ArmPlatformPkg: Updated the stack setup to have the same geometry between the Secure and Normal World

Having a similar setup reduces the error during the MPCore stack setup.
The stack setup is described on this wikipage:
https://sourceforge.net/apps/mediawiki/tianocore/index.php?title=ArmPlatformPkg/Stack



git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13058 6f19259b-4bc3-4df7-8a09-765794883524

6 files changed, 134 insertions, 184 deletions

diff --git a/ArmPlatformPkg/PrePeiCore/PrePeiCoreEntryPoint.S b/ArmPlatformPkg/PrePeiCore/PrePeiCoreEntryPoint.S
index 261f6e554a..737b6ac19d 100644
--- a/ArmPlatformPkg/PrePeiCore/PrePeiCoreEntryPoint.S
+++ b/ArmPlatformPkg/PrePeiCore/PrePeiCoreEntryPoint.S
@@ -30,50 +30,31 @@ ASM_PFX(_ModuleEntryPoint):
   bl    ASM_PFX(ArmReadMpidr)

   // Get ID of this CPU in Multicore system

   LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCoreMask), r1)

-  and   r0, r0, r1

-

-  // Calculate the top of the primary stack

+  and   r5, r0, r1

+  

+  // Get the top of the primary stacks (and the base of the secondary stacks)

   LoadConstantToReg (FixedPcdGet32(PcdCPUCoresStackBase), r1)

   LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), r2)

-  add   r2, r2, r1

+  add   r1, r1, r2

 

   // Is it the Primary Core ?

-  LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCore), r1)

-  cmp   r0, r1

+  LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCore), r3)

+  cmp   r5, r3

   beq   _SetupPrimaryCoreStack

 

 _SetupSecondaryCoreStack:

-  // r2 = Top of the primary stack = Base of the Secondary Stacks

+  // r1 contains the base of the secondary stacks

 

-  // Get the position of the cores (ClusterId * 4) + CoreId

-  GetCorePositionInStack(r3, r0, r1)

+  // Get the Core Position (ClusterId * 4) + CoreId

+  GetCorePositionInStack(r0, r5, r2)

   // The stack starts at the top of the stack region. Add '1' to the Core Position to get the top of the stack

-  add   r3, r3, #1

+  add   r0, r0, #1

 

-  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecondaryStackSize), r1)

   // StackOffset = CorePos * StackSize

-  mul   r3, r3, r1

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecondaryStackSize), r2)

+  mul   r0, r0, r2

   // SP = StackBase + StackOffset

-  add   sp, r2, r3

-

-  b     _PrepareArguments

-

-_SetupPrimaryCoreStack:

-  // r2 = Top of the primary stack

-  LoadConstantToReg (FixedPcdGet32(PcdPeiGlobalVariableSize), r3)

-

-  // The reserved space for global variable must be 8-bytes aligned for pushing

-  // 64-bit variable on the stack

-  SetPrimaryStack (r2, r3, r1)

-

-  // Set all the PEI global variables to 0

-  mov   r3, sp

-  mov   r1, #0x0

-_InitGlobals:

-  cmp   r3, r2

-  beq   _PrepareArguments

-  str   r1, [r3], #4

-  b     _InitGlobals

+  add   sp, r1, r0

 

 _PrepareArguments:

   // The PEI Core Entry Point has been computed by GenFV and stored in the second entry of the Reset Vector

@@ -81,14 +62,24 @@ _PrepareArguments:
   add   r2, r2, #4

   ldr   r1, [r2]

 

-  // move sec startup address into a data register

-  // ensure we're jumping to FV version of the code (not boot remapped alias)

-  ldr   r2, StartupAddr

-

-  // jump to PrePeiCore C code

+  // Move sec startup address into a data register

+  // Ensure we're jumping to FV version of the code (not boot remapped alias)

+  ldr   r3, StartupAddr

+  

+  // Jump to PrePeiCore C code

   //    r0 = mp_id

   //    r1 = pei_core_address

-  blx   r2

+  mov   r0, r5

+  blx   r3

+

+_SetupPrimaryCoreStack:

+  // r1 contains the top of the primary stack

+  LoadConstantToReg (FixedPcdGet32(PcdPeiGlobalVariableSize), r2)

+

+  // The reserved space for global variable must be 8-bytes aligned for pushing

+  // 64-bit variable on the stack

+  SetPrimaryStack (r1, r2, r3)

+  b     _PrepareArguments

 

 _NeverReturn:

   b _NeverReturn

diff --git a/ArmPlatformPkg/PrePeiCore/PrePeiCoreEntryPoint.asm b/ArmPlatformPkg/PrePeiCore/PrePeiCoreEntryPoint.asm
index ce3be2772b..60f6051b90 100644
--- a/ArmPlatformPkg/PrePeiCore/PrePeiCoreEntryPoint.asm
+++ b/ArmPlatformPkg/PrePeiCore/PrePeiCoreEntryPoint.asm
@@ -32,50 +32,31 @@ _ModuleEntryPoint
   bl    ArmReadMpidr

   // Get ID of this CPU in Multicore system

   LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCoreMask), r1)

-  and   r0, r0, r1

-

-  // Calculate the top of the primary stack

+  and   r5, r0, r1

+  

+  // Get the top of the primary stacks (and the base of the secondary stacks)

   LoadConstantToReg (FixedPcdGet32(PcdCPUCoresStackBase), r1)

   LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), r2)

-  add   r2, r2, r1

+  add   r1, r1, r2

 

   // Is it the Primary Core ?

-  LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCore), r1)

-  cmp   r0, r1

+  LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCore), r3)

+  cmp   r5, r3

   beq   _SetupPrimaryCoreStack

 

 _SetupSecondaryCoreStack

-  // r2 = Top of the primary stack = Base of the Secondary Stacks

+  // r1 contains the base of the secondary stacks

 

-  // Get the position of the cores (ClusterId * 4) + CoreId

-  GetCorePositionInStack(r3, r0, r1)

+  // Get the Core Position (ClusterId * 4) + CoreId

+  GetCorePositionInStack(r0, r5, r2)

   // The stack starts at the top of the stack region. Add '1' to the Core Position to get the top of the stack

-  add   r3, r3, #1

+  add   r0, r0, #1

 

-  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecondaryStackSize), r1)

   // StackOffset = CorePos * StackSize

-  mul   r3, r3, r1

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecondaryStackSize), r2)

+  mul   r0, r0, r2

   // SP = StackBase + StackOffset

-  add   sp, r2, r3

-

-  b     _PrepareArguments

-

-_SetupPrimaryCoreStack

-  // r2 = Top of the primary stack

-  LoadConstantToReg (FixedPcdGet32(PcdPeiGlobalVariableSize), r3)

-

-  // The reserved space for global variable must be 8-bytes aligned for pushing

-  // 64-bit variable on the stack

-  SetPrimaryStack (r2, r3, r1)

-

-  // Set all the PEI global variables to 0

-  mov   r3, sp

-  mov   r1, #0x0

-_InitGlobals

-  cmp   r3, r2

-  beq   _PrepareArguments

-  str   r1, [r3], #4

-  b     _InitGlobals

+  add   sp, r1, r0

 

 _PrepareArguments

   // The PEI Core Entry Point has been computed by GenFV and stored in the second entry of the Reset Vector

@@ -83,14 +64,24 @@ _PrepareArguments
   add   r2, r2, #4

   ldr   r1, [r2]

 

-  // move sec startup address into a data register

-  // ensure we're jumping to FV version of the code (not boot remapped alias)

-  ldr   r2, StartupAddr

-

-  // jump to PrePeiCore C code

+  // Move sec startup address into a data register

+  // Ensure we're jumping to FV version of the code (not boot remapped alias)

+  ldr   r3, StartupAddr

+  

+  // Jump to PrePeiCore C code

   //    r0 = mp_id

   //    r1 = pei_core_address

-  blx   r2

+  mov   r0, r5

+  blx   r3

+

+_SetupPrimaryCoreStack

+  // r1 contains the top of the primary stack

+  LoadConstantToReg (FixedPcdGet32(PcdPeiGlobalVariableSize), r2)

+

+  // The reserved space for global variable must be 8-bytes aligned for pushing

+  // 64-bit variable on the stack

+  SetPrimaryStack (r1, r2, r3)

+  b     _PrepareArguments

 

 _NeverReturn

   b _NeverReturn

diff --git a/ArmPlatformPkg/PrePi/ModuleEntryPoint.S b/ArmPlatformPkg/PrePi/ModuleEntryPoint.S
index fe9117218a..52e50921b8 100755
--- a/ArmPlatformPkg/PrePi/ModuleEntryPoint.S
+++ b/ArmPlatformPkg/PrePi/ModuleEntryPoint.S
@@ -103,6 +103,7 @@ _GetStackBase:
   beq   _SetupUnicoreStack

 

 _GetStackBaseMpCore:

+  // r1 = The top of the Mpcore Stacks

   // Stack for the primary core = PrimaryCoreStack

   LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), r2)

   sub   r7, r1, r2

@@ -113,8 +114,12 @@ _GetStackBaseMpCore:
   mul   r2, r2, r3

   sub   r7, r7, r2

 

-  // The top of the Mpcore Stacks is in r1

-  // The base of the MpCore Stacks is in r7

+  // The base of the secondary Stacks = Top of Primary stack

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), r2)

+  add   r1, r7, r2

+

+  // r7 = The base of the MpCore Stacks

+  // r1 = The base of the secondary Stacks = Top of the Primary stack

 

   // Is it the Primary Core ?

   LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCore), r4)

@@ -122,7 +127,7 @@ _GetStackBaseMpCore:
   beq   _SetupPrimaryCoreStack

 

 _SetupSecondaryCoreStack:

-  // Base of the stack for the secondary cores is in r7

+  // r1 = The base of the secondary Stacks

 

   // Get the position of the cores (ClusterId * 4) + CoreId

   GetCorePositionInStack(r0, r5, r4)

@@ -130,28 +135,28 @@ _SetupSecondaryCoreStack:
   add   r0, r0, #1

   // Get the offset for the Secondary Stack

   mul   r0, r0, r3

-  add   sp, r7, r0

+  add   sp, r1, r0

 

   bne   _PrepareArguments

 

 _SetupPrimaryCoreStack:

-  // The top of the Mpcore Stacks is in r1

+  // r1 = Top of the primary stack

   LoadConstantToReg (FixedPcdGet32(PcdPeiGlobalVariableSize), r2)

+  b     _PreparePrimaryStack

+

+_SetupUnicoreStack:

+  // The top of the Unicore Stack is in r1

+  LoadConstantToReg (FixedPcdGet32(PcdPeiGlobalVariableSize), r2)

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), r3)

 

+  // Calculate the bottom of the primary stack (StackBase)

+  sub   r7, r1, r3

+

+_PreparePrimaryStack:

   // The reserved space for global variable must be 8-bytes aligned for pushing

   // 64-bit variable on the stack

   SetPrimaryStack (r1, r2, r3)

 

-_SetGlobals:

-  // Set all the PrePi global variables to 0

-  mov   r3, sp

-  mov   r2, #0x0

-_InitGlobals:

-  cmp   r3, r1

-  beq   _PrepareArguments

-  str   r2, [r3], #4

-  b     _InitGlobals

-

 _PrepareArguments:

   mov   r0, r5

   mov   r1, r6

@@ -172,17 +177,3 @@ _PrepareArguments:
 _NeverReturn:

   b _NeverReturn

 

-_SetupUnicoreStack:

-  // The top of the Unicore Stack is in r1

-  LoadConstantToReg (FixedPcdGet32(PcdPeiGlobalVariableSize), r2)

-  LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), r3)

-

-  // Calculate the bottom of the primary stack (StackBase)

-  sub   r7, r1, r3

-

-  // The reserved space for global variable must be 8-bytes aligned for pushing

-  // 64-bit variable on the stack

-  SetPrimaryStack (r1, r2, r3)

-

-  b _SetGlobals

-

diff --git a/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm b/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm
index d62efb2414..e6b2d71361 100644
--- a/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm
+++ b/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm
@@ -104,6 +104,7 @@ _GetStackBase
   beq   _SetupUnicoreStack

 

 _GetStackBaseMpCore

+  // r1 = The top of the Mpcore Stacks

   // Stack for the primary core = PrimaryCoreStack

   LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), r2)

   sub   r7, r1, r2

@@ -114,8 +115,12 @@ _GetStackBaseMpCore
   mul   r2, r2, r3

   sub   r7, r7, r2

 

-  // The top of the Mpcore Stacks is in r1

-  // The base of the MpCore Stacks is in r7

+  // The base of the secondary Stacks = Top of Primary stack

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), r2)

+  add   r1, r7, r2

+

+  // r7 = The base of the MpCore Stacks

+  // r1 = The base of the secondary Stacks = Top of the Primary stack

 

   // Is it the Primary Core ?

   LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCore), r4)

@@ -123,7 +128,7 @@ _GetStackBaseMpCore
   beq   _SetupPrimaryCoreStack

 

 _SetupSecondaryCoreStack

-  // Base of the stack for the secondary cores is in r7

+  // r1 = The base of the secondary Stacks

 

   // Get the position of the cores (ClusterId * 4) + CoreId

   GetCorePositionInStack(r0, r5, r4)

@@ -131,28 +136,28 @@ _SetupSecondaryCoreStack
   add   r0, r0, #1

   // Get the offset for the Secondary Stack

   mul   r0, r0, r3

-  add   sp, r7, r0

+  add   sp, r1, r0

 

   bne   _PrepareArguments

 

 _SetupPrimaryCoreStack

-  // The top of the Mpcore Stacks is in r1

+  // r1 = Top of the primary stack

   LoadConstantToReg (FixedPcdGet32(PcdPeiGlobalVariableSize), r2)

+  b     _PreparePrimaryStack

+

+_SetupUnicoreStack

+  // The top of the Unicore Stack is in r1

+  LoadConstantToReg (FixedPcdGet32(PcdPeiGlobalVariableSize), r2)

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), r3)

 

+  // Calculate the bottom of the primary stack (StackBase)

+  sub   r7, r1, r3

+

+_PreparePrimaryStack

   // The reserved space for global variable must be 8-bytes aligned for pushing

   // 64-bit variable on the stack

   SetPrimaryStack (r1, r2, r3)

 

-_SetGlobals

-  // Set all the PrePi global variables to 0

-  mov   r3, sp

-  mov   r2, #0x0

-_InitGlobals

-  cmp   r3, r1

-  beq   _PrepareArguments

-  str   r2, [r3], #4

-  b     _InitGlobals

-

 _PrepareArguments

   mov   r0, r5

   mov   r1, r6

@@ -173,18 +178,4 @@ _PrepareArguments
 _NeverReturn

   b _NeverReturn

 

-_SetupUnicoreStack

-  // The top of the Unicore Stack is in r1

-  LoadConstantToReg (FixedPcdGet32(PcdPeiGlobalVariableSize), r2)

-  LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), r3)

-

-  // Calculate the bottom of the primary stack (StackBase)

-  sub   r7, r1, r3

-

-  // The reserved space for global variable must be 8-bytes aligned for pushing

-  // 64-bit variable on the stack

-  SetPrimaryStack (r1, r2, r3)

-

-  b _SetGlobals

-

   END

diff --git a/ArmPlatformPkg/Sec/SecEntryPoint.S b/ArmPlatformPkg/Sec/SecEntryPoint.S
index 6d3eb36531..42b18c40de 100644
--- a/ArmPlatformPkg/Sec/SecEntryPoint.S
+++ b/ArmPlatformPkg/Sec/SecEntryPoint.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         

@@ -53,8 +53,8 @@ _IdentifyCpu:
   and   r5, r0, r1

   

   // Is it the Primary Core ?

-  LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCore), r1)

-  cmp   r5, r1

+  LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCore), r3)

+  cmp   r5, r3

   // Only the primary core initialize the memory (SMC)

   beq   _InitMem

   

@@ -72,42 +72,35 @@ _InitMem:
   LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCore), r5)

 

 _SetupPrimaryCoreStack:

-  LoadConstantToReg (FixedPcdGet32(PcdCPUCoresSecStackBase), r2)

-  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecPrimaryStackSize), r3)

-  // Calculate the Top of the Stack

-  add   r2, r2, r3

-  LoadConstantToReg (FixedPcdGet32(PcdSecGlobalVariableSize), r3)

+  // Get the top of the primary stacks (and the base of the secondary stacks)

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCoresSecStackBase), r1)

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecPrimaryStackSize), r2)

+  add   r1, r1, r2

+

+  LoadConstantToReg (FixedPcdGet32(PcdSecGlobalVariableSize), r2)

 

   // The reserved space for global variable must be 8-bytes aligned for pushing

   // 64-bit variable on the stack

-  SetPrimaryStack (r2, r3, r1)

-

-  // Set all the SEC global variables to 0

-  mov     r3, sp

-  mov     r1, #0x0

-_InitGlobals:

-  cmp     r3, r2

-  beq     _PrepareArguments

-  str     r1, [r3], #4

-  b       _InitGlobals

+  SetPrimaryStack (r1, r2, r3)

+  b     _PrepareArguments

 

 _SetupSecondaryCoreStack:

+  // Get the top of the primary stacks (and the base of the secondary stacks)

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCoresSecStackBase), r1)

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecPrimaryStackSize), r2)

+  add   r1, r1, r2

+

   // Get the Core Position (ClusterId * 4) + CoreId

-  GetCorePositionInStack(r0, r5, r1)

+  GetCorePositionInStack(r0, r5, r2)

   // The stack starts at the top of the stack region. Add '1' to the Core Position to get the top of the stack

   add   r0, r0, #1

 

-  // Get the base of the stack for the secondary cores

-  LoadConstantToReg (FixedPcdGet32(PcdCPUCoresSecStackBase), r1)

-  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecSecondaryStackSize), r2)

-  add   r1, r1, r2

-

   // StackOffset = CorePos * StackSize

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecSecondaryStackSize), r2)

   mul   r0, r0, r2

   // SP = StackBase + StackOffset

   add   sp, r1, r0

 

-

 _PrepareArguments:

   // Move sec startup address into a data register

   // Ensure we're jumping to FV version of the code (not boot remapped alias)

diff --git a/ArmPlatformPkg/Sec/SecEntryPoint.asm b/ArmPlatformPkg/Sec/SecEntryPoint.asm
index fe36288360..df443d055d 100644
--- a/ArmPlatformPkg/Sec/SecEntryPoint.asm
+++ b/ArmPlatformPkg/Sec/SecEntryPoint.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         

@@ -55,8 +55,8 @@ _IdentifyCpu
   and   r5, r0, r1

   

   // Is it the Primary Core ?

-  LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCore), r1)

-  cmp   r5, r1

+  LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCore), r3)

+  cmp   r5, r3

   // Only the primary core initialize the memory (SMC)

   beq   _InitMem

   

@@ -74,42 +74,35 @@ _InitMem
   LoadConstantToReg (FixedPcdGet32(PcdArmPrimaryCore), r5)

 

 _SetupPrimaryCoreStack

-  LoadConstantToReg (FixedPcdGet32(PcdCPUCoresSecStackBase), r2)

-  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecPrimaryStackSize), r3)

-  // Calculate the Top of the Stack

-  add   r2, r2, r3

-  LoadConstantToReg (FixedPcdGet32(PcdSecGlobalVariableSize), r3)

+  // Get the top of the primary stacks (and the base of the secondary stacks)

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCoresSecStackBase), r1)

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecPrimaryStackSize), r2)

+  add   r1, r1, r2

+

+  LoadConstantToReg (FixedPcdGet32(PcdSecGlobalVariableSize), r2)

 

   // The reserved space for global variable must be 8-bytes aligned for pushing

   // 64-bit variable on the stack

-  SetPrimaryStack (r2, r3, r1)

-

-  // Set all the SEC global variables to 0

-  mov     r3, sp

-  mov     r1, #0x0

-_InitGlobals

-  cmp     r3, r2

-  beq     _PrepareArguments

-  str     r1, [r3], #4

-  b       _InitGlobals

+  SetPrimaryStack (r1, r2, r3)

+  b     _PrepareArguments

 

 _SetupSecondaryCoreStack

+  // Get the top of the primary stacks (and the base of the secondary stacks)

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCoresSecStackBase), r1)

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecPrimaryStackSize), r2)

+  add   r1, r1, r2

+

   // Get the Core Position (ClusterId * 4) + CoreId

-  GetCorePositionInStack(r0, r5, r1)

+  GetCorePositionInStack(r0, r5, r2)

   // The stack starts at the top of the stack region. Add '1' to the Core Position to get the top of the stack

   add   r0, r0, #1

 

-  // Get the base of the stack for the secondary cores

-  LoadConstantToReg (FixedPcdGet32(PcdCPUCoresSecStackBase), r1)

-  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecSecondaryStackSize), r2)

-  add   r1, r1, r2

-

   // StackOffset = CorePos * StackSize

+  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecSecondaryStackSize), r2)

   mul   r0, r0, r2

   // SP = StackBase + StackOffset

   add   sp, r1, r0

 

-

 _PrepareArguments

   // Move sec startup address into a data register

   // Ensure we're jumping to FV version of the code (not boot remapped alias)