From 6ac97ad31edbd9c8cdea778f452273974c589bf1 Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date: Tue, 14 Mar 2017 08:01:04 +0000
Subject: [PATCH] EmbeddedPkg/PrePiLib: allocate code pages for DxeCore

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>
Tested-by: Michael Zimmermann <sigmaepsilon92@gmail.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
---
 EmbeddedPkg/Library/PrePiLib/PrePi.h    |  1 +
 EmbeddedPkg/Library/PrePiLib/PrePiLib.c | 33 ++++++++++++++++++++++++-
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/EmbeddedPkg/Library/PrePiLib/PrePi.h b/EmbeddedPkg/Library/PrePiLib/PrePi.h
index 607561cd24..b39c3b4346 100644
--- a/EmbeddedPkg/Library/PrePiLib/PrePi.h
+++ b/EmbeddedPkg/Library/PrePiLib/PrePi.h
@@ -26,6 +26,7 @@
 #include <Library/UefiDecompressLib.h>
 #include <Library/PeCoffLib.h>
 #include <Library/CacheMaintenanceLib.h>
+#include <Library/MemoryAllocationLib.h>
 #include <Library/TimerLib.h>
 #include <Library/PerformanceLib.h>
 
diff --git a/EmbeddedPkg/Library/PrePiLib/PrePiLib.c b/EmbeddedPkg/Library/PrePiLib/PrePiLib.c
index 9a1ef344df..d119cf33a5 100644
--- a/EmbeddedPkg/Library/PrePiLib/PrePiLib.c
+++ b/EmbeddedPkg/Library/PrePiLib/PrePiLib.c
@@ -28,6 +28,37 @@ 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 = GetNextHob (EFI_HOB_TYPE_MEMORY_ALLOCATION, GET_NEXT_HOB (Hob));
+  }
+
+  ASSERT (FALSE);
+
+  FreePages (Alloc, Pages);
+  return NULL;
+}
+
 
 EFI_STATUS
 EFIAPI
@@ -54,7 +85,7 @@ 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);