system76-edk2/OvmfPkg/SmmAccess/SmmAccess2Dxe.c

/** @file

  A DXE_DRIVER providing SMRAM access by producing EFI_SMM_ACCESS2_PROTOCOL.

  Q35 TSEG is expected to have been verified and set up by the SmmAccessPei
  driver.

  Copyright (C) 2013, 2015, Red Hat, Inc.<BR>
  Copyright (c) 2009 - 2010, 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 <Library/DebugLib.h>
#include <Library/PcdLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Protocol/SmmAccess2.h>

#include "SmramInternal.h"

/**
  Opens the SMRAM area to be accessible by a boot-service driver.

  This function "opens" SMRAM so that it is visible while not inside of SMM.
  The function should return EFI_UNSUPPORTED if the hardware does not support
  hiding of SMRAM. The function should return EFI_DEVICE_ERROR if the SMRAM
  configuration is locked.

  @param[in] This           The EFI_SMM_ACCESS2_PROTOCOL instance.

  @retval EFI_SUCCESS       The operation was successful.
  @retval EFI_UNSUPPORTED   The system does not support opening and closing of
                            SMRAM.
  @retval EFI_DEVICE_ERROR  SMRAM cannot be opened, perhaps because it is
                            locked.
**/
STATIC
EFI_STATUS
EFIAPI
SmmAccess2DxeOpen (
  IN EFI_SMM_ACCESS2_PROTOCOL  *This
  )
{
  return SmramAccessOpen (&This->LockState, &This->OpenState);
}

/**
  Inhibits access to the SMRAM.

  This function "closes" SMRAM so that it is not visible while outside of SMM.
  The function should return EFI_UNSUPPORTED if the hardware does not support
  hiding of SMRAM.

  @param[in] This           The EFI_SMM_ACCESS2_PROTOCOL instance.

  @retval EFI_SUCCESS       The operation was successful.
  @retval EFI_UNSUPPORTED   The system does not support opening and closing of
                            SMRAM.
  @retval EFI_DEVICE_ERROR  SMRAM cannot be closed.
**/
STATIC
EFI_STATUS
EFIAPI
SmmAccess2DxeClose (
  IN EFI_SMM_ACCESS2_PROTOCOL  *This
  )
{
  return SmramAccessClose (&This->LockState, &This->OpenState);
}

/**
  Inhibits access to the SMRAM.

  This function prohibits access to the SMRAM region.  This function is usually
  implemented such that it is a write-once operation.

  @param[in] This          The EFI_SMM_ACCESS2_PROTOCOL instance.

  @retval EFI_SUCCESS      The device was successfully locked.
  @retval EFI_UNSUPPORTED  The system does not support locking of SMRAM.
**/
STATIC
EFI_STATUS
EFIAPI
SmmAccess2DxeLock (
  IN EFI_SMM_ACCESS2_PROTOCOL  *This
  )
{
  return SmramAccessLock (&This->LockState, &This->OpenState);
}

/**
  Queries the memory controller for the possible regions that will support
  SMRAM.

  @param[in]     This           The EFI_SMM_ACCESS2_PROTOCOL instance.
  @param[in,out] SmramMapSize   A pointer to the size, in bytes, of the
                                SmramMemoryMap buffer.
  @param[in,out] SmramMap       A pointer to the buffer in which firmware
                                places the current memory map.

  @retval EFI_SUCCESS           The chipset supported the given resource.
  @retval EFI_BUFFER_TOO_SMALL  The SmramMap parameter was too small.  The
                                current buffer size needed to hold the memory
                                map is returned in SmramMapSize.
**/
STATIC
EFI_STATUS
EFIAPI
SmmAccess2DxeGetCapabilities (
  IN CONST EFI_SMM_ACCESS2_PROTOCOL  *This,
  IN OUT UINTN                       *SmramMapSize,
  IN OUT EFI_SMRAM_DESCRIPTOR        *SmramMap
  )
{
  return SmramAccessGetCapabilities (This->LockState, This->OpenState,
           SmramMapSize, SmramMap);
}

//
// LockState and OpenState will be filled in by the entry point.
//
STATIC EFI_SMM_ACCESS2_PROTOCOL mAccess2 = {
  &SmmAccess2DxeOpen,
  &SmmAccess2DxeClose,
  &SmmAccess2DxeLock,
  &SmmAccess2DxeGetCapabilities
};

//
// Entry point of this driver.
//
EFI_STATUS
EFIAPI
SmmAccess2DxeEntryPoint (
  IN EFI_HANDLE       ImageHandle,
  IN EFI_SYSTEM_TABLE *SystemTable
  )
{
  //
  // This module should only be included if SMRAM support is required.
  //
  ASSERT (FeaturePcdGet (PcdSmmSmramRequire));

  InitQ35TsegMbytes ();
  GetStates (&mAccess2.LockState, &mAccess2.OpenState);
  return gBS->InstallMultipleProtocolInterfaces (&ImageHandle,
                &gEfiSmmAccess2ProtocolGuid, &mAccess2,
                NULL);
}