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Macros | Variables
MemoryOverwriteControl.h File Reference

Macros

#define MEMORY_ONLY_RESET_CONTROL_GUID
 
#define MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME   L"MemoryOverwriteRequestControl"
 
#define MOR_CLEAR_MEMORY_BIT_MASK   0x01
 
#define MOR_DISABLEAUTODETECT_BIT_MASK   0x10
 
#define MOR_CLEAR_MEMORY_BIT_OFFSET   0
 
#define MOR_DISABLEAUTODETECT_BIT_OFFSET   4
 
#define MOR_CLEAR_MEMORY_VALUE(mor)   (((UINT8)(mor) & MOR_CLEAR_MEMORY_BIT_MASK) >> MOR_CLEAR_MEMORY_BIT_OFFSET)
 
#define MOR_DISABLE_AUTO_DETECT_VALUE(mor)   (((UINT8)(mor) & MOR_DISABLEAUTODETECT_BIT_MASK) >> MOR_DISABLEAUTODETECT_BIT_OFFSET)
 

Variables

EFI_GUID gEfiMemoryOverwriteControlDataGuid
 

Detailed Description

GUID used for MemoryOverwriteRequestControl UEFI variable defined in TCG Platform Reset Attack Mitigation Specification 1.00. See http://trustedcomputinggroup.org for the latest specification

The purpose of the MemoryOverwriteRequestControl UEFI variable is to give users (e.g., OS, loader) the ability to indicate to the platform that secrets are present in memory and that the platform firmware must clear memory upon a restart. The OS loader should not create the variable. Rather, the firmware is required to create it.

Copyright (c) 2009 - 2018, Intel Corporation. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent

Macro Definition Documentation

#define MEMORY_ONLY_RESET_CONTROL_GUID
Value:
{ \
0xe20939be, 0x32d4, 0x41be, {0xa1, 0x50, 0x89, 0x7f, 0x85, 0xd4, 0x98, 0x29} \
}
#define MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME   L"MemoryOverwriteRequestControl"

Variable name is "MemoryOverwriteRequestControl" and it is a 1 byte unsigned value. The attributes should be: EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS

#define MOR_CLEAR_MEMORY_BIT_MASK   0x01

0 = Firmware MUST clear the MOR bit 1 = Firmware MUST set the MOR bit

#define MOR_CLEAR_MEMORY_BIT_OFFSET   0

MOR field bit offset

#define MOR_CLEAR_MEMORY_VALUE (   mor)    (((UINT8)(mor) & MOR_CLEAR_MEMORY_BIT_MASK) >> MOR_CLEAR_MEMORY_BIT_OFFSET)

Return the ClearMemory bit value 0 or 1.

Parameters
mor1 byte value that contains ClearMemory and DisableAutoDetect bit.
Returns
ClearMemory bit value
#define MOR_DISABLE_AUTO_DETECT_VALUE (   mor)    (((UINT8)(mor) & MOR_DISABLEAUTODETECT_BIT_MASK) >> MOR_DISABLEAUTODETECT_BIT_OFFSET)

Return the DisableAutoDetect bit value 0 or 1.

Parameters
mor1 byte value that contains ClearMemory and DisableAutoDetect bit.
Returns
DisableAutoDetect bit value
#define MOR_DISABLEAUTODETECT_BIT_MASK   0x10

0 = Firmware MAY autodetect a clean shutdown of the Static RTM OS. 1 = Firmware MUST NOT autodetect a clean shutdown of the Static RTM OS.

#define MOR_DISABLEAUTODETECT_BIT_OFFSET   4

Variable Documentation

EFI_GUID gEfiMemoryOverwriteControlDataGuid