mirror of https://github.com/acidanthera/audk.git
83 lines
2.4 KiB
C
83 lines
2.4 KiB
C
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/** @file
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TCG MOR (Memory Overwrite Request) Control Driver.
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This driver initilize MemoryOverwriteRequestControl variable. It
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will clear MOR_CLEAR_MEMORY_BIT bit if it is set.
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Copyright (c) 2009 - 2011, Intel Corporation. All rights reserved.<BR>
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This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include "TcgMor.h"
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/**
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Entry Point for TCG MOR Control driver.
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@param[in] ImageHandle Image handle of this driver.
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@param[in] SystemTable A Pointer to the EFI System Table.
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@retval EFI_SUCEESS
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@return Others Some error occurs.
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**/
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EFI_STATUS
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EFIAPI
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MorDriverEntryPoint (
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IN EFI_HANDLE ImageHandle,
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IN EFI_SYSTEM_TABLE *SystemTable
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)
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{
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EFI_STATUS Status;
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UINT8 MorControl;
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UINTN DataSize;
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///
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/// The firmware is required to create the MemoryOverwriteRequestControl UEFI variable.
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///
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DataSize = sizeof (MorControl);
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Status = gRT->GetVariable (
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MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,
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&gEfiMemoryOverwriteControlDataGuid,
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NULL,
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&DataSize,
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&MorControl
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);
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if (EFI_ERROR (Status)) {
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//
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// Set default value to 0
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//
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MorControl = 0;
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} else {
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if (MOR_CLEAR_MEMORY_VALUE (MorControl) == 0x0) {
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//
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// MorControl is expected, directly return to avoid unnecessary variable operation
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//
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return EFI_SUCCESS;
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}
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//
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// Clear MOR_CLEAR_MEMORY_BIT
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//
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DEBUG ((EFI_D_INFO, "TcgMor: Clear MorClearMemory bit\n"));
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MorControl &= 0xFE;
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}
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Status = gRT->SetVariable (
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MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,
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&gEfiMemoryOverwriteControlDataGuid,
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EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
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DataSize,
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&MorControl
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);
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ASSERT_EFI_ERROR (Status);
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return Status;
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}
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