UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c

/** @file
Agent Module to load other modules to deploy SMM Entry Vector for X86 CPU.

Copyright (c) 2009 - 2024, Intel Corporation. All rights reserved.<BR>
Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
Copyright (C) 2023 - 2024 Advanced Micro Devices, Inc. All rights reserved.<BR>

SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include "PiSmmCpuDxeSmm.h"

//
// SMM CPU Private Data structure that contains SMM Configuration Protocol
// along its supporting fields.
//
SMM_CPU_PRIVATE_DATA  mSmmCpuPrivateData = {
  SMM_CPU_PRIVATE_DATA_SIGNATURE,               // Signature
  NULL,                                         // SmmCpuHandle
  NULL,                                         // Pointer to ProcessorInfo array
  NULL,                                         // Pointer to Operation array
  NULL,                                         // Pointer to CpuSaveStateSize array
  NULL,                                         // Pointer to CpuSaveState array
  {
    { 0    }
  },                                            // SmmReservedSmramRegion
  {
    SmmStartupThisAp,                           // SmmCoreEntryContext.SmmStartupThisAp
    0,                                          // SmmCoreEntryContext.CurrentlyExecutingCpu
    0,                                          // SmmCoreEntryContext.NumberOfCpus
    NULL,                                       // SmmCoreEntryContext.CpuSaveStateSize
    NULL                                        // SmmCoreEntryContext.CpuSaveState
  },
  NULL,                                         // SmmCoreEntry
  {
    mSmmCpuPrivateData.SmmReservedSmramRegion,  // SmmConfiguration.SmramReservedRegions
    RegisterSmmEntry                            // SmmConfiguration.RegisterSmmEntry
  },
  NULL,                                         // pointer to Ap Wrapper Func array
  { NULL, NULL },                               // List_Entry for Tokens.
};

CPU_HOT_PLUG_DATA  mCpuHotPlugData = {
  CPU_HOT_PLUG_DATA_REVISION_1,                 // Revision
  0,                                            // Array Length of SmBase and APIC ID
  NULL,                                         // Pointer to APIC ID array
  NULL,                                         // Pointer to SMBASE array
  0,                                            // Reserved
  0,                                            // SmrrBase
  0                                             // SmrrSize
};

//
// Global pointer used to access mSmmCpuPrivateData from outside and inside SMM
//
SMM_CPU_PRIVATE_DATA  *gSmmCpuPrivate = &mSmmCpuPrivateData;

///
/// Handle for the SMM CPU Protocol
///
EFI_HANDLE  mSmmCpuHandle = NULL;

///
/// SMM CPU Protocol instance
///
EFI_SMM_CPU_PROTOCOL  mSmmCpu = {
  SmmReadSaveState,
  SmmWriteSaveState
};

///
/// SMM Memory Attribute Protocol instance
///
EDKII_SMM_MEMORY_ATTRIBUTE_PROTOCOL  mSmmMemoryAttribute = {
  EdkiiSmmGetMemoryAttributes,
  EdkiiSmmSetMemoryAttributes,
  EdkiiSmmClearMemoryAttributes
};

EFI_CPU_INTERRUPT_HANDLER  mExternalVectorTable[EXCEPTION_VECTOR_NUMBER];

volatile BOOLEAN  *mSmmInitialized = NULL;
UINT32            mBspApicId       = 0;

//
// SMM stack information
//
UINTN  mSmmStackArrayBase;
UINTN  mSmmStackArrayEnd;
UINTN  mSmmStackSize;

UINTN    mSmmShadowStackSize;
BOOLEAN  mCetSupported = TRUE;

UINTN  mMaxNumberOfCpus = 0;
UINTN  mNumberOfCpus    = 0;

//
// SMM ready to lock flag
//
BOOLEAN  mSmmReadyToLock = FALSE;

//
// Global used to cache PCD for SMM Code Access Check enable
//
BOOLEAN  mSmmCodeAccessCheckEnable = FALSE;

//
// Global used to cache SMM Debug Agent Supported ot not
//
BOOLEAN  mSmmDebugAgentSupport = FALSE;

//
// Global copy of the PcdPteMemoryEncryptionAddressOrMask
//
UINT64  mAddressEncMask = 0;

//
// Spin lock used to serialize setting of SMM Code Access Check feature
//
SPIN_LOCK  *mConfigSmmCodeAccessCheckLock = NULL;

//
// Saved SMM ranges information
//
EFI_SMRAM_DESCRIPTOR  *mSmmCpuSmramRanges;
UINTN                 mSmmCpuSmramRangeCount;

UINT8  mPhysicalAddressBits;

/**
  Initialize IDT to setup exception handlers for SMM.

**/
VOID
InitializeSmmIdt (
  VOID
  )
{
  EFI_STATUS       Status;
  BOOLEAN          InterruptState;
  IA32_DESCRIPTOR  DxeIdtr;

  //
  // There are 32 (not 255) entries in it since only processor
  // generated exceptions will be handled.
  //
  gcSmiIdtr.Limit = (sizeof (IA32_IDT_GATE_DESCRIPTOR) * 32) - 1;
  //
  // Allocate page aligned IDT, because it might be set as read only.
  //
  gcSmiIdtr.Base = (UINTN)AllocateCodePages (EFI_SIZE_TO_PAGES (gcSmiIdtr.Limit + 1));
  ASSERT (gcSmiIdtr.Base != 0);
  ZeroMem ((VOID *)gcSmiIdtr.Base, gcSmiIdtr.Limit + 1);

  //
  // Disable Interrupt and save DXE IDT table
  //
  InterruptState = SaveAndDisableInterrupts ();
  AsmReadIdtr (&DxeIdtr);
  //
  // Load SMM temporary IDT table
  //
  AsmWriteIdtr (&gcSmiIdtr);
  //
  // Setup SMM default exception handlers, SMM IDT table
  // will be updated and saved in gcSmiIdtr
  //
  Status = InitializeCpuExceptionHandlers (NULL);
  ASSERT_EFI_ERROR (Status);
  //
  // Restore DXE IDT table and CPU interrupt
  //
  AsmWriteIdtr ((IA32_DESCRIPTOR *)&DxeIdtr);
  SetInterruptState (InterruptState);
}

/**
  Search module name by input IP address and output it.

  @param CallerIpAddress   Caller instruction pointer.

**/
VOID
DumpModuleInfoByIp (
  IN  UINTN  CallerIpAddress
  )
{
  UINTN  Pe32Data;
  VOID   *PdbPointer;

  //
  // Find Image Base
  //
  Pe32Data = PeCoffSearchImageBase (CallerIpAddress);
  if (Pe32Data != 0) {
    DEBUG ((DEBUG_ERROR, "It is invoked from the instruction before IP(0x%p)", (VOID *)CallerIpAddress));
    PdbPointer = PeCoffLoaderGetPdbPointer ((VOID *)Pe32Data);
    if (PdbPointer != NULL) {
      DEBUG ((DEBUG_ERROR, " in module (%a)\n", PdbPointer));
    }
  }
}

/**
  Read information from the CPU save state.

  @param  This      EFI_SMM_CPU_PROTOCOL instance
  @param  Width     The number of bytes to read from the CPU save state.
  @param  Register  Specifies the CPU register to read form the save state.
  @param  CpuIndex  Specifies the zero-based index of the CPU save state.
  @param  Buffer    Upon return, this holds the CPU register value read from the save state.

  @retval EFI_SUCCESS   The register was read from Save State
  @retval EFI_NOT_FOUND The register is not defined for the Save State of Processor
  @retval EFI_INVALID_PARAMETER   This or Buffer is NULL.

**/
EFI_STATUS
EFIAPI
SmmReadSaveState (
  IN CONST EFI_SMM_CPU_PROTOCOL   *This,
  IN UINTN                        Width,
  IN EFI_SMM_SAVE_STATE_REGISTER  Register,
  IN UINTN                        CpuIndex,
  OUT VOID                        *Buffer
  )
{
  EFI_STATUS  Status;

  //
  // Retrieve pointer to the specified CPU's SMM Save State buffer
  //
  if ((CpuIndex >= gSmst->NumberOfCpus) || (Buffer == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  //
  // The SpeculationBarrier() call here is to ensure the above check for the
  // CpuIndex has been completed before the execution of subsequent codes.
  //
  SpeculationBarrier ();

  //
  // Check for special EFI_SMM_SAVE_STATE_REGISTER_PROCESSOR_ID
  //
  if (Register == EFI_SMM_SAVE_STATE_REGISTER_PROCESSOR_ID) {
    //
    // The pseudo-register only supports the 64-bit size specified by Width.
    //
    if (Width != sizeof (UINT64)) {
      return EFI_INVALID_PARAMETER;
    }

    //
    // If the processor is in SMM at the time the SMI occurred,
    // the pseudo register value for EFI_SMM_SAVE_STATE_REGISTER_PROCESSOR_ID is returned in Buffer.
    // Otherwise, EFI_NOT_FOUND is returned.
    //
    if (*(mSmmMpSyncData->CpuData[CpuIndex].Present)) {
      *(UINT64 *)Buffer = gSmmCpuPrivate->ProcessorInfo[CpuIndex].ProcessorId;
      return EFI_SUCCESS;
    } else {
      return EFI_NOT_FOUND;
    }
  }

  if (!(*(mSmmMpSyncData->CpuData[CpuIndex].Present))) {
    return EFI_INVALID_PARAMETER;
  }

  Status = MmSaveStateReadRegister (CpuIndex, Register, Width, Buffer);

  return Status;
}

/**
  Write data to the CPU save state.

  @param  This      EFI_SMM_CPU_PROTOCOL instance
  @param  Width     The number of bytes to read from the CPU save state.
  @param  Register  Specifies the CPU register to write to the save state.
  @param  CpuIndex  Specifies the zero-based index of the CPU save state
  @param  Buffer    Upon entry, this holds the new CPU register value.

  @retval EFI_SUCCESS   The register was written from Save State
  @retval EFI_NOT_FOUND The register is not defined for the Save State of Processor
  @retval EFI_INVALID_PARAMETER   ProcessorIndex or Width is not correct

**/
EFI_STATUS
EFIAPI
SmmWriteSaveState (
  IN CONST EFI_SMM_CPU_PROTOCOL   *This,
  IN UINTN                        Width,
  IN EFI_SMM_SAVE_STATE_REGISTER  Register,
  IN UINTN                        CpuIndex,
  IN CONST VOID                   *Buffer
  )
{
  EFI_STATUS  Status;

  //
  // Retrieve pointer to the specified CPU's SMM Save State buffer
  //
  if ((CpuIndex >= gSmst->NumberOfCpus) || (Buffer == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  //
  // Writes to EFI_SMM_SAVE_STATE_REGISTER_PROCESSOR_ID are ignored
  //
  if (Register == EFI_SMM_SAVE_STATE_REGISTER_PROCESSOR_ID) {
    return EFI_SUCCESS;
  }

  if (!mSmmMpSyncData->CpuData[CpuIndex].Present) {
    return EFI_INVALID_PARAMETER;
  }

  Status = MmSaveStateWriteRegister (CpuIndex, Register, Width, Buffer);

  return Status;
}

/**
  Initialize SMM environment.

**/
VOID
InitializeSmm (
  VOID
  )
{
  UINT32   ApicId;
  UINTN    Index;
  BOOLEAN  IsBsp;

  ApicId = GetApicId ();

  IsBsp = (BOOLEAN)(mBspApicId == ApicId);

  ASSERT (mNumberOfCpus <= mMaxNumberOfCpus);

  for (Index = 0; Index < mNumberOfCpus; Index++) {
    if (ApicId == (UINT32)gSmmCpuPrivate->ProcessorInfo[Index].ProcessorId) {
      PERF_CODE (
        MpPerfBegin (Index, SMM_MP_PERF_PROCEDURE_ID (InitializeSmm));
        );
      //
      // Initialize SMM specific features on the currently executing CPU
      //
      SmmCpuFeaturesInitializeProcessor (
        Index,
        IsBsp,
        gSmmCpuPrivate->ProcessorInfo,
        &mCpuHotPlugData
        );

      if (!mSmmS3Flag) {
        //
        // Check XD and BTS features on each processor on normal boot
        //
        CheckFeatureSupported ();
      } else if (IsBsp) {
        //
        // BSP rebase is already done above.
        // Initialize private data during S3 resume
        //
        InitializeMpSyncData ();
      }

      PERF_CODE (
        MpPerfEnd (Index, SMM_MP_PERF_PROCEDURE_ID (InitializeSmm));
        );

      return;
    }
  }

  ASSERT (FALSE);
}

/**
  Issue SMI IPI (All Excluding Self SMM IPI + BSP SMM IPI) to execute first SMI init.

**/
VOID
ExecuteFirstSmiInit (
  VOID
  )
{
  UINTN  Index;

  PERF_FUNCTION_BEGIN ();

  if (mSmmInitialized == NULL) {
    mSmmInitialized = (BOOLEAN *)AllocatePool (sizeof (BOOLEAN) * mMaxNumberOfCpus);
  }

  ASSERT (mSmmInitialized != NULL);
  if (mSmmInitialized == NULL) {
    PERF_FUNCTION_END ();
    return;
  }

  //
  // Reset the mSmmInitialized to false.
  //
  ZeroMem ((VOID *)mSmmInitialized, sizeof (BOOLEAN) * mMaxNumberOfCpus);

  //
  // Get the BSP ApicId.
  //
  mBspApicId = GetApicId ();

  //
  // Issue SMI IPI (All Excluding Self SMM IPI + BSP SMM IPI) for SMM init
  //
  SendSmiIpi (mBspApicId);
  SendSmiIpiAllExcludingSelf ();

  //
  // Wait for all processors to finish its 1st SMI
  //
  for (Index = 0; Index < mNumberOfCpus; Index++) {
    while (!(BOOLEAN)mSmmInitialized[Index]) {
    }
  }

  PERF_FUNCTION_END ();
}

/**
  SMM Ready To Lock event notification handler.

  mSmmReadyToLock is set to perform additional lock actions that must be
  performed from SMM on the next SMI.

  @param[in] Protocol   Points to the protocol's unique identifier.
  @param[in] Interface  Points to the interface instance.
  @param[in] Handle     The handle on which the interface was installed.

  @retval EFI_SUCCESS   Notification handler runs successfully.
 **/
EFI_STATUS
EFIAPI
SmmReadyToLockEventNotify (
  IN CONST EFI_GUID  *Protocol,
  IN VOID            *Interface,
  IN EFI_HANDLE      Handle
  )
{
  //
  // Cache a copy of UEFI memory map before we start profiling feature.
  //
  GetUefiMemoryMap ();

  //
  // Set SMM ready to lock flag and return
  //
  mSmmReadyToLock = TRUE;
  return EFI_SUCCESS;
}

/**
  Function to compare 2 SMM_BASE_HOB_DATA pointer based on ProcessorIndex.

  @param[in] Buffer1            pointer to SMM_BASE_HOB_DATA poiner to compare
  @param[in] Buffer2            pointer to second SMM_BASE_HOB_DATA pointer to compare

  @retval 0                     Buffer1 equal to Buffer2
  @retval <0                    Buffer1 is less than Buffer2
  @retval >0                    Buffer1 is greater than Buffer2
**/
INTN
EFIAPI
SmBaseHobCompare (
  IN  CONST VOID  *Buffer1,
  IN  CONST VOID  *Buffer2
  )
{
  if ((*(SMM_BASE_HOB_DATA **)Buffer1)->ProcessorIndex > (*(SMM_BASE_HOB_DATA **)Buffer2)->ProcessorIndex) {
    return 1;
  } else if ((*(SMM_BASE_HOB_DATA **)Buffer1)->ProcessorIndex < (*(SMM_BASE_HOB_DATA **)Buffer2)->ProcessorIndex) {
    return -1;
  }

  return 0;
}

/**
  Extract SmBase for all CPU from SmmBase HOB.

  @param[in]  MaxNumberOfCpus        Max NumberOfCpus.

  @param[out] AllocatedSmBaseBuffer  Pointer to SmBase Buffer allocated
                                     by this function. Only set if the
                                     function returns EFI_SUCCESS.

  @retval EFI_SUCCESS           SmBase Buffer output successfully.
  @retval EFI_OUT_OF_RESOURCES  Memory allocation failed.
  @retval EFI_NOT_FOUND         gSmmBaseHobGuid was never created.
**/
STATIC
EFI_STATUS
GetSmBase (
  IN  UINTN  MaxNumberOfCpus,
  OUT UINTN  **AllocatedSmBaseBuffer
  )
{
  UINTN              HobCount;
  EFI_HOB_GUID_TYPE  *GuidHob;
  SMM_BASE_HOB_DATA  *SmmBaseHobData;
  UINTN              NumberOfProcessors;
  SMM_BASE_HOB_DATA  **SmBaseHobs;
  UINTN              *SmBaseBuffer;
  UINTN              HobIndex;
  UINTN              SortBuffer;
  UINTN              ProcessorIndex;
  UINT64             PrevProcessorIndex;
  EFI_HOB_GUID_TYPE  *FirstSmmBaseGuidHob;

  SmmBaseHobData     = NULL;
  HobIndex           = 0;
  ProcessorIndex     = 0;
  HobCount           = 0;
  NumberOfProcessors = 0;

  FirstSmmBaseGuidHob = GetFirstGuidHob (&gSmmBaseHobGuid);
  if (FirstSmmBaseGuidHob == NULL) {
    return EFI_NOT_FOUND;
  }

  GuidHob = FirstSmmBaseGuidHob;
  while (GuidHob != NULL) {
    HobCount++;
    SmmBaseHobData      = GET_GUID_HOB_DATA (GuidHob);
    NumberOfProcessors += SmmBaseHobData->NumberOfProcessors;

    if (NumberOfProcessors >= MaxNumberOfCpus) {
      break;
    }

    GuidHob = GetNextGuidHob (&gSmmBaseHobGuid, GET_NEXT_HOB (GuidHob));
  }

  ASSERT (NumberOfProcessors == MaxNumberOfCpus);
  if (NumberOfProcessors != MaxNumberOfCpus) {
    CpuDeadLoop ();
  }

  SmBaseHobs = AllocatePool (sizeof (SMM_BASE_HOB_DATA *) * HobCount);
  if (SmBaseHobs == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  //
  // Record each SmmBaseHob pointer in the SmBaseHobs.
  // The FirstSmmBaseGuidHob is to speed up this while-loop
  // without needing to look for SmBaseHob from beginning.
  //
  GuidHob = FirstSmmBaseGuidHob;
  while (HobIndex < HobCount) {
    SmBaseHobs[HobIndex++] = GET_GUID_HOB_DATA (GuidHob);
    GuidHob                = GetNextGuidHob (&gSmmBaseHobGuid, GET_NEXT_HOB (GuidHob));
  }

  SmBaseBuffer = (UINTN *)AllocatePool (sizeof (UINTN) * (MaxNumberOfCpus));
  ASSERT (SmBaseBuffer != NULL);
  if (SmBaseBuffer == NULL) {
    FreePool (SmBaseHobs);
    return EFI_OUT_OF_RESOURCES;
  }

  QuickSort (SmBaseHobs, HobCount, sizeof (SMM_BASE_HOB_DATA *), (BASE_SORT_COMPARE)SmBaseHobCompare, &SortBuffer);
  PrevProcessorIndex = 0;
  for (HobIndex = 0; HobIndex < HobCount; HobIndex++) {
    //
    // Make sure no overlap and no gap in the CPU range covered by each HOB
    //
    ASSERT (SmBaseHobs[HobIndex]->ProcessorIndex == PrevProcessorIndex);

    //
    // Cache each SmBase in order.
    //
    for (ProcessorIndex = 0; ProcessorIndex < SmBaseHobs[HobIndex]->NumberOfProcessors; ProcessorIndex++) {
      SmBaseBuffer[PrevProcessorIndex + ProcessorIndex] = (UINTN)SmBaseHobs[HobIndex]->SmBase[ProcessorIndex];
    }

    PrevProcessorIndex += SmBaseHobs[HobIndex]->NumberOfProcessors;
  }

  FreePool (SmBaseHobs);
  *AllocatedSmBaseBuffer = SmBaseBuffer;
  return EFI_SUCCESS;
}

/**
  Function to compare 2 MP_INFORMATION2_HOB_DATA pointer based on ProcessorIndex.

  @param[in] Buffer1            pointer to MP_INFORMATION2_HOB_DATA poiner to compare
  @param[in] Buffer2            pointer to second MP_INFORMATION2_HOB_DATA pointer to compare

  @retval 0                     Buffer1 equal to Buffer2
  @retval <0                    Buffer1 is less than Buffer2
  @retval >0                    Buffer1 is greater than Buffer2
**/
INTN
EFIAPI
MpInformation2HobCompare (
  IN  CONST VOID  *Buffer1,
  IN  CONST VOID  *Buffer2
  )
{
  if ((*(MP_INFORMATION2_HOB_DATA **)Buffer1)->ProcessorIndex > (*(MP_INFORMATION2_HOB_DATA **)Buffer2)->ProcessorIndex) {
    return 1;
  } else if ((*(MP_INFORMATION2_HOB_DATA **)Buffer1)->ProcessorIndex < (*(MP_INFORMATION2_HOB_DATA **)Buffer2)->ProcessorIndex) {
    return -1;
  }

  return 0;
}

/**
  Extract NumberOfCpus, MaxNumberOfCpus and EFI_PROCESSOR_INFORMATION for all CPU from gEfiMpServiceProtocolGuid.

  @param[out] NumberOfCpus           Pointer to NumberOfCpus.
  @param[out] MaxNumberOfCpus        Pointer to MaxNumberOfCpus.

  @retval ProcessorInfo              Pointer to EFI_PROCESSOR_INFORMATION buffer.
**/
EFI_PROCESSOR_INFORMATION *
GetMpInformationFromMpServices (
  OUT UINTN  *NumberOfCpus,
  OUT UINTN  *MaxNumberOfCpus
  )
{
  EFI_STATUS                 Status;
  UINTN                      Index;
  UINTN                      NumberOfEnabledProcessors;
  UINTN                      NumberOfProcessors;
  EFI_MP_SERVICES_PROTOCOL   *MpService;
  EFI_PROCESSOR_INFORMATION  *ProcessorInfo;

  if ((NumberOfCpus == NULL) || (MaxNumberOfCpus == NULL)) {
    ASSERT_EFI_ERROR (EFI_INVALID_PARAMETER);
    return NULL;
  }

  ProcessorInfo    = NULL;
  *NumberOfCpus    = 0;
  *MaxNumberOfCpus = 0;

  /// Get the MP Services Protocol
  Status = gBS->LocateProtocol (&gEfiMpServiceProtocolGuid, NULL, (VOID **)&MpService);
  if (EFI_ERROR (Status)) {
    ASSERT_EFI_ERROR (Status);
    return NULL;
  }

  /// Get the number of processors
  Status = MpService->GetNumberOfProcessors (MpService, &NumberOfProcessors, &NumberOfEnabledProcessors);
  if (EFI_ERROR (Status)) {
    ASSERT_EFI_ERROR (Status);
    return NULL;
  }

  ASSERT (NumberOfProcessors <= PcdGet32 (PcdCpuMaxLogicalProcessorNumber));

  /// Allocate buffer for processor information
  ProcessorInfo = AllocateZeroPool (sizeof (EFI_PROCESSOR_INFORMATION) * NumberOfProcessors);
  if (ProcessorInfo == NULL) {
    ASSERT_EFI_ERROR (EFI_OUT_OF_RESOURCES);
    return NULL;
  }

  /// Get processor information
  for (Index = 0; Index < NumberOfProcessors; Index++) {
    Status = MpService->GetProcessorInfo (MpService, Index | CPU_V2_EXTENDED_TOPOLOGY, &ProcessorInfo[Index]);
    if (EFI_ERROR (Status)) {
      FreePool (ProcessorInfo);
      DEBUG ((DEBUG_ERROR, "%a: Failed to get processor information for processor %d\n", __func__, Index));
      ASSERT_EFI_ERROR (Status);
      return NULL;
    }
  }

  *NumberOfCpus = NumberOfEnabledProcessors;

  ASSERT (*NumberOfCpus <= PcdGet32 (PcdCpuMaxLogicalProcessorNumber));
  //
  // If support CPU hot plug, we need to allocate resources for possibly hot-added processors
  //
  if (FeaturePcdGet (PcdCpuHotPlugSupport)) {
    *MaxNumberOfCpus = PcdGet32 (PcdCpuMaxLogicalProcessorNumber);
  } else {
    *MaxNumberOfCpus = *NumberOfCpus;
  }

  return ProcessorInfo;
}

/**
  Extract NumberOfCpus, MaxNumberOfCpus and EFI_PROCESSOR_INFORMATION for all CPU from MpInformation2 HOB.

  @param[out] NumberOfCpus           Pointer to NumberOfCpus.
  @param[out] MaxNumberOfCpus        Pointer to MaxNumberOfCpus.

  @retval ProcessorInfo              Pointer to EFI_PROCESSOR_INFORMATION buffer.
**/
EFI_PROCESSOR_INFORMATION *
GetMpInformation (
  OUT UINTN  *NumberOfCpus,
  OUT UINTN  *MaxNumberOfCpus
  )
{
  EFI_HOB_GUID_TYPE          *GuidHob;
  EFI_HOB_GUID_TYPE          *FirstMpInfo2Hob;
  MP_INFORMATION2_HOB_DATA   *MpInformation2HobData;
  UINTN                      HobCount;
  UINTN                      HobIndex;
  MP_INFORMATION2_HOB_DATA   **MpInfo2Hobs;
  UINTN                      SortBuffer;
  UINTN                      ProcessorIndex;
  UINT64                     PrevProcessorIndex;
  MP_INFORMATION2_ENTRY      *MpInformation2Entry;
  EFI_PROCESSOR_INFORMATION  *ProcessorInfo;

  GuidHob               = NULL;
  MpInformation2HobData = NULL;
  FirstMpInfo2Hob       = NULL;
  MpInfo2Hobs           = NULL;
  HobIndex              = 0;
  HobCount              = 0;

  FirstMpInfo2Hob = GetFirstGuidHob (&gMpInformation2HobGuid);
  if (FirstMpInfo2Hob == NULL) {
    DEBUG ((DEBUG_INFO, "%a: [INFO] gMpInformation2HobGuid HOB not found.\n", __func__));
    return GetMpInformationFromMpServices (NumberOfCpus, MaxNumberOfCpus);
  }

  GuidHob = FirstMpInfo2Hob;
  while (GuidHob != NULL) {
    MpInformation2HobData = GET_GUID_HOB_DATA (GuidHob);

    //
    // This is the last MpInformationHob in the HOB list.
    //
    if (MpInformation2HobData->NumberOfProcessors == 0) {
      ASSERT (HobCount != 0);
      break;
    }

    HobCount++;
    *NumberOfCpus += MpInformation2HobData->NumberOfProcessors;
    GuidHob        = GetNextGuidHob (&gMpInformation2HobGuid, GET_NEXT_HOB (GuidHob));
  }

  ASSERT (*NumberOfCpus <= PcdGet32 (PcdCpuMaxLogicalProcessorNumber));

  //
  // If support CPU hot plug, we need to allocate resources for possibly hot-added processors
  //
  if (FeaturePcdGet (PcdCpuHotPlugSupport)) {
    *MaxNumberOfCpus = PcdGet32 (PcdCpuMaxLogicalProcessorNumber);
  } else {
    *MaxNumberOfCpus = *NumberOfCpus;
  }

  MpInfo2Hobs = AllocatePool (sizeof (MP_INFORMATION2_HOB_DATA *) * HobCount);
  ASSERT (MpInfo2Hobs != NULL);
  if (MpInfo2Hobs == NULL) {
    return NULL;
  }

  //
  // Record each MpInformation2Hob pointer in the MpInfo2Hobs.
  // The FirstMpInfo2Hob is to speed up this while-loop without
  // needing to look for MpInfo2Hob from beginning.
  //
  GuidHob = FirstMpInfo2Hob;
  while (HobIndex < HobCount) {
    MpInfo2Hobs[HobIndex++] = GET_GUID_HOB_DATA (GuidHob);
    GuidHob                 = GetNextGuidHob (&gMpInformation2HobGuid, GET_NEXT_HOB (GuidHob));
  }

  ProcessorInfo = (EFI_PROCESSOR_INFORMATION *)AllocatePool (sizeof (EFI_PROCESSOR_INFORMATION) * (*MaxNumberOfCpus));
  ASSERT (ProcessorInfo != NULL);
  if (ProcessorInfo == NULL) {
    FreePool (MpInfo2Hobs);
    return NULL;
  }

  QuickSort (MpInfo2Hobs, HobCount, sizeof (MP_INFORMATION2_HOB_DATA *), (BASE_SORT_COMPARE)MpInformation2HobCompare, &SortBuffer);
  PrevProcessorIndex = 0;
  for (HobIndex = 0; HobIndex < HobCount; HobIndex++) {
    //
    // Make sure no overlap and no gap in the CPU range covered by each HOB
    //
    ASSERT (MpInfo2Hobs[HobIndex]->ProcessorIndex == PrevProcessorIndex);

    //
    // Cache each EFI_PROCESSOR_INFORMATION in order.
    //
    for (ProcessorIndex = 0; ProcessorIndex < MpInfo2Hobs[HobIndex]->NumberOfProcessors; ProcessorIndex++) {
      MpInformation2Entry = GET_MP_INFORMATION_ENTRY (MpInfo2Hobs[HobIndex], ProcessorIndex);
      CopyMem (
        &ProcessorInfo[PrevProcessorIndex + ProcessorIndex],
        &MpInformation2Entry->ProcessorInfo,
        sizeof (EFI_PROCESSOR_INFORMATION)
        );
    }

    PrevProcessorIndex += MpInfo2Hobs[HobIndex]->NumberOfProcessors;
  }

  FreePool (MpInfo2Hobs);
  return ProcessorInfo;
}

/**
  The module Entry Point of the CPU SMM driver.

  @param  ImageHandle    The firmware allocated handle for the EFI image.
  @param  SystemTable    A pointer to the EFI System Table.

  @retval EFI_SUCCESS    The entry point is executed successfully.
  @retval Other          Some error occurs when executing this entry point.

**/
EFI_STATUS
EFIAPI
PiCpuSmmEntry (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS  Status;
  UINTN       Index;
  UINTN       TileCodeSize;
  UINTN       TileDataSize;
  UINTN       TileSize;
  UINT8       *Stacks;
  VOID        *Registration;
  UINT32      RegEax;
  UINT32      RegEbx;
  UINT32      RegEcx;
  UINT32      RegEdx;
  UINTN       FamilyId;
  UINTN       ModelId;
  UINT32      Cr3;

  PERF_FUNCTION_BEGIN ();

  //
  // Initialize address fixup
  //
  PiSmmCpuSmiEntryFixupAddress ();

  //
  // Initialize Debug Agent to support source level debug in SMM code
  //
  InitializeDebugAgent (DEBUG_AGENT_INIT_SMM, &mSmmDebugAgentSupport, NULL);

  //
  // Report the start of CPU SMM initialization.
  //
  REPORT_STATUS_CODE (
    EFI_PROGRESS_CODE,
    EFI_COMPUTING_UNIT_HOST_PROCESSOR | EFI_CU_HP_PC_SMM_INIT
    );

  //
  // Find out SMRR Base and SMRR Size
  //
  FindSmramInfo (&mCpuHotPlugData.SmrrBase, &mCpuHotPlugData.SmrrSize);

  //
  // Retrive NumberOfProcessors, MaxNumberOfCpus and EFI_PROCESSOR_INFORMATION for all CPU from MpInformation2 HOB.
  //
  gSmmCpuPrivate->ProcessorInfo = GetMpInformation (&mNumberOfCpus, &mMaxNumberOfCpus);
  ASSERT (gSmmCpuPrivate->ProcessorInfo != NULL);

  //
  // If support CPU hot plug, PcdCpuSmmEnableBspElection should be set to TRUE.
  // A constant BSP index makes no sense because it may be hot removed.
  //
  DEBUG_CODE_BEGIN ();
  if (FeaturePcdGet (PcdCpuHotPlugSupport)) {
    ASSERT (FeaturePcdGet (PcdCpuSmmEnableBspElection));
  }

  DEBUG_CODE_END ();

  //
  // Save the PcdCpuSmmCodeAccessCheckEnable value into a global variable.
  //
  mSmmCodeAccessCheckEnable = PcdGetBool (PcdCpuSmmCodeAccessCheckEnable);
  DEBUG ((DEBUG_INFO, "PcdCpuSmmCodeAccessCheckEnable = %d\n", mSmmCodeAccessCheckEnable));

  //
  // Save the PcdPteMemoryEncryptionAddressOrMask value into a global variable.
  // Make sure AddressEncMask is contained to smallest supported address field.
  //
  mAddressEncMask = PcdGet64 (PcdPteMemoryEncryptionAddressOrMask) & PAGING_1G_ADDRESS_MASK_64;
  DEBUG ((DEBUG_INFO, "mAddressEncMask = 0x%lx\n", mAddressEncMask));

  gSmmCpuPrivate->SmmCoreEntryContext.NumberOfCpus = mMaxNumberOfCpus;

  PERF_CODE (
    InitializeMpPerf (gSmmCpuPrivate->SmmCoreEntryContext.NumberOfCpus);
    );

  //
  // The CPU save state and code for the SMI entry point are tiled within an SMRAM
  // allocated buffer.  The minimum size of this buffer for a uniprocessor system
  // is 32 KB, because the entry point is SMBASE + 32KB, and CPU save state area
  // just below SMBASE + 64KB.  If more than one CPU is present in the platform,
  // then the SMI entry point and the CPU save state areas can be tiles to minimize
  // the total amount SMRAM required for all the CPUs.  The tile size can be computed
  // by adding the   // CPU save state size, any extra CPU specific context, and
  // the size of code that must be placed at the SMI entry point to transfer
  // control to a C function in the native SMM execution mode.  This size is
  // rounded up to the nearest power of 2 to give the tile size for a each CPU.
  // The total amount of memory required is the maximum number of CPUs that
  // platform supports times the tile size.  The picture below shows the tiling,
  // where m is the number of tiles that fit in 32KB.
  //
  //  +-----------------------------+  <-- 2^n offset from Base of allocated buffer
  //  |   CPU m+1 Save State        |
  //  +-----------------------------+
  //  |   CPU m+1 Extra Data        |
  //  +-----------------------------+
  //  |   Padding                   |
  //  +-----------------------------+
  //  |   CPU 2m  SMI Entry         |
  //  +#############################+  <-- Base of allocated buffer + 64 KB
  //  |   CPU m-1 Save State        |
  //  +-----------------------------+
  //  |   CPU m-1 Extra Data        |
  //  +-----------------------------+
  //  |   Padding                   |
  //  +-----------------------------+
  //  |   CPU 2m-1 SMI Entry        |
  //  +=============================+  <-- 2^n offset from Base of allocated buffer
  //  |   . . . . . . . . . . . .   |
  //  +=============================+  <-- 2^n offset from Base of allocated buffer
  //  |   CPU 2 Save State          |
  //  +-----------------------------+
  //  |   CPU 2 Extra Data          |
  //  +-----------------------------+
  //  |   Padding                   |
  //  +-----------------------------+
  //  |   CPU m+1 SMI Entry         |
  //  +=============================+  <-- Base of allocated buffer + 32 KB
  //  |   CPU 1 Save State          |
  //  +-----------------------------+
  //  |   CPU 1 Extra Data          |
  //  +-----------------------------+
  //  |   Padding                   |
  //  +-----------------------------+
  //  |   CPU m SMI Entry           |
  //  +#############################+  <-- Base of allocated buffer + 32 KB == CPU 0 SMBASE + 64 KB
  //  |   CPU 0 Save State          |
  //  +-----------------------------+
  //  |   CPU 0 Extra Data          |
  //  +-----------------------------+
  //  |   Padding                   |
  //  +-----------------------------+
  //  |   CPU m-1 SMI Entry         |
  //  +=============================+  <-- 2^n offset from Base of allocated buffer
  //  |   . . . . . . . . . . . .   |
  //  +=============================+  <-- 2^n offset from Base of allocated buffer
  //  |   Padding                   |
  //  +-----------------------------+
  //  |   CPU 1 SMI Entry           |
  //  +=============================+  <-- 2^n offset from Base of allocated buffer
  //  |   Padding                   |
  //  +-----------------------------+
  //  |   CPU 0 SMI Entry           |
  //  +#############################+  <-- Base of allocated buffer == CPU 0 SMBASE + 32 KB
  //

  //
  // Retrieve CPU Family
  //
  AsmCpuid (CPUID_VERSION_INFO, &RegEax, NULL, NULL, NULL);
  FamilyId = (RegEax >> 8) & 0xf;
  ModelId  = (RegEax >> 4) & 0xf;
  if ((FamilyId == 0x06) || (FamilyId == 0x0f)) {
    ModelId = ModelId | ((RegEax >> 12) & 0xf0);
  }

  RegEdx = 0;
  AsmCpuid (CPUID_EXTENDED_FUNCTION, &RegEax, NULL, NULL, NULL);
  if (RegEax >= CPUID_EXTENDED_CPU_SIG) {
    AsmCpuid (CPUID_EXTENDED_CPU_SIG, NULL, NULL, NULL, &RegEdx);
  }

  //
  // Determine the mode of the CPU at the time an SMI occurs
  //   Intel(R) 64 and IA-32 Architectures Software Developer's Manual
  //   Volume 3C, Section 34.4.1.1
  //
  mSmmSaveStateRegisterLma = EFI_SMM_SAVE_STATE_REGISTER_LMA_32BIT;
  if ((RegEdx & BIT29) != 0) {
    mSmmSaveStateRegisterLma = EFI_SMM_SAVE_STATE_REGISTER_LMA_64BIT;
  }

  if (FamilyId == 0x06) {
    if ((ModelId == 0x17) || (ModelId == 0x0f) || (ModelId == 0x1c)) {
      mSmmSaveStateRegisterLma = EFI_SMM_SAVE_STATE_REGISTER_LMA_64BIT;
    }
  }

  DEBUG ((DEBUG_INFO, "PcdControlFlowEnforcementPropertyMask = %d\n", PcdGet32 (PcdControlFlowEnforcementPropertyMask)));
  if (PcdGet32 (PcdControlFlowEnforcementPropertyMask) != 0) {
    AsmCpuid (CPUID_SIGNATURE, &RegEax, NULL, NULL, NULL);
    if (RegEax >= CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS) {
      AsmCpuidEx (CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS, CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS_SUB_LEAF_INFO, NULL, NULL, &RegEcx, &RegEdx);
      DEBUG ((DEBUG_INFO, "CPUID[7/0] ECX - 0x%08x\n", RegEcx));
      DEBUG ((DEBUG_INFO, "  CET_SS  - 0x%08x\n", RegEcx & CPUID_CET_SS));
      DEBUG ((DEBUG_INFO, "  CET_IBT - 0x%08x\n", RegEdx & CPUID_CET_IBT));
      if ((RegEcx & CPUID_CET_SS) == 0) {
        mCetSupported = FALSE;
        PatchInstructionX86 (mPatchCetSupported, mCetSupported, 1);
      }

      if (mCetSupported) {
        AsmCpuidEx (CPUID_EXTENDED_STATE, CPUID_EXTENDED_STATE_SUB_LEAF, NULL, &RegEbx, &RegEcx, NULL);
        DEBUG ((DEBUG_INFO, "CPUID[D/1] EBX - 0x%08x, ECX - 0x%08x\n", RegEbx, RegEcx));
        AsmCpuidEx (CPUID_EXTENDED_STATE, 11, &RegEax, NULL, &RegEcx, NULL);
        DEBUG ((DEBUG_INFO, "CPUID[D/11] EAX - 0x%08x, ECX - 0x%08x\n", RegEax, RegEcx));
        AsmCpuidEx (CPUID_EXTENDED_STATE, 12, &RegEax, NULL, &RegEcx, NULL);
        DEBUG ((DEBUG_INFO, "CPUID[D/12] EAX - 0x%08x, ECX - 0x%08x\n", RegEax, RegEcx));
      }
    } else {
      mCetSupported = FALSE;
      PatchInstructionX86 (mPatchCetSupported, mCetSupported, 1);
    }
  } else {
    mCetSupported = FALSE;
    PatchInstructionX86 (mPatchCetSupported, mCetSupported, 1);
  }

  //
  // Compute tile size of buffer required to hold the CPU SMRAM Save State Map, extra CPU
  // specific context start starts at SMBASE + SMM_PSD_OFFSET, and the SMI entry point.
  // This size is rounded up to nearest power of 2.
  //
  TileCodeSize = GetSmiHandlerSize ();
  TileCodeSize = ALIGN_VALUE (TileCodeSize, SIZE_4KB);
  TileDataSize = (SMRAM_SAVE_STATE_MAP_OFFSET - SMM_PSD_OFFSET) + sizeof (SMRAM_SAVE_STATE_MAP);
  TileDataSize = ALIGN_VALUE (TileDataSize, SIZE_4KB);
  TileSize     = TileDataSize + TileCodeSize - 1;
  TileSize     = 2 * GetPowerOfTwo32 ((UINT32)TileSize);
  DEBUG ((DEBUG_INFO, "SMRAM TileSize = 0x%08x (0x%08x, 0x%08x)\n", TileSize, TileCodeSize, TileDataSize));

  //
  // If the TileSize is larger than space available for the SMI Handler of
  // CPU[i], the extra CPU specific context of CPU[i+1], and the SMRAM Save
  // State Map of CPU[i+1], then ASSERT().  If this ASSERT() is triggered, then
  // the SMI Handler size must be reduced or the size of the extra CPU specific
  // context must be reduced.
  //
  ASSERT (TileSize <= (SMRAM_SAVE_STATE_MAP_OFFSET + sizeof (SMRAM_SAVE_STATE_MAP) - SMM_HANDLER_OFFSET));

  //
  // Check whether the Required TileSize is enough.
  //
  if (TileSize > SIZE_8KB) {
    DEBUG ((DEBUG_ERROR, "The Range of Smbase in SMRAM is not enough -- Required TileSize = 0x%08x, Actual TileSize = 0x%08x\n", TileSize, SIZE_8KB));
    FreePool (gSmmCpuPrivate->ProcessorInfo);
    CpuDeadLoop ();
    return RETURN_BUFFER_TOO_SMALL;
  }

  //
  // Retrieve the allocated SmmBase from gSmmBaseHobGuid. If found,
  // means the SmBase relocation has been done.
  //
  mCpuHotPlugData.SmBase = NULL;
  Status                 = GetSmBase (mMaxNumberOfCpus, &mCpuHotPlugData.SmBase);
  ASSERT (!EFI_ERROR (Status));
  if (EFI_ERROR (Status)) {
    CpuDeadLoop ();
  }

  //
  // ASSERT SmBase has been relocated.
  //
  ASSERT (mCpuHotPlugData.SmBase != NULL);

  //
  // Allocate buffer for pointers to array in  SMM_CPU_PRIVATE_DATA.
  //
  gSmmCpuPrivate->Operation = (SMM_CPU_OPERATION *)AllocatePool (sizeof (SMM_CPU_OPERATION) * mMaxNumberOfCpus);
  ASSERT (gSmmCpuPrivate->Operation != NULL);

  gSmmCpuPrivate->CpuSaveStateSize = (UINTN *)AllocatePool (sizeof (UINTN) * mMaxNumberOfCpus);
  ASSERT (gSmmCpuPrivate->CpuSaveStateSize != NULL);

  gSmmCpuPrivate->CpuSaveState = (VOID **)AllocatePool (sizeof (VOID *) * mMaxNumberOfCpus);
  ASSERT (gSmmCpuPrivate->CpuSaveState != NULL);

  mSmmCpuPrivateData.SmmCoreEntryContext.CpuSaveStateSize = gSmmCpuPrivate->CpuSaveStateSize;
  mSmmCpuPrivateData.SmmCoreEntryContext.CpuSaveState     = gSmmCpuPrivate->CpuSaveState;

  //
  // Allocate buffer for pointers to array in CPU_HOT_PLUG_DATA.
  //
  mCpuHotPlugData.ApicId = (UINT64 *)AllocatePool (sizeof (UINT64) * mMaxNumberOfCpus);
  ASSERT (mCpuHotPlugData.ApicId != NULL);
  mCpuHotPlugData.ArrayLength = (UINT32)mMaxNumberOfCpus;

  //
  // Retrieve APIC ID of each enabled processor from the MP Services protocol.
  // Also compute the SMBASE address, CPU Save State address, and CPU Save state
  // size for each CPU in the platform
  //
  for (Index = 0; Index < mMaxNumberOfCpus; Index++) {
    gSmmCpuPrivate->CpuSaveStateSize[Index] = sizeof (SMRAM_SAVE_STATE_MAP);
    gSmmCpuPrivate->CpuSaveState[Index]     = (VOID *)(mCpuHotPlugData.SmBase[Index] + SMRAM_SAVE_STATE_MAP_OFFSET);
    gSmmCpuPrivate->Operation[Index]        = SmmCpuNone;

    if (Index < mNumberOfCpus) {
      mCpuHotPlugData.ApicId[Index] = gSmmCpuPrivate->ProcessorInfo[Index].ProcessorId;

      DEBUG ((
        DEBUG_INFO,
        "CPU[%03x]  APIC ID=%04x  SMBASE=%08x  SaveState=%08x  Size=%08x\n",
        Index,
        (UINT32)gSmmCpuPrivate->ProcessorInfo[Index].ProcessorId,
        mCpuHotPlugData.SmBase[Index],
        gSmmCpuPrivate->CpuSaveState[Index],
        gSmmCpuPrivate->CpuSaveStateSize[Index]
        ));
    } else {
      gSmmCpuPrivate->ProcessorInfo[Index].ProcessorId = INVALID_APIC_ID;
      mCpuHotPlugData.ApicId[Index]                    = INVALID_APIC_ID;
    }
  }

  //
  // Allocate SMI stacks for all processors.
  //
  mSmmStackSize = EFI_PAGES_TO_SIZE (EFI_SIZE_TO_PAGES (PcdGet32 (PcdCpuSmmStackSize)));
  if (FeaturePcdGet (PcdCpuSmmStackGuard)) {
    //
    // SMM Stack Guard Enabled
    //   2 more pages is allocated for each processor, one is guard page and the other is known good stack.
    //
    // +--------------------------------------------------+-----+--------------------------------------------------+
    // | Known Good Stack | Guard Page |     SMM Stack    | ... | Known Good Stack | Guard Page |     SMM Stack    |
    // +--------------------------------------------------+-----+--------------------------------------------------+
    // |        4K        |    4K       PcdCpuSmmStackSize|     |        4K        |    4K       PcdCpuSmmStackSize|
    // |<---------------- mSmmStackSize ----------------->|     |<---------------- mSmmStackSize ----------------->|
    // |                                                  |     |                                                  |
    // |<------------------ Processor 0 ----------------->|     |<------------------ Processor n ----------------->|
    //
    mSmmStackSize += EFI_PAGES_TO_SIZE (2);
  }

  mSmmShadowStackSize = 0;
  if ((PcdGet32 (PcdControlFlowEnforcementPropertyMask) != 0) && mCetSupported) {
    mSmmShadowStackSize = EFI_PAGES_TO_SIZE (EFI_SIZE_TO_PAGES (PcdGet32 (PcdCpuSmmShadowStackSize)));

    if (FeaturePcdGet (PcdCpuSmmStackGuard)) {
      //
      // SMM Stack Guard Enabled
      // Append Shadow Stack after normal stack
      //   2 more pages is allocated for each processor, one is guard page and the other is known good shadow stack.
      //
      // |= Stacks
      // +--------------------------------------------------+---------------------------------------------------------------+
      // | Known Good Stack | Guard Page |    SMM Stack     | Known Good Shadow Stack | Guard Page |    SMM Shadow Stack    |
      // +--------------------------------------------------+---------------------------------------------------------------+
      // |         4K       |    4K      |PcdCpuSmmStackSize|            4K           |    4K      |PcdCpuSmmShadowStackSize|
      // |<---------------- mSmmStackSize ----------------->|<--------------------- mSmmShadowStackSize ------------------->|
      // |                                                                                                                  |
      // |<-------------------------------------------- Processor N ------------------------------------------------------->|
      //
      mSmmShadowStackSize += EFI_PAGES_TO_SIZE (2);
    } else {
      //
      // SMM Stack Guard Disabled (Known Good Stack is still required for potential stack switch.)
      //   Append Shadow Stack after normal stack with 1 more page as known good shadow stack.
      //   1 more pages is allocated for each processor, it is known good stack.
      //
      //
      // |= Stacks
      // +-------------------------------------+--------------------------------------------------+
      // | Known Good Stack |    SMM Stack     | Known Good Shadow Stack |    SMM Shadow Stack    |
      // +-------------------------------------+--------------------------------------------------+
      // |        4K        |PcdCpuSmmStackSize|          4K             |PcdCpuSmmShadowStackSize|
      // |<---------- mSmmStackSize ---------->|<--------------- mSmmShadowStackSize ------------>|
      // |                                                                                        |
      // |<-------------------------------- Processor N ----------------------------------------->|
      //
      mSmmShadowStackSize += EFI_PAGES_TO_SIZE (1);
      mSmmStackSize       += EFI_PAGES_TO_SIZE (1);
    }
  }

  Stacks = (UINT8 *)AllocatePages (gSmmCpuPrivate->SmmCoreEntryContext.NumberOfCpus * (EFI_SIZE_TO_PAGES (mSmmStackSize + mSmmShadowStackSize)));
  ASSERT (Stacks != NULL);
  mSmmStackArrayBase = (UINTN)Stacks;
  mSmmStackArrayEnd  = mSmmStackArrayBase + gSmmCpuPrivate->SmmCoreEntryContext.NumberOfCpus * (mSmmStackSize + mSmmShadowStackSize) - 1;

  DEBUG ((DEBUG_INFO, "Stacks                   - 0x%x\n", Stacks));
  DEBUG ((DEBUG_INFO, "mSmmStackSize            - 0x%x\n", mSmmStackSize));
  DEBUG ((DEBUG_INFO, "PcdCpuSmmStackGuard      - 0x%x\n", FeaturePcdGet (PcdCpuSmmStackGuard)));
  if ((PcdGet32 (PcdControlFlowEnforcementPropertyMask) != 0) && mCetSupported) {
    DEBUG ((DEBUG_INFO, "mSmmShadowStackSize      - 0x%x\n", mSmmShadowStackSize));
  }

  //
  // Initialize IDT
  //
  InitializeSmmIdt ();

  //
  // SMM Time initialization
  //
  InitializeSmmTimer ();

  //
  // Initialize MP globals
  //
  Cr3 = InitializeMpServiceData (Stacks, mSmmStackSize, mSmmShadowStackSize);

  if ((PcdGet32 (PcdControlFlowEnforcementPropertyMask) != 0) && mCetSupported) {
    for (Index = 0; Index < gSmmCpuPrivate->SmmCoreEntryContext.NumberOfCpus; Index++) {
      SetShadowStack (
        Cr3,
        (EFI_PHYSICAL_ADDRESS)(UINTN)Stacks + mSmmStackSize + (mSmmStackSize + mSmmShadowStackSize) * Index,
        mSmmShadowStackSize
        );
      if (FeaturePcdGet (PcdCpuSmmStackGuard)) {
        ConvertMemoryPageAttributes (
          Cr3,
          mPagingMode,
          (EFI_PHYSICAL_ADDRESS)(UINTN)Stacks + mSmmStackSize + EFI_PAGES_TO_SIZE (1) + (mSmmStackSize + mSmmShadowStackSize) * Index,
          EFI_PAGES_TO_SIZE (1),
          EFI_MEMORY_RP,
          TRUE,
          NULL
          );
      }
    }
  }

  //
  // For relocated SMBASE, some MSRs & CSRs are still required to be configured in SMM Mode for SMM Initialization.
  // Those MSRs & CSRs must be configured before normal SMI sources happen.
  // So, here is to issue SMI IPI (All Excluding  Self SMM IPI + BSP SMM IPI) to execute first SMI init.
  //
  ExecuteFirstSmiInit ();

  //
  // Call hook for BSP to perform extra actions in normal mode after all
  // SMM base addresses have been relocated on all CPUs
  //
  SmmCpuFeaturesSmmRelocationComplete ();

  DEBUG ((DEBUG_INFO, "mXdSupported - 0x%x\n", mXdSupported));

  //
  // Fill in SMM Reserved Regions
  //
  gSmmCpuPrivate->SmmReservedSmramRegion[0].SmramReservedStart = 0;
  gSmmCpuPrivate->SmmReservedSmramRegion[0].SmramReservedSize  = 0;

  //
  // Install the SMM Configuration Protocol onto a new handle on the handle database.
  // The entire SMM Configuration Protocol is allocated from SMRAM, so only a pointer
  // to an SMRAM address will be present in the handle database
  //
  Status = SystemTable->BootServices->InstallMultipleProtocolInterfaces (
                                        &gSmmCpuPrivate->SmmCpuHandle,
                                        &gEfiSmmConfigurationProtocolGuid,
                                        &gSmmCpuPrivate->SmmConfiguration,
                                        NULL
                                        );
  ASSERT_EFI_ERROR (Status);

  //
  // Install the SMM CPU Protocol into SMM protocol database
  //
  Status = gSmst->SmmInstallProtocolInterface (
                    &mSmmCpuHandle,
                    &gEfiSmmCpuProtocolGuid,
                    EFI_NATIVE_INTERFACE,
                    &mSmmCpu
                    );
  ASSERT_EFI_ERROR (Status);

  //
  // Install the SMM Memory Attribute Protocol into SMM protocol database
  //
  Status = gSmst->SmmInstallProtocolInterface (
                    &mSmmCpuHandle,
                    &gEdkiiSmmMemoryAttributeProtocolGuid,
                    EFI_NATIVE_INTERFACE,
                    &mSmmMemoryAttribute
                    );
  ASSERT_EFI_ERROR (Status);

  //
  // Initialize global buffer for MM MP.
  //
  InitializeDataForMmMp ();

  //
  // Initialize Package First Thread Index Info.
  //
  InitPackageFirstThreadIndexInfo ();

  //
  // Install the SMM Mp Protocol into SMM protocol database
  //
  Status = gSmst->SmmInstallProtocolInterface (
                    &mSmmCpuHandle,
                    &gEfiMmMpProtocolGuid,
                    EFI_NATIVE_INTERFACE,
                    &mSmmMp
                    );
  ASSERT_EFI_ERROR (Status);

  //
  // Expose address of CPU Hot Plug Data structure if CPU hot plug is supported.
  //
  if (FeaturePcdGet (PcdCpuHotPlugSupport)) {
    Status = PcdSet64S (PcdCpuHotPlugDataAddress, (UINT64)(UINTN)&mCpuHotPlugData);
    ASSERT_EFI_ERROR (Status);
  }

  //
  // Initialize SMM CPU Services Support
  //
  Status = InitializeSmmCpuServices (mSmmCpuHandle);
  ASSERT_EFI_ERROR (Status);

  //
  // register SMM Ready To Lock Protocol notification
  //
  Status = gSmst->SmmRegisterProtocolNotify (
                    &gEfiSmmReadyToLockProtocolGuid,
                    SmmReadyToLockEventNotify,
                    &Registration
                    );
  ASSERT_EFI_ERROR (Status);

  //
  // Initialize SMM Profile feature
  //
  InitSmmProfile (Cr3);

  GetAcpiS3EnableFlag ();
  InitSmmS3ResumeState (Cr3);

  DEBUG ((DEBUG_INFO, "SMM CPU Module exit from SMRAM with EFI_SUCCESS\n"));

  PERF_FUNCTION_END ();
  return EFI_SUCCESS;
}

/**
  Function to compare 2 EFI_SMRAM_DESCRIPTOR based on CpuStart.

  @param[in] Buffer1            pointer to Device Path poiner to compare
  @param[in] Buffer2            pointer to second DevicePath pointer to compare

  @retval 0                     Buffer1 equal to Buffer2
  @retval <0                    Buffer1 is less than Buffer2
  @retval >0                    Buffer1 is greater than Buffer2
**/
INTN
EFIAPI
CpuSmramRangeCompare (
  IN  CONST VOID  *Buffer1,
  IN  CONST VOID  *Buffer2
  )
{
  if (((EFI_SMRAM_DESCRIPTOR *)Buffer1)->CpuStart > ((EFI_SMRAM_DESCRIPTOR *)Buffer2)->CpuStart) {
    return 1;
  } else if (((EFI_SMRAM_DESCRIPTOR *)Buffer1)->CpuStart < ((EFI_SMRAM_DESCRIPTOR *)Buffer2)->CpuStart) {
    return -1;
  }

  return 0;
}

/**

  Find out SMRAM information including SMRR base and SMRR size.

  @param          SmrrBase          SMRR base
  @param          SmrrSize          SMRR size

**/
VOID
FindSmramInfo (
  OUT UINT32  *SmrrBase,
  OUT UINT32  *SmrrSize
  )
{
  EFI_STATUS                Status;
  UINTN                     Size;
  EFI_SMM_ACCESS2_PROTOCOL  *SmmAccess;
  EFI_SMRAM_DESCRIPTOR      *CurrentSmramRange;
  UINTN                     Index;
  UINT64                    MaxSize;
  BOOLEAN                   Found;
  EFI_SMRAM_DESCRIPTOR      SmramDescriptor;

  //
  // Get SMM Access Protocol
  //
  Status = gBS->LocateProtocol (&gEfiSmmAccess2ProtocolGuid, NULL, (VOID **)&SmmAccess);
  ASSERT_EFI_ERROR (Status);

  //
  // Get SMRAM information
  //
  Size   = 0;
  Status = SmmAccess->GetCapabilities (SmmAccess, &Size, NULL);
  ASSERT (Status == EFI_BUFFER_TOO_SMALL);

  mSmmCpuSmramRanges = (EFI_SMRAM_DESCRIPTOR *)AllocatePool (Size);
  ASSERT (mSmmCpuSmramRanges != NULL);

  Status = SmmAccess->GetCapabilities (SmmAccess, &Size, mSmmCpuSmramRanges);
  ASSERT_EFI_ERROR (Status);

  mSmmCpuSmramRangeCount = Size / sizeof (EFI_SMRAM_DESCRIPTOR);

  //
  // Sort the mSmmCpuSmramRanges
  //
  QuickSort (mSmmCpuSmramRanges, mSmmCpuSmramRangeCount, sizeof (EFI_SMRAM_DESCRIPTOR), (BASE_SORT_COMPARE)CpuSmramRangeCompare, &SmramDescriptor);

  //
  // Find the largest SMRAM range between 1MB and 4GB that is at least 256K - 4K in size
  //
  CurrentSmramRange = NULL;
  for (Index = 0, MaxSize = SIZE_256KB - EFI_PAGE_SIZE; Index < mSmmCpuSmramRangeCount; Index++) {
    //
    // Skip any SMRAM region that is already allocated, needs testing, or needs ECC initialization
    //
    if ((mSmmCpuSmramRanges[Index].RegionState & (EFI_ALLOCATED | EFI_NEEDS_TESTING | EFI_NEEDS_ECC_INITIALIZATION)) != 0) {
      continue;
    }

    if (mSmmCpuSmramRanges[Index].CpuStart >= BASE_1MB) {
      if ((mSmmCpuSmramRanges[Index].CpuStart + mSmmCpuSmramRanges[Index].PhysicalSize) <= SMRR_MAX_ADDRESS) {
        if (mSmmCpuSmramRanges[Index].PhysicalSize >= MaxSize) {
          MaxSize           = mSmmCpuSmramRanges[Index].PhysicalSize;
          CurrentSmramRange = &mSmmCpuSmramRanges[Index];
        }
      }
    }
  }

  ASSERT (CurrentSmramRange != NULL);

  *SmrrBase = (UINT32)CurrentSmramRange->CpuStart;
  *SmrrSize = (UINT32)CurrentSmramRange->PhysicalSize;

  do {
    Found = FALSE;
    for (Index = 0; Index < mSmmCpuSmramRangeCount; Index++) {
      if ((mSmmCpuSmramRanges[Index].CpuStart < *SmrrBase) &&
          (*SmrrBase == (mSmmCpuSmramRanges[Index].CpuStart + mSmmCpuSmramRanges[Index].PhysicalSize)))
      {
        *SmrrBase = (UINT32)mSmmCpuSmramRanges[Index].CpuStart;
        *SmrrSize = (UINT32)(*SmrrSize + mSmmCpuSmramRanges[Index].PhysicalSize);
        Found     = TRUE;
      } else if (((*SmrrBase + *SmrrSize) == mSmmCpuSmramRanges[Index].CpuStart) && (mSmmCpuSmramRanges[Index].PhysicalSize > 0)) {
        *SmrrSize = (UINT32)(*SmrrSize + mSmmCpuSmramRanges[Index].PhysicalSize);
        Found     = TRUE;
      }
    }
  } while (Found);

  DEBUG ((DEBUG_INFO, "SMRR Base: 0x%x, SMRR Size: 0x%x\n", *SmrrBase, *SmrrSize));
}

/**
Configure SMM Code Access Check feature on an AP.
SMM Feature Control MSR will be locked after configuration.

@param[in,out] Buffer  Pointer to private data buffer.
**/
VOID
EFIAPI
ConfigSmmCodeAccessCheckOnCurrentProcessor (
  IN OUT VOID  *Buffer
  )
{
  UINTN   CpuIndex;
  UINT64  SmmFeatureControlMsr;
  UINT64  NewSmmFeatureControlMsr;

  //
  // Retrieve the CPU Index from the context passed in
  //
  CpuIndex = *(UINTN *)Buffer;

  //
  // Get the current SMM Feature Control MSR value
  //
  SmmFeatureControlMsr = SmmCpuFeaturesGetSmmRegister (CpuIndex, SmmRegFeatureControl);

  //
  // Compute the new SMM Feature Control MSR value
  //
  NewSmmFeatureControlMsr = SmmFeatureControlMsr;
  if (mSmmCodeAccessCheckEnable) {
    NewSmmFeatureControlMsr |= SMM_CODE_CHK_EN_BIT;
    if (FeaturePcdGet (PcdCpuSmmFeatureControlMsrLock)) {
      NewSmmFeatureControlMsr |= SMM_FEATURE_CONTROL_LOCK_BIT;
    }
  }

  //
  // Only set the SMM Feature Control MSR value if the new value is different than the current value
  //
  if (NewSmmFeatureControlMsr != SmmFeatureControlMsr) {
    SmmCpuFeaturesSetSmmRegister (CpuIndex, SmmRegFeatureControl, NewSmmFeatureControlMsr);
  }

  //
  // Release the spin lock user to serialize the updates to the SMM Feature Control MSR
  //
  ReleaseSpinLock (mConfigSmmCodeAccessCheckLock);
}

/**
Configure SMM Code Access Check feature for all processors.
SMM Feature Control MSR will be locked after configuration.
**/
VOID
ConfigSmmCodeAccessCheck (
  VOID
  )
{
  UINTN       Index;
  EFI_STATUS  Status;

  PERF_FUNCTION_BEGIN ();

  //
  // Check to see if the Feature Control MSR is supported on this CPU
  //
  Index = gSmmCpuPrivate->SmmCoreEntryContext.CurrentlyExecutingCpu;
  if (!SmmCpuFeaturesIsSmmRegisterSupported (Index, SmmRegFeatureControl)) {
    mSmmCodeAccessCheckEnable = FALSE;
    PERF_FUNCTION_END ();
    return;
  }

  //
  // Check to see if the CPU supports the SMM Code Access Check feature
  // Do not access this MSR unless the CPU supports the SmmRegFeatureControl
  //
  if ((AsmReadMsr64 (EFI_MSR_SMM_MCA_CAP) & SMM_CODE_ACCESS_CHK_BIT) == 0) {
    mSmmCodeAccessCheckEnable = FALSE;
    PERF_FUNCTION_END ();
    return;
  }

  //
  // Initialize the lock used to serialize the MSR programming in BSP and all APs
  //
  InitializeSpinLock (mConfigSmmCodeAccessCheckLock);

  //
  // Acquire Config SMM Code Access Check spin lock.  The BSP will release the
  // spin lock when it is done executing ConfigSmmCodeAccessCheckOnCurrentProcessor().
  //
  AcquireSpinLock (mConfigSmmCodeAccessCheckLock);

  //
  // Enable SMM Code Access Check feature on the BSP.
  //
  ConfigSmmCodeAccessCheckOnCurrentProcessor (&Index);

  //
  // Enable SMM Code Access Check feature for the APs.
  //
  for (Index = 0; Index < gSmst->NumberOfCpus; Index++) {
    if (Index != gSmmCpuPrivate->SmmCoreEntryContext.CurrentlyExecutingCpu) {
      if (gSmmCpuPrivate->ProcessorInfo[Index].ProcessorId == INVALID_APIC_ID) {
        //
        // If this processor does not exist
        //
        continue;
      }

      //
      // Acquire Config SMM Code Access Check spin lock.  The AP will release the
      // spin lock when it is done executing ConfigSmmCodeAccessCheckOnCurrentProcessor().
      //
      AcquireSpinLock (mConfigSmmCodeAccessCheckLock);

      //
      // Call SmmStartupThisAp() to enable SMM Code Access Check on an AP.
      //
      Status = gSmst->SmmStartupThisAp (ConfigSmmCodeAccessCheckOnCurrentProcessor, Index, &Index);
      ASSERT_EFI_ERROR (Status);

      //
      // Wait for the AP to release the Config SMM Code Access Check spin lock.
      //
      while (!AcquireSpinLockOrFail (mConfigSmmCodeAccessCheckLock)) {
        CpuPause ();
      }

      //
      // Release the Config SMM Code Access Check spin lock.
      //
      ReleaseSpinLock (mConfigSmmCodeAccessCheckLock);
    }
  }

  PERF_FUNCTION_END ();
}

/**
  Allocate pages for code.

  @param[in]  Pages Number of pages to be allocated.

  @return Allocated memory.
**/
VOID *
AllocateCodePages (
  IN UINTN  Pages
  )
{
  EFI_STATUS            Status;
  EFI_PHYSICAL_ADDRESS  Memory;

  if (Pages == 0) {
    return NULL;
  }

  Status = gSmst->SmmAllocatePages (AllocateAnyPages, EfiRuntimeServicesCode, Pages, &Memory);
  if (EFI_ERROR (Status)) {
    return NULL;
  }

  return (VOID *)(UINTN)Memory;
}

/**
  Perform the remaining tasks.

**/
VOID
PerformRemainingTasks (
  VOID
  )
{
  if (mSmmReadyToLock) {
    PERF_FUNCTION_BEGIN ();

    //
    // Check if all Aps enter SMM. In Relaxed-AP Sync Mode, BSP will not wait for
    // all Aps arrive. However,PerformRemainingTasks() needs to wait all Aps arrive before calling
    // SetMemMapAttributes() and ConfigSmmCodeAccessCheck() when mSmmReadyToLock
    // is true. In SetMemMapAttributes(), SmmSetMemoryAttributesEx() will call
    // FlushTlbForAll() that need to start up the aps. So it need to let all
    // aps arrive. Same as SetMemMapAttributes(), ConfigSmmCodeAccessCheck()
    // also will start up the aps.
    //
    if (EFI_ERROR (SmmCpuRendezvous (NULL, TRUE))) {
      DEBUG ((DEBUG_ERROR, "PerformRemainingTasks: fail to wait for all AP check in SMM!\n"));
    }

    //
    // Start SMM Profile feature
    //
    if (FeaturePcdGet (PcdCpuSmmProfileEnable)) {
      SmmProfileStart ();
    }

    //
    // Create a mix of 2MB and 4KB page table. Update some memory ranges absent and execute-disable.
    //
    InitPaging ();

    //
    // Mark critical region to be read-only in page table
    //
    SetMemMapAttributes ();

    if (IsRestrictedMemoryAccess ()) {
      //
      // For outside SMRAM, we only map SMM communication buffer or MMIO.
      //
      SetUefiMemMapAttributes ();

      //
      // Set page table itself to be read-only
      //
      SetPageTableAttributes ();
    }

    //
    // Configure SMM Code Access Check feature if available.
    //
    ConfigSmmCodeAccessCheck ();

    //
    // Measure performance of SmmCpuFeaturesCompleteSmmReadyToLock() from caller side
    // as the implementation is provided by platform.
    //
    PERF_START (NULL, "SmmCompleteReadyToLock", NULL, 0);
    SmmCpuFeaturesCompleteSmmReadyToLock ();
    PERF_END (NULL, "SmmCompleteReadyToLock", NULL, 0);

    //
    // Clean SMM ready to lock flag
    //
    mSmmReadyToLock = FALSE;

    PERF_FUNCTION_END ();
  }
}

/**
  Perform the pre tasks.

**/
VOID
PerformPreTasks (
  VOID
  )
{
  RestoreSmmConfigurationInS3 ();
}