audk/MdePkg/Library/SmmMemoryAllocationLib/MemoryAllocationLib.c

/** @file
  Support routines for memory allocation routines based 
  on SMM Services Table services for SMM phase drivers.
  
  The PI System Management Mode Core Interface Specification only allows the use
  of EfiRuntimeServicesCode and EfiRuntimeServicesData memory types for memory 
  allocations through the SMM Services Table as the SMRAM space should be 
  reserved after BDS phase.  The functions in the Memory Allocation Library use
  EfiBootServicesData as the default memory allocation type.  For this SMM 
  specific instance of the Memory Allocation Library, EfiRuntimeServicesData 
  is used as the default memory type for all allocations. In addition, 
  allocation for the Reserved memory types are not supported and will always 
  return NULL.

  Copyright (c) 2006 - 2017, 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 <PiSmm.h>

#include <Protocol/SmmAccess2.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/SmmServicesTableLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>

EFI_SMRAM_DESCRIPTOR  *mSmramRanges;
UINTN                 mSmramRangeCount;

/**
  The constructor function caches SMRAM ranges that are present in the system.
    
  It will ASSERT() if SMM Access2 Protocol doesn't exist.
  It will ASSERT() if SMRAM ranges can't be got.
  It will ASSERT() if Resource can't be allocated for cache SMRAM range. 
  It will always return EFI_SUCCESS.

  @param  ImageHandle   The firmware allocated handle for the EFI image.
  @param  SystemTable   A pointer to the EFI System Table.

  @retval EFI_SUCCESS   The constructor always returns EFI_SUCCESS.

**/
EFI_STATUS
EFIAPI
SmmMemoryAllocationLibConstructor (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS                Status;
  EFI_SMM_ACCESS2_PROTOCOL  *SmmAccess;
  UINTN                     Size;

  //
  // Locate SMM Access2 Protocol
  //
  Status = gBS->LocateProtocol (
                  &gEfiSmmAccess2ProtocolGuid, 
                  NULL, 
                  (VOID **)&SmmAccess
                  );
  ASSERT_EFI_ERROR (Status);

  //
  // Get SMRAM range information
  //
  Size = 0;
  Status = SmmAccess->GetCapabilities (SmmAccess, &Size, NULL);
  ASSERT (Status == EFI_BUFFER_TOO_SMALL);

  mSmramRanges = (EFI_SMRAM_DESCRIPTOR *) AllocatePool (Size);
  ASSERT (mSmramRanges != NULL);

  Status = SmmAccess->GetCapabilities (SmmAccess, &Size, mSmramRanges);
  ASSERT_EFI_ERROR (Status);

  mSmramRangeCount = Size / sizeof (EFI_SMRAM_DESCRIPTOR);

  return EFI_SUCCESS;
}

/**
  If SMM driver exits with an error, it must call this routine 
  to free the allocated resource before the exiting.

  @param[in]  ImageHandle   The firmware allocated handle for the EFI image.
  @param[in]  SystemTable   A pointer to the EFI System Table.

  @retval     EFI_SUCCESS   The deconstructor always returns EFI_SUCCESS.
**/
EFI_STATUS
EFIAPI
SmmMemoryAllocationLibDestructor (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  FreePool (mSmramRanges);

  return EFI_SUCCESS;
}

/**
  Check whether the start address of buffer is within any of the SMRAM ranges.

  @param[in]  Buffer   The pointer to the buffer to be checked.

  @retval     TRUE     The buffer is in SMRAM ranges.
  @retval     FALSE    The buffer is out of SMRAM ranges.
**/
BOOLEAN
EFIAPI
BufferInSmram (
  IN VOID *Buffer
  )
{
  UINTN  Index;

  for (Index = 0; Index < mSmramRangeCount; Index ++) {
    if (((EFI_PHYSICAL_ADDRESS) (UINTN) Buffer >= mSmramRanges[Index].CpuStart) && 
        ((EFI_PHYSICAL_ADDRESS) (UINTN) Buffer < (mSmramRanges[Index].CpuStart + mSmramRanges[Index].PhysicalSize))) {
      return TRUE;
    }
  }

  return FALSE;
}

/**
  Allocates one or more 4KB pages of a certain memory type.

  Allocates the number of 4KB pages of a certain memory type and returns a pointer 
  to the allocated buffer.  The buffer returned is aligned on a 4KB boundary.  If 
  Pages is 0, then NULL is returned.   If there is not enough memory remaining to 
  satisfy the request, then NULL is returned.

  @param  MemoryType            The type of memory to allocate.
  @param  Pages                 The number of 4 KB pages to allocate.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
InternalAllocatePages (
  IN EFI_MEMORY_TYPE  MemoryType,  
  IN UINTN            Pages
  )
{
  EFI_STATUS            Status;
  EFI_PHYSICAL_ADDRESS  Memory; 

  if (Pages == 0) {
    return NULL;
  }

  Status = gSmst->SmmAllocatePages (AllocateAnyPages, MemoryType, Pages, &Memory);
  if (EFI_ERROR (Status)) {
    return NULL;
  }
  return (VOID *) (UINTN) Memory;
}

/**
  Allocates one or more 4KB pages of type EfiRuntimeServicesData.

  Allocates the number of 4KB pages of type EfiRuntimeServicesData and returns a pointer 
  to the allocated buffer.  The buffer returned is aligned on a 4KB boundary.  If 
  Pages is 0, then NULL is returned.  If there is not enough memory remaining to 
  satisfy the request, then NULL is returned.

  @param  Pages                 The number of 4 KB pages to allocate.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
AllocatePages (
  IN UINTN  Pages
  )
{
  return InternalAllocatePages (EfiRuntimeServicesData, Pages);
}

/**
  Allocates one or more 4KB pages of type EfiRuntimeServicesData.

  Allocates the number of 4KB pages of type EfiRuntimeServicesData and returns a 
  pointer to the allocated buffer.  The buffer returned is aligned on a 4KB boundary.  
  If Pages is 0, then NULL is returned.  If there is not enough memory remaining 
  to satisfy the request, then NULL is returned.

  @param  Pages                 The number of 4 KB pages to allocate.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
AllocateRuntimePages (
  IN UINTN  Pages
  )
{
  return InternalAllocatePages (EfiRuntimeServicesData, Pages);
}

/**
  Allocates one or more 4KB pages of type EfiReservedMemoryType.

  Allocates the number of 4KB pages of type EfiReservedMemoryType and returns a 
  pointer to the allocated buffer.  The buffer returned is aligned on a 4KB boundary.  
  If Pages is 0, then NULL is returned.  If there is not enough memory remaining 
  to satisfy the request, then NULL is returned.

  @param  Pages                 The number of 4 KB pages to allocate.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
AllocateReservedPages (
  IN UINTN  Pages
  )
{
  return NULL;
}

/**
  Frees one or more 4KB pages that were previously allocated with one of the page allocation
  functions in the Memory Allocation Library.

  Frees the number of 4KB pages specified by Pages from the buffer specified by Buffer.  
  Buffer must have been allocated on a previous call to the page allocation services 
  of the Memory Allocation Library.  If it is not possible to free allocated pages, 
  then this function will perform no actions.
  
  If Buffer was not allocated with a page allocation function in the Memory Allocation 
  Library, then ASSERT().
  If Pages is zero, then ASSERT().
 
  @param  Buffer                The pointer to the buffer of pages to free.
  @param  Pages                 The number of 4 KB pages to free.

**/
VOID
EFIAPI
FreePages (
  IN VOID   *Buffer,
  IN UINTN  Pages
  )
{
  EFI_STATUS  Status;

  ASSERT (Pages != 0);
  if (BufferInSmram (Buffer)) {
    //
    // When Buffer is in SMRAM range, it should be allocated by gSmst->SmmAllocatePages() service.
    // So, gSmst->SmmFreePages() service is used to free it.
    //
    Status = gSmst->SmmFreePages ((EFI_PHYSICAL_ADDRESS) (UINTN) Buffer, Pages);
  } else {
    //
    // When Buffer is out of SMRAM range, it should be allocated by gBS->AllocatePages() service.
    // So, gBS->FreePages() service is used to free it.
    //
    Status = gBS->FreePages ((EFI_PHYSICAL_ADDRESS) (UINTN) Buffer, Pages);
  }
  ASSERT_EFI_ERROR (Status);
}

/**
  Allocates one or more 4KB pages of a certain memory type at a specified alignment.

  Allocates the number of 4KB pages specified by Pages of a certain memory type 
  with an alignment specified by Alignment.  The allocated buffer is returned.  
  If Pages is 0, then NULL is returned. If there is not enough memory at the 
  specified alignment remaining to satisfy the request, then NULL is returned.
  If Alignment is not a power of two and Alignment is not zero, then ASSERT().
  If Pages plus EFI_SIZE_TO_PAGES (Alignment) overflows, then ASSERT().

  @param  MemoryType            The type of memory to allocate.
  @param  Pages                 The number of 4 KB pages to allocate.
  @param  Alignment             The requested alignment of the allocation.  
                                Must be a power of two.
                                If Alignment is zero, then byte alignment is used.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
InternalAllocateAlignedPages (
  IN EFI_MEMORY_TYPE  MemoryType,  
  IN UINTN            Pages,
  IN UINTN            Alignment
  )
{
  EFI_STATUS            Status;
  EFI_PHYSICAL_ADDRESS  Memory;
  UINTN                 AlignedMemory;
  UINTN                 AlignmentMask;
  UINTN                 UnalignedPages;
  UINTN                 RealPages;

  //
  // Alignment must be a power of two or zero.
  //
  ASSERT ((Alignment & (Alignment - 1)) == 0);
 
  if (Pages == 0) {
    return NULL;
  }
  if (Alignment > EFI_PAGE_SIZE) {
    //
    // Calculate the total number of pages since alignment is larger than page size.
    //
    AlignmentMask  = Alignment - 1;
    RealPages      = Pages + EFI_SIZE_TO_PAGES (Alignment);
    //
    // Make sure that Pages plus EFI_SIZE_TO_PAGES (Alignment) does not overflow.
    //
    ASSERT (RealPages > Pages);
 
    Status         = gSmst->SmmAllocatePages (AllocateAnyPages, MemoryType, RealPages, &Memory);
    if (EFI_ERROR (Status)) {
      return NULL;
    }
    AlignedMemory  = ((UINTN) Memory + AlignmentMask) & ~AlignmentMask;
    UnalignedPages = EFI_SIZE_TO_PAGES (AlignedMemory - (UINTN) Memory);
    if (UnalignedPages > 0) {
      //
      // Free first unaligned page(s).
      //
      Status = gSmst->SmmFreePages (Memory, UnalignedPages);
      ASSERT_EFI_ERROR (Status);
    }
    Memory         = AlignedMemory + EFI_PAGES_TO_SIZE (Pages);
    UnalignedPages = RealPages - Pages - UnalignedPages;
    if (UnalignedPages > 0) {
      //
      // Free last unaligned page(s).
      //
      Status = gSmst->SmmFreePages (Memory, UnalignedPages);
      ASSERT_EFI_ERROR (Status);
    }
  } else {
    //
    // Do not over-allocate pages in this case.
    //
    Status = gSmst->SmmAllocatePages (AllocateAnyPages, MemoryType, Pages, &Memory);
    if (EFI_ERROR (Status)) {
      return NULL;
    }
    AlignedMemory  = (UINTN) Memory;
  }
  return (VOID *) AlignedMemory;
}

/**
  Allocates one or more 4KB pages of type EfiRuntimeServicesData at a specified alignment.

  Allocates the number of 4KB pages specified by Pages of type EfiRuntimeServicesData 
  with an alignment specified by Alignment.  The allocated buffer is returned.  
  If Pages is 0, then NULL is returned.  If there is not enough memory at the 
  specified alignment remaining to satisfy the request, then NULL is returned.
  
  If Alignment is not a power of two and Alignment is not zero, then ASSERT().
  If Pages plus EFI_SIZE_TO_PAGES (Alignment) overflows, then ASSERT().

  @param  Pages                 The number of 4 KB pages to allocate.
  @param  Alignment             The requested alignment of the allocation.  
                                Must be a power of two.
                                If Alignment is zero, then byte alignment is used.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
AllocateAlignedPages (
  IN UINTN  Pages,
  IN UINTN  Alignment
  )
{
  return InternalAllocateAlignedPages (EfiRuntimeServicesData, Pages, Alignment);
}

/**
  Allocates one or more 4KB pages of type EfiRuntimeServicesData at a specified alignment.

  Allocates the number of 4KB pages specified by Pages of type EfiRuntimeServicesData 
  with an alignment specified by Alignment.  The allocated buffer is returned.  
  If Pages is 0, then NULL is returned.  If there is not enough memory at the 
  specified alignment remaining to satisfy the request, then NULL is returned.
  
  If Alignment is not a power of two and Alignment is not zero, then ASSERT().
  If Pages plus EFI_SIZE_TO_PAGES (Alignment) overflows, then ASSERT().

  @param  Pages                 The number of 4 KB pages to allocate.
  @param  Alignment             The requested alignment of the allocation.  
                                Must be a power of two.
                                If Alignment is zero, then byte alignment is used.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
AllocateAlignedRuntimePages (
  IN UINTN  Pages,
  IN UINTN  Alignment
  )
{
  return InternalAllocateAlignedPages (EfiRuntimeServicesData, Pages, Alignment);
}

/**
  Allocates one or more 4KB pages of type EfiReservedMemoryType at a specified alignment.

  Allocates the number of 4KB pages specified by Pages of type EfiReservedMemoryType 
  with an alignment specified by Alignment.  The allocated buffer is returned.  
  If Pages is 0, then NULL is returned.  If there is not enough memory at the 
  specified alignment remaining to satisfy the request, then NULL is returned.
  
  If Alignment is not a power of two and Alignment is not zero, then ASSERT().
  If Pages plus EFI_SIZE_TO_PAGES (Alignment) overflows, then ASSERT().

  @param  Pages                 The number of 4 KB pages to allocate.
  @param  Alignment             The requested alignment of the allocation.  
                                Must be a power of two.
                                If Alignment is zero, then byte alignment is used.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
AllocateAlignedReservedPages (
  IN UINTN  Pages,
  IN UINTN  Alignment
  )
{
  return NULL;
}

/**
  Frees one or more 4KB pages that were previously allocated with one of the aligned page
  allocation functions in the Memory Allocation Library.

  Frees the number of 4KB pages specified by Pages from the buffer specified by 
  Buffer.  Buffer must have been allocated on a previous call to the aligned page 
  allocation services of the Memory Allocation Library.  If it is not possible to 
  free allocated pages, then this function will perform no actions.
  
  If Buffer was not allocated with an aligned page allocation function in the 
  Memory Allocation Library, then ASSERT().
  If Pages is zero, then ASSERT().
  
  @param  Buffer                The pointer to the buffer of pages to free.
  @param  Pages                 The number of 4 KB pages to free.

**/
VOID
EFIAPI
FreeAlignedPages (
  IN VOID   *Buffer,
  IN UINTN  Pages
  )
{
  EFI_STATUS  Status;

  ASSERT (Pages != 0);
  if (BufferInSmram (Buffer)) {
    //
    // When Buffer is in SMRAM range, it should be allocated by gSmst->SmmAllocatePages() service.
    // So, gSmst->SmmFreePages() service is used to free it.
    //
    Status = gSmst->SmmFreePages ((EFI_PHYSICAL_ADDRESS) (UINTN) Buffer, Pages);
  } else {
    //
    // When Buffer is out of SMRAM range, it should be allocated by gBS->AllocatePages() service.
    // So, gBS->FreePages() service is used to free it.
    //
    Status = gBS->FreePages ((EFI_PHYSICAL_ADDRESS) (UINTN) Buffer, Pages);
  }
  ASSERT_EFI_ERROR (Status);
}

/**
  Allocates a buffer of a certain pool type.

  Allocates the number bytes specified by AllocationSize of a certain pool type 
  and returns a pointer to the allocated buffer.  If AllocationSize is 0, then a 
  valid buffer of 0 size is returned.  If there is not enough memory remaining to 
  satisfy the request, then NULL is returned.

  @param  MemoryType            The type of memory to allocate.
  @param  AllocationSize        The number of bytes to allocate.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
InternalAllocatePool (
  IN EFI_MEMORY_TYPE  MemoryType,  
  IN UINTN            AllocationSize
  )
{
  EFI_STATUS  Status;
  VOID        *Memory;

  Status = gSmst->SmmAllocatePool (MemoryType, AllocationSize, &Memory);
  if (EFI_ERROR (Status)) {
    Memory = NULL;
  }
  return Memory;
}

/**
  Allocates a buffer of type EfiRuntimeServicesData.

  Allocates the number bytes specified by AllocationSize of type EfiRuntimeServicesData 
  and returns a pointer to the allocated buffer.  If AllocationSize is 0, then a 
  valid buffer of 0 size is returned.  If there is not enough memory remaining to 
  satisfy the request, then NULL is returned.

  @param  AllocationSize        The number of bytes to allocate.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
AllocatePool (
  IN UINTN  AllocationSize
  )
{
  return InternalAllocatePool (EfiRuntimeServicesData, AllocationSize);
}

/**
  Allocates a buffer of type EfiRuntimeServicesData.

  Allocates the number bytes specified by AllocationSize of type EfiRuntimeServicesData 
  and returns a pointer to the allocated buffer.  If AllocationSize is 0, then a 
  valid buffer of 0 size is returned.  If there is not enough memory remaining to 
  satisfy the request, then NULL is returned.

  @param  AllocationSize        The number of bytes to allocate.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
AllocateRuntimePool (
  IN UINTN  AllocationSize
  )
{
  return InternalAllocatePool (EfiRuntimeServicesData, AllocationSize);
}

/**
  Allocates a buffer of type EfiReservedMemoryType.

  Allocates the number bytes specified by AllocationSize of type EfiReservedMemoryType 
  and returns a pointer to the allocated buffer.  If AllocationSize is 0, then a 
  valid buffer of 0 size is returned.  If there is not enough memory remaining to 
  satisfy the request, then NULL is returned.

  @param  AllocationSize        The number of bytes to allocate.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
AllocateReservedPool (
  IN UINTN  AllocationSize
  )
{
  return NULL;
}

/**
  Allocates and zeros a buffer of a certain pool type.

  Allocates the number bytes specified by AllocationSize of a certain pool type, 
  clears the buffer with zeros, and returns a pointer to the allocated buffer.  
  If AllocationSize is 0, then a valid buffer of 0 size is returned.  If there is 
  not enough memory remaining to satisfy the request, then NULL is returned.

  @param  PoolType              The type of memory to allocate.
  @param  AllocationSize        The number of bytes to allocate and zero.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
InternalAllocateZeroPool (
  IN EFI_MEMORY_TYPE  PoolType,  
  IN UINTN            AllocationSize
  ) 
{
  VOID  *Memory;

  Memory = InternalAllocatePool (PoolType, AllocationSize);
  if (Memory != NULL) {
    Memory = ZeroMem (Memory, AllocationSize);
  }
  return Memory;
}

/**
  Allocates and zeros a buffer of type EfiRuntimeServicesData.

  Allocates the number bytes specified by AllocationSize of type EfiRuntimeServicesData, 
  clears the buffer with zeros, and returns a pointer to the allocated buffer.  
  If AllocationSize is 0, then a valid buffer of 0 size is returned.  If there is 
  not enough memory remaining to satisfy the request, then NULL is returned.

  @param  AllocationSize        The number of bytes to allocate and zero.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
AllocateZeroPool (
  IN UINTN  AllocationSize
  )
{
  return InternalAllocateZeroPool (EfiRuntimeServicesData, AllocationSize);
}

/**
  Allocates and zeros a buffer of type EfiRuntimeServicesData.

  Allocates the number bytes specified by AllocationSize of type EfiRuntimeServicesData, 
  clears the buffer with zeros, and returns a pointer to the allocated buffer.  
  If AllocationSize is 0, then a valid buffer of 0 size is returned.  If there is 
  not enough memory remaining to satisfy the request, then NULL is returned.

  @param  AllocationSize        The number of bytes to allocate and zero.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
AllocateRuntimeZeroPool (
  IN UINTN  AllocationSize
  )
{
  return InternalAllocateZeroPool (EfiRuntimeServicesData, AllocationSize);
}

/**
  Allocates and zeros a buffer of type EfiReservedMemoryType.

  Allocates the number bytes specified by AllocationSize of type EfiReservedMemoryType, 
  clears the   buffer with zeros, and returns a pointer to the allocated buffer.  
  If AllocationSize is 0, then a valid buffer of 0 size is returned.  If there is 
  not enough memory remaining to satisfy the request, then NULL is returned.

  @param  AllocationSize        The number of bytes to allocate and zero.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
AllocateReservedZeroPool (
  IN UINTN  AllocationSize
  )
{
  return NULL;
}

/**
  Copies a buffer to an allocated buffer of a certain pool type.

  Allocates the number bytes specified by AllocationSize of a certain pool type, 
  copies AllocationSize bytes from Buffer to the newly allocated buffer, and returns 
  a pointer to the allocated buffer.  If AllocationSize is 0, then a valid buffer 
  of 0 size is returned.  If there is not enough memory remaining to satisfy the 
  request, then NULL is returned. If Buffer is NULL, then ASSERT().
  If AllocationSize is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT(). 

  @param  PoolType              The type of pool to allocate.
  @param  AllocationSize        The number of bytes to allocate and zero.
  @param  Buffer                The buffer to copy to the allocated buffer.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
InternalAllocateCopyPool (
  IN EFI_MEMORY_TYPE  PoolType,  
  IN UINTN            AllocationSize,
  IN CONST VOID       *Buffer
  ) 
{
  VOID  *Memory;

  ASSERT (Buffer != NULL);
  ASSERT (AllocationSize <= (MAX_ADDRESS - (UINTN) Buffer + 1));

  Memory = InternalAllocatePool (PoolType, AllocationSize);
  if (Memory != NULL) {
     Memory = CopyMem (Memory, Buffer, AllocationSize);
  }
  return Memory;
} 

/**
  Copies a buffer to an allocated buffer of type EfiRuntimeServicesData.

  Allocates the number bytes specified by AllocationSize of type EfiRuntimeServicesData, 
  copies AllocationSize bytes from Buffer to the newly allocated buffer, and returns 
  a pointer to the allocated buffer.  If AllocationSize is 0, then a valid buffer 
  of 0 size is returned.  If there is not enough memory remaining to satisfy the 
  request, then NULL is returned.
  
  If Buffer is NULL, then ASSERT().
  If AllocationSize is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT(). 

  @param  AllocationSize        The number of bytes to allocate and zero.
  @param  Buffer                The buffer to copy to the allocated buffer.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
AllocateCopyPool (
  IN UINTN       AllocationSize,
  IN CONST VOID  *Buffer
  )
{
  return InternalAllocateCopyPool (EfiRuntimeServicesData, AllocationSize, Buffer);
}

/**
  Copies a buffer to an allocated buffer of type EfiRuntimeServicesData.

  Allocates the number bytes specified by AllocationSize of type EfiRuntimeServicesData, 
  copies AllocationSize bytes from Buffer to the newly allocated buffer, and returns 
  a pointer to the allocated buffer.  If AllocationSize is 0, then a valid buffer 
  of 0 size is returned.  If there is not enough memory remaining to satisfy the 
  request, then NULL is returned.
  
  If Buffer is NULL, then ASSERT().
  If AllocationSize is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT(). 

  @param  AllocationSize        The number of bytes to allocate and zero.
  @param  Buffer                The buffer to copy to the allocated buffer.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
AllocateRuntimeCopyPool (
  IN UINTN       AllocationSize,
  IN CONST VOID  *Buffer
  )
{
  return InternalAllocateCopyPool (EfiRuntimeServicesData, AllocationSize, Buffer);
}

/**
  Copies a buffer to an allocated buffer of type EfiReservedMemoryType.

  Allocates the number bytes specified by AllocationSize of type EfiReservedMemoryType, 
  copies AllocationSize bytes from Buffer to the newly allocated buffer, and returns 
  a pointer to the allocated buffer.  If AllocationSize is 0, then a valid buffer 
  of 0 size is returned.  If there is not enough memory remaining to satisfy the 
  request, then NULL is returned.
  
  If Buffer is NULL, then ASSERT().
  If AllocationSize is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT(). 

  @param  AllocationSize        The number of bytes to allocate and zero.
  @param  Buffer                The buffer to copy to the allocated buffer.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
AllocateReservedCopyPool (
  IN UINTN       AllocationSize,
  IN CONST VOID  *Buffer
  )
{
  return NULL;
}

/**
  Reallocates a buffer of a specified memory type.

  Allocates and zeros the number bytes specified by NewSize from memory of the type
  specified by PoolType.  If OldBuffer is not NULL, then the smaller of OldSize and 
  NewSize bytes are copied from OldBuffer to the newly allocated buffer, and 
  OldBuffer is freed.  A pointer to the newly allocated buffer is returned.  
  If NewSize is 0, then a valid buffer of 0 size is  returned.  If there is not 
  enough memory remaining to satisfy the request, then NULL is returned.
  
  If the allocation of the new buffer is successful and the smaller of NewSize 
  and OldSize is greater than (MAX_ADDRESS - OldBuffer + 1), then ASSERT().

  @param  PoolType       The type of pool to allocate.
  @param  OldSize        The size, in bytes, of OldBuffer.
  @param  NewSize        The size, in bytes, of the buffer to reallocate.
  @param  OldBuffer      The buffer to copy to the allocated buffer.  This is an 
                         optional parameter that may be NULL.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
InternalReallocatePool (
  IN EFI_MEMORY_TYPE  PoolType,  
  IN UINTN            OldSize,
  IN UINTN            NewSize,
  IN VOID             *OldBuffer  OPTIONAL
  )
{
  VOID  *NewBuffer;

  NewBuffer = InternalAllocateZeroPool (PoolType, NewSize);
  if (NewBuffer != NULL && OldBuffer != NULL) {
    CopyMem (NewBuffer, OldBuffer, MIN (OldSize, NewSize));
    FreePool (OldBuffer);
  }
  return NewBuffer;
}

/**
  Reallocates a buffer of type EfiRuntimeServicesData.

  Allocates and zeros the number bytes specified by NewSize from memory of type
  EfiRuntimeServicesData.  If OldBuffer is not NULL, then the smaller of OldSize and 
  NewSize bytes are copied from OldBuffer to the newly allocated buffer, and 
  OldBuffer is freed.  A pointer to the newly allocated buffer is returned.  
  If NewSize is 0, then a valid buffer of 0 size is  returned.  If there is not 
  enough memory remaining to satisfy the request, then NULL is returned.
  
  If the allocation of the new buffer is successful and the smaller of NewSize 
  and OldSize is greater than (MAX_ADDRESS - OldBuffer + 1), then ASSERT().

  @param  OldSize        The size, in bytes, of OldBuffer.
  @param  NewSize        The size, in bytes, of the buffer to reallocate.
  @param  OldBuffer      The buffer to copy to the allocated buffer.  This is an 
                         optional parameter that may be NULL.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
ReallocatePool (
  IN UINTN  OldSize,
  IN UINTN  NewSize,
  IN VOID   *OldBuffer  OPTIONAL
  )
{
  return InternalReallocatePool (EfiRuntimeServicesData, OldSize, NewSize, OldBuffer);
}

/**
  Reallocates a buffer of type EfiRuntimeServicesData.

  Allocates and zeros the number bytes specified by NewSize from memory of type
  EfiRuntimeServicesData.  If OldBuffer is not NULL, then the smaller of OldSize 
  and NewSize bytes are copied from OldBuffer to the newly allocated buffer, and 
  OldBuffer is freed.  A pointer to the newly allocated buffer is returned.  
  If NewSize is 0, then a valid buffer of 0 size is  returned.  If there is not 
  enough memory remaining to satisfy the request, then NULL is returned.

  If the allocation of the new buffer is successful and the smaller of NewSize 
  and OldSize is greater than (MAX_ADDRESS - OldBuffer + 1), then ASSERT().

  @param  OldSize        The size, in bytes, of OldBuffer.
  @param  NewSize        The size, in bytes, of the buffer to reallocate.
  @param  OldBuffer      The buffer to copy to the allocated buffer.  This is an 
                         optional parameter that may be NULL.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
ReallocateRuntimePool (
  IN UINTN  OldSize,
  IN UINTN  NewSize,
  IN VOID   *OldBuffer  OPTIONAL
  )
{
  return InternalReallocatePool (EfiRuntimeServicesData, OldSize, NewSize, OldBuffer);
}

/**
  Reallocates a buffer of type EfiReservedMemoryType.

  Allocates and zeros the number bytes specified by NewSize from memory of type
  EfiReservedMemoryType.  If OldBuffer is not NULL, then the smaller of OldSize 
  and NewSize bytes are copied from OldBuffer to the newly allocated buffer, and 
  OldBuffer is freed.  A pointer to the newly allocated buffer is returned.  
  If NewSize is 0, then a valid buffer of 0 size is  returned.  If there is not 
  enough memory remaining to satisfy the request, then NULL is returned.

  If the allocation of the new buffer is successful and the smaller of NewSize 
  and OldSize is greater than (MAX_ADDRESS - OldBuffer + 1), then ASSERT().

  @param  OldSize        The size, in bytes, of OldBuffer.
  @param  NewSize        The size, in bytes, of the buffer to reallocate.
  @param  OldBuffer      The buffer to copy to the allocated buffer.  This is an 
                         optional parameter that may be NULL.

  @return A pointer to the allocated buffer or NULL if allocation fails.

**/
VOID *
EFIAPI
ReallocateReservedPool (
  IN UINTN  OldSize,
  IN UINTN  NewSize,
  IN VOID   *OldBuffer  OPTIONAL
  )
{
  return NULL;
}

/**
  Frees a buffer that was previously allocated with one of the pool allocation 
  functions in the Memory Allocation Library.

  Frees the buffer specified by Buffer.  Buffer must have been allocated on a 
  previous call to the pool allocation services of the Memory Allocation Library.  
  If it is not possible to free pool resources, then this function will perform 
  no actions.
  
  If Buffer was not allocated with a pool allocation function in the Memory 
  Allocation Library, then ASSERT().

  @param  Buffer                The pointer to the buffer to free.

**/
VOID
EFIAPI
FreePool (
  IN VOID   *Buffer
  )
{
  EFI_STATUS    Status;

  if (BufferInSmram (Buffer)) {
    //
    // When Buffer is in SMRAM range, it should be allocated by gSmst->SmmAllocatePool() service.
    // So, gSmst->SmmFreePool() service is used to free it.
    //
    Status = gSmst->SmmFreePool (Buffer);
  } else {
    //
    // When Buffer is out of SMRAM range, it should be allocated by gBS->AllocatePool() service.
    // So, gBS->FreePool() service is used to free it.
    //
    Status = gBS->FreePool (Buffer);
  }
  ASSERT_EFI_ERROR (Status);
}