/** @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.
Copyright (c) 2009 - 2024, Intel Corporation. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include
#include
#include
#include
#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 (
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);
//
// SmramAccessLock() depends on "mQ35SmramAtDefaultSmbase"; init the latter
// just before exposing the former via EFI_SMM_ACCESS2_PROTOCOL.Lock().
//
InitQ35SmramAtDefaultSmbase ();
return gBS->InstallMultipleProtocolInterfaces (
&ImageHandle,
&gEfiSmmAccess2ProtocolGuid,
&mAccess2,
NULL
);
}