ArmPlatformPkg/ArmPlatformLib: Added support for ArmPlatformIsPrimaryCore()

Checking if a core if the primary/boot core used to be done with the macro
IS_PRIMARY_CORE().
Some platforms exposes configuration registers to change the primary core.
Replacing the macro IS_PRIMARY_CORE() by ArmPlatformIsPrimaryCore() allows
some flexibility in the way to check the primary core.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Acked-by: Ryan Harkin <ryan.harkin@linaro.org>


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14344 6f19259b-4bc3-4df7-8a09-765794883524

ArmPlatformPkg/PrePi/Arm/ModuleEntryPoint.asm

@@ -21,6 +21,7 @@
   INCLUDE AsmMacroIoLib.inc
   
   IMPORT  CEntryPoint
+  IMPORT  ArmPlatformIsPrimaryCore
   IMPORT  ArmReadMpidr
   IMPORT  ArmPlatformStackSet
   
@@ -34,8 +35,8 @@ StartupAddr        DCD      CEntryPoint
 _ModuleEntryPoint
   // Get ID of this CPU in Multicore system
   bl    ArmReadMpidr
-  LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCoreMask), r1)
-  and   r6, r0, r1
+  // Keep a copy of the MpId register value
+  mov   r6, r0
 
 _SetSVCMode
   // Enter SVC mode, Disable FIQ and IRQ
@@ -120,8 +121,9 @@ _GetStackBase
   bl	ArmPlatformStackSet
 
   // Is it the Primary Core ?
-  LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCore), r4)
-  cmp   r6, r4
+  mov   r0, r6
+  bl    ArmPlatformIsPrimaryCore
+  cmp   r0, #1
   bne   _PrepareArguments
 
 _ReserveGlobalVariable