Next, the default extra action load/unload trigger must be disabled to allow adding a custom trigger, which is to read register CR3. This is done by changing the value of PcdDebugLoadImageMethod when not building with $(SOURCE_DEBUG_ENABLE). Search for PcdDebugLoadImageMethod, in the platform description file and add this before the !endif:


!else
  gEfiSourceLevelDebugPkgTokenSpaceGuid.PcdDebugLoadImageMethod|0x0

The end result should be:


!ifdef $(SOURCE_DEBUG_ENABLE)
  gEfiSourceLevelDebugPkgTokenSpaceGuid.PcdDebugLoadImageMethod|0x2
!else
  gEfiSourceLevelDebugPkgTokenSpaceGuid.PcdDebugLoadImageMethod|0x0
!endif

This will disable the default trigger of PeCoffLoaderExtraActionCommon and allow us to add our own trigger, which is described in the next step.

B.1 Step 1 - Add Extra Action (PeCoffExtraActionLib) B.3 Step 3 - Add Custom Trigger (Read CR3)

B.2 Step 2 - Disable Default Extra Action Trigger