UefiCpuPkg: Add common architecture level library support

Introduce fundamental architecture-level functionalities which should
be implemented cross different architectures.

Signed-off-by: Ajan Zhong <ajan.zhong@newfw.com>

UefiCpuPkg/Include/Library/BaseArchLibSupport.h

@@ -0,0 +1,30 @@
+/** @file
+
+  Base Architecture Libraries Support.
+
+  Copyright 2024 Google LLC
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#ifndef BASE_ARCH_LIB_SUPPORT_H
+#define BASE_ARCH_LIB_SUPPORT_H
+
+#include <Base.h>
+
+/**
+  Report the Physical Address size supported by Processor.
+
+  For X86, returns the actual Physical Address size reported by CPUID.
+  For AArch64, returns the actual Physical Address range reported by
+    ID_ARCH64MMFR0_EL1.
+
+  @return                         Physical Address Bits
+
+**/
+UINT8
+ArchGetPhysicalAddressBits (
+  VOID
+  );
+
+#endif

UefiCpuPkg/Library/BaseArchSupportLib/AArch64/AArch64LibSupport.c

@@ -0,0 +1,27 @@
+/** @file
+  UefiCpu AArch64 architecture support library.
+
+  Copyright 2024 Google LLC
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Base.h>
+#include <Library/ArmLib.h>
+
+VOID
+EFIAPI
+InitializeFloatingPointUnits (
+  VOID
+  )
+{
+  return;
+}
+
+UINTN
+ArchGetPhysicalAddressBits (
+  VOID
+  )
+{
+  return ArmGetPhysicalAddressBits ();
+}

UefiCpuPkg/Library/BaseArchSupportLib/BaseArchSupportLib.inf

@@ -0,0 +1,29 @@
+## @file
+#  UefiCpu AArch64 architecture support library.
+#
+#  Copyright 2024 Google LLC
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION         = 0x0001001b
+  BASE_NAME           = UefiCpuBaseArchSupportLib
+  FILE_GUID           = 692f5af5-e629-4ead-ade1-db353d59bcb9
+  MODULE_TYPE         = BASE
+  VERSION_STRING      = 1.0
+  LIBRARY_CLASS       = UefiCpuBaseArchSupportLib
+
+[Sources.AARCH64]
+  AArch64/AArch64LibSupport.c
+
+[Sources.IA32, Sources.X64]
+  X86/X86LibSupport.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  UefiCpuPkg/UefiCpuPkg.dec
+
+[LibraryClasses]
+  BaseLib

UefiCpuPkg/Library/BaseArchSupportLib/X86/X86LibSupport.c

@@ -0,0 +1,26 @@
+/** @file
+  UefiCpu X86 architectures support library for both Ia32 and X64.
+
+  Copyright 2024 Google LLC
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Base.h>
+#include <Library/BaseLib.h>
+
+UINT8
+ArchGetPhysicalAddressBits (
+  VOID
+  )
+{
+  UINT32  RegEax;
+
+  AsmCpuid (0x80000000, &RegEax, NULL, NULL, NULL);
+  if (RegEax >= 0x80000008) {
+    AsmCpuid (0x80000008, &RegEax, NULL, NULL, NULL);
+    return (UINT8)RegEax;
+  }
+
+  return 36;
+}

UefiCpuPkg/UefiCpuPkg.dec

@@ -25,6 +25,11 @@
   ##
   RegisterCpuFeaturesLib|Include/Library/RegisterCpuFeaturesLib.h
 
+  ##  @libraryclass  Defines some common architecture-level fundamental routines which
+  ##                 are supported at different architectures.
+  ##
+  UefiCpuBaseArchSupportLib|Include/Library/BaseArchLibSupport.h
+
 [LibraryClasses.IA32, LibraryClasses.X64]
   ##  @libraryclass  Provides functions to manage MTRR settings on IA32 and X64 CPUs.
   ##

UefiCpuPkg/UefiCpuPkg.dsc

@@ -151,6 +151,7 @@
   UefiCpuPkg/CpuIo2Smm/CpuIo2StandaloneMm.inf
   UefiCpuPkg/CpuMpPei/CpuMpPei.inf
   UefiCpuPkg/CpuS3DataDxe/CpuS3DataDxe.inf
+  UefiCpuPkg/Library/BaseArchSupportLib/BaseArchSupportLib.inf
   UefiCpuPkg/Library/BaseXApicLib/BaseXApicLib.inf
   UefiCpuPkg/Library/BaseXApicX2ApicLib/BaseXApicX2ApicLib.inf
   UefiCpuPkg/Library/CpuCommonFeaturesLib/CpuCommonFeaturesLib.inf
@@ -227,6 +228,9 @@
   UefiCpuPkg/CpuDxeRiscV64/CpuDxeRiscV64.inf
   UefiCpuPkg/CpuMmio2Dxe/CpuMmio2Dxe.inf
 
+[Components.AARCH64]
+  UefiCpuPkg/Library/BaseArchSupportLib/BaseArchSupportLib.inf
+
 [Components.LOONGARCH64]
   UefiCpuPkg/Library/CpuMmuLib/CpuMmuLib.inf
   UefiCpuPkg/CpuMmio2Dxe/CpuMmio2Dxe.inf