From 44d2e8d7cab3ee1be0cf02f604d833e6b75b04b2 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 28 Feb 2018 15:31:34 +0000 Subject: [PATCH] ArmPlatformPkg/MemoryInitPeiLib: reserve rather than remove FV memory Instead of completely removing the memory occupied by the primary PrePi FV from the memory map, thereby making it inaccessible to the OS, mark it as boot services data. This will ensure that the memory is left untouched by the firmware, but will release it to the OS when it calls ExitBootServices(). Note that for reasons that are not entirely clear, this only works as desired if the memory allocation HOB and the resource descriptor HOB that describe the region are identical in offset and size, and so we still need to iterate over the descriptors and split them up. Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Ard Biesheuvel Reviewed-by: Leif Lindholm --- .../MemoryInitPei/MemoryInitPeiLib.c | 21 ++++++++++++------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/ArmPlatformPkg/MemoryInitPei/MemoryInitPeiLib.c b/ArmPlatformPkg/MemoryInitPei/MemoryInitPeiLib.c index 2feb11f21d..01fd028dbd 100644 --- a/ArmPlatformPkg/MemoryInitPei/MemoryInitPeiLib.c +++ b/ArmPlatformPkg/MemoryInitPei/MemoryInitPeiLib.c @@ -129,7 +129,8 @@ MemoryPeim ( FdTop = (EFI_PHYSICAL_ADDRESS)PcdGet64 (PcdFdBaseAddress) + (EFI_PHYSICAL_ADDRESS)PcdGet32 (PcdFdSize); // EDK2 does not have the concept of boot firmware copied into DRAM. To avoid the DXE - // core to overwrite this area we must mark the region with the attribute non-present + // core to overwrite this area we must create a memory allocation HOB for the region, + // but this only works if we split off the underlying resource descriptor as well. if ((PcdGet64 (PcdFdBaseAddress) >= PcdGet64 (PcdSystemMemoryBase)) && (FdTop <= SystemMemoryTop)) { Found = FALSE; @@ -145,12 +146,10 @@ MemoryPeim ( ResourceTop = NextHob.ResourceDescriptor->PhysicalStart + ResourceLength; if (PcdGet64 (PcdFdBaseAddress) == NextHob.ResourceDescriptor->PhysicalStart) { - if (SystemMemoryTop == FdTop) { - NextHob.ResourceDescriptor->ResourceAttribute = ResourceAttributes & ~EFI_RESOURCE_ATTRIBUTE_PRESENT; - } else { - // Create the System Memory HOB for the firmware with the non-present attribute + if (SystemMemoryTop != FdTop) { + // Create the System Memory HOB for the firmware BuildResourceDescriptorHob (EFI_RESOURCE_SYSTEM_MEMORY, - ResourceAttributes & ~EFI_RESOURCE_ATTRIBUTE_PRESENT, + ResourceAttributes, PcdGet64 (PcdFdBaseAddress), PcdGet32 (PcdFdSize)); @@ -159,9 +158,9 @@ MemoryPeim ( NextHob.ResourceDescriptor->ResourceLength -= PcdGet32(PcdFdSize); } } else { - // Create the System Memory HOB for the firmware with the non-present attribute + // Create the System Memory HOB for the firmware BuildResourceDescriptorHob (EFI_RESOURCE_SYSTEM_MEMORY, - ResourceAttributes & ~EFI_RESOURCE_ATTRIBUTE_PRESENT, + ResourceAttributes, PcdGet64 (PcdFdBaseAddress), PcdGet32 (PcdFdSize)); @@ -177,6 +176,12 @@ MemoryPeim ( ResourceTop - FdTop); } } + + // Mark the memory covering the Firmware Device as boot services data + BuildMemoryAllocationHob (PcdGet64 (PcdFdBaseAddress), + PcdGet32 (PcdFdSize), + EfiBootServicesData); + Found = TRUE; break; } -- 2.39.2