diff options
| -rwxr-xr-x | ArmPlatformPkg/PrePi/ModuleEntryPoint.S | 22 | ||||
| -rw-r--r-- | ArmPlatformPkg/PrePi/ModuleEntryPoint.asm | 22 |
2 files changed, 42 insertions, 2 deletions
diff --git a/ArmPlatformPkg/PrePi/ModuleEntryPoint.S b/ArmPlatformPkg/PrePi/ModuleEntryPoint.S index 75728c9..fe91172 100755 --- a/ArmPlatformPkg/PrePi/ModuleEntryPoint.S +++ b/ArmPlatformPkg/PrePi/ModuleEntryPoint.S @@ -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
@@ -45,11 +45,13 @@ _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)
@@ -71,6 +73,24 @@ _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
diff --git a/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm b/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm index 5392e80..d62efb2 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
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