blob: 9fba7eaf3a55f3dc4361721aaa745ad75a5fa579 [file] [log] [blame]
Subrata Banik20fe24b2021-12-09 02:46:38 +05301/** @file
2 GUID used for MemoryOverwriteRequestControl UEFI variable defined in
3 TCG Platform Reset Attack Mitigation Specification 1.00.
4 See http://trustedcomputinggroup.org for the latest specification
5
6 The purpose of the MemoryOverwriteRequestControl UEFI variable is to give users (e.g., OS, loader) the ability to
7 indicate to the platform that secrets are present in memory and that the platform firmware must clear memory upon
8 a restart. The OS loader should not create the variable. Rather, the firmware is required to create it.
9
10 Copyright (c) 2009 - 2018, Intel Corporation. All rights reserved.<BR>
11 SPDX-License-Identifier: BSD-2-Clause-Patent
12
13**/
14
15#ifndef _MEMORY_OVERWRITE_CONTROL_DATA_GUID_H_
16#define _MEMORY_OVERWRITE_CONTROL_DATA_GUID_H_
17
18#define MEMORY_ONLY_RESET_CONTROL_GUID \
19 { \
20 0xe20939be, 0x32d4, 0x41be, {0xa1, 0x50, 0x89, 0x7f, 0x85, 0xd4, 0x98, 0x29} \
21 }
22
23///
24/// Variable name is "MemoryOverwriteRequestControl" and it is a 1 byte unsigned value.
25/// The attributes should be:
26/// EFI_VARIABLE_NON_VOLATILE |
27/// EFI_VARIABLE_BOOTSERVICE_ACCESS |
28/// EFI_VARIABLE_RUNTIME_ACCESS
29///
30#define MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME L"MemoryOverwriteRequestControl"
31
32///
33/// 0 = Firmware MUST clear the MOR bit
34/// 1 = Firmware MUST set the MOR bit
35///
36#define MOR_CLEAR_MEMORY_BIT_MASK 0x01
37
38///
39/// 0 = Firmware MAY autodetect a clean shutdown of the Static RTM OS.
40/// 1 = Firmware MUST NOT autodetect a clean shutdown of the Static RTM OS.
41///
42#define MOR_DISABLEAUTODETECT_BIT_MASK 0x10
43
44///
45/// MOR field bit offset
46///
47#define MOR_CLEAR_MEMORY_BIT_OFFSET 0
48#define MOR_DISABLEAUTODETECT_BIT_OFFSET 4
49
50/**
51 Return the ClearMemory bit value 0 or 1.
52
53 @param mor 1 byte value that contains ClearMemory and DisableAutoDetect bit.
54
55 @return ClearMemory bit value
56**/
57#define MOR_CLEAR_MEMORY_VALUE(mor) (((UINT8)(mor) & MOR_CLEAR_MEMORY_BIT_MASK) >> MOR_CLEAR_MEMORY_BIT_OFFSET)
58
59/**
60 Return the DisableAutoDetect bit value 0 or 1.
61
62 @param mor 1 byte value that contains ClearMemory and DisableAutoDetect bit.
63
64 @return DisableAutoDetect bit value
65**/
66#define MOR_DISABLE_AUTO_DETECT_VALUE(mor) (((UINT8)(mor) & MOR_DISABLEAUTODETECT_BIT_MASK) >> MOR_DISABLEAUTODETECT_BIT_OFFSET)
67
68extern EFI_GUID gEfiMemoryOverwriteControlDataGuid;
69
70#endif