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 - 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 68 extern EFI_GUID gEfiMemoryOverwriteControlDataGuid; 69 70 #endif 71