1 files changed, 21 insertions, 1 deletions

diff --git a/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm b/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm
index 5392e80925..d62efb2414 100644
--- a/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm
+++ b/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm
@@ -1,5 +1,5 @@
 //

-//  Copyright (c) 2011, ARM Limited. All rights reserved.

+//  Copyright (c) 2011-2012, ARM Limited. All rights reserved.

 //

 //  This program and the accompanying materials

 //  are licensed and made available under the terms and conditions of the BSD License

@@ -46,11 +46,13 @@ _SetupStackPosition
   // Compute Top of System Memory

   LoadConstantToReg (FixedPcdGet32(PcdSystemMemoryBase), r1)

   LoadConstantToReg (FixedPcdGet32(PcdSystemMemorySize), r2)

+  sub   r2, r2, #1

   add   r1, r1, r2      // r1 = SystemMemoryTop = PcdSystemMemoryBase + PcdSystemMemorySize

 

   // Calculate Top of the Firmware Device

   LoadConstantToReg (FixedPcdGet32(PcdFdBaseAddress), r2)

   LoadConstantToReg (FixedPcdGet32(PcdFdSize), r3)

+  sub   r3, r3, #1

   add   r3, r3, r2      // r4 = FdTop = PcdFdBaseAddress + PcdFdSize

 

   // UEFI Memory Size (stacks are allocated in this region)

@@ -72,6 +74,24 @@ _SetupStackPosition
 _SetupStack

   // r1 contains the top of the stack (and the UEFI Memory)

 

+  // Because the 'push' instruction is equivalent to 'stmdb' (decrement before), we need to increment

+  // one to the top of the stack. We check if incrementing one does not overflow (case of DRAM at the

+  // top of the memory space)

+  adds  r6, r1, #1

+  bcs   _SetupOverflowStack

+

+_SetupAlignedStack

+  mov   r1, r6

+  b     _GetBaseUefiMemory

+

+_SetupOverflowStack

+  // Case memory at the top of the address space. Ensure the top of the stack is EFI_PAGE_SIZE

+  // aligned (4KB)

+  LoadConstantToReg (EFI_PAGE_MASK, r6)

+  and   r6, r6, r1

+  sub   r1, r1, r6

+

+_GetBaseUefiMemory

   // Calculate the Base of the UEFI Memory

   sub   r6, r1, r4