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/** @file
TCG MOR (Memory Overwrite Request) Control Driver.
This driver initilize MemoryOverwriteRequestControl variable. It
will clear MOR_CLEAR_MEMORY_BIT bit if it is set.
Copyright (c) 2009 - 2014, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include "TcgMor.h"
UINT8 mMorControl;
/**
Ready to Boot Event notification handler.
Sequence of OS boot events is measured in this event notification handler.
@param[in] Event Event whose notification function is being invoked
@param[in] Context Pointer to the notification function's context
**/
VOID
EFIAPI
OnReadyToBoot (
IN EFI_EVENT Event,
IN VOID *Context
)
{
EFI_STATUS Status;
UINTN DataSize;
if (MOR_CLEAR_MEMORY_VALUE (mMorControl) == 0x0) {
//
// MorControl is expected, directly return to avoid unnecessary variable operation
//
return ;
}
//
// Clear MOR_CLEAR_MEMORY_BIT
//
DEBUG ((EFI_D_INFO, "TcgMor: Clear MorClearMemory bit\n"));
mMorControl &= 0xFE;
DataSize = sizeof (mMorControl);
Status = gRT->SetVariable (
MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,
&gEfiMemoryOverwriteControlDataGuid,
EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
DataSize,
&mMorControl
);
if (EFI_ERROR (Status)) {
DEBUG ((EFI_D_ERROR, "TcgMor: Clear MOR_CLEAR_MEMORY_BIT failure, Status = %r\n"));
}
}
/**
Entry Point for TCG MOR Control driver.
@param[in] ImageHandle Image handle of this driver.
@param[in] SystemTable A Pointer to the EFI System Table.
@retval EFI_SUCEESS
@return Others Some error occurs.
**/
EFI_STATUS
EFIAPI
MorDriverEntryPoint (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
EFI_STATUS Status;
UINTN DataSize;
EFI_EVENT Event;
///
/// The firmware is required to create the MemoryOverwriteRequestControl UEFI variable.
///
DataSize = sizeof (mMorControl);
Status = gRT->GetVariable (
MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,
&gEfiMemoryOverwriteControlDataGuid,
NULL,
&DataSize,
&mMorControl
);
if (EFI_ERROR (Status)) {
//
// Set default value to 0
//
mMorControl = 0;
Status = gRT->SetVariable (
MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,
&gEfiMemoryOverwriteControlDataGuid,
EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
DataSize,
&mMorControl
);
DEBUG ((EFI_D_INFO, "TcgMor: Create MOR variable! Status = %r\n", Status));
} else {
//
// Create a Ready To Boot Event and Clear the MorControl bit in the call back function.
//
DEBUG ((EFI_D_INFO, "TcgMor: Create ReadyToBoot Event for MorControl Bit cleanning!\n"));
Status = EfiCreateEventReadyToBootEx (
TPL_CALLBACK,
OnReadyToBoot,
NULL,
&Event
);
}
return Status;
}
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