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   SPDX-License-Identifier: BSD-2-Clause-Patent
   7
   8 **/
   9
  10 #include <PiDxe.h>
  11 #include <Library/HobLib.h>
  12 #include <Library/UefiBootServicesTableLib.h>
  13 #include <Library/DxeServicesLib.h>
  14
  15 /**
  16   Allocates one or more 4KB pages of a given type from a memory region that is
  17   accessible to PEI.
  18
  19   Allocates the number of 4KB pages of type 'MemoryType' and returns a
  20   pointer to the allocated buffer.  The buffer returned is aligned on a 4KB
  21   boundary.  If Pages is 0, then NULL is returned.  If there is not enough
  22   memory remaining to satisfy the request, then NULL is returned.
  23
  24   @param[in]  MemoryType            The memory type to allocate
  25   @param[in]  Pages                 The number of 4 KB pages to allocate.
  26
  27   @return A pointer to the allocated buffer or NULL if allocation fails.
  28
  29 **/
  30 VOID *
  31 EFIAPI
  32 AllocatePeiAccessiblePages (
  33   IN EFI_MEMORY_TYPE  MemoryType,
  34   IN UINTN            Pages
  35   )
  36 {
  37   EFI_STATUS                  Status;
  38   EFI_ALLOCATE_TYPE           AllocType;
  39   EFI_PHYSICAL_ADDRESS        Memory;
  40   EFI_HOB_HANDOFF_INFO_TABLE  *PhitHob;
  41
  42   if (Pages == 0) {
  43     return NULL;
  44   }
  45
  46   AllocType = AllocateAnyPages;
  47   //
  48   // A X64 build of DXE may be combined with a 32-bit build of PEI, and so we
  49   // need to check the memory limit set by PEI, and allocate below 4 GB if the
  50   // limit is set to 4 GB or lower.
  51   //
  52   PhitHob = (EFI_HOB_HANDOFF_INFO_TABLE *)GetHobList ();
  53   if (PhitHob->EfiFreeMemoryTop <= MAX_UINT32) {
  54     AllocType = AllocateMaxAddress;
  55     Memory = MAX_UINT32;
  56   }
  57
  58   Status = gBS->AllocatePages (AllocType, MemoryType, Pages, &Memory);
  59   if (EFI_ERROR (Status)) {
  60     return NULL;
  61   }
  62   return (VOID *)(UINTN)Memory;
  63 }