[PATCH] EmbeddedPkg/PrePiLib: allocate code pages for DxeCore

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

The recently introduced memory protection features inadvertently broke
the boot on all PrePi platforms, because the changes to explicitly use
EfiBootServicesCode for loading the DxeCore PE/COFF image need to be
applied in a different way for PrePi. So add a simple helper function
that sets the type of an allocation to EfiBootServicesCode, and invoke
it to allocate the space for DxeCore.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 EmbeddedPkg/Library/PrePiLib/PrePiLib.c | 34 +++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/EmbeddedPkg/Library/PrePiLib/PrePiLib.c b/EmbeddedPkg/Library/PrePiLib/PrePiLib.c
index 9a1ef344df6e..bba8e7384edc 100644
--- a/EmbeddedPkg/Library/PrePiLib/PrePiLib.c
+++ b/EmbeddedPkg/Library/PrePiLib/PrePiLib.c
@@ -28,6 +28,38 @@ SecWinNtPeiLoadFile (
   IN  EFI_PHYSICAL_ADDRESS    *EntryPoint
   );
 
+STATIC
+VOID*
+EFIAPI
+AllocateCodePages (
+  IN  UINTN     Pages
+  )
+{
+  VOID                    *Alloc;
+  EFI_PEI_HOB_POINTERS    Hob;
+
+  Alloc = AllocatePages (Pages);
+  if (Alloc == NULL) {
+    return NULL;
+  }
+
+  // find the HOB we just created, and change the type to EfiBootServicesCode
+  Hob.Raw = GetFirstHob (EFI_HOB_TYPE_MEMORY_ALLOCATION);
+  while (Hob.Raw != NULL) {
+    if (Hob.MemoryAllocation->AllocDescriptor.MemoryBaseAddress == (UINTN)Alloc) {
+      Hob.MemoryAllocation->AllocDescriptor.MemoryType = EfiBootServicesCode;
+      return Alloc;
+    }
+    Hob.Raw = GET_NEXT_HOB (Hob);
+    Hob.Raw = GetNextHob (EFI_HOB_TYPE_MEMORY_ALLOCATION, Hob.Raw);
+  }
+
+  ASSERT (FALSE);
+
+  FreePages (Alloc, Pages);
+  return NULL;
+}
+
 
 EFI_STATUS
 EFIAPI
@@ -54,7 +86,7 @@ LoadPeCoffImage (
   //
   // Allocate Memory for the image
   //
-  Buffer = AllocatePages (EFI_SIZE_TO_PAGES((UINT32)ImageContext.ImageSize));
+  Buffer = AllocateCodePages (EFI_SIZE_TO_PAGES((UINT32)ImageContext.ImageSize));
   ASSERT (Buffer != 0);
 
 
-- 
2.7.4