MdePkg/Include/Guid/MemoryOverwriteControl.h

   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