[Xen-devel] [PATCH v2 09/29] ArmPlatformPkg/PrePi: allow use of patchable PCDs

[Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>]

Avoid using FixedPcdGetXX () to reference system memory and FD
base address PCDs so that the platform can choose to use patchable
PCDs instead. This allows a runtime self-relocating PrePi to poke
alternate values into them that can only be discovered at runtime.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
 ArmPlatformPkg/PrePi/AArch64/ModuleEntryPoint.S | 8 ++++----
 ArmPlatformPkg/PrePi/PrePi.c                    | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/ArmPlatformPkg/PrePi/AArch64/ModuleEntryPoint.S 
b/ArmPlatformPkg/PrePi/AArch64/ModuleEntryPoint.S
index fcea9496cbd5..3fa6bf1f0322 100644
--- a/ArmPlatformPkg/PrePi/AArch64/ModuleEntryPoint.S
+++ b/ArmPlatformPkg/PrePi/AArch64/ModuleEntryPoint.S
@@ -42,14 +42,14 @@ _SetSVCMode:
 // at the top of the DRAM)
 _SetupStackPosition:
   // Compute Top of System Memory
-  LoadConstantToReg (FixedPcdGet64 (PcdSystemMemoryBase), x1)
-  LoadConstantToReg (FixedPcdGet64 (PcdSystemMemorySize), x2)
+  ldr   x1, PcdGet64 (PcdSystemMemoryBase)
+  ldr   x2, PcdGet64 (PcdSystemMemorySize)
   sub   x2, x2, #1
   add   x1, x1, x2      // x1 = SystemMemoryTop = PcdSystemMemoryBase + 
PcdSystemMemorySize
 
   // Calculate Top of the Firmware Device
-  LoadConstantToReg (FixedPcdGet32(PcdFdBaseAddress), x2)
-  LoadConstantToReg (FixedPcdGet32(PcdFdSize), x3)
+  ldr   x2, PcdGet64 (PcdFdBaseAddress)
+  ldr   w3, PcdGet32 (PcdFdSize)
   sub   x3, x3, #1
   add   x3, x3, x2      // x3 = FdTop = PcdFdBaseAddress + PcdFdSize
 
diff --git a/ArmPlatformPkg/PrePi/PrePi.c b/ArmPlatformPkg/PrePi/PrePi.c
index 9a5e067ef537..0e551c518d6b 100755
--- a/ArmPlatformPkg/PrePi/PrePi.c
+++ b/ArmPlatformPkg/PrePi/PrePi.c
@@ -30,8 +30,8 @@
 #include "PrePi.h"
 #include "LzmaDecompress.h"
 
-#define IS_XIP() (((UINT32)FixedPcdGet32 (PcdFdBaseAddress) > 
(UINT32)(FixedPcdGet64 (PcdSystemMemoryBase) + FixedPcdGet32 
(PcdSystemMemorySize))) || \
-                  ((FixedPcdGet32 (PcdFdBaseAddress) + FixedPcdGet32 
(PcdFdSize)) < FixedPcdGet64 (PcdSystemMemoryBase)))
+#define IS_XIP() (((UINT32)PcdGet64 (PcdFdBaseAddress) > (UINT32)(PcdGet64 
(PcdSystemMemoryBase) + PcdGet64 (PcdSystemMemorySize))) || \
+                  ((PcdGet64 (PcdFdBaseAddress) + PcdGet32 (PcdFdSize)) < 
PcdGet64 (PcdSystemMemoryBase)))
 
 // Not used when PrePi in run in XIP mode
 UINTN mGlobalVariableBase = 0;
@@ -108,8 +108,8 @@ PrePiMain (
 
   // If ensure the FD is either part of the System Memory or totally outside 
of the System Memory (XIP)
   ASSERT (IS_XIP() ||
-          ((FixedPcdGet32 (PcdFdBaseAddress) >= FixedPcdGet64 
(PcdSystemMemoryBase)) &&
-           ((UINT32)(FixedPcdGet32 (PcdFdBaseAddress) + FixedPcdGet32 
(PcdFdSize)) <= (UINT32)(FixedPcdGet64 (PcdSystemMemoryBase) + FixedPcdGet64 
(PcdSystemMemorySize)))));
+          ((PcdGet64 (PcdFdBaseAddress) >= PcdGet64 (PcdSystemMemoryBase)) &&
+           ((UINT32)(PcdGet64 (PcdFdBaseAddress) + PcdGet32 (PcdFdSize)) <= 
(UINT32)(PcdGet64 (PcdSystemMemoryBase) + PcdGet64 (PcdSystemMemorySize)))));
 
   // Initialize the architecture specific bits
   ArchInitialize ();
-- 
1.8.3.2


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