[RFC PATCH 1/4] MdeModulePkg/DxeCore: allow BootServicesData->BootServicesCode conversion

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

Unlike all other PE/COFF images loaded after it, the DXE core is loaded
into BootServicesData memory rather than BootServicesCode memory, due to
the fact that the PEI phase memory allocation routines only distinguish
between boot-time and runtime.

So in preparation of adding support for restricted permissions, allow the
direct conversion of BootServicesData to BootServicesCode.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 MdeModulePkg/Core/Dxe/Mem/Page.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/MdeModulePkg/Core/Dxe/Mem/Page.c b/MdeModulePkg/Core/Dxe/Mem/Page.c
index bda4f6397e91..b0939c596991 100644
--- a/MdeModulePkg/Core/Dxe/Mem/Page.c
+++ b/MdeModulePkg/Core/Dxe/Mem/Page.c
@@ -773,7 +773,8 @@ CoreConvertPagesEx (
       //
       // Debug code - verify conversion is allowed
       //
-      if (!(NewType == EfiConventionalMemory ? 1 : 0) ^ (Entry->Type == EfiConventionalMemory ? 1 : 0)) {
+      if (!(NewType == EfiConventionalMemory ? 1 : 0) ^ (Entry->Type == EfiConventionalMemory ? 1 : 0) &&
+          !(NewType == EfiBootServicesCode && Entry->Type == EfiBootServicesData)) {
         DEBUG ((DEBUG_ERROR | DEBUG_PAGE, "ConvertPages: Incompatible memory types\n"));
         return EFI_NOT_FOUND;
       }
-- 
2.7.4