MdePkg/Library/DxeServicesLib/Allocate.c

/** @file
  DxeServicesLib memory allocation routines

  Copyright (c) 2018, Linaro, Ltd. 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 <PiDxe.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/DxeServicesLib.h>

/**
  Allocates one or more 4KB pages of a given type from a memory region that is
  accessible to PEI.

  Allocates the number of 4KB pages of type 'MemoryType' 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[in]  MemoryType            The memory type to allocate
  @param[in]  Pages                 The number of 4 KB pages to allocate.

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

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

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

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