audk/SecurityPkg/Tcg/PhysicalPresencePei/PhysicalPresencePei.c

/** @file
  This driver produces PEI_LOCK_PHYSICAL_PRESENCE_PPI to indicate 
  whether TPM need be locked or not. It can be replaced by a platform 
  specific driver.

Copyright (c) 2005 - 2011, 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 <PiPei.h>
#include <Ppi/LockPhysicalPresence.h>
#include <Ppi/ReadOnlyVariable2.h>
#include <Guid/PhysicalPresenceData.h>
#include <Library/PcdLib.h>
#include <Library/PeiServicesLib.h>

/**
  This interface returns whether TPM physical presence needs be locked or not.

  @param[in]  PeiServices       The pointer to the PEI Services Table.

  @retval     TRUE              The TPM physical presence should be locked.
  @retval     FALSE             The TPM physical presence cannot be locked.

**/
BOOLEAN
EFIAPI
LockTpmPhysicalPresence (
  IN CONST  EFI_PEI_SERVICES             **PeiServices
  );

//
// Gobal defintions for lock physical presence PPI and its descriptor.
//
PEI_LOCK_PHYSICAL_PRESENCE_PPI    mLockPhysicalPresencePpi = {
  LockTpmPhysicalPresence
};

EFI_PEI_PPI_DESCRIPTOR       mLockPhysicalPresencePpiList = {
  EFI_PEI_PPI_DESCRIPTOR_PPI | EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST,
  &gPeiLockPhysicalPresencePpiGuid,
  &mLockPhysicalPresencePpi
};

/**
  This interface returns whether TPM physical presence needs be locked or not.

  @param[in]  PeiServices       The pointer to the PEI Services Table.

  @retval     TRUE              The TPM physical presence should be locked.
  @retval     FALSE             The TPM physical presence cannot be locked.

**/
BOOLEAN
EFIAPI
LockTpmPhysicalPresence (
  IN CONST  EFI_PEI_SERVICES             **PeiServices
  )
{
  EFI_STATUS                         Status;
  EFI_PEI_READ_ONLY_VARIABLE2_PPI    *Variable;
  UINTN                              DataSize;
  EFI_PHYSICAL_PRESENCE              TcgPpData;

  //
  // The CRTM has sensed the physical presence assertion of the user. For example, 
  // the user has pressed the startup button or inserted a USB dongle. The details 
  // of the implementation are vendor-specific. Here we read a PCD value to indicate
  // whether operator physical presence.
  // 
  if (!PcdGetBool (PcdTpmPhysicalPresence)) {
    return TRUE;
  }

  //
  // Check the pending TPM requests. Lock TPM physical presence if there is no TPM 
  // request.  
  //
  Status = PeiServicesLocatePpi (
             &gEfiPeiReadOnlyVariable2PpiGuid,
             0,
             NULL,
             (VOID **)&Variable
             );
  if (!EFI_ERROR (Status)) {
    DataSize = sizeof (EFI_PHYSICAL_PRESENCE);
    Status = Variable->GetVariable ( 
                         Variable, 
                         PHYSICAL_PRESENCE_VARIABLE,
                         &gEfiPhysicalPresenceGuid,
                         NULL,
                         &DataSize,
                         &TcgPpData
                         );
    if (!EFI_ERROR (Status)) {
      if (TcgPpData.PPRequest != 0) {
        return FALSE;
      }
    }
  }

  //
  // Lock TPM physical presence by default.
  //
  return TRUE;
}

/**
  Entry point of this module.

  It installs lock physical presence PPI. 

  @param[in] FileHandle   Handle of the file being invoked.
  @param[in] PeiServices  Describes the list of possible PEI Services.

  @return                 Status of install lock physical presence PPI.

**/
EFI_STATUS
EFIAPI
PeimEntry (
  IN       EFI_PEI_FILE_HANDLE       FileHandle,
  IN CONST EFI_PEI_SERVICES          **PeiServices
  )
{
  return PeiServicesInstallPpi (&mLockPhysicalPresencePpiList);
}