From 5f7dcf079de8caa5ef9c332c928bd6a3c3d12335 Mon Sep 17 00:00:00 2001 From: Heinrich Schuchardt Date: Thu, 19 Mar 2020 18:21:58 +0000 Subject: efi_loader: UEFI variable persistence Persist non-volatile UEFI variables in a file on the EFI system partition. The file is written whenever a non-volatile UEFI variable is changed after initialization of the UEFI sub-system. The file is read during the UEFI sub-system initialization to restore non-volatile UEFI variables. Signed-off-by: Heinrich Schuchardt --- include/efi_variable.h | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) (limited to 'include/efi_variable.h') diff --git a/include/efi_variable.h b/include/efi_variable.h index 3ba274fce17..01054209c4f 100644 --- a/include/efi_variable.h +++ b/include/efi_variable.h @@ -79,4 +79,66 @@ efi_status_t efi_query_variable_info_int(u32 attributes, 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 -- cgit v1.2.3