ArmPkg/Library/StandaloneMmMmuLib/ArmMmuStandaloneMmLib.c - edk2 - Git at Google

 /** @file
   File managing the MMU for ARMv8 architecture in S-EL0

   Copyright (c) 2017 - 2021, Arm Limited. All rights reserved.<BR>
   Copyright (c) 2021, Linaro Limited
   SPDX-License-Identifier: BSD-2-Clause-Patent

   @par Reference(s):
   - [1] SPM based on the MM interface.
         (https://trustedfirmware-a.readthedocs.io/en/latest/components/
          secure-partition-manager-mm.html)
   - [2] Arm Firmware Framework for Armv8-A, DEN0077A, version 1.0
         (https://developer.arm.com/documentation/den0077/a)
 **/

 #include <Uefi.h>
 #include <IndustryStandard/ArmMmSvc.h>
 #include <IndustryStandard/ArmFfaSvc.h>

 #include <Library/ArmLib.h>
 #include <Library/ArmMmuLib.h>
 #include <Library/ArmSvcLib.h>
 #include <Library/BaseLib.h>
 #include <Library/BaseMemoryLib.h>
 #include <Library/DebugLib.h>
 #include <Library/PcdLib.h>

 /** Send memory permission request to target.

   @param [in, out]  SvcArgs     Pointer to SVC arguments to send. On
                                 return it contains the response parameters.
   @param [out]      RetVal      Pointer to return the response value.

   @retval EFI_SUCCESS           Request successfull.
   @retval EFI_INVALID_PARAMETER A parameter is invalid.
   @retval EFI_NOT_READY         Callee is busy or not in a state to handle
                                 this request.
   @retval EFI_UNSUPPORTED       This function is not implemented by the
                                 callee.
   @retval EFI_ABORTED           Message target ran into an unexpected error
                                 and has aborted.
   @retval EFI_ACCESS_DENIED     Access denied.
   @retval EFI_OUT_OF_RESOURCES  Out of memory to perform operation.
 **/
 STATIC
 EFI_STATUS
 SendMemoryPermissionRequest (
   IN OUT  ARM_SVC_ARGS  *SvcArgs,
   OUT  INT32            *RetVal
   )
 {
   if ((SvcArgs == NULL) || (RetVal == NULL)) {
     return EFI_INVALID_PARAMETER;
   }

   ArmCallSvc (SvcArgs);
   if (FeaturePcdGet (PcdFfaEnable)) {
     // Get/Set memory attributes is an atomic call, with
     // StandaloneMm at S-EL0 being the caller and the SPM
     // core being the callee. Thus there won't be a
     // FFA_INTERRUPT or FFA_SUCCESS response to the Direct
     // Request sent above. This will have to be considered
     // for other Direct Request calls which are not atomic
     // We therefore check only for Direct Response by the
     // callee.
     if (SvcArgs->Arg0 == ARM_SVC_ID_FFA_MSG_SEND_DIRECT_RESP) {
       // A Direct Response means FF-A success
       // Now check the payload for errors
       // The callee sends back the return value
       // in Arg3
       *RetVal = SvcArgs->Arg3;
     } else {
       // If Arg0 is not a Direct Response, that means we
       // have an FF-A error. We need to check Arg2 for the
       // FF-A error code.
       // See [2], Table 10.8: FFA_ERROR encoding.
       *RetVal = SvcArgs->Arg2;
       switch (*RetVal) {
         case ARM_FFA_SPM_RET_INVALID_PARAMETERS:
           return EFI_INVALID_PARAMETER;

         case ARM_FFA_SPM_RET_DENIED:
           return EFI_ACCESS_DENIED;

         case ARM_FFA_SPM_RET_NOT_SUPPORTED:
           return EFI_UNSUPPORTED;

         case ARM_FFA_SPM_RET_BUSY:
           return EFI_NOT_READY;

         case ARM_FFA_SPM_RET_ABORTED:
           return EFI_ABORTED;

         default:
           // Undefined error code received.
           ASSERT (0);
           return EFI_INVALID_PARAMETER;
       }
     }
   } else {
     *RetVal = SvcArgs->Arg0;
   }

   // Check error response from Callee.
   if ((*RetVal & BIT31) != 0) {
     // Bit 31 set means there is an error returned
     // See [1], Section 13.5.5.1 MM_SP_MEMORY_ATTRIBUTES_GET_AARCH64 and
     // Section 13.5.5.2 MM_SP_MEMORY_ATTRIBUTES_SET_AARCH64.
     switch (*RetVal) {
       case ARM_SVC_SPM_RET_NOT_SUPPORTED:
         return EFI_UNSUPPORTED;

       case ARM_SVC_SPM_RET_INVALID_PARAMS:
         return EFI_INVALID_PARAMETER;

       case ARM_SVC_SPM_RET_DENIED:
         return EFI_ACCESS_DENIED;

       case ARM_SVC_SPM_RET_NO_MEMORY:
         return EFI_OUT_OF_RESOURCES;

       default:
         // Undefined error code received.
         ASSERT (0);
         return EFI_INVALID_PARAMETER;
     }
   }

   return EFI_SUCCESS;
 }

 /** Request the permission attributes of a memory region from S-EL0.

   @param [in]   BaseAddress          Base address for the memory region.
   @param [out]  MemoryAttributes     Pointer to return the memory attributes.

   @retval EFI_SUCCESS             Request successfull.
   @retval EFI_INVALID_PARAMETER   A parameter is invalid.
   @retval EFI_NOT_READY           Callee is busy or not in a state to handle
                                   this request.
   @retval EFI_UNSUPPORTED         This function is not implemented by the
                                   callee.
   @retval EFI_ABORTED             Message target ran into an unexpected error
                                   and has aborted.
   @retval EFI_ACCESS_DENIED       Access denied.
   @retval EFI_OUT_OF_RESOURCES    Out of memory to perform operation.
 **/
 STATIC
 EFI_STATUS
 GetMemoryPermissions (
   IN  EFI_PHYSICAL_ADDRESS  BaseAddress,
   OUT UINT32                *MemoryAttributes
   )
 {
   EFI_STATUS    Status;
   INT32         Ret;
   ARM_SVC_ARGS  SvcArgs;

   if (MemoryAttributes == NULL) {
     return EFI_INVALID_PARAMETER;
   }

   // Prepare the message parameters.
   // See [1], Section 13.5.5.1 MM_SP_MEMORY_ATTRIBUTES_GET_AARCH64.
   ZeroMem (&SvcArgs, sizeof (ARM_SVC_ARGS));
   if (FeaturePcdGet (PcdFfaEnable)) {
     // See [2], Section 10.2 FFA_MSG_SEND_DIRECT_REQ.
     SvcArgs.Arg0 = ARM_SVC_ID_FFA_MSG_SEND_DIRECT_REQ;
     SvcArgs.Arg1 = ARM_FFA_DESTINATION_ENDPOINT_ID;
     SvcArgs.Arg2 = 0;
     SvcArgs.Arg3 = ARM_SVC_ID_SP_GET_MEM_ATTRIBUTES;
     SvcArgs.Arg4 = BaseAddress;
   } else {
     SvcArgs.Arg0 = ARM_SVC_ID_SP_GET_MEM_ATTRIBUTES;
     SvcArgs.Arg1 = BaseAddress;
     SvcArgs.Arg2 = 0;
     SvcArgs.Arg3 = 0;
   }

   Status = SendMemoryPermissionRequest (&SvcArgs, &Ret);
   if (EFI_ERROR (Status)) {
     *MemoryAttributes = 0;
     return Status;
   }

   *MemoryAttributes = Ret;
   return Status;
 }

 /** Set the permission attributes of a memory region from S-EL0.

   @param [in]  BaseAddress     Base address for the memory region.
   @param [in]  Length          Length of the memory region.
   @param [in]  Permissions     Memory access controls attributes.

   @retval EFI_SUCCESS             Request successfull.
   @retval EFI_INVALID_PARAMETER   A parameter is invalid.
   @retval EFI_NOT_READY           Callee is busy or not in a state to handle
                                   this request.
   @retval EFI_UNSUPPORTED         This function is not implemented by the
                                   callee.
   @retval EFI_ABORTED             Message target ran into an unexpected error
                                   and has aborted.
   @retval EFI_ACCESS_DENIED       Access denied.
   @retval EFI_OUT_OF_RESOURCES    Out of memory to perform operation.
 **/
 STATIC
 EFI_STATUS
 RequestMemoryPermissionChange (
   IN  EFI_PHYSICAL_ADDRESS  BaseAddress,
   IN  UINT64                Length,
   IN  UINT32                Permissions
   )
 {
   INT32         Ret;
   ARM_SVC_ARGS  SvcArgs;

   // Prepare the message parameters.
   // See [1], Section 13.5.5.2 MM_SP_MEMORY_ATTRIBUTES_SET_AARCH64.
   ZeroMem (&SvcArgs, sizeof (ARM_SVC_ARGS));
   if (FeaturePcdGet (PcdFfaEnable)) {
     // See [2], Section 10.2 FFA_MSG_SEND_DIRECT_REQ.
     SvcArgs.Arg0 = ARM_SVC_ID_FFA_MSG_SEND_DIRECT_REQ;
     SvcArgs.Arg1 = ARM_FFA_DESTINATION_ENDPOINT_ID;
     SvcArgs.Arg2 = 0;
     SvcArgs.Arg3 = ARM_SVC_ID_SP_SET_MEM_ATTRIBUTES;
     SvcArgs.Arg4 = BaseAddress;
     SvcArgs.Arg5 = EFI_SIZE_TO_PAGES (Length);
     SvcArgs.Arg6 = Permissions;
   } else {
     SvcArgs.Arg0 = ARM_SVC_ID_SP_SET_MEM_ATTRIBUTES;
     SvcArgs.Arg1 = BaseAddress;
     SvcArgs.Arg2 = EFI_SIZE_TO_PAGES (Length);
     SvcArgs.Arg3 = Permissions;
   }

   return SendMemoryPermissionRequest (&SvcArgs, &Ret);
 }

 EFI_STATUS
 ArmSetMemoryRegionNoExec (
   IN  EFI_PHYSICAL_ADDRESS  BaseAddress,
   IN  UINT64                Length
   )
 {
   EFI_STATUS  Status;
   UINT32      MemoryAttributes;
   UINT32      CodePermission;

   Status = GetMemoryPermissions (BaseAddress, &MemoryAttributes);
   if (!EFI_ERROR (Status)) {
     CodePermission = SET_MEM_ATTR_CODE_PERM_XN << SET_MEM_ATTR_CODE_PERM_SHIFT;
     return RequestMemoryPermissionChange (
              BaseAddress,
              Length,
              MemoryAttributes | CodePermission
              );
   }

   return Status;
 }

 EFI_STATUS
 ArmClearMemoryRegionNoExec (
   IN  EFI_PHYSICAL_ADDRESS  BaseAddress,
   IN  UINT64                Length
   )
 {
   EFI_STATUS  Status;
   UINT32      MemoryAttributes;
   UINT32      CodePermission;

   Status = GetMemoryPermissions (BaseAddress, &MemoryAttributes);
   if (!EFI_ERROR (Status)) {
     CodePermission = SET_MEM_ATTR_CODE_PERM_XN << SET_MEM_ATTR_CODE_PERM_SHIFT;
     return RequestMemoryPermissionChange (
              BaseAddress,
              Length,
              MemoryAttributes & ~CodePermission
              );
   }

   return Status;
 }

 EFI_STATUS
 ArmSetMemoryRegionReadOnly (
   IN  EFI_PHYSICAL_ADDRESS  BaseAddress,
   IN  UINT64                Length
   )
 {
   EFI_STATUS  Status;
   UINT32      MemoryAttributes;
   UINT32      DataPermission;

   Status = GetMemoryPermissions (BaseAddress, &MemoryAttributes);
   if (!EFI_ERROR (Status)) {
     DataPermission = SET_MEM_ATTR_DATA_PERM_RO << SET_MEM_ATTR_DATA_PERM_SHIFT;
     return RequestMemoryPermissionChange (
              BaseAddress,
              Length,
              MemoryAttributes | DataPermission
              );
   }

   return Status;
 }

 EFI_STATUS
 ArmClearMemoryRegionReadOnly (
   IN  EFI_PHYSICAL_ADDRESS  BaseAddress,
   IN  UINT64                Length
   )
 {
   EFI_STATUS  Status;
   UINT32      MemoryAttributes;
   UINT32      PermissionRequest;

   Status = GetMemoryPermissions (BaseAddress, &MemoryAttributes);
   if (!EFI_ERROR (Status)) {
     PermissionRequest = SET_MEM_ATTR_MAKE_PERM_REQUEST (
                           SET_MEM_ATTR_DATA_PERM_RW,
                           MemoryAttributes
                           );
     return RequestMemoryPermissionChange (
              BaseAddress,
              Length,
              PermissionRequest
              );
   }

   return Status;
 }
	/** @file
	File managing the MMU for ARMv8 architecture in S-EL0

	Copyright (c) 2017 - 2021, Arm Limited. All rights reserved.<BR>
	Copyright (c) 2021, Linaro Limited
	SPDX-License-Identifier: BSD-2-Clause-Patent

	@par Reference(s):
	- [1] SPM based on the MM interface.
	(https://trustedfirmware-a.readthedocs.io/en/latest/components/
	secure-partition-manager-mm.html)
	- [2] Arm Firmware Framework for Armv8-A, DEN0077A, version 1.0
	(https://developer.arm.com/documentation/den0077/a)
	**/

	#include <Uefi.h>
	#include <IndustryStandard/ArmMmSvc.h>
	#include <IndustryStandard/ArmFfaSvc.h>

	#include <Library/ArmLib.h>
	#include <Library/ArmMmuLib.h>
	#include <Library/ArmSvcLib.h>
	#include <Library/BaseLib.h>
	#include <Library/BaseMemoryLib.h>
	#include <Library/DebugLib.h>
	#include <Library/PcdLib.h>

	/** Send memory permission request to target.

	@param [in, out] SvcArgs Pointer to SVC arguments to send. On
	return it contains the response parameters.
	@param [out] RetVal Pointer to return the response value.

	@retval EFI_SUCCESS Request successfull.
	@retval EFI_INVALID_PARAMETER A parameter is invalid.
	@retval EFI_NOT_READY Callee is busy or not in a state to handle
	this request.
	@retval EFI_UNSUPPORTED This function is not implemented by the
	callee.
	@retval EFI_ABORTED Message target ran into an unexpected error
	and has aborted.
	@retval EFI_ACCESS_DENIED Access denied.
	@retval EFI_OUT_OF_RESOURCES Out of memory to perform operation.
	**/
	STATIC
	EFI_STATUS
	SendMemoryPermissionRequest (
	IN OUT ARM_SVC_ARGS *SvcArgs,
	OUT INT32 *RetVal
	)
	{
	if ((SvcArgs == NULL) \|\| (RetVal == NULL)) {
	return EFI_INVALID_PARAMETER;
	}

	ArmCallSvc (SvcArgs);
	if (FeaturePcdGet (PcdFfaEnable)) {
	// Get/Set memory attributes is an atomic call, with
	// StandaloneMm at S-EL0 being the caller and the SPM
	// core being the callee. Thus there won't be a
	// FFA_INTERRUPT or FFA_SUCCESS response to the Direct
	// Request sent above. This will have to be considered
	// for other Direct Request calls which are not atomic
	// We therefore check only for Direct Response by the
	// callee.
	if (SvcArgs->Arg0 == ARM_SVC_ID_FFA_MSG_SEND_DIRECT_RESP) {
	// A Direct Response means FF-A success
	// Now check the payload for errors
	// The callee sends back the return value
	// in Arg3
	*RetVal = SvcArgs->Arg3;
	} else {
	// If Arg0 is not a Direct Response, that means we
	// have an FF-A error. We need to check Arg2 for the
	// FF-A error code.
	// See [2], Table 10.8: FFA_ERROR encoding.
	*RetVal = SvcArgs->Arg2;
	switch (*RetVal) {
	case ARM_FFA_SPM_RET_INVALID_PARAMETERS:
	return EFI_INVALID_PARAMETER;

	case ARM_FFA_SPM_RET_DENIED:
	return EFI_ACCESS_DENIED;

	case ARM_FFA_SPM_RET_NOT_SUPPORTED:
	return EFI_UNSUPPORTED;

	case ARM_FFA_SPM_RET_BUSY:
	return EFI_NOT_READY;

	case ARM_FFA_SPM_RET_ABORTED:
	return EFI_ABORTED;

	default:
	// Undefined error code received.
	ASSERT (0);
	return EFI_INVALID_PARAMETER;
	}
	}
	} else {
	*RetVal = SvcArgs->Arg0;
	}

	// Check error response from Callee.
	if ((*RetVal & BIT31) != 0) {
	// Bit 31 set means there is an error returned
	// See [1], Section 13.5.5.1 MM_SP_MEMORY_ATTRIBUTES_GET_AARCH64 and
	// Section 13.5.5.2 MM_SP_MEMORY_ATTRIBUTES_SET_AARCH64.
	switch (*RetVal) {
	case ARM_SVC_SPM_RET_NOT_SUPPORTED:
	return EFI_UNSUPPORTED;

	case ARM_SVC_SPM_RET_INVALID_PARAMS:
	return EFI_INVALID_PARAMETER;

	case ARM_SVC_SPM_RET_DENIED:
	return EFI_ACCESS_DENIED;

	case ARM_SVC_SPM_RET_NO_MEMORY:
	return EFI_OUT_OF_RESOURCES;

	default:
	// Undefined error code received.
	ASSERT (0);
	return EFI_INVALID_PARAMETER;
	}
	}

	return EFI_SUCCESS;
	}

	/** Request the permission attributes of a memory region from S-EL0.

	@param [in] BaseAddress Base address for the memory region.
	@param [out] MemoryAttributes Pointer to return the memory attributes.

	@retval EFI_SUCCESS Request successfull.
	@retval EFI_INVALID_PARAMETER A parameter is invalid.
	@retval EFI_NOT_READY Callee is busy or not in a state to handle
	this request.
	@retval EFI_UNSUPPORTED This function is not implemented by the
	callee.
	@retval EFI_ABORTED Message target ran into an unexpected error
	and has aborted.
	@retval EFI_ACCESS_DENIED Access denied.
	@retval EFI_OUT_OF_RESOURCES Out of memory to perform operation.
	**/
	STATIC
	EFI_STATUS
	GetMemoryPermissions (
	IN EFI_PHYSICAL_ADDRESS BaseAddress,
	OUT UINT32 *MemoryAttributes
	)
	{
	EFI_STATUS Status;
	INT32 Ret;
	ARM_SVC_ARGS SvcArgs;

	if (MemoryAttributes == NULL) {
	return EFI_INVALID_PARAMETER;
	}

	// Prepare the message parameters.
	// See [1], Section 13.5.5.1 MM_SP_MEMORY_ATTRIBUTES_GET_AARCH64.
	ZeroMem (&SvcArgs, sizeof (ARM_SVC_ARGS));
	if (FeaturePcdGet (PcdFfaEnable)) {
	// See [2], Section 10.2 FFA_MSG_SEND_DIRECT_REQ.
	SvcArgs.Arg0 = ARM_SVC_ID_FFA_MSG_SEND_DIRECT_REQ;
	SvcArgs.Arg1 = ARM_FFA_DESTINATION_ENDPOINT_ID;
	SvcArgs.Arg2 = 0;
	SvcArgs.Arg3 = ARM_SVC_ID_SP_GET_MEM_ATTRIBUTES;
	SvcArgs.Arg4 = BaseAddress;
	} else {
	SvcArgs.Arg0 = ARM_SVC_ID_SP_GET_MEM_ATTRIBUTES;
	SvcArgs.Arg1 = BaseAddress;
	SvcArgs.Arg2 = 0;
	SvcArgs.Arg3 = 0;
	}

	Status = SendMemoryPermissionRequest (&SvcArgs, &Ret);
	if (EFI_ERROR (Status)) {
	*MemoryAttributes = 0;
	return Status;
	}

	*MemoryAttributes = Ret;
	return Status;
	}

	/** Set the permission attributes of a memory region from S-EL0.

	@param [in] BaseAddress Base address for the memory region.
	@param [in] Length Length of the memory region.
	@param [in] Permissions Memory access controls attributes.

	@retval EFI_SUCCESS Request successfull.
	@retval EFI_INVALID_PARAMETER A parameter is invalid.
	@retval EFI_NOT_READY Callee is busy or not in a state to handle
	this request.
	@retval EFI_UNSUPPORTED This function is not implemented by the
	callee.
	@retval EFI_ABORTED Message target ran into an unexpected error
	and has aborted.
	@retval EFI_ACCESS_DENIED Access denied.
	@retval EFI_OUT_OF_RESOURCES Out of memory to perform operation.
	**/
	STATIC
	EFI_STATUS
	RequestMemoryPermissionChange (
	IN EFI_PHYSICAL_ADDRESS BaseAddress,
	IN UINT64 Length,
	IN UINT32 Permissions
	)
	{
	INT32 Ret;
	ARM_SVC_ARGS SvcArgs;

	// Prepare the message parameters.
	// See [1], Section 13.5.5.2 MM_SP_MEMORY_ATTRIBUTES_SET_AARCH64.
	ZeroMem (&SvcArgs, sizeof (ARM_SVC_ARGS));
	if (FeaturePcdGet (PcdFfaEnable)) {
	// See [2], Section 10.2 FFA_MSG_SEND_DIRECT_REQ.
	SvcArgs.Arg0 = ARM_SVC_ID_FFA_MSG_SEND_DIRECT_REQ;
	SvcArgs.Arg1 = ARM_FFA_DESTINATION_ENDPOINT_ID;
	SvcArgs.Arg2 = 0;
	SvcArgs.Arg3 = ARM_SVC_ID_SP_SET_MEM_ATTRIBUTES;
	SvcArgs.Arg4 = BaseAddress;
	SvcArgs.Arg5 = EFI_SIZE_TO_PAGES (Length);
	SvcArgs.Arg6 = Permissions;
	} else {
	SvcArgs.Arg0 = ARM_SVC_ID_SP_SET_MEM_ATTRIBUTES;
	SvcArgs.Arg1 = BaseAddress;
	SvcArgs.Arg2 = EFI_SIZE_TO_PAGES (Length);
	SvcArgs.Arg3 = Permissions;
	}

	return SendMemoryPermissionRequest (&SvcArgs, &Ret);
	}

	EFI_STATUS
	ArmSetMemoryRegionNoExec (
	IN EFI_PHYSICAL_ADDRESS BaseAddress,
	IN UINT64 Length
	)
	{
	EFI_STATUS Status;
	UINT32 MemoryAttributes;
	UINT32 CodePermission;

	Status = GetMemoryPermissions (BaseAddress, &MemoryAttributes);
	if (!EFI_ERROR (Status)) {
	CodePermission = SET_MEM_ATTR_CODE_PERM_XN << SET_MEM_ATTR_CODE_PERM_SHIFT;
	return RequestMemoryPermissionChange (
	BaseAddress,
	Length,
	MemoryAttributes \| CodePermission
	);
	}

	return Status;
	}

	EFI_STATUS
	ArmClearMemoryRegionNoExec (
	IN EFI_PHYSICAL_ADDRESS BaseAddress,
	IN UINT64 Length
	)
	{
	EFI_STATUS Status;
	UINT32 MemoryAttributes;
	UINT32 CodePermission;

	Status = GetMemoryPermissions (BaseAddress, &MemoryAttributes);
	if (!EFI_ERROR (Status)) {
	CodePermission = SET_MEM_ATTR_CODE_PERM_XN << SET_MEM_ATTR_CODE_PERM_SHIFT;
	return RequestMemoryPermissionChange (
	BaseAddress,
	Length,
	MemoryAttributes & ~CodePermission
	);
	}

	return Status;
	}

	EFI_STATUS
	ArmSetMemoryRegionReadOnly (
	IN EFI_PHYSICAL_ADDRESS BaseAddress,
	IN UINT64 Length
	)
	{
	EFI_STATUS Status;
	UINT32 MemoryAttributes;
	UINT32 DataPermission;

	Status = GetMemoryPermissions (BaseAddress, &MemoryAttributes);
	if (!EFI_ERROR (Status)) {
	DataPermission = SET_MEM_ATTR_DATA_PERM_RO << SET_MEM_ATTR_DATA_PERM_SHIFT;
	return RequestMemoryPermissionChange (
	BaseAddress,
	Length,
	MemoryAttributes \| DataPermission
	);
	}

	return Status;
	}

	EFI_STATUS
	ArmClearMemoryRegionReadOnly (
	IN EFI_PHYSICAL_ADDRESS BaseAddress,
	IN UINT64 Length
	)
	{
	EFI_STATUS Status;
	UINT32 MemoryAttributes;
	UINT32 PermissionRequest;

	Status = GetMemoryPermissions (BaseAddress, &MemoryAttributes);
	if (!EFI_ERROR (Status)) {
	PermissionRequest = SET_MEM_ATTR_MAKE_PERM_REQUEST (
	SET_MEM_ATTR_DATA_PERM_RW,
	MemoryAttributes
	);
	return RequestMemoryPermissionChange (
	BaseAddress,
	Length,
	PermissionRequest
	);
	}

	return Status;
	}