1 /** @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, Intel Corporation. All rights reserved.<BR> 11 This program and the accompanying materials 12 are licensed and made available under the terms and conditions of the BSD License 13 which accompanies this distribution. The full text of the license may be found at 14 http://opensource.org/licenses/bsd-license.php 15 16 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 17 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 18 19 **/ 20 21 #ifndef _MEMORY_OVERWRITE_CONTROL_DATA_GUID_H_ 22 #define _MEMORY_OVERWRITE_CONTROL_DATA_GUID_H_ 23 24 #define MEMORY_ONLY_RESET_CONTROL_GUID \ 25 { \ 26 0xe20939be, 0x32d4, 0x41be, {0xa1, 0x50, 0x89, 0x7f, 0x85, 0xd4, 0x98, 0x29} \ 27 } 28 29 /// 30 /// Variable name is "MemoryOverwriteRequestControl" and it is a 1 byte unsigned value. 31 /// The attributes should be: 32 /// EFI_VARIABLE_NON_VOLATILE | 33 /// EFI_VARIABLE_BOOTSERVICE_ACCESS | 34 /// EFI_VARIABLE_RUNTIME_ACCESS 35 /// 36 #define MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME L"MemoryOverwriteRequestControl" 37 38 /// 39 /// 0 = Firmware MUST clear the MOR bi 40 /// 1 = Firmware MUST set the MOR bit 41 /// 42 #define MOR_CLEAR_MEMORY_BIT_MASK 0x01 43 44 /// 45 /// 0 = Firmware MAY autodetect a clean shutdown of the Static RTM OS. 46 /// 1 = Firmware MUST NOT autodetect a clean shutdown of the Static RTM OS. 47 /// 48 #define MOR_DISABLEAUTODETECT_BIT_MASK 0x10 49 50 /// 51 /// MOR field bit offset 52 /// 53 #define MOR_CLEAR_MEMORY_BIT_OFFSET 0 54 #define MOR_DISABLEAUTODETECT_BIT_OFFSET 4 55 56 /** 57 Return the ClearMemory bit value 0 or 1. 58 59 @param mor 1 byte value that contains ClearMemory and DisableAutoDetect bit. 60 61 @return ClearMemory bit value 62 **/ 63 #define MOR_CLEAR_MEMORY_VALUE(mor) (((UINT8)(mor) & MOR_CLEAR_MEMORY_BIT_MASK) >> MOR_CLEAR_MEMORY_BIT_OFFSET) 64 65 /** 66 Return the DisableAutoDetect bit value 0 or 1. 67 68 @param mor 1 byte value that contains ClearMemory and DisableAutoDetect bit. 69 70 @return DisableAutoDetect bit value 71 **/ 72 #define MOR_DISABLE_AUTO_DETECT_VALUE(mor) (((UINT8)(mor) & MOR_DISABLEAUTODETECT_BIT_MASK) >> MOR_DISABLEAUTODETECT_BIT_OFFSET) 73 74 extern EFI_GUID gEfiMemoryOverwriteControlDataGuid; 75 76 #endif 77