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ArmPlatformPkg/PrePi: Make dynamic the top of the System Memory

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This change allows to change the top of the System Memory that
was hardcoded by:
FixedPcdGet64 (PcdSystemMemoryBase) + FixedPcdGet64 (PcdSystemMemorySize)

It allows to add support when the Trusted Firmware reserves the
top of the System Memory as Trusted. The size of this region
might not be known in advance.

Note: The reason why the start of the System Memory has not been
made dynamic is because the early code calculates where to place
the stack from the top of the System Memory.
So there is no need to make the start of the System Memory a
dynamic value at the early stage of the boot phase.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <Olivier.Martin@arm.com>
Reviewed-by: Ronald Cron <Ronald.Cron@arm.com>



git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17835 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
Olivier Martin
2015-07-06 16:56:31 +00:00
committed by oliviermartin
parent 40a3f38f67
commit 5dbacdb21b
7 changed files with 72 additions and 31 deletions
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25
ArmPlatformPkg/PrePi/Arm/ModuleEntryPoint.asm
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@@ -1,5 +1,5 @@
//
// Copyright (c) 2011-2014, ARM Limited. All rights reserved.
// Copyright (c) 2011-2015, 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
@@ -27,11 +27,13 @@
IMPORT ArmPlatformStackSet
EXPORT _ModuleEntryPoint
EXPORT mSystemMemoryEnd
PRESERVE8
AREA PrePiCoreEntryPoint, CODE, READONLY
StartupAddr DCD CEntryPoint
mSystemMemoryEnd DCQ 0
_ModuleEntryPoint
// Do early platform specific actions
@@ -50,12 +52,23 @@ _SetSVCMode
// Check if we can install the stack at the top of the System Memory or if we need
// to install the stacks at the bottom of the Firmware Device (case the FD is located
// at the top of the DRAM)
_SetupStackPosition
// Compute Top of System Memory
LoadConstantToReg (FixedPcdGet64 (PcdSystemMemoryBase), r1)
LoadConstantToReg (FixedPcdGet64 (PcdSystemMemorySize), r2)
_SystemMemoryEndInit
ldr r1, mSystemMemoryEnd
// Is mSystemMemoryEnd initialized?
cmp r1, #0
bne _SetupStackPosition
LoadConstantToReg (FixedPcdGet32(PcdSystemMemoryBase), r1)
LoadConstantToReg (FixedPcdGet32(PcdSystemMemorySize), r2)
sub r2, r2, #1
add r1, r1, r2 // r1 = SystemMemoryTop = PcdSystemMemoryBase + PcdSystemMemorySize
add r1, r1, r2
// Update the global variable
adr r2, mSystemMemoryEnd
str r1, [r2]
_SetupStackPosition
// r1 = SystemMemoryTop
// Calculate Top of the Firmware Device
LoadConstantToReg (FixedPcdGet32(PcdFdBaseAddress), r2)