[PATCH 1/2] ArmPlatformPkg/MemoryInitPeiLib: revert "don't reserve primary FV in memory"

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

Commit 8ae5fc182941 ("ArmPlatformPkg/MemoryInitPeiLib: don't reserve
primary FV in memory") deleted the code that removes the memory covering
the primary firmware volume from the memory map. The assumption was that
this is no longer necessary now that we no longer expose compression and
PE/COFF loader library code from the PrePi module to DXE core.

However, the FV is still declared, and so code may attempt to access it
anyway, which may cause unexpected results depending on whether the
memory has been reused for other purposes in the mean time. So revert
this change in preparation of dealing with this in a better way.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 ArmPlatformPkg/MemoryInitPei/MemoryInitPeiLib.c | 69 ++++++++++++++++++++
 1 file changed, 69 insertions(+)

diff --git a/ArmPlatformPkg/MemoryInitPei/MemoryInitPeiLib.c b/ArmPlatformPkg/MemoryInitPei/MemoryInitPeiLib.c
index d03214b5df66..2feb11f21d5d 100644
--- a/ArmPlatformPkg/MemoryInitPei/MemoryInitPeiLib.c
+++ b/ArmPlatformPkg/MemoryInitPei/MemoryInitPeiLib.c
@@ -70,7 +70,11 @@ MemoryPeim (
 {
   ARM_MEMORY_REGION_DESCRIPTOR *MemoryTable;
   EFI_RESOURCE_ATTRIBUTE_TYPE  ResourceAttributes;
+  UINT64                       ResourceLength;
   EFI_PEI_HOB_POINTERS         NextHob;
+  EFI_PHYSICAL_ADDRESS         FdTop;
+  EFI_PHYSICAL_ADDRESS         SystemMemoryTop;
+  EFI_PHYSICAL_ADDRESS         ResourceTop;
   BOOLEAN                      Found;
 
   // Get Virtual Memory Map from the Platform Library
@@ -117,6 +121,71 @@ MemoryPeim (
     );
   }
 
+  //
+  // Reserved the memory space occupied by the firmware volume
+  //
+
+  SystemMemoryTop = (EFI_PHYSICAL_ADDRESS)PcdGet64 (PcdSystemMemoryBase) + (EFI_PHYSICAL_ADDRESS)PcdGet64 (PcdSystemMemorySize);
+  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
+  if ((PcdGet64 (PcdFdBaseAddress) >= PcdGet64 (PcdSystemMemoryBase)) && (FdTop <= SystemMemoryTop)) {
+    Found = FALSE;
+
+    // Search for System Memory Hob that contains the firmware
+    NextHob.Raw = GetHobList ();
+    while ((NextHob.Raw = GetNextHob (EFI_HOB_TYPE_RESOURCE_DESCRIPTOR, NextHob.Raw)) != NULL) {
+      if ((NextHob.ResourceDescriptor->ResourceType == EFI_RESOURCE_SYSTEM_MEMORY) &&
+          (PcdGet64 (PcdFdBaseAddress) >= NextHob.ResourceDescriptor->PhysicalStart) &&
+          (FdTop <= NextHob.ResourceDescriptor->PhysicalStart + NextHob.ResourceDescriptor->ResourceLength))
+      {
+        ResourceAttributes = NextHob.ResourceDescriptor->ResourceAttribute;
+        ResourceLength = NextHob.ResourceDescriptor->ResourceLength;
+        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
+            BuildResourceDescriptorHob (EFI_RESOURCE_SYSTEM_MEMORY,
+                                        ResourceAttributes & ~EFI_RESOURCE_ATTRIBUTE_PRESENT,
+                                        PcdGet64 (PcdFdBaseAddress),
+                                        PcdGet32 (PcdFdSize));
+
+            // Top of the FD is system memory available for UEFI
+            NextHob.ResourceDescriptor->PhysicalStart += PcdGet32(PcdFdSize);
+            NextHob.ResourceDescriptor->ResourceLength -= PcdGet32(PcdFdSize);
+          }
+        } else {
+          // Create the System Memory HOB for the firmware with the non-present attribute
+          BuildResourceDescriptorHob (EFI_RESOURCE_SYSTEM_MEMORY,
+                                      ResourceAttributes & ~EFI_RESOURCE_ATTRIBUTE_PRESENT,
+                                      PcdGet64 (PcdFdBaseAddress),
+                                      PcdGet32 (PcdFdSize));
+
+          // Update the HOB
+          NextHob.ResourceDescriptor->ResourceLength = PcdGet64 (PcdFdBaseAddress) - NextHob.ResourceDescriptor->PhysicalStart;
+
+          // If there is some memory available on the top of the FD then create a HOB
+          if (FdTop < NextHob.ResourceDescriptor->PhysicalStart + ResourceLength) {
+            // Create the System Memory HOB for the remaining region (top of the FD)
+            BuildResourceDescriptorHob (EFI_RESOURCE_SYSTEM_MEMORY,
+                                        ResourceAttributes,
+                                        FdTop,
+                                        ResourceTop - FdTop);
+          }
+        }
+        Found = TRUE;
+        break;
+      }
+      NextHob.Raw = GET_NEXT_HOB (NextHob);
+    }
+
+    ASSERT(Found);
+  }
+
   // Build Memory Allocation Hob
   InitMmu (MemoryTable);
 
-- 
2.11.0