• Set the default value of PcdDxeIplSwitchToLongMode to TRUE.

•	Make access to PcdDxeIplSwitchToLongMode to Ia32 specific code.
•	Introduce another feature flag named PcdDxeIplBuildShareCodeHobs to define whether to build hobs to DXE core to share code.
•	Remove the #progma bug 

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@2026 6f19259b-4bc3-4df7-8a09-765794883524

EdkModulePkg/Core/DxeIplPeim/DxeIpl.h

@@ -27,38 +27,6 @@ Abstract:
 
 extern BOOLEAN gInMemory;
 
-/**
-  Transfers control to a function starting with a new stack.
-
-  Transfers control to the function specified by EntryPoint using the new stack
-  specified by NewStack and passing in the parameters specified by Context1 and
-  Context2. Context1 and Context2 are optional and may be NULL. The function
-  EntryPoint must never return.
-
-  If EntryPoint is NULL, then ASSERT().
-  If NewStack is NULL, then ASSERT().
-
-  @param  EntryPoint  A pointer to function to call with the new stack.
-  @param  Context1    A pointer to the context to pass into the EntryPoint
-                      function.
-  @param  Context2    A pointer to the context to pass into the EntryPoint
-                      function.
-  @param  NewStack    A pointer to the new stack to use for the EntryPoint
-                      function.
-  @param  NewBsp      A pointer to the new BSP for the EntryPoint on IPF. It's
-                      Reserved on other architectures.
-
-**/
-VOID
-EFIAPI
-SwitchIplStacks (
-  IN      SWITCH_STACK_ENTRY_POINT  EntryPoint,
-  IN      VOID                      *Context1,  OPTIONAL
-  IN      VOID                      *Context2,  OPTIONAL
-  IN      VOID                      *NewStack,
-  IN      VOID                      *NewBsp
-  );
-
 EFI_STATUS
 PeiFindFile (
   IN  UINT8                  Type,
@@ -79,12 +47,6 @@ PeiLoadFile (
 ;
 
 
-EFI_STATUS
-CreateArchSpecificHobs (
-  OUT EFI_PHYSICAL_ADDRESS                      *BspStore
-  )
-;
-
 EFI_STATUS
 GetImageReadFunction (
   IN      PE_COFF_LOADER_IMAGE_CONTEXT  *ImageContext
@@ -124,6 +86,12 @@ DxeLoadCore (
   IN EFI_PEI_HOB_POINTERS  HobList
   );
 
+VOID
+HandOffToDxeCore (
+  IN EFI_PHYSICAL_ADDRESS   DxeCoreEntryPoint,
+  IN EFI_PEI_HOB_POINTERS   HobList
+  );
+
 EFI_STATUS
 PeiProcessFile (
   IN      UINT16                 SectionType,
@@ -139,17 +107,6 @@ PeimInitializeDxeIpl (
   IN EFI_PEI_SERVICES          **PeiServices
   );
 
-EFI_STATUS
-PeiLoadx64File (
-  IN  EFI_PEI_PE_COFF_LOADER_PROTOCOL           *PeiEfiPeiPeCoffLoader,
-  IN  VOID                                      *Pe32Data,
-  IN  EFI_MEMORY_TYPE                           MemoryType,
-  OUT EFI_PHYSICAL_ADDRESS                      *ImageAddress,
-  OUT UINT64                                    *ImageSize,
-  OUT EFI_PHYSICAL_ADDRESS                      *EntryPoint
-  )
-;
-
 EFI_PHYSICAL_ADDRESS
 CreateIdentityMappingPageTables (
   IN UINT32                NumberOfProcessorPhysicalAddressBits

EdkModulePkg/Core/DxeIplPeim/DxeIpl.msa

@@ -75,19 +75,15 @@
     <Filename>DxeLoad.c</Filename>
     <Filename>DxeIpl.h</Filename>
     <Filename>DxeIpl.dxs</Filename>
-    <Filename SupArchList="IA32">Ia32/ImageRead.c</Filename>
+    <Filename SupArchList="IA32 X64 EBC">Ia32/ImageRead.c</Filename>
     <Filename SupArchList="IA32">Ia32/DxeLoadFunc.c</Filename>
     <Filename SupArchList="IA32">Ia32/LongMode.asm</Filename>
     <Filename ToolChainFamily="GCC" SupArchList="IA32">Ia32/LongMode.S</Filename>
     <Filename SupArchList="IA32">Ia32/VirtualMemory.c</Filename>
     <Filename SupArchList="IA32">Ia32/VirtualMemory.h</Filename>
-    <Filename SupArchList="X64">Ia32/ImageRead.c</Filename>
+    <Filename SupArchList="X64 EBC">X64/DxeLoadFunc.c</Filename>
-    <Filename SupArchList="X64">Ia32/DxeLoadFunc.c</Filename>
     <Filename SupArchList="IPF">ipf/ImageRead.c</Filename>
     <Filename SupArchList="IPF">ipf/DxeLoadFunc.c</Filename>
-    <Filename SupArchList="EBC">Ia32/ImageRead.c</Filename>
-    <Filename SupArchList="EBC">Ia32/DxeLoadFunc.c</Filename>
-    <Filename SupArchList="X64 IPF EBC">Non-existing.c</Filename>
   </SourceFiles>
   <PackageDependencies>
     <Package PackageGuid="5e0e9358-46b6-4ae2-8218-4ab8b9bbdcec"/>
@@ -143,9 +139,15 @@
     <PcdEntry PcdItemType="FEATURE_FLAG" Usage="ALWAYS_CONSUMED">
       <C_Name>PcdDxeIplSwitchToLongMode</C_Name>
       <TokenSpaceGuidCName>gEfiEdkModulePkgTokenSpaceGuid</TokenSpaceGuidCName>
-      <DefaultValue>FALSE</DefaultValue>
+      <DefaultValue>TRUE</DefaultValue>
       <HelpText>If this feature is enabled, then the DXE IPL will load a 64-bit DxeCore.</HelpText>
     </PcdEntry>
+    <PcdEntry PcdItemType="FEATURE_FLAG" Usage="ALWAYS_CONSUMED">
+      <C_Name>PcdDxeIplBuildShareCodeHobs</C_Name>
+      <TokenSpaceGuidCName>gEfiEdkModulePkgTokenSpaceGuid</TokenSpaceGuidCName>
+      <DefaultValue>TRUE</DefaultValue>
+      <HelpText>If this feature is enabled, DXE IPL will build a series of HOBs to share code with DXE Core.</HelpText>
+    </PcdEntry>
     <PcdEntry PcdItemType="FEATURE_FLAG" Usage="ALWAYS_CONSUMED">
       <C_Name>PcdDxeIplSupportEfiDecompress</C_Name>
       <TokenSpaceGuidCName>gEfiEdkModulePkgTokenSpaceGuid</TokenSpaceGuidCName>

EdkModulePkg/Core/DxeIplPeim/DxeLoad.c

@@ -22,10 +22,6 @@ Abstract:
 
 #include "DxeIpl.h"
 
-#ifndef __GNUC__
-#pragma warning( disable : 4305 )
-#endif
-
 BOOLEAN gInMemory = FALSE;
 
 //
@@ -151,9 +147,6 @@ Returns:
 --*/
 {
   EFI_STATUS                                Status;
-  EFI_PHYSICAL_ADDRESS                      TopOfStack;
-  EFI_PHYSICAL_ADDRESS                      BaseOfStack;
-  EFI_PHYSICAL_ADDRESS                      BspStore;
   EFI_GUID                                  DxeCoreFileName;
   EFI_GUID                                  FirmwareFileName;
   VOID                                      *Pe32Data;
@@ -165,13 +158,8 @@ Returns:
   EFI_BOOT_MODE                             BootMode;
   EFI_PEI_RECOVERY_MODULE_PPI               *PeiRecovery;
   EFI_PEI_S3_RESUME_PPI                     *S3Resume;
-  EFI_PHYSICAL_ADDRESS                      PageTables;
 
 //  PERF_START (PeiServices, L"DxeIpl", NULL, 0);
-  TopOfStack  = 0;
-  BaseOfStack = 0;
-  BspStore    = 0;
-  PageTables  = 0;
 
   //
   // if in S3 Resume, restore configure
@@ -217,17 +205,6 @@ Returns:
   PeiEfiPeiPeCoffLoader = (EFI_PEI_PE_COFF_LOADER_PROTOCOL *)GetPeCoffLoaderProtocol ();
   ASSERT (PeiEfiPeiPeCoffLoader != NULL);
 
-  //
-  // Allocate 128KB for the Stack
-  //
-  PeiServicesAllocatePages (EfiBootServicesData, EFI_SIZE_TO_PAGES (STACK_SIZE), &BaseOfStack);
-  ASSERT (BaseOfStack != 0);
-
-  //
-  // Add architecture-specifc HOBs (including the BspStore HOB)
-  //
-  Status = CreateArchSpecificHobs (&BspStore);
-  ASSERT_EFI_ERROR (Status);
 
   //
   // Find the EFI_FV_FILETYPE_FIRMWARE_VOLUME_IMAGE type compressed Firmware Volume file
@@ -290,70 +267,37 @@ Returns:
     EFI_SOFTWARE_PEI_MODULE | EFI_SW_PEI_CORE_PC_HANDOFF_TO_NEXT
     );
 
-  DEBUG ((EFI_D_INFO, "DXE Core Entry\n"));
+  if (FeaturePcdGet (PcdDxeIplBuildShareCodeHobs)) {
-  if (FeaturePcdGet(PcdDxeIplSwitchToLongMode)) {
+    if (FeaturePcdGet (PcdDxeIplSupportEfiDecompress)) {
-    //
+      //
-    // Compute the top of the stack we were allocated, which is used to load X64 dxe core. 
+      // Add HOB for the EFI Decompress Protocol
-    // Pre-allocate a 32 bytes which confroms to x64 calling convention.
+      //
-    //
+      BuildGuidDataHob (
-    // The first four parameters to a function are passed in rcx, rdx, r8 and r9. 
+        &gEfiDecompressProtocolGuid,
-    // Any further parameters are pushed on the stack. Furthermore, space (4 * 8bytes) for the 
+        (VOID *)&gEfiDecompress,
-    // register parameters is reserved on the stack, in case the called function 
+        sizeof (gEfiDecompress)
-    // wants to spill them; this is important if the function is variadic. 
+        );
-    //
+    }
-    TopOfStack = BaseOfStack + EFI_SIZE_TO_PAGES (STACK_SIZE) * EFI_PAGE_SIZE - 32;
+    if (FeaturePcdGet (PcdDxeIplSupportTianoDecompress)) {
-
+      //
-    //
+      // Add HOB for the Tiano Decompress Protocol
-    //  X64 Calling Conventions requires that the stack must be aligned to 16 bytes
+      //
-    //
+      BuildGuidDataHob (
-    TopOfStack = (EFI_PHYSICAL_ADDRESS) (UINTN) ALIGN_POINTER (TopOfStack, 16);
+        &gEfiTianoDecompressProtocolGuid,
-    //
+        (VOID *)&gTianoDecompress,
-    // Load the GDT of Go64. Since the GDT of 32-bit Tiano locates in the BS_DATA
+        sizeof (gTianoDecompress)
-    // memory, it may be corrupted when copying FV to high-end memory 
+        );
-    //
+    }
-    LoadGo64Gdt();
+    if (FeaturePcdGet (PcdDxeIplSupportCustomDecompress)) {
-    //
+      //
-    // Limit to 36 bits of addressing for debug. Should get it from CPU
+      // Add HOB for the user customized Decompress Protocol
-    //
+      //
-    PageTables = CreateIdentityMappingPageTables (36);
+      BuildGuidDataHob (
-    //
+        &gEfiCustomizedDecompressProtocolGuid,
-    // Go to Long Mode. Interrupts will not get turned on until the CPU AP is loaded.
+        (VOID *)&gCustomDecompress,
-    // Call x64 drivers passing in single argument, a pointer to the HOBs.
+        sizeof (gCustomDecompress)
-    //
+        );
-    ActivateLongMode (
+    }
-      PageTables, 
-      (EFI_PHYSICAL_ADDRESS)(UINTN)(HobList.Raw), 
-      TopOfStack,
-      0x00000000,
-      DxeCoreEntryPoint
-      );
-  } else {
-    //
-    // Add HOB for the EFI Decompress Protocol
-    //
-    BuildGuidDataHob (
-      &gEfiDecompressProtocolGuid,
-      (VOID *)&gEfiDecompress,
-      sizeof (gEfiDecompress)
-      );
-
-    //
-    // Add HOB for the Tiano Decompress Protocol
-    //
-    BuildGuidDataHob (
-      &gEfiTianoDecompressProtocolGuid,
-      (VOID *)&gTianoDecompress,
-      sizeof (gTianoDecompress)
-      );
-
-    //
-    // Add HOB for the user customized Decompress Protocol
-    //
-    BuildGuidDataHob (
-      &gEfiCustomizedDecompressProtocolGuid,
-      (VOID *)&gCustomDecompress,
-      sizeof (gCustomDecompress)
-      );
 
     //
     // Add HOB for the PE/COFF Loader Protocol
@@ -363,21 +307,10 @@ Returns:
       (VOID *)&PeiEfiPeiPeCoffLoader,
       sizeof (VOID *)
       );
-    //
-    // Compute the top of the stack we were allocated. Pre-allocate a UINTN
-    // for safety.
-    //
-    TopOfStack = BaseOfStack + EFI_SIZE_TO_PAGES (STACK_SIZE) * EFI_PAGE_SIZE - CPU_STACK_ALIGNMENT;
-    TopOfStack = (EFI_PHYSICAL_ADDRESS) (UINTN) ALIGN_POINTER (TopOfStack, CPU_STACK_ALIGNMENT);
-
-    SwitchIplStacks (
-      (SWITCH_STACK_ENTRY_POINT)(UINTN)DxeCoreEntryPoint,
-      HobList.Raw,
-      NULL,
-      (VOID *) (UINTN) TopOfStack,
-      (VOID *) (UINTN) BspStore
-      );
   }
+
+  DEBUG ((EFI_D_INFO, "DXE Core Entry\n"));
+  HandOffToDxeCore (DxeCoreEntryPoint, HobList);
   //
   // If we get here, then the DXE Core returned.  This is an error
   // Dxe Core should not return.

EdkModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c

@@ -21,66 +21,69 @@ Abstract:
 
 #include "DxeIpl.h"
 
-EFI_STATUS
-CreateArchSpecificHobs (
-  OUT EFI_PHYSICAL_ADDRESS      *BspStore
-  )
-/*++
-
-Routine Description:
-
-  Creates architecture-specific HOBs.
-
-  Note: New parameters should NOT be added for any HOBs that are added to this
-        function.  BspStore is a special case because it is required for the
-        call to SwitchStacks() in DxeLoad().
-
-Arguments:
-
-  BspStore    - The address of the BSP Store for those architectures that need
-                it.  Otherwise 0.
-
-Returns:
-
-  EFI_SUCCESS   - The HOBs were created successfully.
-
---*/
-{
-  *BspStore = 0;
-  return EFI_SUCCESS;
-}
-
-/**
-  Transfers control to a function starting with a new stack.
-
-  Transfers control to the function specified by EntryPoint using the new stack
-  specified by NewStack and passing in the parameters specified by Context1 and
-  Context2. Context1 and Context2 are optional and may be NULL. The function
-  EntryPoint must never return.
-
-  If EntryPoint is NULL, then ASSERT().
-  If NewStack is NULL, then ASSERT().
-
-  @param  EntryPoint  A pointer to function to call with the new stack.
-  @param  Context1    A pointer to the context to pass into the EntryPoint
-                      function.
-  @param  Context2    A pointer to the context to pass into the EntryPoint
-                      function.
-  @param  NewStack    A pointer to the new stack to use for the EntryPoint
-                      function.
-  @param  NewBsp      A pointer to the new BSP for the EntryPoint on IPF. It's
-                      Reserved on other architectures.
-
-**/
 VOID
-EFIAPI
+HandOffToDxeCore (
-SwitchIplStacks (
+  IN EFI_PHYSICAL_ADDRESS   DxeCoreEntryPoint,
-  IN      SWITCH_STACK_ENTRY_POINT  EntryPoint,
+  IN EFI_PEI_HOB_POINTERS   HobList
-  IN      VOID                      *Context1,  OPTIONAL
-  IN      VOID                      *Context2,  OPTIONAL
-  IN      VOID                      *NewStack,
-  IN      VOID                      *NewBsp
   )
 {
-  SwitchStack (EntryPoint, Context1, Context2, NewStack);
+  EFI_STATUS                Status;
+  EFI_PHYSICAL_ADDRESS      BaseOfStack;
+  EFI_PHYSICAL_ADDRESS      TopOfStack;
+  EFI_PHYSICAL_ADDRESS      PageTables;
+
+  Status = PeiServicesAllocatePages (EfiBootServicesData, EFI_SIZE_TO_PAGES (STACK_SIZE), &BaseOfStack);
+  ASSERT_EFI_ERROR (Status);
+  
+  if (FeaturePcdGet(PcdDxeIplSwitchToLongMode)) {
+    //
+    // Compute the top of the stack we were allocated, which is used to load X64 dxe core. 
+    // Pre-allocate a 32 bytes which confroms to x64 calling convention.
+    //
+    // The first four parameters to a function are passed in rcx, rdx, r8 and r9. 
+    // Any further parameters are pushed on the stack. Furthermore, space (4 * 8bytes) for the 
+    // register parameters is reserved on the stack, in case the called function 
+    // wants to spill them; this is important if the function is variadic. 
+    //
+    TopOfStack = BaseOfStack + EFI_SIZE_TO_PAGES (STACK_SIZE) * EFI_PAGE_SIZE - 32;
+
+    //
+    //  X64 Calling Conventions requires that the stack must be aligned to 16 bytes
+    //
+    TopOfStack = (EFI_PHYSICAL_ADDRESS) (UINTN) ALIGN_POINTER (TopOfStack, 16);
+    //
+    // Load the GDT of Go64. Since the GDT of 32-bit Tiano locates in the BS_DATA
+    // memory, it may be corrupted when copying FV to high-end memory 
+    //
+    LoadGo64Gdt();
+    //
+    // Limit to 36 bits of addressing for debug. Should get it from CPU
+    //
+    PageTables = CreateIdentityMappingPageTables (36);
+    //
+    // Go to Long Mode. Interrupts will not get turned on until the CPU AP is loaded.
+    // Call x64 drivers passing in single argument, a pointer to the HOBs.
+    //
+    ActivateLongMode (
+      PageTables, 
+      (EFI_PHYSICAL_ADDRESS)(UINTN)(HobList.Raw), 
+      TopOfStack,
+      0x00000000,
+      DxeCoreEntryPoint
+      );
+  } else {
+    //
+    // Compute the top of the stack we were allocated. Pre-allocate a UINTN
+    // for safety.
+    //
+    TopOfStack = BaseOfStack + EFI_SIZE_TO_PAGES (STACK_SIZE) * EFI_PAGE_SIZE - CPU_STACK_ALIGNMENT;
+    TopOfStack = (EFI_PHYSICAL_ADDRESS) (UINTN) ALIGN_POINTER (TopOfStack, CPU_STACK_ALIGNMENT);
+
+    SwitchStack (
+      (SWITCH_STACK_ENTRY_POINT)(UINTN)DxeCoreEntryPoint,
+      HobList.Raw,
+      NULL,
+      (VOID *) (UINTN) TopOfStack
+      );
+  } 
 }

EdkModulePkg/Core/DxeIplPeim/Ipf/DxeLoadFunc.c

@@ -21,91 +21,44 @@ Abstract:
 
 #include "DxeIpl.h"
 
-EFI_STATUS
+VOID
-CreateArchSpecificHobs (
+HandOffToDxeCore (
-  OUT EFI_PHYSICAL_ADDRESS      *BspStore
+  IN EFI_PHYSICAL_ADDRESS   DxeCoreEntryPoint,
+  IN EFI_PEI_HOB_POINTERS   HobList
   )
-/*++
-
-Routine Description:
-
-  Creates architecture-specific HOBs.
-
-  Note: New parameters should NOT be added for any HOBs that are added to this
-        function.  BspStore is a special case because it is required for the
-        call to SwitchStacks() in DxeLoad().
-
-Arguments:
-
-  BspStore    - The address of the BSP Store for those architectures that need
-                it.  Otherwise 0.
-
-Returns:
-
-  EFI_SUCCESS   - The HOBs were created successfully.
-
---*/
 {
-  EFI_STATUS  Status;
+  VOID                *BaseOfStack;
+  VOID                *TopOfStack;
+  VOID                *BspStore;
 
-  Status = EFI_SUCCESS;
+  //
-
+  // Allocate 128KB for the Stack
-  ASSERT (NULL != BspStore);
+  //
+  BaseOfStack = AllocatePages (EFI_SIZE_TO_PAGES (STACK_SIZE));
+  ASSERT (BaseOfStack != NULL);
 
   //
   // Allocate 16KB for the BspStore
   //
-  Status = PeiServicesAllocatePages (EfiBootServicesData, EFI_SIZE_TO_PAGES (BSP_STORE_SIZE), BspStore);
+  BspStore    = AllocatePages (EFI_SIZE_TO_PAGES (BSP_STORE_SIZE));
-  if (EFI_ERROR (Status)) {
+  ASSERT (BspStore != NULL);
-    return Status;
+  //
-  }
+  // Build BspStoreHob
+  //
+  BuildBspStoreHob ((EFI_PHYSICAL_ADDRESS) (UINTN) BspStore, BSP_STORE_SIZE, EfiBootServicesData);
 
-  BuildBspStoreHob (
+  //
-    *BspStore,
+  // Compute the top of the stack we were allocated. Pre-allocate a UINTN
-    BSP_STORE_SIZE,
+  // for safety.
-    EfiBootServicesData
+  //
-    );
+  TopOfStack = (VOID *) ((UINTN) BaseOfStack + EFI_SIZE_TO_PAGES (STACK_SIZE) * EFI_PAGE_SIZE - CPU_STACK_ALIGNMENT);
+  TopOfStack = ALIGN_POINTER (TopOfStack, CPU_STACK_ALIGNMENT);
 
-  return EFI_SUCCESS;
-}
-
-/**
-  Transfers control to a function starting with a new stack.
-
-  Transfers control to the function specified by EntryPoint using the new stack
-  specified by NewStack and passing in the parameters specified by Context1 and
-  Context2. Context1 and Context2 are optional and may be NULL. The function
-  EntryPoint must never return.
-
-  If EntryPoint is NULL, then ASSERT().
-  If NewStack is NULL, then ASSERT().
-
-  @param  EntryPoint  A pointer to function to call with the new stack.
-  @param  Context1    A pointer to the context to pass into the EntryPoint
-                      function.
-  @param  Context2    A pointer to the context to pass into the EntryPoint
-                      function.
-  @param  NewStack    A pointer to the new stack to use for the EntryPoint
-                      function.
-  @param  NewBsp      A pointer to the new BSP for the EntryPoint on IPF. It's
-                      Reserved on other architectures.
-
-**/
-VOID
-EFIAPI
-SwitchIplStacks (
-  IN      SWITCH_STACK_ENTRY_POINT  EntryPoint,
-  IN      VOID                      *Context1,  OPTIONAL
-  IN      VOID                      *Context2,  OPTIONAL
-  IN      VOID                      *NewStack,
-  IN      VOID                      *NewBsp
-  )
-{
   AsmSwitchStackAndBackingStore (
-    EntryPoint,
+    (SWITCH_STACK_ENTRY_POINT)(UINTN)DxeCoreEntryPoint,
-    Context1,
+    HobList.Raw,
-    Context2,
+    NULL,
-    NewStack,
+    TopOfStack,
-    NewBsp
+    BspStore
     );
 }

EdkModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c

@@ -0,0 +1,52 @@
+/*++
+
+Copyright (c) 2006, Intel Corporation
+All rights reserved. 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
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+Module Name:
+
+  DxeLoadFunc.c
+
+Abstract:
+
+  Ia32-specifc functionality for DxeLoad.
+
+--*/
+
+#include "DxeIpl.h"
+
+VOID
+HandOffToDxeCore (
+  IN EFI_PHYSICAL_ADDRESS   DxeCoreEntryPoint,
+  IN EFI_PEI_HOB_POINTERS   HobList
+  )
+{
+  VOID                *BaseOfStack;
+  VOID                *TopOfStack;
+
+  //
+  // Allocate 128KB for the Stack
+  //
+  BaseOfStack = AllocatePages (EFI_SIZE_TO_PAGES (STACK_SIZE));
+  ASSERT (BaseOfStack != NULL);
+
+  //
+  // Compute the top of the stack we were allocated. Pre-allocate a UINTN
+  // for safety.
+  //
+  TopOfStack = (VOID *) ((UINTN) BaseOfStack + EFI_SIZE_TO_PAGES (STACK_SIZE) * EFI_PAGE_SIZE - CPU_STACK_ALIGNMENT);
+  TopOfStack = ALIGN_POINTER (TopOfStack, CPU_STACK_ALIGNMENT);
+
+  SwitchStack (
+    (SWITCH_STACK_ENTRY_POINT)(UINTN)DxeCoreEntryPoint,
+    HobList.Raw,
+    NULL,
+    TopOfStack
+    );
+}

EdkModulePkg/EdkModulePkg.fpd

@@ -1018,6 +1018,14 @@
           <MaxDatumSize>1</MaxDatumSize>
           <Value>TRUE</Value>
         </PcdData>
+        <PcdData ItemType="FEATURE_FLAG">
+          <C_Name>PcdDxeIplBuildShareCodeHobs</C_Name>
+          <Token>0x0001003c</Token>
+          <TokenSpaceGuidCName>gEfiEdkModulePkgTokenSpaceGuid</TokenSpaceGuidCName>
+          <DatumType>BOOLEAN</DatumType>
+          <MaxDatumSize>1</MaxDatumSize>
+          <Value>TRUE</Value>
+        </PcdData>
       </PcdBuildDefinition>
       <ModuleSaBuildOptions>
         <FvBinding>NULL</FvBinding>
@@ -6684,6 +6692,14 @@
           <MaxDatumSize>1</MaxDatumSize>
           <Value>TRUE</Value>
         </PcdData>
+        <PcdData ItemType="FEATURE_FLAG">
+          <C_Name>PcdDxeIplBuildShareCodeHobs</C_Name>
+          <Token>0x0001003c</Token>
+          <TokenSpaceGuidCName>gEfiEdkModulePkgTokenSpaceGuid</TokenSpaceGuidCName>
+          <DatumType>BOOLEAN</DatumType>
+          <MaxDatumSize>1</MaxDatumSize>
+          <Value>TRUE</Value>
+        </PcdData>
       </PcdBuildDefinition>
       <ModuleSaBuildOptions>
         <FvBinding>NULL</FvBinding>
@@ -11131,6 +11147,14 @@
           <MaxDatumSize>1</MaxDatumSize>
           <Value>TRUE</Value>
         </PcdData>
+        <PcdData ItemType="FEATURE_FLAG">
+          <C_Name>PcdDxeIplBuildShareCodeHobs</C_Name>
+          <Token>0x0001003c</Token>
+          <TokenSpaceGuidCName>gEfiEdkModulePkgTokenSpaceGuid</TokenSpaceGuidCName>
+          <DatumType>BOOLEAN</DatumType>
+          <MaxDatumSize>1</MaxDatumSize>
+          <Value>TRUE</Value>
+        </PcdData>
       </PcdBuildDefinition>
       <ModuleSaBuildOptions>
         <FvBinding>NULL</FvBinding>
@@ -15582,6 +15606,14 @@
           <MaxDatumSize>1</MaxDatumSize>
           <Value>TRUE</Value>
         </PcdData>
+        <PcdData ItemType="FEATURE_FLAG">
+          <C_Name>PcdDxeIplBuildShareCodeHobs</C_Name>
+          <Token>0x0001003c</Token>
+          <TokenSpaceGuidCName>gEfiEdkModulePkgTokenSpaceGuid</TokenSpaceGuidCName>
+          <DatumType>BOOLEAN</DatumType>
+          <MaxDatumSize>1</MaxDatumSize>
+          <Value>TRUE</Value>
+        </PcdData>
       </PcdBuildDefinition>
       <ModuleSaBuildOptions>
         <FvBinding>NULL</FvBinding>

EdkModulePkg/EdkModulePkg.spd

@@ -1247,14 +1247,23 @@
       <DefaultValue>FALSE</DefaultValue>
       <HelpText>Whether VGA decoding is enabled on this platform so we should avoid those aliased resources</HelpText>
     </PcdEntry>
-    <PcdEntry>
+    <PcdEntry SupArchList="IA32">
       <C_Name>PcdDxeIplSwitchToLongMode</C_Name>
       <Token>0x0001003b</Token>
       <TokenSpaceGuidCName>gEfiEdkModulePkgTokenSpaceGuid</TokenSpaceGuidCName>
       <DatumType>BOOLEAN</DatumType>
       <ValidUsage>FEATURE_FLAG</ValidUsage>
-      <DefaultValue>FALSE</DefaultValue>
+      <DefaultValue>TRUE</DefaultValue>
       <HelpText>If this feature is enabled, then the DXE IPL will load a 64-bit DxeCore.</HelpText>
     </PcdEntry>
+    <PcdEntry>
+      <C_Name>PcdDxeIplBuildShareCodeHobs</C_Name>
+      <Token>0x0001003c</Token>
+      <TokenSpaceGuidCName>gEfiEdkModulePkgTokenSpaceGuid</TokenSpaceGuidCName>
+      <DatumType>BOOLEAN</DatumType>
+      <ValidUsage>FEATURE_FLAG</ValidUsage>
+      <DefaultValue>FALSE</DefaultValue>
+      <HelpText>If this feature is enabled, DXE IPL will build a series of HOBs to share code with DXE Core.</HelpText>
+    </PcdEntry>
   </PcdDeclarations>
 </PackageSurfaceArea>