1 files changed, 76 insertions, 0 deletions
diff --git a/UefiCpuPkg/CpuDxe/X64/MpAsm.asm b/UefiCpuPkg/CpuDxe/X64/MpAsm.asm
new file mode 100644
index 0000000000..308de51330
--- /dev/null
+++ b/UefiCpuPkg/CpuDxe/X64/MpAsm.asm
@@ -0,0 +1,76 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (c) 2006 - 2014, 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 <Base.h>
+
+extern ASM_PFX(mTopOfApCommonStack):QWORD
+extern ASM_PFX(ApEntryPointInC):PROC
+
+.data
+
+;
+; This lock only allows one AP to use the mTopOfApCommonStack stack at a time
+;
+ApStackLock:
+    dd      0
+
+.code
+
+;------------------------------------------------------------------------------
+; VOID
+; EFIAPI
+; AsmApEntryPoint (
+;   VOID
+;   );
+;------------------------------------------------------------------------------
+ASM_PFX(AsmApEntryPoint) PROC PUBLIC
+
+    cli
+AsmApEntryPointAcquireLock:
+lock bts    dword ptr [ApStackLock], 0
+    pause
+    jc      AsmApEntryPointAcquireLock
+
+    mov     rsp, [ASM_PFX(mTopOfApCommonStack)]
+    call    ASM_PFX(ApEntryPointInC)
+
+    cli
+
+lock btc    dword ptr [ApStackLock], 0
+
+    mov     eax, 100h
+AsmApEntryPointShareLock:
+    pause
+    dec     eax
+    jnz     AsmApEntryPointShareLock
+
+    jmp     ASM_PFX(AsmApEntryPoint)
+
+ASM_PFX(AsmApEntryPoint) ENDP
+
+;------------------------------------------------------------------------------
+; VOID
+; EFIAPI
+; AsmApDoneWithCommonStack (
+;   VOID
+;   );
+;------------------------------------------------------------------------------
+ASM_PFX(AsmApDoneWithCommonStack) PROC PUBLIC
+
+lock btc    dword ptr [ApStackLock], 0
+    ret
+
+ASM_PFX(AsmApDoneWithCommonStack) ENDP
+
+END
+