UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/Semaphore.c

   1 /** @file
   2 Semaphore mechanism to indicate to the BSP that an AP has exited SMM
   3 after SMBASE relocation.
   4
   5 Copyright (c) 2009 - 2015, Intel Corporation. All rights reserved.<BR>
   6 This program and the accompanying materials
   7 are licensed and made available under the terms and conditions of the BSD License
   8 which accompanies this distribution.  The full text of the license may be found at
   9 http://opensource.org/licenses/bsd-license.php
  10
  11 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13
  14 **/
  15
  16 #include "PiSmmCpuDxeSmm.h"
  17
  18 UINTN             mSmmRelocationOriginalAddress;
  19 volatile BOOLEAN  *mRebasedFlag;
  20
  21 /**
  22   Hook return address of SMM Save State so that semaphore code
  23   can be executed immediately after AP exits SMM to indicate to
  24   the BSP that an AP has exited SMM after SMBASE relocation.
  25
  26   @param[in] CpuIndex     The processor index.
  27   @param[in] RebasedFlag  A pointer to a flag that is set to TRUE
  28                           immediately after AP exits SMM.
  29
  30 **/
  31 VOID
  32 SemaphoreHook (
  33   IN UINTN             CpuIndex,
  34   IN volatile BOOLEAN  *RebasedFlag
  35   )
  36 {
  37   SMRAM_SAVE_STATE_MAP  *CpuState;
  38
  39   mRebasedFlag = RebasedFlag;
  40
  41   CpuState = (SMRAM_SAVE_STATE_MAP *)(UINTN)(SMM_DEFAULT_SMBASE + SMRAM_SAVE_STATE_MAP_OFFSET);
  42   mSmmRelocationOriginalAddress = (UINTN)HookReturnFromSmm (
  43                                            CpuIndex,
  44                                            CpuState,
  45                                            (UINT64)(UINTN)&SmmRelocationSemaphoreComplete,
  46                                            (UINT64)(UINTN)&SmmRelocationSemaphoreComplete
  47                                            );
  48 }