ArmVirtPkg/PrePi: use correct callee saved regs

Both the ARM and the AARCH64 versions of the PrePi code (shared between
ArmVirtQemuKernel and ArmVirtXen) 'preserve' values across a function
call using registers that are not in fact callee saved. So fix that.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Laszlo Ersek <lersek@redhat.com>

2 files changed, 20 insertions, 20 deletions

diff --git a/ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S b/ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S
index 68049d5df2..d6be345418 100644
--- a/ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S
+++ b/ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S
@@ -71,7 +71,7 @@ ASM_PFX(_ModuleEntryPoint):
   // Get ID of this CPU in Multicore system

   bl    ASM_PFX(ArmReadMpidr)

   // Keep a copy of the MpId register value

-  mov   x10, x0

+  mov   x20, x0

 

 // 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

@@ -113,40 +113,40 @@ _SetupStack:
   // 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  x11, x1, #1

+  adds  x21, x1, #1

   b.cs  _SetupOverflowStack

 

 _SetupAlignedStack:

-  mov   x1, x11

+  mov   x1, x21

   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, x11)

-  and   x11, x11, x1

-  sub   x1, x1, x11

+  LoadConstantToReg (EFI_PAGE_MASK, x21)

+  and   x21, x21, x1

+  sub   x1, x1, x21

 

 _GetBaseUefiMemory:

   // Calculate the Base of the UEFI Memory

-  sub   x11, x1, x4

+  sub   x21, x1, x4

 

 _GetStackBase:

   // r1 = The top of the Mpcore Stacks

   // Stack for the primary core = PrimaryCoreStack

   LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), x2)

-  sub   x12, x1, x2

+  sub   x22, x1, x2

 

   // Stack for the secondary core = Number of Cores - 1

   LoadConstantToReg (FixedPcdGet32(PcdCoreCount), x0)

   sub   x0, x0, #1

   LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecondaryStackSize), x1)

   mul   x1, x1, x0

-  sub   x12, x12, x1

+  sub   x22, x22, x1

 

-  // x12 = The base of the MpCore Stacks (primary stack & secondary stacks)

-  mov   x0, x12

-  mov   x1, x10

+  // x22 = The base of the MpCore Stacks (primary stack & secondary stacks)

+  mov   x0, x22

+  mov   x1, x20

   //ArmPlatformStackSet(StackBase, MpId, PrimaryStackSize, SecondaryStackSize)

   LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), x2)

   LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecondaryStackSize), x3)

@@ -159,9 +159,9 @@ _GetStackBase:
   bne   _PrepareArguments

 

 _PrepareArguments:

-  mov   x0, x10

-  mov   x1, x11

-  mov   x2, x12

+  mov   x0, x20

+  mov   x1, x21

+  mov   x2, x22

 

   // 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/ArmVirtPkg/PrePi/Arm/ModuleEntryPoint.S b/ArmVirtPkg/PrePi/Arm/ModuleEntryPoint.S
index 441db36857..3215c7d558 100644
--- a/ArmVirtPkg/PrePi/Arm/ModuleEntryPoint.S
+++ b/ArmVirtPkg/PrePi/Arm/ModuleEntryPoint.S
@@ -154,17 +154,17 @@ _GetStackBase:
   // r1 = The top of the Mpcore Stacks

   // Stack for the primary core = PrimaryCoreStack

   LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), r2)

-  sub   r12, r1, r2

+  sub   r9, r1, r2

 

   // Stack for the secondary core = Number of Cores - 1

   LoadConstantToReg (FixedPcdGet32(PcdCoreCount), r0)

   sub   r0, r0, #1

   LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecondaryStackSize), r1)

   mul   r1, r1, r0

-  sub   r12, r12, r1

+  sub   r9, r9, r1

 

-  // r12 = The base of the MpCore Stacks (primary stack & secondary stacks)

-  mov   r0, r12

+  // r9 = The base of the MpCore Stacks (primary stack & secondary stacks)

+  mov   r0, r9

   mov   r1, r10

   //ArmPlatformStackSet(StackBase, MpId, PrimaryStackSize, SecondaryStackSize)

   LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), r2)

@@ -180,7 +180,7 @@ _GetStackBase:
 _PrepareArguments:

   mov   r0, r10

   mov   r1, r11

-  mov   r2, r12

+  mov   r2, r9

 

   // Move sec startup address into a data register

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