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diff --git a/Core/UefiCpuPkg/PiSmmCpuDxeSmm/X64/Semaphore.c b/Core/UefiCpuPkg/PiSmmCpuDxeSmm/X64/Semaphore.c
new file mode 100644
index 0000000000..6dbcb086aa
--- /dev/null
+++ b/Core/UefiCpuPkg/PiSmmCpuDxeSmm/X64/Semaphore.c
@@ -0,0 +1,67 @@
+/** @file
+Semaphore mechanism to indicate to the BSP that an AP has exited SMM
+after SMBASE relocation.
+
+Copyright (c) 2009 - 2015, Intel Corporation. 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
+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.
+
+**/
+
+#include "PiSmmCpuDxeSmm.h"
+
+extern UINT32 mSmmRelocationOriginalAddressPtr32;
+extern UINT32 mRebasedFlagAddr32;
+
+UINTN mSmmRelocationOriginalAddress;
+volatile BOOLEAN *mRebasedFlag;
+
+/**
+AP Semaphore operation in 32-bit mode while BSP runs in 64-bit mode.
+**/
+VOID
+SmmRelocationSemaphoreComplete32 (
+ VOID
+ );
+
+/**
+ Hook return address of SMM Save State so that semaphore code
+ can be executed immediately after AP exits SMM to indicate to
+ the BSP that an AP has exited SMM after SMBASE relocation.
+
+ @param[in] CpuIndex The processor index.
+ @param[in] RebasedFlag A pointer to a flag that is set to TRUE
+ immediately after AP exits SMM.
+
+**/
+VOID
+SemaphoreHook (
+ IN UINTN CpuIndex,
+ IN volatile BOOLEAN *RebasedFlag
+ )
+{
+ SMRAM_SAVE_STATE_MAP *CpuState;
+ UINTN TempValue;
+
+ mRebasedFlag = RebasedFlag;
+ mRebasedFlagAddr32 = (UINT32)(UINTN)mRebasedFlag;
+
+ CpuState = (SMRAM_SAVE_STATE_MAP *)(UINTN)(SMM_DEFAULT_SMBASE + SMRAM_SAVE_STATE_MAP_OFFSET);
+ mSmmRelocationOriginalAddress = HookReturnFromSmm (
+ CpuIndex,
+ CpuState,
+ (UINT64)(UINTN)&SmmRelocationSemaphoreComplete32,
+ (UINT64)(UINTN)&SmmRelocationSemaphoreComplete
+ );
+
+ //
+ // Use temp value to fix ICC complier warning
+ //
+ TempValue = (UINTN)&mSmmRelocationOriginalAddress;
+ mSmmRelocationOriginalAddressPtr32 = (UINT32)TempValue;
+}