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/** @file
This driver publishes the SMM Access 2 Protocol.
Copyright (c) 2021, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "SmmAccessDxe.h"
SMM_ACCESS_PRIVATE_DATA mSmmAccess;
/**
Update region state from SMRAM description
@param[in] OrLogic Indicate to use OR if true or AND if false.
@param[in] Value The value to set to region state based on OrLogic.
**/
VOID
SyncRegionState2SmramDesc(
IN BOOLEAN OrLogic,
IN UINT64 Value
)
{
UINT32 Index;
for (Index = 0; Index < mSmmAccess.NumberRegions; Index++) {
if (OrLogic) {
mSmmAccess.SmramDesc[Index].RegionState |= Value;
} else {
mSmmAccess.SmramDesc[Index].RegionState &= Value;
}
}
}
/**
This routine accepts a request to "open" a region of SMRAM. The
region could be legacy ABSEG, HSEG, or TSEG near top of physical memory.
The use of "open" means that the memory is visible from all boot-service
and SMM agents.
@param This Pointer to the SMM Access Interface.
@retval EFI_SUCCESS The region was successfully opened.
@retval EFI_DEVICE_ERROR The region could not be opened because locked by chipset.
@retval EFI_INVALID_PARAMETER The descriptor index was out of bounds.
**/
EFI_STATUS
EFIAPI
Open (
IN EFI_SMM_ACCESS2_PROTOCOL *This
)
{
if ((mSmmAccess.SmmRegionState & EFI_SMRAM_LOCKED) != 0) {
//
// Cannot open a "locked" region
//
DEBUG ((DEBUG_INFO, "Cannot open the locked SMRAM Region\n"));
return EFI_DEVICE_ERROR;
}
mSmmAccess.SmmRegionState &= ~(EFI_SMRAM_CLOSED | EFI_ALLOCATED);
SyncRegionState2SmramDesc(FALSE, (UINT64)(UINTN)(~(EFI_SMRAM_CLOSED | EFI_ALLOCATED)));
mSmmAccess.SmmRegionState |= EFI_SMRAM_OPEN;
SyncRegionState2SmramDesc(TRUE, EFI_SMRAM_OPEN);
mSmmAccess.SmmAccess.OpenState = TRUE;
return EFI_SUCCESS;
}
/**
This routine accepts a request to "close" a region of SMRAM. The region
could be legacy AB or TSEG near top of physical memory.
The use of "close" means that the memory is only visible from SMM agents,
not from BS or RT code.
@param This Pointer to the SMM Access Interface.
@retval EFI_SUCCESS The region was successfully closed.
@retval EFI_DEVICE_ERROR The region could not be closed because locked by
chipset.
@retval EFI_INVALID_PARAMETER The descriptor index was out of bounds.
**/
EFI_STATUS
EFIAPI
Close (
IN EFI_SMM_ACCESS2_PROTOCOL *This
)
{
if ((mSmmAccess.SmmRegionState & EFI_SMRAM_LOCKED) != 0) {
//
// Cannot close a "locked" region
//
DEBUG ((DEBUG_INFO, "Cannot close the locked SMRAM Region\n"));
return EFI_DEVICE_ERROR;
}
if ((mSmmAccess.SmmRegionState & EFI_SMRAM_CLOSED) != 0) {
return EFI_DEVICE_ERROR;
}
mSmmAccess.SmmRegionState &= ~EFI_SMRAM_OPEN;
SyncRegionState2SmramDesc(FALSE, (UINT64)(UINTN)(~EFI_SMRAM_OPEN));
mSmmAccess.SmmRegionState |= (EFI_SMRAM_CLOSED | EFI_ALLOCATED);
SyncRegionState2SmramDesc(TRUE, EFI_SMRAM_CLOSED | EFI_ALLOCATED);
mSmmAccess.SmmAccess.OpenState = FALSE;
return EFI_SUCCESS;
}
/**
This routine accepts a request to "lock" SMRAM. The
region could be legacy AB or TSEG near top of physical memory.
The use of "lock" means that the memory can no longer be opened
to BS state.
@param This Pointer to the SMM Access Interface.
@retval EFI_SUCCESS The region was successfully locked.
@retval EFI_DEVICE_ERROR The region could not be locked because at least
one range is still open.
@retval EFI_INVALID_PARAMETER The descriptor index was out of bounds.
**/
EFI_STATUS
EFIAPI
Lock (
IN EFI_SMM_ACCESS2_PROTOCOL *This
)
{
if (mSmmAccess.SmmAccess.OpenState) {
DEBUG ((DEBUG_INFO, "Cannot lock SMRAM when it is still open\n"));
return EFI_DEVICE_ERROR;
}
mSmmAccess.SmmRegionState |= EFI_SMRAM_LOCKED;
SyncRegionState2SmramDesc(TRUE, EFI_SMRAM_LOCKED);
mSmmAccess.SmmAccess.LockState = TRUE;
return EFI_SUCCESS;
}
/**
This routine services a user request to discover the SMRAM
capabilities of this platform. This will report the possible
ranges that are possible for SMRAM access, based upon the
memory controller capabilities.
@param This Pointer to the SMRAM Access Interface.
@param SmramMapSize Pointer to the variable containing size of the
buffer to contain the description information.
@param SmramMap Buffer containing the data describing the Smram
region descriptors.
@retval EFI_BUFFER_TOO_SMALL The user did not provide a sufficient buffer.
@retval EFI_SUCCESS The user provided a sufficiently-sized buffer.
**/
EFI_STATUS
EFIAPI
GetCapabilities (
IN CONST EFI_SMM_ACCESS2_PROTOCOL *This,
IN OUT UINTN *SmramMapSize,
IN OUT EFI_SMRAM_DESCRIPTOR *SmramMap
)
{
EFI_STATUS Status;
UINTN NecessaryBufferSize;
NecessaryBufferSize = mSmmAccess.NumberRegions * sizeof(EFI_SMRAM_DESCRIPTOR);
if (*SmramMapSize < NecessaryBufferSize) {
Status = EFI_BUFFER_TOO_SMALL;
} else {
CopyMem(SmramMap, mSmmAccess.SmramDesc, NecessaryBufferSize);
Status = EFI_SUCCESS;
}
*SmramMapSize = NecessaryBufferSize;
return Status;
}
/**
This function installs EFI_SMM_ACCESS_PROTOCOL.
@param ImageHandle Handle for the image of this driver
@param SystemTable Pointer to the EFI System Table
@retval EFI_UNSUPPORTED There's no Intel ICH on this platform
@return The status returned from InstallProtocolInterface().
**/
EFI_STATUS
EFIAPI
SmmAccessEntryPoint (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
EFI_STATUS Status;
EFI_HOB_GUID_TYPE *GuidHob;
UINT32 SmmRegionNum;
EFI_SMRAM_HOB_DESCRIPTOR_BLOCK *SmramHob;
UINT32 Index;
//
// Get SMRAM info HOB
//
GuidHob = GetFirstGuidHob (&gEfiSmmSmramMemoryGuid);
if (GuidHob == NULL) {
DEBUG ((DEBUG_INFO, "SMRAM HOB NOT found\n"));
return EFI_NOT_FOUND;
}
SmramHob = (EFI_SMRAM_HOB_DESCRIPTOR_BLOCK *) GET_GUID_HOB_DATA(GuidHob);
SmmRegionNum = SmramHob->NumberOfSmmReservedRegions;
mSmmAccess.SmramDesc = AllocateZeroPool (sizeof (EFI_SMRAM_DESCRIPTOR) * SmmRegionNum);
if (mSmmAccess.SmramDesc == NULL) {
return EFI_OUT_OF_RESOURCES;
}
CopyMem (mSmmAccess.SmramDesc, &SmramHob->Descriptor, sizeof (EFI_SMRAM_DESCRIPTOR) * SmmRegionNum);
DEBUG ((DEBUG_INFO, "NumberOfSmmReservedRegions = 0x%x\n", SmmRegionNum));
for (Index = 0; Index < SmmRegionNum; Index++) {
DEBUG ((DEBUG_INFO, "%d: base=0x%x, size = 0x%x, State=0x%x\n",Index,
SmramHob->Descriptor[Index].PhysicalStart,
SmramHob->Descriptor[Index].PhysicalSize,
SmramHob->Descriptor[Index].RegionState));
mSmmAccess.SmramDesc[Index].RegionState &= EFI_ALLOCATED;
mSmmAccess.SmramDesc[Index].RegionState |= EFI_SMRAM_CLOSED | EFI_CACHEABLE;
}
mSmmAccess.Signature = SMM_ACCESS_PRIVATE_DATA_SIGNATURE;
mSmmAccess.NumberRegions = SmmRegionNum;
mSmmAccess.SmmAccess.Open = Open;
mSmmAccess.SmmAccess.Close = Close;
mSmmAccess.SmmAccess.Lock = Lock;
mSmmAccess.SmmAccess.GetCapabilities = GetCapabilities;
mSmmAccess.SmmAccess.LockState = FALSE;
mSmmAccess.SmmAccess.OpenState = FALSE;
mSmmAccess.SmmRegionState = EFI_SMRAM_CLOSED;
Status = gBS->InstallMultipleProtocolInterfaces (
&mSmmAccess.Handle,
&gEfiSmmAccess2ProtocolGuid,
&mSmmAccess.SmmAccess,
NULL
);
return Status;
}
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