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, Intel Corporation
  11   All rights reserved. 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