diff --git a/ArmPlatformPkg/ArmPlatformPkg.dec b/ArmPlatformPkg/ArmPlatformPkg.dec
index e881c13439..2d06275953 100644
--- a/ArmPlatformPkg/ArmPlatformPkg.dec
+++ b/ArmPlatformPkg/ArmPlatformPkg.dec
@@ -62,7 +62,7 @@
   gArmPlatformTokenSpaceGuid.PcdClusterCount|1|UINT32|0x00000038
 
   # Stack for CPU Cores in Secure Mode
-  gArmPlatformTokenSpaceGuid.PcdCPUCoresSecStackBase|0|UINT32|0x00000005
+  gArmPlatformTokenSpaceGuid.PcdCPUCoresSecStackBase|0|UINT64|0x00000005
   gArmPlatformTokenSpaceGuid.PcdCPUCoreSecPrimaryStackSize|0x10000|UINT32|0x00000036
   gArmPlatformTokenSpaceGuid.PcdCPUCoreSecSecondaryStackSize|0x1000|UINT32|0x00000006
 
@@ -188,13 +188,13 @@
 
 [PcdsFixedAtBuild.ARM]
   # Stack for CPU Cores in Secure Monitor Mode
-  gArmPlatformTokenSpaceGuid.PcdCPUCoresSecMonStackBase|0|UINT32|0x00000007
+  gArmPlatformTokenSpaceGuid.PcdCPUCoresSecMonStackBase|0|UINT64|0x00000007
   gArmPlatformTokenSpaceGuid.PcdCPUCoreSecMonStackSize|0x1000|UINT32|0x00000008
 
 [PcdsFixedAtBuild.AARCH64]
   # The Secure World is only running in EL3. Only one set of stacks is needed for AArch64.
   # The Secure stacks are described by PcdCPUCoresSecStackBase, PcdCPUCoreSecPrimaryStackSize
   # and PcdCPUCoreSecSecondaryStackSize
-  gArmPlatformTokenSpaceGuid.PcdCPUCoresSecMonStackBase|0|UINT32|0x00000007
+  gArmPlatformTokenSpaceGuid.PcdCPUCoresSecMonStackBase|0|UINT64|0x00000007
   gArmPlatformTokenSpaceGuid.PcdCPUCoreSecMonStackSize|0x0|UINT32|0x00000008
 
diff --git a/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S b/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S
index 85d3450f62..34bf3a4e68 100644
--- a/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S
+++ b/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S
@@ -60,7 +60,7 @@ ASM_PFX(MainEntryPoint):
   bl    ASM_PFX(ArmPlatformIsPrimaryCore)
 
   // Get the top of the primary stacks (and the base of the secondary stacks)
-  LoadConstantToReg (FixedPcdGet32(PcdCPUCoresStackBase), x1)
+  LoadConstantToReg (FixedPcdGet64(PcdCPUCoresStackBase), x1)
   LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), x2)
   add   x1, x1, x2
 
diff --git a/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.S b/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.S
index ba1bd09b67..1693f52e26 100644
--- a/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.S
+++ b/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.S
@@ -41,7 +41,7 @@ ASM_PFX(_ModuleEntryPoint):
   bl    ASM_PFX(ArmPlatformIsPrimaryCore)
 
   // Get the top of the primary stacks (and the base of the secondary stacks)
-  LoadConstantToReg (FixedPcdGet32(PcdCPUCoresStackBase), r1)
+  LoadConstantToReg (FixedPcdGet64(PcdCPUCoresStackBase), r1)
   LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), r2)
   add   r1, r1, r2
 
diff --git a/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.asm b/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.asm
index c316379f05..9a8ca0b174 100644
--- a/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.asm
+++ b/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.asm
@@ -43,7 +43,7 @@ _ModuleEntryPoint
   bl    ArmPlatformIsPrimaryCore
 
   // Get the top of the primary stacks (and the base of the secondary stacks)
-  LoadConstantToReg (FixedPcdGet32(PcdCPUCoresStackBase), r1)
+  LoadConstantToReg (FixedPcdGet64(PcdCPUCoresStackBase), r1)
   LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), r2)
   add   r1, r1, r2
 
diff --git a/ArmPlatformPkg/PrePi/AArch64/ModuleEntryPoint.S b/ArmPlatformPkg/PrePi/AArch64/ModuleEntryPoint.S
index f63fd44067..9538c70a23 100644
--- a/ArmPlatformPkg/PrePi/AArch64/ModuleEntryPoint.S
+++ b/ArmPlatformPkg/PrePi/AArch64/ModuleEntryPoint.S
@@ -49,8 +49,8 @@ _SystemMemoryEndInit:
   cmp   x1, #0
   bne   _SetupStackPosition
 
-  LoadConstantToReg (FixedPcdGet32(PcdSystemMemoryBase), x1)
-  LoadConstantToReg (FixedPcdGet32(PcdSystemMemorySize), x2)
+  LoadConstantToReg (FixedPcdGet64(PcdSystemMemoryBase), x1)
+  LoadConstantToReg (FixedPcdGet64(PcdSystemMemorySize), x2)
   sub   x2, x2, #1
   add   x1, x1, x2
   // Update the global variable
@@ -61,7 +61,7 @@ _SetupStackPosition:
   // r1 = SystemMemoryTop
 
   // Calculate Top of the Firmware Device
-  LoadConstantToReg (FixedPcdGet32(PcdFdBaseAddress), x2)
+  LoadConstantToReg (FixedPcdGet64(PcdFdBaseAddress), x2)
   LoadConstantToReg (FixedPcdGet32(PcdFdSize), x3)
   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 b563b5ee3a..8740b2a9e8 100644
--- a/ArmPlatformPkg/PrePi/PrePi.c
+++ b/ArmPlatformPkg/PrePi/PrePi.c
@@ -29,8 +29,8 @@
 #include "PrePi.h"
 #include "LzmaDecompress.h"
 
-#define IS_XIP() (((UINT32)FixedPcdGet32 (PcdFdBaseAddress) > mSystemMemoryEnd) || \
-                  ((FixedPcdGet32 (PcdFdBaseAddress) + FixedPcdGet32 (PcdFdSize)) < FixedPcdGet64 (PcdSystemMemoryBase)))
+#define IS_XIP() (((UINT64)FixedPcdGet64 (PcdFdBaseAddress) > mSystemMemoryEnd) || \
+                  ((FixedPcdGet64 (PcdFdBaseAddress) + FixedPcdGet32 (PcdFdSize)) < FixedPcdGet64 (PcdSystemMemoryBase)))
 
 EFI_STATUS
 EFIAPI
@@ -86,8 +86,8 @@ 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)mSystemMemoryEnd)));
+          ((FixedPcdGet64 (PcdFdBaseAddress) >= FixedPcdGet64 (PcdSystemMemoryBase)) &&
+           ((UINT64)(FixedPcdGet64 (PcdFdBaseAddress) + FixedPcdGet32 (PcdFdSize)) <= (UINT64)mSystemMemoryEnd)));
 
   // Initialize the architecture specific bits
   ArchInitialize ();