diff --git a/MdeModulePkg/MdeModulePkg.dec b/MdeModulePkg/MdeModulePkg.dec
index 623d8ed68286..af7bcab3baf6 100644
--- a/MdeModulePkg/MdeModulePkg.dec
+++ b/MdeModulePkg/MdeModulePkg.dec
@@ -4,6 +4,7 @@
 # and libraries instances, which are used for those modules.
 #
 # Copyright (c) 2007 - 2016, Intel Corporation. All rights reserved.<BR>
+# Copyright (c) 2016, Linaro Ltd. All rights reserved.<BR>
 # This program and the accompanying materials are licensed and made available under
 # the terms and conditions of the BSD License that accompanies this distribution.
 # The full text of the license may be found at
@@ -1049,6 +1050,16 @@ [PcdsFixedAtBuild, PcdsPatchableInModule]
   # @Prompt Driver guid array of VFR drivers for VarCheckHiiBin generation.
   gEfiMdeModulePkgTokenSpaceGuid.PcdVarCheckVfrDriverGuidArray|{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }|VOID*|0x3000103A
 
+  ## Indicates which ACPI versions are targeted by the ACPI tables exposed to the OS
+  #  These values are aligned with the definitions in MdePkg/Include/Protocol/AcpiSystemDescriptionTable.h
+  #   BIT 1 - EFI_ACPI_TABLE_VERSION_1_0B.<BR>
+  #   BIT 2 - EFI_ACPI_TABLE_VERSION_2_0.<BR>
+  #   BIT 3 - EFI_ACPI_TABLE_VERSION_3_0.<BR>
+  #   BIT 4 - EFI_ACPI_TABLE_VERSION_4_0.<BR>
+  #   BIT 5 - EFI_ACPI_TABLE_VERSION_5_0.<BR>
+  # @Prompt Exposed ACPI table versions.
+  gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiExposedTableVersions|0x3E|UINT32|0x0001004c
+
 [PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]
   ## This PCD defines the Console output row. The default value is 25 according to UEFI spec.
   #  This PCD could be set to 0 then console output would be at max column and max row.
diff --git a/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiSdt.c b/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiSdt.c
index 57fdc7844e93..db693900758a 100644
--- a/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiSdt.c
+++ b/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiSdt.c
@@ -19,7 +19,7 @@
 
 GLOBAL_REMOVE_IF_UNREFERENCED
 EFI_ACPI_SDT_PROTOCOL  mAcpiSdtProtocolTemplate = {
-  EFI_ACPI_TABLE_VERSION_NONE | EFI_ACPI_TABLE_VERSION_1_0B | ACPI_TABLE_VERSION_GTE_2_0,
+  EFI_ACPI_TABLE_VERSION_NONE,
   GetAcpiTable2,
   RegisterNotify,
   Open,
@@ -1102,6 +1102,7 @@ SdtAcpiTableAcpiSdtConstructor (
 
   InitializeListHead (&AcpiTableInstance->NotifyList);
   CopyMem (&AcpiTableInstance->AcpiSdtProtocol, &mAcpiSdtProtocolTemplate, sizeof(mAcpiSdtProtocolTemplate));
+  AcpiTableInstance->AcpiSdtProtocol.AcpiVersion = (EFI_ACPI_TABLE_VERSION)PcdGet32 (PcdAcpiExposedTableVersions);
 
   //
   // Register event for ExitPmAuth, so that we can uninstall ACPI SDT protocol after ExitPmAuth.
diff --git a/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableDxe.inf b/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableDxe.inf
index e9cd728dbfb6..669df15c5c59 100644
--- a/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableDxe.inf
+++ b/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableDxe.inf
@@ -2,6 +2,7 @@
 #  ACPI Table Protocol Driver
 #
 #  Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>
+#  Copyright (c) 2016, Linaro Ltd. All rights reserved.<BR>
 #  This program and the accompanying materials are
 #  licensed and made available under the terms and conditions of the BSD License
 #  which accompanies this distribution.  The full text of the license may be found at
@@ -60,6 +61,7 @@ [Guids]
 
 [FeaturePcd]
   gEfiMdeModulePkgTokenSpaceGuid.PcdInstallAcpiSdtProtocol  ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdDxeIplSwitchToLongMode  ## CONSUMES
 
 [Pcd]
   gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiDefaultOemId            ## CONSUMES
@@ -67,6 +69,7 @@ [Pcd]
   gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiDefaultOemRevision      ## CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiDefaultCreatorId        ## CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiDefaultCreatorRevision  ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiExposedTableVersions    ## CONSUMES
 
 [Protocols]
   gEfiAcpiTableProtocolGuid                     ## PRODUCES
diff --git a/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableProtocol.c b/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableProtocol.c
index c6abf1bf0c52..f069458b1cba 100644
--- a/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableProtocol.c
+++ b/MdeModulePkg/Universal/Acpi/AcpiTableDxe/AcpiTableProtocol.c
@@ -2,6 +2,7 @@
   ACPI Table Protocol Implementation
 
   Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2016, Linaro Ltd. All rights reserved.<BR>
   This program and the accompanying materials
   are licensed and made available under the terms and conditions of the BSD License
   which accompanies this distribution.  The full text of the license may be found at
@@ -21,6 +22,12 @@
 //
 UINTN         mEfiAcpiMaxNumTables = EFI_ACPI_MAX_NUM_TABLES; 
 
+//
+// Allocation strategy to use for AllocatePages ().
+// Runtime value depends on PcdExposedAcpiTableVersions.
+//
+STATIC EFI_ALLOCATE_TYPE      mAcpiTableAllocType;
+
 /**
   This function adds an ACPI table to the table list.  It will detect FACS and
   allocate the correct type of memory and properly align the table.
@@ -133,10 +140,11 @@ PublishTables (
   if ((Version & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
     CurrentRsdtEntry  = (UINT32 *) ((UINT8 *) AcpiTableInstance->Rsdt1 + sizeof (EFI_ACPI_DESCRIPTION_HEADER));
     *CurrentRsdtEntry = (UINT32) (UINTN) AcpiTableInstance->Fadt1;
-  }
-  if ((Version & ACPI_TABLE_VERSION_GTE_2_0) != 0) {
+
     CurrentRsdtEntry  = (UINT32 *) ((UINT8 *) AcpiTableInstance->Rsdt3 + sizeof (EFI_ACPI_DESCRIPTION_HEADER));
     *CurrentRsdtEntry = (UINT32) (UINTN) AcpiTableInstance->Fadt3;
+  }
+  if ((Version & ACPI_TABLE_VERSION_GTE_2_0) != 0) {
     CurrentXsdtEntry  = (VOID *) ((UINT8 *) AcpiTableInstance->Xsdt + sizeof (EFI_ACPI_DESCRIPTION_HEADER));
     //
     // Add entry to XSDT, XSDT expects 64 bit pointers, but
@@ -209,6 +217,7 @@ InstallAcpiTable (
   EFI_ACPI_TABLE_INSTANCE   *AcpiTableInstance;
   EFI_STATUS                Status;
   VOID                      *AcpiTableBufferConst;
+  EFI_ACPI_TABLE_VERSION    Version;
 
   //
   // Check for invalid input parameters
@@ -218,6 +227,8 @@ InstallAcpiTable (
     return EFI_INVALID_PARAMETER;
   }
 
+  Version = PcdGet32 (PcdAcpiExposedTableVersions);
+
   //
   // Get the instance of the ACPI table protocol
   //
@@ -232,13 +243,13 @@ InstallAcpiTable (
              AcpiTableInstance,
              AcpiTableBufferConst,
              TRUE,
-             EFI_ACPI_TABLE_VERSION_1_0B | ACPI_TABLE_VERSION_GTE_2_0,
+             Version,
              TableKey
              );
   if (!EFI_ERROR (Status)) {
     Status = PublishTables (
                AcpiTableInstance,
-               EFI_ACPI_TABLE_VERSION_1_0B | ACPI_TABLE_VERSION_GTE_2_0
+               Version
                );
   }
   FreePool (AcpiTableBufferConst);
@@ -250,7 +261,7 @@ InstallAcpiTable (
     if (!EFI_ERROR (Status)) {
       SdtNotifyAcpiList (
         AcpiTableInstance,
-        EFI_ACPI_TABLE_VERSION_1_0B | ACPI_TABLE_VERSION_GTE_2_0,
+        Version,
         *TableKey
         );
     }
@@ -337,13 +348,16 @@ ReallocateAcpiTableBuffer (
   //
   // Create RSDT, XSDT structures and allocate buffers.
   //
-  TotalSize = sizeof (EFI_ACPI_DESCRIPTION_HEADER) +         // for ACPI 1.0 RSDT
-              NewMaxTableNumber * sizeof (UINT32) +
-              sizeof (EFI_ACPI_DESCRIPTION_HEADER) +         // for ACPI 2.0/3.0 RSDT
-              NewMaxTableNumber * sizeof (UINT32) +
-              sizeof (EFI_ACPI_DESCRIPTION_HEADER) +         // for ACPI 2.0/3.0 XSDT
+  TotalSize = sizeof (EFI_ACPI_DESCRIPTION_HEADER) +         // for ACPI 2.0/3.0 XSDT
               NewMaxTableNumber * sizeof (UINT64);
 
+  if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+    TotalSize += sizeof (EFI_ACPI_DESCRIPTION_HEADER) +      // for ACPI 1.0 RSDT
+                 NewMaxTableNumber * sizeof (UINT32) +
+                 sizeof (EFI_ACPI_DESCRIPTION_HEADER) +      // for ACPI 2.0/3.0 RSDT
+                 NewMaxTableNumber * sizeof (UINT32);
+  }
+
   //
   // Allocate memory in the lower 32 bit of address range for
   // compatibility with ACPI 1.0 OS.
@@ -355,7 +369,7 @@ ReallocateAcpiTableBuffer (
   //
   PageAddress = 0xFFFFFFFF;
   Status = gBS->AllocatePages (
-                  AllocateMaxAddress,
+                  mAcpiTableAllocType,
                   EfiACPIReclaimMemory,
                   EFI_SIZE_TO_PAGES (TotalSize),
                   &PageAddress
@@ -369,35 +383,45 @@ ReallocateAcpiTableBuffer (
   ZeroMem (Pointer, TotalSize);
   
   AcpiTableInstance->Rsdt1 = (EFI_ACPI_DESCRIPTION_HEADER *) Pointer;
-  Pointer += (sizeof (EFI_ACPI_DESCRIPTION_HEADER) + NewMaxTableNumber * sizeof (UINT32));
-  AcpiTableInstance->Rsdt3 = (EFI_ACPI_DESCRIPTION_HEADER *) Pointer;
-  Pointer += (sizeof (EFI_ACPI_DESCRIPTION_HEADER) + NewMaxTableNumber * sizeof (UINT32));
+  if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+    Pointer += (sizeof (EFI_ACPI_DESCRIPTION_HEADER) + NewMaxTableNumber * sizeof (UINT32));
+    AcpiTableInstance->Rsdt3 = (EFI_ACPI_DESCRIPTION_HEADER *) Pointer;
+    Pointer += (sizeof (EFI_ACPI_DESCRIPTION_HEADER) + NewMaxTableNumber * sizeof (UINT32));
+  }
   AcpiTableInstance->Xsdt = (EFI_ACPI_DESCRIPTION_HEADER *) Pointer;
 
   //
   // Update RSDP to point to the new Rsdt and Xsdt address.
   //
-  AcpiTableInstance->Rsdp1->RsdtAddress = (UINT32) (UINTN) AcpiTableInstance->Rsdt1;
-  AcpiTableInstance->Rsdp3->RsdtAddress = (UINT32) (UINTN) AcpiTableInstance->Rsdt3;
+  if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+    AcpiTableInstance->Rsdp1->RsdtAddress = (UINT32) (UINTN) AcpiTableInstance->Rsdt1;
+    AcpiTableInstance->Rsdp3->RsdtAddress = (UINT32) (UINTN) AcpiTableInstance->Rsdt3;
+  }
   CurrentData = (UINT64) (UINTN) AcpiTableInstance->Xsdt;
   CopyMem (&AcpiTableInstance->Rsdp3->XsdtAddress, &CurrentData, sizeof (UINT64));
 
   //
   // copy the original Rsdt1, Rsdt3 and Xsdt structure to new buffer 
   //
-  CopyMem (AcpiTableInstance->Rsdt1, TempPrivateData.Rsdt1, (sizeof (EFI_ACPI_DESCRIPTION_HEADER) + mEfiAcpiMaxNumTables * sizeof (UINT32))); 
-  CopyMem (AcpiTableInstance->Rsdt3, TempPrivateData.Rsdt3, (sizeof (EFI_ACPI_DESCRIPTION_HEADER) + mEfiAcpiMaxNumTables * sizeof (UINT32))); 
+  if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+    CopyMem (AcpiTableInstance->Rsdt1, TempPrivateData.Rsdt1, (sizeof (EFI_ACPI_DESCRIPTION_HEADER) + mEfiAcpiMaxNumTables * sizeof (UINT32))); 
+    CopyMem (AcpiTableInstance->Rsdt3, TempPrivateData.Rsdt3, (sizeof (EFI_ACPI_DESCRIPTION_HEADER) + mEfiAcpiMaxNumTables * sizeof (UINT32))); 
+  }
   CopyMem (AcpiTableInstance->Xsdt, TempPrivateData.Xsdt, (sizeof (EFI_ACPI_DESCRIPTION_HEADER) + mEfiAcpiMaxNumTables * sizeof (UINT64)));
   
   //
   // Calculate orignal ACPI table buffer size
   //
-  TotalSize = sizeof (EFI_ACPI_DESCRIPTION_HEADER) +         // for ACPI 1.0 RSDT
-              mEfiAcpiMaxNumTables * sizeof (UINT32) +
-              sizeof (EFI_ACPI_DESCRIPTION_HEADER) +         // for ACPI 2.0/3.0 RSDT
-              mEfiAcpiMaxNumTables * sizeof (UINT32) +
-              sizeof (EFI_ACPI_DESCRIPTION_HEADER) +         // for ACPI 2.0/3.0 XSDT
+  TotalSize = sizeof (EFI_ACPI_DESCRIPTION_HEADER) +         // for ACPI 2.0/3.0 XSDT
               mEfiAcpiMaxNumTables * sizeof (UINT64);
+
+  if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+    TotalSize += sizeof (EFI_ACPI_DESCRIPTION_HEADER) +         // for ACPI 1.0 RSDT
+                 mEfiAcpiMaxNumTables * sizeof (UINT32) +
+                 sizeof (EFI_ACPI_DESCRIPTION_HEADER) +         // for ACPI 2.0/3.0 RSDT
+                 mEfiAcpiMaxNumTables * sizeof (UINT32);
+  }
+
   gBS->FreePages ((EFI_PHYSICAL_ADDRESS)(UINTN)TempPrivateData.Rsdt1, EFI_SIZE_TO_PAGES (TotalSize));
   
   //
@@ -504,7 +528,7 @@ AddTableToList (
     // All other tables are ACPI reclaim memory, no alignment requirements.
     //
     Status = gBS->AllocatePages (
-                    AllocateMaxAddress,
+                    mAcpiTableAllocType,
                     EfiACPIReclaimMemory,
                     CurrentTableList->NumberOfPages,
                     &CurrentTableList->PageAddress
@@ -621,13 +645,18 @@ AddTableToList (
           );
         AcpiTableInstance->Fadt3->FirmwareCtrl = 0;
       }
-      AcpiTableInstance->Fadt3->Dsdt  = (UINT32) (UINTN) AcpiTableInstance->Dsdt3;
-      Buffer64                          = (UINT64) (UINTN) AcpiTableInstance->Dsdt3;
-      CopyMem (
-        &AcpiTableInstance->Fadt3->XDsdt,
-        &Buffer64,
-        sizeof (UINT64)
-        );
+      if ((UINT64)(UINTN)AcpiTableInstance->Dsdt3 < BASE_4GB) {
+        AcpiTableInstance->Fadt3->Dsdt  = (UINT32) (UINTN) AcpiTableInstance->Dsdt3;
+        ZeroMem (&AcpiTableInstance->Fadt3->XDsdt, sizeof (UINT64));
+      } else {
+        Buffer64                          = (UINT64) (UINTN) AcpiTableInstance->Dsdt3;
+        CopyMem (
+          &AcpiTableInstance->Fadt3->XDsdt,
+          &Buffer64,
+          sizeof (UINT64)
+          );
+        AcpiTableInstance->Fadt3->Dsdt = 0;
+      }
 
       //
       // RSDP OEM information is updated to match the FADT OEM information
@@ -638,21 +667,23 @@ AddTableToList (
         6
         );
       
-      //
-      // RSDT OEM information is updated to match FADT OEM information.
-      //
-      CopyMem (
-        &AcpiTableInstance->Rsdt3->OemId,
-        &AcpiTableInstance->Fadt3->Header.OemId,
-        6
-        );
-      CopyMem (
-        &AcpiTableInstance->Rsdt3->OemTableId,
-        &AcpiTableInstance->Fadt3->Header.OemTableId,
-        sizeof (UINT64)
-        );
-      AcpiTableInstance->Rsdt3->OemRevision = AcpiTableInstance->Fadt3->Header.OemRevision;
-      
+      if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+        //
+        // RSDT OEM information is updated to match FADT OEM information.
+        //
+        CopyMem (
+          &AcpiTableInstance->Rsdt3->OemId,
+          &AcpiTableInstance->Fadt3->Header.OemId,
+          6
+          );
+        CopyMem (
+          &AcpiTableInstance->Rsdt3->OemTableId,
+          &AcpiTableInstance->Fadt3->Header.OemTableId,
+          sizeof (UINT64)
+          );
+        AcpiTableInstance->Rsdt3->OemRevision = AcpiTableInstance->Fadt3->Header.OemRevision;
+      }
+
       //
       // XSDT OEM information is updated to match FADT OEM information.
       //
@@ -818,7 +849,9 @@ AddTableToList (
       // If FADT already exists, update table pointers.
       //
       if (AcpiTableInstance->Fadt3 != NULL) {
-        AcpiTableInstance->Fadt3->Dsdt  = (UINT32) (UINTN) AcpiTableInstance->Dsdt3;
+        if ((UINT64)(UINTN)AcpiTableInstance->Dsdt3 < BASE_4GB) {
+          AcpiTableInstance->Fadt3->Dsdt  = (UINT32) (UINTN) AcpiTableInstance->Dsdt3;
+        }
         Buffer64                          = (UINT64) (UINTN) AcpiTableInstance->Dsdt3;
         CopyMem (
           &AcpiTableInstance->Fadt3->XDsdt,
@@ -909,65 +942,70 @@ AddTableToList (
   // Add to ACPI 2.0/3.0  table tree
   //
   if ((Version & ACPI_TABLE_VERSION_GTE_2_0) != 0) {
-     if (AddToRsdt) {
-       //
-       // If the table number exceed the gEfiAcpiMaxNumTables, enlarge the table buffer
-       //
-       if (AcpiTableInstance->NumberOfTableEntries3 >= mEfiAcpiMaxNumTables) {
-         Status = ReallocateAcpiTableBuffer (AcpiTableInstance);
-         ASSERT_EFI_ERROR (Status);
-       }
-       //
-       // At this time, it is assumed that RSDT and XSDT maintain parallel lists of tables.
-       // If it becomes necessary to maintain separate table lists, changes will be required.
-       //
-       CurrentRsdtEntry = (UINT32 *)
+    if (AddToRsdt) {
+      //
+      // If the table number exceed the gEfiAcpiMaxNumTables, enlarge the table buffer
+      //
+      if (AcpiTableInstance->NumberOfTableEntries3 >= mEfiAcpiMaxNumTables) {
+        Status = ReallocateAcpiTableBuffer (AcpiTableInstance);
+        ASSERT_EFI_ERROR (Status);
+      }
+
+      if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+        //
+        // At this time, it is assumed that RSDT and XSDT maintain parallel lists of tables.
+        // If it becomes necessary to maintain separate table lists, changes will be required.
+        //
+        CurrentRsdtEntry = (UINT32 *)
          (
            (UINT8 *) AcpiTableInstance->Rsdt3 +
            sizeof (EFI_ACPI_DESCRIPTION_HEADER) +
            AcpiTableInstance->NumberOfTableEntries3 *
            sizeof (UINT32)
          );
+      }
 
-       //
-       // This pointer must not be directly dereferenced as the XSDT entries may not
-       // be 64 bit aligned resulting in a possible fault.  Use CopyMem to update.
-       //
-       CurrentXsdtEntry = (VOID *)
-         (
-           (UINT8 *) AcpiTableInstance->Xsdt +
-           sizeof (EFI_ACPI_DESCRIPTION_HEADER) +
-           AcpiTableInstance->NumberOfTableEntries3 *
-           sizeof (UINT64)
-         );
+      //
+      // This pointer must not be directly dereferenced as the XSDT entries may not
+      // be 64 bit aligned resulting in a possible fault.  Use CopyMem to update.
+      //
+      CurrentXsdtEntry = (VOID *)
+        (
+          (UINT8 *) AcpiTableInstance->Xsdt +
+          sizeof (EFI_ACPI_DESCRIPTION_HEADER) +
+          AcpiTableInstance->NumberOfTableEntries3 *
+          sizeof (UINT64)
+        );
 
-       //
-       // Add entry to the RSDT
-       //
-       *CurrentRsdtEntry = (UINT32) (UINTN) CurrentTableList->Table;
-
-       //
-       // Update RSDT length
-       //
-       AcpiTableInstance->Rsdt3->Length = AcpiTableInstance->Rsdt3->Length + sizeof (UINT32);
-
-       //
-       // Add entry to XSDT, XSDT expects 64 bit pointers, but
-       // the table pointers in XSDT are not aligned on 8 byte boundary.
-       //
-       Buffer64 = (UINT64) (UINTN) CurrentTableList->Table;
-       CopyMem (
-         CurrentXsdtEntry,
-         &Buffer64,
-         sizeof (UINT64)
-         );
+      if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+        //
+        // Add entry to the RSDT
+        //
+        *CurrentRsdtEntry = (UINT32) (UINTN) CurrentTableList->Table;
+
+        //
+        // Update RSDT length
+        //
+        AcpiTableInstance->Rsdt3->Length = AcpiTableInstance->Rsdt3->Length + sizeof (UINT32);
+      }
 
-       //
-       // Update length
-       //
-       AcpiTableInstance->Xsdt->Length = AcpiTableInstance->Xsdt->Length + sizeof (UINT64);
+      //
+      // Add entry to XSDT, XSDT expects 64 bit pointers, but
+      // the table pointers in XSDT are not aligned on 8 byte boundary.
+      //
+      Buffer64 = (UINT64) (UINTN) CurrentTableList->Table;
+      CopyMem (
+        CurrentXsdtEntry,
+        &Buffer64,
+        sizeof (UINT64)
+        );
 
-       AcpiTableInstance->NumberOfTableEntries3++;
+      //
+      // Update length
+      //
+      AcpiTableInstance->Xsdt->Length = AcpiTableInstance->Xsdt->Length + sizeof (UINT64);
+
+      AcpiTableInstance->NumberOfTableEntries3++;
     }
   }
 
@@ -1046,7 +1084,7 @@ EFI_STATUS
 RemoveTableFromRsdt (
   IN OUT EFI_ACPI_TABLE_LIST              * Table,
   IN OUT UINTN                            *NumberOfTableEntries,
-  IN OUT EFI_ACPI_DESCRIPTION_HEADER      * Rsdt,
+  IN OUT EFI_ACPI_DESCRIPTION_HEADER      * Rsdt OPTIONAL,
   IN OUT EFI_ACPI_DESCRIPTION_HEADER      * Xsdt OPTIONAL
   )
 {
@@ -1060,7 +1098,7 @@ RemoveTableFromRsdt (
   //
   ASSERT (Table);
   ASSERT (NumberOfTableEntries);
-  ASSERT (Rsdt);
+  ASSERT (Rsdt || Xsdt);
 
   //
   // Find the table entry in the RSDT and XSDT
@@ -1070,7 +1108,11 @@ RemoveTableFromRsdt (
     // At this time, it is assumed that RSDT and XSDT maintain parallel lists of tables.
     // If it becomes necessary to maintain separate table lists, changes will be required.
     //
-    CurrentRsdtEntry = (UINT32 *) ((UINT8 *) Rsdt + sizeof (EFI_ACPI_DESCRIPTION_HEADER) + Index * sizeof (UINT32));
+    if (Rsdt != NULL) {
+      CurrentRsdtEntry = (UINT32 *) ((UINT8 *) Rsdt + sizeof (EFI_ACPI_DESCRIPTION_HEADER) + Index * sizeof (UINT32));
+    } else {
+      CurrentRsdtEntry = NULL;
+    }
     if (Xsdt != NULL) {
       //
       // This pointer must not be directly dereferenced as the XSDT entries may not
@@ -1092,7 +1134,7 @@ RemoveTableFromRsdt (
     //
     // Check if we have found the corresponding entry in both RSDT and XSDT
     //
-    if (*CurrentRsdtEntry == (UINT32) (UINTN) Table->Table &&
+    if ((CurrentRsdtEntry == NULL || *CurrentRsdtEntry == (UINT32) (UINTN) Table->Table) &&
         ((Xsdt == NULL) || CurrentTablePointer64 == (UINT64) (UINTN) Table->Table)
         ) {
       //
@@ -1100,8 +1142,10 @@ RemoveTableFromRsdt (
       // We actually copy all + 1 to copy the initialized value of memory over
       // the last entry.
       //
-      CopyMem (CurrentRsdtEntry, CurrentRsdtEntry + 1, (*NumberOfTableEntries - Index) * sizeof (UINT32));
-      Rsdt->Length = Rsdt->Length - sizeof (UINT32);
+      if (Rsdt != NULL) {
+        CopyMem (CurrentRsdtEntry, CurrentRsdtEntry + 1, (*NumberOfTableEntries - Index) * sizeof (UINT32));
+        Rsdt->Length = Rsdt->Length - sizeof (UINT32);
+      }
       if (Xsdt != NULL) {
         CopyMem (CurrentXsdtEntry, ((UINT64 *) CurrentXsdtEntry) + 1, (*NumberOfTableEntries - Index) * sizeof (UINT64));
         Xsdt->Length = Xsdt->Length - sizeof (UINT64);
@@ -1117,12 +1161,14 @@ RemoveTableFromRsdt (
   //
   // Checksum the tables
   //
-  AcpiPlatformChecksum (
-    Rsdt,
-    Rsdt->Length,
-    OFFSET_OF (EFI_ACPI_DESCRIPTION_HEADER,
-    Checksum)
-    );
+  if (Rsdt != NULL) {
+    AcpiPlatformChecksum (
+      Rsdt,
+      Rsdt->Length,
+      OFFSET_OF (EFI_ACPI_DESCRIPTION_HEADER,
+      Checksum)
+      );
+  }
 
   if (Xsdt != NULL) {
     AcpiPlatformChecksum (
@@ -1508,12 +1554,14 @@ ChecksumCommonTables (
   //
   // RSDP ACPI 1.0 checksum for 1.0 table.  This is only the first 20 bytes of the structure
   //
-  AcpiPlatformChecksum (
-    AcpiTableInstance->Rsdp1,
-    sizeof (EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER),
-    OFFSET_OF (EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER,
-    Checksum)
-    );
+  if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+    AcpiPlatformChecksum (
+      AcpiTableInstance->Rsdp1,
+      sizeof (EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER),
+      OFFSET_OF (EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER,
+      Checksum)
+      );
+  }
 
   //
   // RSDP ACPI 1.0 checksum for 2.0/3.0 table.  This is only the first 20 bytes of the structure
@@ -1535,22 +1583,24 @@ ChecksumCommonTables (
     ExtendedChecksum)
     );
 
-  //
-  // RSDT checksums
-  //
-  AcpiPlatformChecksum (
-    AcpiTableInstance->Rsdt1,
-    AcpiTableInstance->Rsdt1->Length,
-    OFFSET_OF (EFI_ACPI_DESCRIPTION_HEADER,
-    Checksum)
-    );
+  if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+    //
+    // RSDT checksums
+    //
+    AcpiPlatformChecksum (
+      AcpiTableInstance->Rsdt1,
+      AcpiTableInstance->Rsdt1->Length,
+      OFFSET_OF (EFI_ACPI_DESCRIPTION_HEADER,
+      Checksum)
+      );
 
-  AcpiPlatformChecksum (
-    AcpiTableInstance->Rsdt3,
-    AcpiTableInstance->Rsdt3->Length,
-    OFFSET_OF (EFI_ACPI_DESCRIPTION_HEADER,
-    Checksum)
-    );
+    AcpiPlatformChecksum (
+      AcpiTableInstance->Rsdt3,
+      AcpiTableInstance->Rsdt3->Length,
+      OFFSET_OF (EFI_ACPI_DESCRIPTION_HEADER,
+      Checksum)
+      );
+  }
 
   //
   // XSDT checksum
@@ -1593,6 +1643,16 @@ AcpiTableAcpiTableConstructor (
   //
   ASSERT (AcpiTableInstance);
 
+  //
+  // If ACPI v1.0b is among the ACPI versions we aim to support, we have to
+  // ensure that all memory allocations are below 4 GB.
+  //
+  if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+    mAcpiTableAllocType = AllocateMaxAddress;
+  } else {
+    mAcpiTableAllocType = AllocateAnyPages;
+  }
+
   InitializeListHead (&AcpiTableInstance->TableList);
   AcpiTableInstance->CurrentHandle              = 1;
 
@@ -1606,12 +1666,14 @@ AcpiTableAcpiTableConstructor (
   //
   // Create RSDP table
   //
-  RsdpTableSize = sizeof (EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER) +
-                  sizeof (EFI_ACPI_3_0_ROOT_SYSTEM_DESCRIPTION_POINTER);
+  RsdpTableSize = sizeof (EFI_ACPI_3_0_ROOT_SYSTEM_DESCRIPTION_POINTER);
+  if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+    RsdpTableSize += sizeof (EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER);
+  }
 
   PageAddress = 0xFFFFFFFF;
   Status = gBS->AllocatePages (
-                  AllocateMaxAddress,
+                  mAcpiTableAllocType,
                   EfiACPIReclaimMemory,
                   EFI_SIZE_TO_PAGES (RsdpTableSize),
                   &PageAddress
@@ -1625,19 +1687,24 @@ AcpiTableAcpiTableConstructor (
   ZeroMem (Pointer, RsdpTableSize);
 
   AcpiTableInstance->Rsdp1 = (EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER *) Pointer;
-  Pointer += sizeof (EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER);
+  if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+    Pointer += sizeof (EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER);
+  }
   AcpiTableInstance->Rsdp3 = (EFI_ACPI_3_0_ROOT_SYSTEM_DESCRIPTION_POINTER *) Pointer;
 
   //
   // Create RSDT, XSDT structures
   //
-  TotalSize = sizeof (EFI_ACPI_DESCRIPTION_HEADER) +         // for ACPI 1.0 RSDT
-              mEfiAcpiMaxNumTables * sizeof (UINT32) +
-              sizeof (EFI_ACPI_DESCRIPTION_HEADER) +         // for ACPI 2.0/3.0 RSDT
-              mEfiAcpiMaxNumTables * sizeof (UINT32) +
-              sizeof (EFI_ACPI_DESCRIPTION_HEADER) +         // for ACPI 2.0/3.0 XSDT
+  TotalSize = sizeof (EFI_ACPI_DESCRIPTION_HEADER) +         // for ACPI 2.0/3.0 XSDT
               mEfiAcpiMaxNumTables * sizeof (UINT64);
 
+  if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+    TotalSize += sizeof (EFI_ACPI_DESCRIPTION_HEADER) +      // for ACPI 1.0 RSDT
+                 mEfiAcpiMaxNumTables * sizeof (UINT32) +
+                 sizeof (EFI_ACPI_DESCRIPTION_HEADER) +      // for ACPI 2.0/3.0 RSDT
+                 mEfiAcpiMaxNumTables * sizeof (UINT32);
+  }
+
   //
   // Allocate memory in the lower 32 bit of address range for
   // compatibility with ACPI 1.0 OS.
@@ -1649,7 +1716,7 @@ AcpiTableAcpiTableConstructor (
   //
   PageAddress = 0xFFFFFFFF;
   Status = gBS->AllocatePages (
-                  AllocateMaxAddress,
+                  mAcpiTableAllocType,
                   EfiACPIReclaimMemory,
                   EFI_SIZE_TO_PAGES (TotalSize),
                   &PageAddress
@@ -1664,66 +1731,74 @@ AcpiTableAcpiTableConstructor (
   ZeroMem (Pointer, TotalSize);
 
   AcpiTableInstance->Rsdt1 = (EFI_ACPI_DESCRIPTION_HEADER *) Pointer;
-  Pointer += (sizeof (EFI_ACPI_DESCRIPTION_HEADER) + EFI_ACPI_MAX_NUM_TABLES * sizeof (UINT32));
-  AcpiTableInstance->Rsdt3 = (EFI_ACPI_DESCRIPTION_HEADER *) Pointer;
-  Pointer += (sizeof (EFI_ACPI_DESCRIPTION_HEADER) + EFI_ACPI_MAX_NUM_TABLES * sizeof (UINT32));
+  if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+    Pointer += (sizeof (EFI_ACPI_DESCRIPTION_HEADER) + EFI_ACPI_MAX_NUM_TABLES * sizeof (UINT32));
+    AcpiTableInstance->Rsdt3 = (EFI_ACPI_DESCRIPTION_HEADER *) Pointer;
+    Pointer += (sizeof (EFI_ACPI_DESCRIPTION_HEADER) + EFI_ACPI_MAX_NUM_TABLES * sizeof (UINT32));
+  }
   AcpiTableInstance->Xsdt = (EFI_ACPI_DESCRIPTION_HEADER *) Pointer;
 
   //
   // Initialize RSDP
   //
-  CurrentData = EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER_SIGNATURE;
-  CopyMem (&AcpiTableInstance->Rsdp1->Signature, &CurrentData, sizeof (UINT64));
-  CopyMem (AcpiTableInstance->Rsdp1->OemId, PcdGetPtr (PcdAcpiDefaultOemId), sizeof (AcpiTableInstance->Rsdp1->OemId));
-  AcpiTableInstance->Rsdp1->Reserved    = EFI_ACPI_RESERVED_BYTE;
-  AcpiTableInstance->Rsdp1->RsdtAddress = (UINT32) (UINTN) AcpiTableInstance->Rsdt1;
+  if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+    CurrentData = EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_POINTER_SIGNATURE;
+    CopyMem (&AcpiTableInstance->Rsdp1->Signature, &CurrentData, sizeof (UINT64));
+    CopyMem (AcpiTableInstance->Rsdp1->OemId, PcdGetPtr (PcdAcpiDefaultOemId), sizeof (AcpiTableInstance->Rsdp1->OemId));
+    AcpiTableInstance->Rsdp1->Reserved    = EFI_ACPI_RESERVED_BYTE;
+    AcpiTableInstance->Rsdp1->RsdtAddress = (UINT32) (UINTN) AcpiTableInstance->Rsdt1;
+  }
 
   CurrentData = EFI_ACPI_3_0_ROOT_SYSTEM_DESCRIPTION_POINTER_SIGNATURE;
   CopyMem (&AcpiTableInstance->Rsdp3->Signature, &CurrentData, sizeof (UINT64));
   CopyMem (AcpiTableInstance->Rsdp3->OemId, PcdGetPtr (PcdAcpiDefaultOemId), sizeof (AcpiTableInstance->Rsdp3->OemId));
   AcpiTableInstance->Rsdp3->Revision    = EFI_ACPI_3_0_ROOT_SYSTEM_DESCRIPTION_POINTER_REVISION;
-  AcpiTableInstance->Rsdp3->RsdtAddress = (UINT32) (UINTN) AcpiTableInstance->Rsdt3;
   AcpiTableInstance->Rsdp3->Length      = sizeof (EFI_ACPI_3_0_ROOT_SYSTEM_DESCRIPTION_POINTER);
+  if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+    AcpiTableInstance->Rsdp3->RsdtAddress = (UINT32) (UINTN) AcpiTableInstance->Rsdt3;
+  }
   CurrentData = (UINT64) (UINTN) AcpiTableInstance->Xsdt;
   CopyMem (&AcpiTableInstance->Rsdp3->XsdtAddress, &CurrentData, sizeof (UINT64));
   SetMem (AcpiTableInstance->Rsdp3->Reserved, 3, EFI_ACPI_RESERVED_BYTE);
 
-  //
-  // Initialize Rsdt
-  //
-  // Note that we "reserve" one entry for the FADT so it can always be
-  // at the beginning of the list of tables.  Some OS don't seem
-  // to find it correctly if it is too far down the list.
-  //
-  AcpiTableInstance->Rsdt1->Signature = EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_TABLE_SIGNATURE;
-  AcpiTableInstance->Rsdt1->Length    = sizeof (EFI_ACPI_DESCRIPTION_HEADER);
-  AcpiTableInstance->Rsdt1->Revision  = EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_TABLE_REVISION;
-  CopyMem (AcpiTableInstance->Rsdt1->OemId, PcdGetPtr (PcdAcpiDefaultOemId), sizeof (AcpiTableInstance->Rsdt1->OemId));
-  CurrentData = PcdGet64 (PcdAcpiDefaultOemTableId);
-  CopyMem (&AcpiTableInstance->Rsdt1->OemTableId, &CurrentData, sizeof (UINT64));
-  AcpiTableInstance->Rsdt1->OemRevision     = PcdGet32 (PcdAcpiDefaultOemRevision);
-  AcpiTableInstance->Rsdt1->CreatorId       = PcdGet32 (PcdAcpiDefaultCreatorId);
-  AcpiTableInstance->Rsdt1->CreatorRevision = PcdGet32 (PcdAcpiDefaultCreatorRevision);
-  //
-  // We always reserve first one for FADT
-  //
-  AcpiTableInstance->NumberOfTableEntries1  = 1;
-  AcpiTableInstance->Rsdt1->Length          = AcpiTableInstance->Rsdt1->Length + sizeof(UINT32);
-
-  AcpiTableInstance->Rsdt3->Signature       = EFI_ACPI_3_0_ROOT_SYSTEM_DESCRIPTION_TABLE_SIGNATURE;
-  AcpiTableInstance->Rsdt3->Length          = sizeof (EFI_ACPI_DESCRIPTION_HEADER);
-  AcpiTableInstance->Rsdt3->Revision        = EFI_ACPI_3_0_ROOT_SYSTEM_DESCRIPTION_TABLE_REVISION;
-  CopyMem (AcpiTableInstance->Rsdt3->OemId, PcdGetPtr (PcdAcpiDefaultOemId), sizeof (AcpiTableInstance->Rsdt3->OemId));
-  CurrentData = PcdGet64 (PcdAcpiDefaultOemTableId);
-  CopyMem (&AcpiTableInstance->Rsdt3->OemTableId, &CurrentData, sizeof (UINT64));
-  AcpiTableInstance->Rsdt3->OemRevision     = PcdGet32 (PcdAcpiDefaultOemRevision);
-  AcpiTableInstance->Rsdt3->CreatorId       = PcdGet32 (PcdAcpiDefaultCreatorId);
-  AcpiTableInstance->Rsdt3->CreatorRevision = PcdGet32 (PcdAcpiDefaultCreatorRevision);
-  //
-  // We always reserve first one for FADT
-  //
+  if ((PcdGet32 (PcdAcpiExposedTableVersions) & EFI_ACPI_TABLE_VERSION_1_0B) != 0) {
+    //
+    // Initialize Rsdt
+    //
+    // Note that we "reserve" one entry for the FADT so it can always be
+    // at the beginning of the list of tables.  Some OS don't seem
+    // to find it correctly if it is too far down the list.
+    //
+    AcpiTableInstance->Rsdt1->Signature = EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_TABLE_SIGNATURE;
+    AcpiTableInstance->Rsdt1->Length    = sizeof (EFI_ACPI_DESCRIPTION_HEADER);
+    AcpiTableInstance->Rsdt1->Revision  = EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_TABLE_REVISION;
+    CopyMem (AcpiTableInstance->Rsdt1->OemId, PcdGetPtr (PcdAcpiDefaultOemId), sizeof (AcpiTableInstance->Rsdt1->OemId));
+    CurrentData = PcdGet64 (PcdAcpiDefaultOemTableId);
+    CopyMem (&AcpiTableInstance->Rsdt1->OemTableId, &CurrentData, sizeof (UINT64));
+    AcpiTableInstance->Rsdt1->OemRevision     = PcdGet32 (PcdAcpiDefaultOemRevision);
+    AcpiTableInstance->Rsdt1->CreatorId       = PcdGet32 (PcdAcpiDefaultCreatorId);
+    AcpiTableInstance->Rsdt1->CreatorRevision = PcdGet32 (PcdAcpiDefaultCreatorRevision);
+    //
+    // We always reserve first one for FADT
+    //
+    AcpiTableInstance->NumberOfTableEntries1  = 1;
+    AcpiTableInstance->Rsdt1->Length          = AcpiTableInstance->Rsdt1->Length + sizeof(UINT32);
+
+    AcpiTableInstance->Rsdt3->Signature       = EFI_ACPI_3_0_ROOT_SYSTEM_DESCRIPTION_TABLE_SIGNATURE;
+    AcpiTableInstance->Rsdt3->Length          = sizeof (EFI_ACPI_DESCRIPTION_HEADER);
+    AcpiTableInstance->Rsdt3->Revision        = EFI_ACPI_3_0_ROOT_SYSTEM_DESCRIPTION_TABLE_REVISION;
+    CopyMem (AcpiTableInstance->Rsdt3->OemId, PcdGetPtr (PcdAcpiDefaultOemId), sizeof (AcpiTableInstance->Rsdt3->OemId));
+    CurrentData = PcdGet64 (PcdAcpiDefaultOemTableId);
+    CopyMem (&AcpiTableInstance->Rsdt3->OemTableId, &CurrentData, sizeof (UINT64));
+    AcpiTableInstance->Rsdt3->OemRevision     = PcdGet32 (PcdAcpiDefaultOemRevision);
+    AcpiTableInstance->Rsdt3->CreatorId       = PcdGet32 (PcdAcpiDefaultCreatorId);
+    AcpiTableInstance->Rsdt3->CreatorRevision = PcdGet32 (PcdAcpiDefaultCreatorRevision);
+    //
+    // We always reserve first one for FADT
+    //
+    AcpiTableInstance->Rsdt3->Length          = AcpiTableInstance->Rsdt3->Length + sizeof(UINT32);
+  }
   AcpiTableInstance->NumberOfTableEntries3  = 1;
-  AcpiTableInstance->Rsdt3->Length          = AcpiTableInstance->Rsdt3->Length + sizeof(UINT32);
 
   //
   // Initialize Xsdt
