[mirror_edk2.git] / UefiCpuPkg / Library / MpInitLib / DxeMpLib.c

/** @file\r
  MP initialize support functions for DXE phase.\r
\r
  Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>\r
  This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#include "MpLib.h"\r
\r
#include <Library/UefiLib.h>\r
#include <Library/UefiBootServicesTableLib.h>\r
#include <Library/DebugAgentLib.h>\r
\r
#include <Protocol/Timer.h>\r
\r
#define  AP_CHECK_INTERVAL     (EFI_TIMER_PERIOD_MILLISECONDS (100))\r
#define  AP_SAFE_STACK_SIZE    128\r
\r
CPU_MP_DATA      *mCpuMpData = NULL;\r
EFI_EVENT        mCheckAllApsEvent = NULL;\r
EFI_EVENT        mMpInitExitBootServicesEvent = NULL;\r
EFI_EVENT        mLegacyBootEvent = NULL;\r
volatile BOOLEAN mStopCheckAllApsStatus = TRUE;\r
VOID             *mReservedApLoopFunc = NULL;\r
UINTN            mReservedTopOfApStack;\r
volatile UINT32  mNumberToFinish = 0;\r
\r
/**\r
  Enable Debug Agent to support source debugging on AP function.\r
\r
**/\r
VOID\r
EnableDebugAgent (\r
  VOID\r
  )\r
{\r
  //\r
  // Initialize Debug Agent to support source level debug in DXE phase\r
  //\r
  InitializeDebugAgent (DEBUG_AGENT_INIT_DXE_AP, NULL, NULL);\r
}\r
\r
/**\r
  Get the pointer to CPU MP Data structure.\r
\r
  @return  The pointer to CPU MP Data structure.\r
**/\r
CPU_MP_DATA *\r
GetCpuMpData (\r
  VOID\r
  )\r
{\r
  ASSERT (mCpuMpData != NULL);\r
  return mCpuMpData;\r
}\r
\r
/**\r
  Save the pointer to CPU MP Data structure.\r
\r
  @param[in] CpuMpData  The pointer to CPU MP Data structure will be saved.\r
**/\r
VOID\r
SaveCpuMpData (\r
  IN CPU_MP_DATA   *CpuMpData\r
  )\r
{\r
  mCpuMpData = CpuMpData;\r
}\r
\r
/**\r
  Allocate reset vector buffer.\r
\r
  @param[in, out]  CpuMpData  The pointer to CPU MP Data structure.\r
**/\r
VOID\r
AllocateResetVector (\r
  IN OUT CPU_MP_DATA          *CpuMpData\r
  )\r
{\r
  EFI_STATUS            Status;\r
  UINTN                 ApResetVectorSize;\r
  EFI_PHYSICAL_ADDRESS  StartAddress;\r
\r
  if (CpuMpData->SaveRestoreFlag) {\r
    BackupAndPrepareWakeupBuffer (CpuMpData);\r
  } else {\r
    ApResetVectorSize = CpuMpData->AddressMap.RendezvousFunnelSize +\r
                        sizeof (MP_CPU_EXCHANGE_INFO);\r
\r
    StartAddress = BASE_1MB;\r
    Status = gBS->AllocatePages (\r
                    AllocateMaxAddress,\r
                    EfiACPIMemoryNVS,\r
                    EFI_SIZE_TO_PAGES (ApResetVectorSize),\r
                    &StartAddress\r
                    );\r
    ASSERT_EFI_ERROR (Status);\r
\r
    CpuMpData->WakeupBuffer      = (UINTN) StartAddress;\r
    CpuMpData->MpCpuExchangeInfo = (MP_CPU_EXCHANGE_INFO *) (UINTN)\r
                  (CpuMpData->WakeupBuffer + CpuMpData->AddressMap.RendezvousFunnelSize);\r
    //\r
    // copy AP reset code in it\r
    //\r
    CopyMem (\r
      (VOID *) CpuMpData->WakeupBuffer,\r
      (VOID *) CpuMpData->AddressMap.RendezvousFunnelAddress,\r
      CpuMpData->AddressMap.RendezvousFunnelSize\r
      );\r
  }\r
}\r
\r
/**\r
  Free AP reset vector buffer.\r
\r
  @param[in]  CpuMpData  The pointer to CPU MP Data structure.\r
**/\r
VOID\r
FreeResetVector (\r
  IN CPU_MP_DATA              *CpuMpData\r
  )\r
{\r
  EFI_STATUS            Status;\r
  UINTN                 ApResetVectorSize;\r
\r
  if (CpuMpData->SaveRestoreFlag) {\r
    RestoreWakeupBuffer (CpuMpData);\r
  } else {\r
    ApResetVectorSize = CpuMpData->AddressMap.RendezvousFunnelSize +\r
                        sizeof (MP_CPU_EXCHANGE_INFO);\r
    Status = gBS->FreePages(\r
               (EFI_PHYSICAL_ADDRESS)CpuMpData->WakeupBuffer,\r
               EFI_SIZE_TO_PAGES (ApResetVectorSize)\r
               );\r
    ASSERT_EFI_ERROR (Status);\r
  }\r
}\r
\r
/**\r
  Checks APs status and updates APs status if needed.\r
\r
**/\r
VOID\r
CheckAndUpdateApsStatus (\r
  VOID\r
  )\r
{\r
  UINTN                   ProcessorNumber;\r
  EFI_STATUS              Status;\r
  CPU_MP_DATA             *CpuMpData;\r
\r
  CpuMpData = GetCpuMpData ();\r
\r
  //\r
  // First, check whether pending StartupAllAPs() exists.\r
  //\r
  if (CpuMpData->WaitEvent != NULL) {\r
\r
    Status = CheckAllAPs ();\r
    //\r
    // If all APs finish for StartupAllAPs(), signal the WaitEvent for it.\r
    //\r
    if (Status != EFI_NOT_READY) {\r
      Status = gBS->SignalEvent (CpuMpData->WaitEvent);\r
      CpuMpData->WaitEvent = NULL;\r
    }\r
  }\r
\r
  //\r
  // Second, check whether pending StartupThisAPs() callings exist.\r
  //\r
  for (ProcessorNumber = 0; ProcessorNumber < CpuMpData->CpuCount; ProcessorNumber++) {\r
\r
    if (CpuMpData->CpuData[ProcessorNumber].WaitEvent == NULL) {\r
      continue;\r
    }\r
\r
    Status = CheckThisAP (ProcessorNumber);\r
\r
    if (Status != EFI_NOT_READY) {\r
      gBS->SignalEvent (CpuMpData->CpuData[ProcessorNumber].WaitEvent);\r
     CpuMpData->CpuData[ProcessorNumber].WaitEvent = NULL;\r
    }\r
  }\r
}\r
\r
/**\r
  Checks APs' status periodically.\r
\r
  This function is triggered by timer periodically to check the\r
  state of APs for StartupAllAPs() and StartupThisAP() executed\r
  in non-blocking mode.\r
\r
  @param[in]  Event    Event triggered.\r
  @param[in]  Context  Parameter passed with the event.\r
\r
**/\r
VOID\r
EFIAPI\r
CheckApsStatus (\r
  IN  EFI_EVENT                           Event,\r
  IN  VOID                                *Context\r
  )\r
{\r
  //\r
  // If CheckApsStatus() is not stopped, otherwise return immediately.\r
  //\r
  if (!mStopCheckAllApsStatus) {\r
    CheckAndUpdateApsStatus ();\r
  }\r
}\r
\r
/**\r
  Get Protected mode code segment from current GDT table.\r
\r
  @return  Protected mode code segment value.\r
**/\r
UINT16\r
GetProtectedModeCS (\r
  VOID\r
  )\r
{\r
  IA32_DESCRIPTOR          GdtrDesc;\r
  IA32_SEGMENT_DESCRIPTOR  *GdtEntry;\r
  UINTN                    GdtEntryCount;\r
  UINT16                   Index;\r
\r
  Index = (UINT16) -1;\r
  AsmReadGdtr (&GdtrDesc);\r
  GdtEntryCount = (GdtrDesc.Limit + 1) / sizeof (IA32_SEGMENT_DESCRIPTOR);\r
  GdtEntry = (IA32_SEGMENT_DESCRIPTOR *) GdtrDesc.Base;\r
  for (Index = 0; Index < GdtEntryCount; Index++) {\r
    if (GdtEntry->Bits.L == 0) {\r
      if (GdtEntry->Bits.Type > 8 && GdtEntry->Bits.L == 0) {\r
        break;\r
      }\r
    }\r
    GdtEntry++;\r
  }\r
  ASSERT (Index != -1);\r
  return Index * 8;\r
}\r
\r
/**\r
  Do sync on APs.\r
\r
  @param[in, out] Buffer  Pointer to private data buffer.\r
**/\r
VOID\r
EFIAPI\r
RelocateApLoop (\r
  IN OUT VOID  *Buffer\r
  )\r
{\r
  CPU_MP_DATA            *CpuMpData;\r
  BOOLEAN                MwaitSupport;\r
  ASM_RELOCATE_AP_LOOP   AsmRelocateApLoopFunc;\r
  UINTN                  ProcessorNumber;\r
\r
  MpInitLibWhoAmI (&ProcessorNumber); \r
  CpuMpData    = GetCpuMpData ();\r
  MwaitSupport = IsMwaitSupport ();\r
  AsmRelocateApLoopFunc = (ASM_RELOCATE_AP_LOOP) (UINTN) mReservedApLoopFunc;\r
  AsmRelocateApLoopFunc (\r
    MwaitSupport,\r
    CpuMpData->ApTargetCState,\r
    CpuMpData->PmCodeSegment,\r
    mReservedTopOfApStack - ProcessorNumber * AP_SAFE_STACK_SIZE,\r
    (UINTN) &mNumberToFinish\r
    );\r
  //\r
  // It should never reach here\r
  //\r
  ASSERT (FALSE);\r
}\r
\r
/**\r
  Callback function for ExitBootServices.\r
\r
  @param[in]  Event             Event whose notification function is being invoked.\r
  @param[in]  Context           The pointer to the notification function's context,\r
                                which is implementation-dependent.\r
\r
**/\r
VOID\r
EFIAPI\r
MpInitChangeApLoopCallback (\r
  IN EFI_EVENT                Event,\r
  IN VOID                     *Context\r
  )\r
{\r
  CPU_MP_DATA               *CpuMpData;\r
\r
  CpuMpData = GetCpuMpData ();\r
  CpuMpData->SaveRestoreFlag = TRUE;\r
  CpuMpData->PmCodeSegment = GetProtectedModeCS ();\r
  CpuMpData->ApLoopMode = PcdGet8 (PcdCpuApLoopMode);\r
  mNumberToFinish = CpuMpData->CpuCount - 1;\r
  WakeUpAP (CpuMpData, TRUE, 0, RelocateApLoop, NULL);\r
  while (mNumberToFinish > 0) {\r
    CpuPause ();\r
  }\r
  DEBUG ((DEBUG_INFO, "%a() done!\n", __FUNCTION__));\r
}\r
\r
/**\r
  Initialize global data for MP support.\r
\r
  @param[in] CpuMpData  The pointer to CPU MP Data structure.\r
**/\r
VOID\r
InitMpGlobalData (\r
  IN CPU_MP_DATA               *CpuMpData\r
  )\r
{\r
  EFI_STATUS                 Status;\r
  EFI_PHYSICAL_ADDRESS       Address;\r
  UINTN                      ApSafeBufferSize;\r
\r
  SaveCpuMpData (CpuMpData);\r
\r
  if (CpuMpData->CpuCount == 1) {\r
    //\r
    // If only BSP exists, return\r
    //\r
    return;\r
  }\r
\r
  //\r
  // Avoid APs access invalid buffer data which allocated by BootServices,\r
  // so we will allocate reserved data for AP loop code. We also need to\r
  // allocate this buffer below 4GB due to APs may be transferred to 32bit\r
  // protected mode on long mode DXE.\r
  // Allocating it in advance since memory services are not available in\r
  // Exit Boot Services callback function.\r
  //\r
  ApSafeBufferSize  = CpuMpData->AddressMap.RelocateApLoopFuncSize;\r
  ApSafeBufferSize += CpuMpData->CpuCount * AP_SAFE_STACK_SIZE;\r
\r
  Address = BASE_4GB - 1;\r
  Status  = gBS->AllocatePages (\r
                   AllocateMaxAddress,\r
                   EfiReservedMemoryType,\r
                   EFI_SIZE_TO_PAGES (ApSafeBufferSize),\r
                   &Address\r
                   );\r
  ASSERT_EFI_ERROR (Status);\r
  mReservedApLoopFunc = (VOID *) (UINTN) Address;\r
  ASSERT (mReservedApLoopFunc != NULL);\r
  mReservedTopOfApStack = (UINTN) Address + EFI_PAGES_TO_SIZE (EFI_SIZE_TO_PAGES (ApSafeBufferSize));\r
  ASSERT ((mReservedTopOfApStack & (UINTN)(CPU_STACK_ALIGNMENT - 1)) == 0);\r
  CopyMem (\r
    mReservedApLoopFunc,\r
    CpuMpData->AddressMap.RelocateApLoopFuncAddress,\r
    CpuMpData->AddressMap.RelocateApLoopFuncSize\r
    );\r
\r
  Status = gBS->CreateEvent (\r
                  EVT_TIMER | EVT_NOTIFY_SIGNAL,\r
                  TPL_NOTIFY,\r
                  CheckApsStatus,\r
                  NULL,\r
                  &mCheckAllApsEvent\r
                  );\r
  ASSERT_EFI_ERROR (Status);\r
\r
  //\r
  // Set timer to check all APs status.\r
  //\r
  Status = gBS->SetTimer (\r
                  mCheckAllApsEvent,\r
                  TimerPeriodic,\r
                  AP_CHECK_INTERVAL\r
                  );\r
  ASSERT_EFI_ERROR (Status);\r
\r
  Status = gBS->CreateEvent (\r
                  EVT_SIGNAL_EXIT_BOOT_SERVICES,\r
                  TPL_CALLBACK,\r
                  MpInitChangeApLoopCallback,\r
                  NULL,\r
                  &mMpInitExitBootServicesEvent\r
                  );\r
  ASSERT_EFI_ERROR (Status);\r
\r
  Status = gBS->CreateEventEx (\r
                  EVT_NOTIFY_SIGNAL,\r
                  TPL_CALLBACK,\r
                  MpInitChangeApLoopCallback,\r
                  NULL,\r
                  &gEfiEventLegacyBootGuid,\r
                  &mLegacyBootEvent\r
                  );\r
  ASSERT_EFI_ERROR (Status);\r
}\r
\r
/**\r
  This service executes a caller provided function on all enabled APs.\r
\r
  @param[in]  Procedure               A pointer to the function to be run on\r
                                      enabled APs of the system. See type\r
                                      EFI_AP_PROCEDURE.\r
  @param[in]  SingleThread            If TRUE, then all the enabled APs execute\r
                                      the function specified by Procedure one by\r
                                      one, in ascending order of processor handle\r
                                      number.  If FALSE, then all the enabled APs\r
                                      execute the function specified by Procedure\r
                                      simultaneously.\r
  @param[in]  WaitEvent               The event created by the caller with CreateEvent()\r
                                      service.  If it is NULL, then execute in\r
                                      blocking mode. BSP waits until all APs finish\r
                                      or TimeoutInMicroSeconds expires.  If it's\r
                                      not NULL, then execute in non-blocking mode.\r
                                      BSP requests the function specified by\r
                                      Procedure to be started on all the enabled\r
                                      APs, and go on executing immediately. If\r
                                      all return from Procedure, or TimeoutInMicroSeconds\r
                                      expires, this event is signaled. The BSP\r
                                      can use the CheckEvent() or WaitForEvent()\r
                                      services to check the state of event.  Type\r
                                      EFI_EVENT is defined in CreateEvent() in\r
                                      the Unified Extensible Firmware Interface\r
                                      Specification.\r
  @param[in]  TimeoutInMicroseconds   Indicates the time limit in microseconds for\r
                                      APs to return from Procedure, either for\r
                                      blocking or non-blocking mode. Zero means\r
                                      infinity.  If the timeout expires before\r
                                      all APs return from Procedure, then Procedure\r
                                      on the failed APs is terminated. All enabled\r
                                      APs are available for next function assigned\r
                                      by MpInitLibStartupAllAPs() or\r
                                      MPInitLibStartupThisAP().\r
                                      If the timeout expires in blocking mode,\r
                                      BSP returns EFI_TIMEOUT.  If the timeout\r
                                      expires in non-blocking mode, WaitEvent\r
                                      is signaled with SignalEvent().\r
  @param[in]  ProcedureArgument       The parameter passed into Procedure for\r
                                      all APs.\r
  @param[out] FailedCpuList           If NULL, this parameter is ignored. Otherwise,\r
                                      if all APs finish successfully, then its\r
                                      content is set to NULL. If not all APs\r
                                      finish before timeout expires, then its\r
                                      content is set to address of the buffer\r
                                      holding handle numbers of the failed APs.\r
                                      The buffer is allocated by MP Initialization\r
                                      library, and it's the caller's responsibility to\r
                                      free the buffer with FreePool() service.\r
                                      In blocking mode, it is ready for consumption\r
                                      when the call returns. In non-blocking mode,\r
                                      it is ready when WaitEvent is signaled.  The\r
                                      list of failed CPU is terminated by\r
                                      END_OF_CPU_LIST.\r
\r
  @retval EFI_SUCCESS             In blocking mode, all APs have finished before\r
                                  the timeout expired.\r
  @retval EFI_SUCCESS             In non-blocking mode, function has been dispatched\r
                                  to all enabled APs.\r
  @retval EFI_UNSUPPORTED         A non-blocking mode request was made after the\r
                                  UEFI event EFI_EVENT_GROUP_READY_TO_BOOT was\r
                                  signaled.\r
  @retval EFI_UNSUPPORTED         WaitEvent is not NULL if non-blocking mode is not\r
                                  supported.\r
  @retval EFI_DEVICE_ERROR        Caller processor is AP.\r
  @retval EFI_NOT_STARTED         No enabled APs exist in the system.\r
  @retval EFI_NOT_READY           Any enabled APs are busy.\r
  @retval EFI_NOT_READY           MP Initialize Library is not initialized.\r
  @retval EFI_TIMEOUT             In blocking mode, the timeout expired before\r
                                  all enabled APs have finished.\r
  @retval EFI_INVALID_PARAMETER   Procedure is NULL.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
MpInitLibStartupAllAPs (\r
  IN  EFI_AP_PROCEDURE          Procedure,\r
  IN  BOOLEAN                   SingleThread,\r
  IN  EFI_EVENT                 WaitEvent               OPTIONAL,\r
  IN  UINTN                     TimeoutInMicroseconds,\r
  IN  VOID                      *ProcedureArgument      OPTIONAL,\r
  OUT UINTN                     **FailedCpuList         OPTIONAL\r
  )\r
{\r
  EFI_STATUS              Status;\r
\r
  //\r
  // Temporarily stop checkAllApsStatus for avoid resource dead-lock.\r
  //\r
  mStopCheckAllApsStatus = TRUE;\r
\r
  Status = StartupAllAPsWorker (\r
             Procedure,\r
             SingleThread,\r
             WaitEvent,\r
             TimeoutInMicroseconds,\r
             ProcedureArgument,\r
             FailedCpuList\r
             );\r
\r
  //\r
  // Start checkAllApsStatus\r
  //\r
  mStopCheckAllApsStatus = FALSE;\r
\r
  return Status;\r
}\r
\r
/**\r
  This service lets the caller get one enabled AP to execute a caller-provided\r
  function.\r
\r
  @param[in]  Procedure               A pointer to the function to be run on the\r
                                      designated AP of the system. See type\r
                                      EFI_AP_PROCEDURE.\r
  @param[in]  ProcessorNumber         The handle number of the AP. The range is\r
                                      from 0 to the total number of logical\r
                                      processors minus 1. The total number of\r
                                      logical processors can be retrieved by\r
                                      MpInitLibGetNumberOfProcessors().\r
  @param[in]  WaitEvent               The event created by the caller with CreateEvent()\r
                                      service.  If it is NULL, then execute in\r
                                      blocking mode. BSP waits until this AP finish\r
                                      or TimeoutInMicroSeconds expires.  If it's\r
                                      not NULL, then execute in non-blocking mode.\r
                                      BSP requests the function specified by\r
                                      Procedure to be started on this AP,\r
                                      and go on executing immediately. If this AP\r
                                      return from Procedure or TimeoutInMicroSeconds\r
                                      expires, this event is signaled. The BSP\r
                                      can use the CheckEvent() or WaitForEvent()\r
                                      services to check the state of event.  Type\r
                                      EFI_EVENT is defined in CreateEvent() in\r
                                      the Unified Extensible Firmware Interface\r
                                      Specification.\r
  @param[in]  TimeoutInMicroseconds   Indicates the time limit in microseconds for\r
                                      this AP to finish this Procedure, either for\r
                                      blocking or non-blocking mode. Zero means\r
                                      infinity.  If the timeout expires before\r
                                      this AP returns from Procedure, then Procedure\r
                                      on the AP is terminated. The\r
                                      AP is available for next function assigned\r
                                      by MpInitLibStartupAllAPs() or\r
                                      MpInitLibStartupThisAP().\r
                                      If the timeout expires in blocking mode,\r
                                      BSP returns EFI_TIMEOUT.  If the timeout\r
                                      expires in non-blocking mode, WaitEvent\r
                                      is signaled with SignalEvent().\r
  @param[in]  ProcedureArgument       The parameter passed into Procedure on the\r
                                      specified AP.\r
  @param[out] Finished                If NULL, this parameter is ignored.  In\r
                                      blocking mode, this parameter is ignored.\r
                                      In non-blocking mode, if AP returns from\r
                                      Procedure before the timeout expires, its\r
                                      content is set to TRUE. Otherwise, the\r
                                      value is set to FALSE. The caller can\r
                                      determine if the AP returned from Procedure\r
                                      by evaluating this value.\r
\r
  @retval EFI_SUCCESS             In blocking mode, specified AP finished before\r
                                  the timeout expires.\r
  @retval EFI_SUCCESS             In non-blocking mode, the function has been\r
                                  dispatched to specified AP.\r
  @retval EFI_UNSUPPORTED         A non-blocking mode request was made after the\r
                                  UEFI event EFI_EVENT_GROUP_READY_TO_BOOT was\r
                                  signaled.\r
  @retval EFI_UNSUPPORTED         WaitEvent is not NULL if non-blocking mode is not\r
                                  supported.\r
  @retval EFI_DEVICE_ERROR        The calling processor is an AP.\r
  @retval EFI_TIMEOUT             In blocking mode, the timeout expired before\r
                                  the specified AP has finished.\r
  @retval EFI_NOT_READY           The specified AP is busy.\r
  @retval EFI_NOT_READY           MP Initialize Library is not initialized.\r
  @retval EFI_NOT_FOUND           The processor with the handle specified by\r
                                  ProcessorNumber does not exist.\r
  @retval EFI_INVALID_PARAMETER   ProcessorNumber specifies the BSP or disabled AP.\r
  @retval EFI_INVALID_PARAMETER   Procedure is NULL.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
MpInitLibStartupThisAP (\r
  IN  EFI_AP_PROCEDURE          Procedure,\r
  IN  UINTN                     ProcessorNumber,\r
  IN  EFI_EVENT                 WaitEvent               OPTIONAL,\r
  IN  UINTN                     TimeoutInMicroseconds,\r
  IN  VOID                      *ProcedureArgument      OPTIONAL,\r
  OUT BOOLEAN                   *Finished               OPTIONAL\r
  )\r
{\r
  EFI_STATUS              Status;\r
\r
  //\r
  // temporarily stop checkAllApsStatus for avoid resource dead-lock.\r
  //\r
  mStopCheckAllApsStatus = TRUE;\r
\r
  Status = StartupThisAPWorker (\r
             Procedure,\r
             ProcessorNumber,\r
             WaitEvent,\r
             TimeoutInMicroseconds,\r
             ProcedureArgument,\r
             Finished\r
             );\r
\r
  mStopCheckAllApsStatus = FALSE;\r
\r
  return Status;\r
}\r
\r
/**\r
  This service switches the requested AP to be the BSP from that point onward.\r
  This service changes the BSP for all purposes. This call can only be performed\r
  by the current BSP.\r
\r
  @param[in] ProcessorNumber   The handle number of AP that is to become the new\r
                               BSP. The range is from 0 to the total number of\r
                               logical processors minus 1. The total number of\r
                               logical processors can be retrieved by\r
                               MpInitLibGetNumberOfProcessors().\r
  @param[in] EnableOldBSP      If TRUE, then the old BSP will be listed as an\r
                               enabled AP. Otherwise, it will be disabled.\r
\r
  @retval EFI_SUCCESS             BSP successfully switched.\r
  @retval EFI_UNSUPPORTED         Switching the BSP cannot be completed prior to\r
                                  this service returning.\r
  @retval EFI_UNSUPPORTED         Switching the BSP is not supported.\r
  @retval EFI_DEVICE_ERROR        The calling processor is an AP.\r
  @retval EFI_NOT_FOUND           The processor with the handle specified by\r
                                  ProcessorNumber does not exist.\r
  @retval EFI_INVALID_PARAMETER   ProcessorNumber specifies the current BSP or\r
                                  a disabled AP.\r
  @retval EFI_NOT_READY           The specified AP is busy.\r
  @retval EFI_NOT_READY           MP Initialize Library is not initialized.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
MpInitLibSwitchBSP (\r
  IN UINTN                     ProcessorNumber,\r
  IN BOOLEAN                   EnableOldBSP\r
  )\r
{\r
  EFI_STATUS                   Status;\r
  EFI_TIMER_ARCH_PROTOCOL      *Timer;\r
  UINT64                       TimerPeriod;\r
\r
  //\r
  // Locate Timer Arch Protocol\r
  //\r
  Status = gBS->LocateProtocol (&gEfiTimerArchProtocolGuid, NULL, (VOID **) &Timer);\r
  if (EFI_ERROR (Status)) {\r
    Timer = NULL;\r
  }\r
\r
  if (Timer != NULL) {\r
    //\r
    // Save current rate of DXE Timer\r
    //\r
    Timer->GetTimerPeriod (Timer, &TimerPeriod);\r
    //\r
    // Disable DXE Timer and drain pending interrupts\r
    //\r
    Timer->SetTimerPeriod (Timer, 0);\r
  }\r
\r
  Status = SwitchBSPWorker (ProcessorNumber, EnableOldBSP);\r
\r
  if (Timer != NULL) {\r
    //\r
    // Enable and restore rate of DXE Timer\r
    //\r
    Timer->SetTimerPeriod (Timer, TimerPeriod);\r
  }\r
\r
  return Status;\r
}\r
\r
/**\r
  This service lets the caller enable or disable an AP from this point onward.\r
  This service may only be called from the BSP.\r
\r
  @param[in] ProcessorNumber   The handle number of AP.\r
                               The range is from 0 to the total number of\r
                               logical processors minus 1. The total number of\r
                               logical processors can be retrieved by\r
                               MpInitLibGetNumberOfProcessors().\r
  @param[in] EnableAP          Specifies the new state for the processor for\r
                               enabled, FALSE for disabled.\r
  @param[in] HealthFlag        If not NULL, a pointer to a value that specifies\r
                               the new health status of the AP. This flag\r
                               corresponds to StatusFlag defined in\r
                               EFI_MP_SERVICES_PROTOCOL.GetProcessorInfo(). Only\r
                               the PROCESSOR_HEALTH_STATUS_BIT is used. All other\r
                               bits are ignored.  If it is NULL, this parameter\r
                               is ignored.\r
\r
  @retval EFI_SUCCESS             The specified AP was enabled or disabled successfully.\r
  @retval EFI_UNSUPPORTED         Enabling or disabling an AP cannot be completed\r
                                  prior to this service returning.\r
  @retval EFI_UNSUPPORTED         Enabling or disabling an AP is not supported.\r
  @retval EFI_DEVICE_ERROR        The calling processor is an AP.\r
  @retval EFI_NOT_FOUND           Processor with the handle specified by ProcessorNumber\r
                                  does not exist.\r
  @retval EFI_INVALID_PARAMETER   ProcessorNumber specifies the BSP.\r
  @retval EFI_NOT_READY           MP Initialize Library is not initialized.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
MpInitLibEnableDisableAP (\r
  IN  UINTN                     ProcessorNumber,\r
  IN  BOOLEAN                   EnableAP,\r
  IN  UINT32                    *HealthFlag OPTIONAL\r
  )\r
{\r
  EFI_STATUS     Status;\r
  BOOLEAN        TempStopCheckState;\r
\r
  TempStopCheckState = FALSE;\r
  //\r
  // temporarily stop checkAllAPsStatus for initialize parameters.\r
  //\r
  if (!mStopCheckAllApsStatus) {\r
    mStopCheckAllApsStatus = TRUE;\r
    TempStopCheckState     = TRUE;\r
  }\r
\r
  Status = EnableDisableApWorker (ProcessorNumber, EnableAP, HealthFlag);\r
\r
  if (TempStopCheckState) {\r
    mStopCheckAllApsStatus = FALSE;\r
  }\r
\r
  return Status;\r
}\r