MdePkg/Library/DxeServicesLib/X64/Allocate.c

   1 /** @file
   2   DxeServicesLib memory allocation routines
   3
   4   Copyright (c) 2018, Linaro, Ltd. All rights reserved.<BR>
   5
   6   This program and the accompanying materials are licensed and made available
   7   under the terms and conditions of the BSD License which accompanies this
   8   distribution.  The full text of the license may be found at
   9   http://opensource.org/licenses/bsd-license.php.
  10
  11   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13
  14 **/
  15
  16 #include <PiDxe.h>
  17 #include <Library/HobLib.h>
  18 #include <Library/UefiBootServicesTableLib.h>
  19 #include <Library/DxeServicesLib.h>
  20
  21 /**
  22   Allocates one or more 4KB pages of a given type from a memory region that is
  23   accessible to PEI.
  24
  25   Allocates the number of 4KB pages of type 'MemoryType' and returns a
  26   pointer to the allocated buffer.  The buffer returned is aligned on a 4KB
  27   boundary.  If Pages is 0, then NULL is returned.  If there is not enough
  28   memory remaining to satisfy the request, then NULL is returned.
  29
  30   @param[in]  MemoryType            The memory type to allocate
  31   @param[in]  Pages                 The number of 4 KB pages to allocate.
  32
  33   @return A pointer to the allocated buffer or NULL if allocation fails.
  34
  35 **/
  36 VOID *
  37 EFIAPI
  38 AllocatePeiAccessiblePages (
  39   IN EFI_MEMORY_TYPE  MemoryType,
  40   IN UINTN            Pages
  41   )
  42 {
  43   EFI_STATUS                  Status;
  44   EFI_ALLOCATE_TYPE           AllocType;
  45   EFI_PHYSICAL_ADDRESS        Memory;
  46   EFI_HOB_HANDOFF_INFO_TABLE  *PhitHob;
  47
  48   if (Pages == 0) {
  49     return NULL;
  50   }
  51
  52   AllocType = AllocateAnyPages;
  53   //
  54   // A X64 build of DXE may be combined with a 32-bit build of PEI, and so we
  55   // need to check the memory limit set by PEI, and allocate below 4 GB if the
  56   // limit is set to 4 GB or lower.
  57   //
  58   PhitHob = (EFI_HOB_HANDOFF_INFO_TABLE *)GetHobList ();
  59   if (PhitHob->EfiFreeMemoryTop <= MAX_UINT32) {
  60     AllocType = AllocateMaxAddress;
  61     Memory = MAX_UINT32;
  62   }
  63
  64   Status = gBS->AllocatePages (AllocType, MemoryType, Pages, &Memory);
  65   if (EFI_ERROR (Status)) {
  66     return NULL;
  67   }
  68   return (VOID *)(UINTN)Memory;
  69 }