[PATCH v2] ArmPlatformPkg/PrePeiCore: seed temporary stack before entering PEI core

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

DEBUG builds of PEI code will print a diagnostic message regarding
the utilization of temporary RAM before switching to permanent RAM.
For example,

  Total temporary memory:    16352 bytes.
    temporary memory stack ever used:       4820 bytes.
    temporary memory heap used for HobList: 4720 bytes.

Tracking stack utilization like this requires the stack to be seeded
with a known magic value, and this needs to occur before entering C
code, given that it uses the stack. Currently, only Nt32Pkg appears
to implement this feature, but it is useful nonetheless, so let's
wire it up for PrePeiCore as well.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=748
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
v2: switch to newly introduced PCD

 ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S | 6 ++++++
 ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.S     | 8 ++++++++
 ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.asm   | 8 ++++++++
 ArmPlatformPkg/PrePeiCore/PrePeiCoreMPCore.inf           | 2 ++
 ArmPlatformPkg/PrePeiCore/PrePeiCoreUniCore.inf          | 2 ++
 5 files changed, 26 insertions(+)

diff --git a/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S b/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S
index aab5edab0c42..0950fd0c0cdb 100644
--- a/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S
+++ b/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S
@@ -84,4 +84,10 @@ _PrepareArguments:
 
 _SetupPrimaryCoreStack:
   mov   sp, x1
+  MOV64 (x8, FixedPcdGet64 (PcdCPUCoresStackBase))
+  MOV64 (x9, FixedPcdGet32 (PcdInitValueInTempStack) |\
+             FixedPcdGet32 (PcdInitValueInTempStack) << 32)
+0:stp   x9, x9, [x8], #16
+  cmp   x8, x1
+  b.lt  0b
   b     _PrepareArguments
diff --git a/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.S b/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.S
index 14344425ad4c..a491af30a048 100644
--- a/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.S
+++ b/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.S
@@ -65,6 +65,14 @@ _PrepareArguments:
 
 _SetupPrimaryCoreStack:
   mov   sp, r1
+  MOV32 (r8, FixedPcdGet64 (PcdCPUCoresStackBase))
+  MOV32 (r9, FixedPcdGet32 (PcdInitValueInTempStack))
+  mov   r10, r9
+  mov   r11, r9
+  mov   r12, r9
+0:stm   r8!, {r9-r12}
+  cmp   r8, r1
+  blt   0b
   b     _PrepareArguments
 
 _NeverReturn:
diff --git a/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.asm b/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.asm
index abea675828df..dc1ad8144492 100644
--- a/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.asm
+++ b/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.asm
@@ -79,6 +79,14 @@ _PrepareArguments
 
 _SetupPrimaryCoreStack
   mov   sp, r1
+  mov32 r8, FixedPcdGet64 (PcdCPUCoresStackBase)
+  mov32 r9, FixedPcdGet32 (PcdInitValueInTempStack)
+  mov   r10, r9
+  mov   r11, r9
+  mov   r12, r9
+0:stm   r8!, {r9-r12}
+  cmp   r8, r1
+  blt   0b
   b     _PrepareArguments
 
 _NeverReturn
diff --git a/ArmPlatformPkg/PrePeiCore/PrePeiCoreMPCore.inf b/ArmPlatformPkg/PrePeiCore/PrePeiCoreMPCore.inf
index ecdbccb8d620..8e0456f8dc2a 100644
--- a/ArmPlatformPkg/PrePeiCore/PrePeiCoreMPCore.inf
+++ b/ArmPlatformPkg/PrePeiCore/PrePeiCoreMPCore.inf
@@ -75,3 +75,5 @@ [FixedPcd]
   gArmTokenSpaceGuid.PcdGicDistributorBase
   gArmTokenSpaceGuid.PcdGicInterruptInterfaceBase
   gArmTokenSpaceGuid.PcdGicSgiIntId
+
+  gEfiMdeModulePkgTokenSpaceGuid.PcdInitValueInTempStack
diff --git a/ArmPlatformPkg/PrePeiCore/PrePeiCoreUniCore.inf b/ArmPlatformPkg/PrePeiCore/PrePeiCoreUniCore.inf
index b5d4e389b2a4..ec83cec2d879 100644
--- a/ArmPlatformPkg/PrePeiCore/PrePeiCoreUniCore.inf
+++ b/ArmPlatformPkg/PrePeiCore/PrePeiCoreUniCore.inf
@@ -69,3 +69,5 @@ [FixedPcd]
   gArmPlatformTokenSpaceGuid.PcdCPUCoresStackBase
   gArmPlatformTokenSpaceGuid.PcdCPUCorePrimaryStackSize
   gArmPlatformTokenSpaceGuid.PcdCPUCoreSecondaryStackSize
+
+  gEfiMdeModulePkgTokenSpaceGuid.PcdInitValueInTempStack
-- 
2.11.0