UefiCpuPkg/CpuDxe/X64/MpAsm.asm

   1 ;------------------------------------------------------------------------------
   2 ;
   3 ; Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>
   4 ; This program and the accompanying materials
   5 ; are licensed and made available under the terms and conditions of the BSD License
   6 ; which accompanies this distribution.  The full text of the license may be found at
   7 ; http://opensource.org/licenses/bsd-license.php.
   8 ;
   9 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11 ;
  12 ;------------------------------------------------------------------------------
  13
  14 #include <Base.h>
  15
  16 extern ASM_PFX(mTopOfApCommonStack):QWORD
  17 extern ASM_PFX(ApEntryPointInC):PROC
  18
  19 .data
  20
  21 ;
  22 ; This lock only allows one AP to use the mTopOfApCommonStack stack at a time
  23 ;
  24 ApStackLock:
  25     dd      0
  26
  27 .code
  28
  29 ;------------------------------------------------------------------------------
  30 ; VOID
  31 ; EFIAPI
  32 ; AsmApEntryPoint (
  33 ;   VOID
  34 ;   );
  35 ;------------------------------------------------------------------------------
  36 ASM_PFX(AsmApEntryPoint) PROC PUBLIC
  37
  38     cli
  39 AsmApEntryPointAcquireLock:
  40 lock bts    dword ptr [ApStackLock], 0
  41     pause
  42     jc      AsmApEntryPointAcquireLock
  43
  44     mov     rsp, [ASM_PFX(mTopOfApCommonStack)]
  45     call    ASM_PFX(ApEntryPointInC)
  46
  47     cli
  48
  49 lock btc    dword ptr [ApStackLock], 0
  50
  51     mov     eax, 100h
  52 AsmApEntryPointShareLock:
  53     pause
  54     dec     eax
  55     jnz     AsmApEntryPointShareLock
  56
  57     jmp     ASM_PFX(AsmApEntryPoint)
  58
  59 ASM_PFX(AsmApEntryPoint) ENDP
  60
  61 ;------------------------------------------------------------------------------
  62 ; VOID
  63 ; EFIAPI
  64 ; AsmApDoneWithCommonStack (
  65 ;   VOID
  66 ;   );
  67 ;------------------------------------------------------------------------------
  68 ASM_PFX(AsmApDoneWithCommonStack) PROC PUBLIC
  69
  70 lock btc    dword ptr [ApStackLock], 0
  71     ret
  72
  73 ASM_PFX(AsmApDoneWithCommonStack) ENDP
  74
  75 END
  76