1 files changed, 63 insertions, 0 deletions
diff --git a/MdePkg/Library/DxeServicesLib/X64/Allocate.c b/MdePkg/Library/DxeServicesLib/X64/Allocate.c
new file mode 100644
index 000000000000..9346ae19232f
--- /dev/null
+++ b/MdePkg/Library/DxeServicesLib/X64/Allocate.c
@@ -0,0 +1,63 @@
+/** @file
+  DxeServicesLib memory allocation routines
+
+  Copyright (c) 2018, Linaro, Ltd. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <PiDxe.h>
+#include <Library/HobLib.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_ALLOCATE_TYPE           AllocType;
+  EFI_PHYSICAL_ADDRESS        Memory;
+  EFI_HOB_HANDOFF_INFO_TABLE  *PhitHob;
+
+  if (Pages == 0) {
+    return NULL;
+  }
+
+  AllocType = AllocateAnyPages;
+  //
+  // A X64 build of DXE may be combined with a 32-bit build of PEI, and so we
+  // need to check the memory limit set by PEI, and allocate below 4 GB if the
+  // limit is set to 4 GB or lower.
+  //
+  PhitHob = (EFI_HOB_HANDOFF_INFO_TABLE *)GetHobList ();
+  if (PhitHob->EfiFreeMemoryTop <= MAX_UINT32) {
+    AllocType = AllocateMaxAddress;
+    Memory = MAX_UINT32;
+  }
+
+  Status = gBS->AllocatePages (AllocType, MemoryType, Pages, &Memory);
+  if (EFI_ERROR (Status)) {
+    return NULL;
+  }
+  return (VOID *)(UINTN)Memory;
+}