable_info_int(u32 attributes,
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u64 *maximum_variable_storage_size,
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u64 *remaining_variable_storage_size,
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u64 *maximum_variable_size);
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#define EFI_VAR_FILE_NAME "ubootefi.var"
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#define EFI_VAR_BUF_SIZE CONFIG_EFI_VAR_BUF_SIZE
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/*
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* This constant identifies the file format for storing UEFI variables in
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* struct efi_var_file.
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*/
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#define EFI_VAR_FILE_MAGIC 0x0161566966456255 /* UbEfiVa, version 1 */
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/**
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* struct efi_var_entry - UEFI variable file entry
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*
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* @length: length of enty, multiple of 8
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* @attr: variable attributes
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* @time: authentication time (seconds since start of epoch)
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* @guid: vendor GUID
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* @name: UTF16 variable name
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*/
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struct efi_var_entry {
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u32 length;
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u32 attr;
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u64 time;
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efi_guid_t guid;
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u16 name[];
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};
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/**
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* struct efi_var_file - file for storing UEFI variables
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*
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* @reserved: unused, may be overwritten by memory probing
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* @magic: identifies file format, takes value %EFI_VAR_FILE_MAGIC
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* @length: length including header
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* @crc32: CRC32 without header
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* @var: variables
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*/
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struct efi_var_file {
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u64 reserved;
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u64 magic;
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u32 length;
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u32 crc32;
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struct efi_var_entry var[];
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};
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/**
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* efi_var_to_file() - save non-volatile variables as file
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*
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* File ubootefi.var is created on the EFI system partion.
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*
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* Return: status code
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*/
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efi_status_t efi_var_to_file(void);
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/**
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* efi_var_collect() - collect variables in buffer
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*
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* A buffer is allocated and filled with variables in a format ready to be
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* written to disk.
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*
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* @bufp: pointer to pointer of buffer with collected variables
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* @lenp: pointer to length of buffer
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* @check_attr_mask: bitmask with required attributes of variables to be collected.
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* variables are only collected if all of the required
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* attributes are set.
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* Return: status code
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*/
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efi_status_t __maybe_unused efi_var_collect(struct efi_var_file **bufp, loff_t *lenp,
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u32 check_attr_mask);
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/**
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* efi_var_restore() - restore EFI variables from buffer
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*
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* @buf: buffer
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* Return: status code
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*/
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efi_status_t efi_var_restore(struct efi_var_file *buf);
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/**
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* efi_var_from_file() - read variables from file
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*
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* File ubootefi.var is read from the EFI system partitions and the variables
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* stored in the file are created.
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*
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* In case the file does not exist yet or a variable cannot be set EFI_SUCCESS
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* is returned.
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*
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* Return: status code
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*/
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efi_status_t efi_var_from_file(void);
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/**
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* efi_var_mem_init() - set-up variable list
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*
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* Return: status code
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*/
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efi_status_t efi_var_mem_init(void);
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/**
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* efi_var_mem_find() - find a variable in the list
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*
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* @guid: GUID of the variable
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* @name: name of the variable
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* @next: on exit pointer to the next variable after the found one
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* Return: found variable
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*/
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struct efi_var_entry *efi_var_mem_find(const efi_guid_t *guid, const u16 *name,
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struct efi_var_entry **next);
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/**
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* efi_var_mem_del() - delete a variable from the list of variables
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*
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* @var: variable to delete
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*/
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void efi_var_mem_del(struct efi_var_entry *var);
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/**
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* efi_var_mem_ins() - append a variable to the list of variables
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*
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* The variable is appended without checking if a variable of the same name
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* already exists. The two data buffers are concatenated.
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*
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* @variable_name: variable name
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* @vendor: GUID
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* @attributes: variable attributes
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* @size1: size of the first data buffer
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* @data1: first data buffer
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* @size2: size of the second data field
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* @data2: second data buffer
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* @time: time of authentication (as seconds since start of epoch)
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* Result: status code
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*/
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efi_status_t efi_var_mem_ins(u16 *variable_name,
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const efi_guid_t *vendor, u32 attributes,
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const efi_uintn_t size1, const void *data1,
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const efi_uintn_t size2, const void *data2,
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const u64 time);
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/**
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* efi_var_mem_free() - determine free memory for variables
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*
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* Return: maximum data size plus variable name size
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*/
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u64 efi_var_mem_free(void);
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/**
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* efi_init_secure_state - initialize secure boot state
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*
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* Return: status code
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*/
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efi_status_t efi_init_secure_state(void);
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/**
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* efi_auth_var_get_type() - convert variable name and guid to enum
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*
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* @name: name of UEFI variable
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* @guid: guid of UEFI variable
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* Return: identifier for authentication related variables
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*/
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enum efi_auth_var_type efi_auth_var_get_type(u16 *name, const efi_guid_t *guid);
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/**
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* efi_get_next_variable_name_mem() - Runtime common code across efi variable
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* implementations for GetNextVariable()
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* from the cached memory copy
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* @variable_name_size: size of variable_name buffer in byte
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* @variable_name: name of uefi variable's name in u16
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* @vendor: vendor's guid
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*
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* Return: status code
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*/
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efi_status_t __efi_runtime
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efi_get_next_variable_name_mem(efi_uintn_t *variable_name_size, u16 *variable_name,
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efi_guid_t *vendor);
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/**
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* efi_get_variable_mem() - Runtime common code across efi variable
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* implementations for GetVariable() from
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* the cached memory copy
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*
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* @variable_name: name of the variable
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* @vendor: vendor GUID
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* @attributes: attributes of the variable
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* @data_size: size of the buffer to which the variable value is copied
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* @data: buffer to which the variable value is copied
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* @timep: authentication time (seconds since start of epoch)
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* Return: status code
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*/
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efi_status_t __efi_runtime
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efi_get_variable_mem(u16 *variable_name, const efi_guid_t *vendor, u32 *attributes,
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efi_uintn_t *data_size, void *data, u64 *timep);
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/**
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* efi_get_variable_runtime() - runtime implementation of GetVariable()
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*
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* @variable_name: name of the variable
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* @guid: vendor GUID
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* @attributes: attributes of the variable
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* @data_size: size of the buffer to which the variable value is copied
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* @data: buffer to which the variable value is copied
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* Return: status code
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*/
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efi_status_t __efi_runtime EFIAPI
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efi_get_variable_runtime(u16 *variable_name, const efi_guid_t *guid,
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u32 *attributes, efi_uintn_t *data_size, void *data);
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/**
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* efi_get_next_variable_name_runtime() - runtime implementation of
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* GetNextVariable()
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*
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* @variable_name_size: size of variable_name buffer in byte
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* @variable_name: name of uefi variable's name in u16
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* @guid: vendor's guid
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* Return: status code
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*/
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efi_status_t __efi_runtime EFIAPI
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efi_get_next_variable_name_runtime(efi_uintn_t *variable_name_size,
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u16 *variable_name, efi_guid_t *guid);
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/**
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* efi_var_buf_update() - udpate memory buffer for variables
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*
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* @var_buf: source buffer
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*
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* This function copies to the memory buffer for UEFI variables. Call this
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* function in ExitBootServices() if memory backed variables are only used
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* at runtime to fill the buffer.
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*/
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void efi_var_buf_update(struct efi_var_file *var_buf);
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#endif
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