UefiCpuPkg/PiSmmCpuDxeSmm: Modify PcdCpuSmmRestrictedMemoryAccess retrieval

Currently if PcdCpuSmmRestrictedMemoryAccess is a DynamicPcd
it will be accessed during SMM entry causing an error since code
outside of SMM will be called (PcdGetBool).
To fix that PcdCpuSmmRestrictedMemoryAccess is retrieved during
SMM initialization and cached value is used at runtime

Signed-off-by: Sienski Piotr <piotr.sienski@intel.com>

UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c

@@ -389,5 +389,10 @@ PiCpuSmmEntry (
                     );
   ASSERT_EFI_ERROR (Status);
 
+  //
+  // Initialize value of mIsRestrictedMemoryAccess
+  //
+  IsRestrictedMemoryAccess ();
+
   return Status;
 }

UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArchDxeSmm.c

@@ -7,6 +7,9 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 
 #include "PiSmmCpuCommon.h"
 
+BOOLEAN  mIsRestrictedMemoryAccess            = TRUE;
+BOOLEAN  mIsRestrictedMemoryAccessInitialized = FALSE;
+
 /**
   Return whether access to non-SMRAM is restricted.
 
@@ -18,5 +21,10 @@ IsRestrictedMemoryAccess (
   VOID
   )
 {
-  return PcdGetBool (PcdCpuSmmRestrictedMemoryAccess);
+  if (!mIsRestrictedMemoryAccessInitialized) {
+    mIsRestrictedMemoryAccess            = PcdGetBool (PcdCpuSmmRestrictedMemoryAccess);
+    mIsRestrictedMemoryAccessInitialized = TRUE;
+  }
+
+  return mIsRestrictedMemoryAccess;
 }