Dispatcher.c

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#include "PiSmmCore.h"
 
//
// SMM Dispatcher Data structures
//
#define KNOWN_HANDLE_SIGNATURE  SIGNATURE_32('k','n','o','w')
typedef struct {
  UINTN         Signature;
  LIST_ENTRY    Link;           // mFvHandleList
  EFI_HANDLE    Handle;
} KNOWN_HANDLE;
 
//
// Function Prototypes
//
 
VOID
SmmInsertOnScheduledQueueWhileProcessingBeforeAndAfter (
  IN  EFI_SMM_DRIVER_ENTRY  *InsertedDriverEntry
  );
 
//
// The Driver List contains one copy of every driver that has been discovered.
// Items are never removed from the driver list. List of EFI_SMM_DRIVER_ENTRY
//
LIST_ENTRY  mDiscoveredList = INITIALIZE_LIST_HEAD_VARIABLE (mDiscoveredList);
 
//
// Queue of drivers that are ready to dispatch. This queue is a subset of the
// mDiscoveredList.list of EFI_SMM_DRIVER_ENTRY.
//
LIST_ENTRY  mScheduledQueue = INITIALIZE_LIST_HEAD_VARIABLE (mScheduledQueue);
 
//
// List of handles who's Fv's have been parsed and added to the mFwDriverList.
//
LIST_ENTRY  mFvHandleList = INITIALIZE_LIST_HEAD_VARIABLE (mFvHandleList);
 
//
// Flag for the SMM Dispatcher.  TRUE if dispatcher is executing.
//
BOOLEAN  gDispatcherRunning = FALSE;
 
//
// Flag for the SMM Dispatcher.  TRUE if there is one or more SMM drivers ready to be dispatched
//
BOOLEAN  gRequestDispatch = FALSE;
 
//
// List of file types supported by dispatcher
//
EFI_FV_FILETYPE  mSmmFileTypes[] = {
  EFI_FV_FILETYPE_SMM,
  EFI_FV_FILETYPE_COMBINED_SMM_DXE,
  EFI_FV_FILETYPE_SMM_CORE,
  //
  // Note: DXE core will process the FV image file, so skip it in SMM core
  // EFI_FV_FILETYPE_FIRMWARE_VOLUME_IMAGE
  //
};
 
typedef struct {
  MEDIA_FW_VOL_FILEPATH_DEVICE_PATH    File;
  EFI_DEVICE_PATH_PROTOCOL             End;
} FV_FILEPATH_DEVICE_PATH;
 
FV_FILEPATH_DEVICE_PATH  mFvDevicePath;
 
//
// DXE Architecture Protocols
//
EFI_SECURITY_ARCH_PROTOCOL   *mSecurity  = NULL;
EFI_SECURITY2_ARCH_PROTOCOL  *mSecurity2 = NULL;
 
//
// The global variable is defined for Loading modules at fixed address feature to track the SMM code
// memory range usage. It is a bit mapped array in which every bit indicates the corresponding
// memory page available or not.
//
GLOBAL_REMOVE_IF_UNREFERENCED    UINT64  *mSmmCodeMemoryRangeUsageBitMap = NULL;
 
EFI_STATUS
CheckAndMarkFixLoadingMemoryUsageBitMap (
  IN  EFI_PHYSICAL_ADDRESS  ImageBase,
  IN  UINTN                 ImageSize
  )
{
  UINT32                SmmCodePageNumber;
  UINT64                SmmCodeSize;
  EFI_PHYSICAL_ADDRESS  SmmCodeBase;
  UINTN                 BaseOffsetPageNumber;
  UINTN                 TopOffsetPageNumber;
  UINTN                 Index;
 
  //
  // Build tool will calculate the smm code size and then patch the PcdLoadFixAddressSmmCodePageNumber
  //
  SmmCodePageNumber = PcdGet32 (PcdLoadFixAddressSmmCodePageNumber);
  SmmCodeSize       = EFI_PAGES_TO_SIZE (SmmCodePageNumber);
  SmmCodeBase       = gLoadModuleAtFixAddressSmramBase;
 
  //
  // If the memory usage bit map is not initialized,  do it. Every bit in the array
  // indicate the status of the corresponding memory page, available or not
  //
  if (mSmmCodeMemoryRangeUsageBitMap == NULL) {
    mSmmCodeMemoryRangeUsageBitMap = AllocateZeroPool (((SmmCodePageNumber / 64) + 1)*sizeof (UINT64));
  }
 
  //
  // If the Dxe code memory range is not allocated or the bit map array allocation failed, return EFI_NOT_FOUND
  //
  if (mSmmCodeMemoryRangeUsageBitMap == NULL) {
    return EFI_NOT_FOUND;
  }
 
  //
  // see if the memory range for loading the image is in the SMM code range.
  //
  if ((SmmCodeBase + SmmCodeSize <  ImageBase + ImageSize) || (SmmCodeBase >  ImageBase)) {
    return EFI_NOT_FOUND;
  }
 
  //
  // Test if the memory is available or not.
  //
  BaseOffsetPageNumber = EFI_SIZE_TO_PAGES ((UINT32)(ImageBase - SmmCodeBase));
  TopOffsetPageNumber  = EFI_SIZE_TO_PAGES ((UINT32)(ImageBase + ImageSize - SmmCodeBase));
  for (Index = BaseOffsetPageNumber; Index < TopOffsetPageNumber; Index++) {
    if ((mSmmCodeMemoryRangeUsageBitMap[Index / 64] & LShiftU64 (1, (Index % 64))) != 0) {
      //
      // This page is already used.
      //
      return EFI_NOT_FOUND;
    }
  }
 
  //
  // Being here means the memory range is available.  So mark the bits for the memory range
  //
  for (Index = BaseOffsetPageNumber; Index < TopOffsetPageNumber; Index++) {
    mSmmCodeMemoryRangeUsageBitMap[Index / 64] |= LShiftU64 (1, (Index % 64));
  }
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
GetPeCoffImageFixLoadingAssignedAddress (
  IN OUT PE_COFF_LOADER_IMAGE_CONTEXT  *ImageContext
  )
{
  UINTN                            SectionHeaderOffset;
  EFI_STATUS                       Status;
  EFI_IMAGE_SECTION_HEADER         SectionHeader;
  EFI_IMAGE_OPTIONAL_HEADER_UNION  *ImgHdr;
  EFI_PHYSICAL_ADDRESS             FixLoadingAddress;
  UINT16                           Index;
  UINTN                            Size;
  UINT16                           NumberOfSections;
  UINT64                           ValueInSectionHeader;
 
  FixLoadingAddress = 0;
  Status            = EFI_NOT_FOUND;
 
  //
  // Get PeHeader pointer
  //
  ImgHdr              = (EFI_IMAGE_OPTIONAL_HEADER_UNION *)((CHAR8 *)ImageContext->Handle + ImageContext->PeCoffHeaderOffset);
  SectionHeaderOffset = ImageContext->PeCoffHeaderOffset +
                        sizeof (UINT32) +
                        sizeof (EFI_IMAGE_FILE_HEADER) +
                        ImgHdr->Pe32.FileHeader.SizeOfOptionalHeader;
  NumberOfSections = ImgHdr->Pe32.FileHeader.NumberOfSections;
 
  //
  // Get base address from the first section header that doesn't point to code section.
  //
  for (Index = 0; Index < NumberOfSections; Index++) {
    //
    // Read section header from file
    //
    Size   = sizeof (EFI_IMAGE_SECTION_HEADER);
    Status = ImageContext->ImageRead (
                             ImageContext->Handle,
                             SectionHeaderOffset,
                             &Size,
                             &SectionHeader
                             );
    if (EFI_ERROR (Status)) {
      return Status;
    }
 
    Status = EFI_NOT_FOUND;
 
    if ((SectionHeader.Characteristics & EFI_IMAGE_SCN_CNT_CODE) == 0) {
      //
      // Build tool will save the address in PointerToRelocations & PointerToLineNumbers fields in the first section header
      // that doesn't point to code section in image header.So there is an assumption that when the feature is enabled,
      // if a module with a loading address assigned by tools, the PointerToRelocations & PointerToLineNumbers fields
      // should not be Zero, or else, these 2 fields should be set to Zero
      //
      ValueInSectionHeader = ReadUnaligned64 ((UINT64 *)&SectionHeader.PointerToRelocations);
      if (ValueInSectionHeader != 0) {
        //
        // Found first section header that doesn't point to code section in which build tool saves the
        // offset to SMRAM base as image base in PointerToRelocations & PointerToLineNumbers fields
        //
        FixLoadingAddress = (EFI_PHYSICAL_ADDRESS)(gLoadModuleAtFixAddressSmramBase + (INT64)ValueInSectionHeader);
        //
        // Check if the memory range is available.
        //
        Status = CheckAndMarkFixLoadingMemoryUsageBitMap (FixLoadingAddress, (UINTN)(ImageContext->ImageSize + ImageContext->SectionAlignment));
        if (!EFI_ERROR (Status)) {
          //
          // The assigned address is valid. Return the specified loading address
          //
          ImageContext->ImageAddress = FixLoadingAddress;
        }
      }
 
      break;
    }
 
    SectionHeaderOffset += sizeof (EFI_IMAGE_SECTION_HEADER);
  }
 
  DEBUG ((DEBUG_INFO|DEBUG_LOAD, "LOADING MODULE FIXED INFO: Loading module at fixed address %x, Status = %r\n", FixLoadingAddress, Status));
  return Status;
}
 
EFI_STATUS
EFIAPI
SmmLoadImage (
  IN OUT EFI_SMM_DRIVER_ENTRY  *DriverEntry
  )
{
  UINT32                         AuthenticationStatus;
  UINTN                          FilePathSize;
  VOID                           *Buffer;
  UINTN                          Size;
  UINTN                          PageCount;
  EFI_GUID                       *NameGuid;
  EFI_STATUS                     Status;
  EFI_STATUS                     SecurityStatus;
  EFI_HANDLE                     DeviceHandle;
  EFI_PHYSICAL_ADDRESS           DstBuffer;
  EFI_DEVICE_PATH_PROTOCOL       *FilePath;
  EFI_DEVICE_PATH_PROTOCOL       *OriginalFilePath;
  EFI_DEVICE_PATH_PROTOCOL       *HandleFilePath;
  EFI_FIRMWARE_VOLUME2_PROTOCOL  *Fv;
  PE_COFF_LOADER_IMAGE_CONTEXT   ImageContext;
  UINTN                          Index;
  UINTN                          StartIndex;
  CHAR8                          EfiFileName[512];
 
  PERF_LOAD_IMAGE_BEGIN (DriverEntry->ImageHandle);
 
  Buffer   = NULL;
  Size     = 0;
  Fv       = DriverEntry->Fv;
  NameGuid = &DriverEntry->FileName;
  FilePath = DriverEntry->FvFileDevicePath;
 
  OriginalFilePath     = FilePath;
  HandleFilePath       = FilePath;
  DeviceHandle         = NULL;
  SecurityStatus       = EFI_SUCCESS;
  Status               = EFI_SUCCESS;
  AuthenticationStatus = 0;
 
  //
  // Try to get the image device handle by checking the match protocol.
  //
  Status = gBS->LocateDevicePath (&gEfiFirmwareVolume2ProtocolGuid, &HandleFilePath, &DeviceHandle);
  if (EFI_ERROR (Status)) {
    return Status;
  }
 
  //
  // If the Security2 and Security Architectural Protocol has not been located yet, then attempt to locate it
  //
  if (mSecurity2 == NULL) {
    gBS->LocateProtocol (&gEfiSecurity2ArchProtocolGuid, NULL, (VOID **)&mSecurity2);
  }
 
  if (mSecurity == NULL) {
    gBS->LocateProtocol (&gEfiSecurityArchProtocolGuid, NULL, (VOID **)&mSecurity);
  }
 
  //
  // When Security2 is installed, Security Architectural Protocol must be published.
  //
  ASSERT (mSecurity2 == NULL || mSecurity != NULL);
 
  //
  // Pull out just the file portion of the DevicePath for the LoadedImage FilePath
  //
  FilePath = OriginalFilePath;
  Status   = gBS->HandleProtocol (DeviceHandle, &gEfiDevicePathProtocolGuid, (VOID **)&HandleFilePath);
  if (!EFI_ERROR (Status)) {
    FilePathSize = GetDevicePathSize (HandleFilePath) - sizeof (EFI_DEVICE_PATH_PROTOCOL);
    FilePath     = (EFI_DEVICE_PATH_PROTOCOL *)(((UINT8 *)FilePath) + FilePathSize);
  }
 
  //
  // Try reading PE32 section firstly
  //
  Status = Fv->ReadSection (
                 Fv,
                 NameGuid,
                 EFI_SECTION_PE32,
                 0,
                 &Buffer,
                 &Size,
                 &AuthenticationStatus
                 );
 
  if (EFI_ERROR (Status)) {
    //
    // Try reading TE section secondly
    //
    Buffer = NULL;
    Size   = 0;
    Status = Fv->ReadSection (
                   Fv,
                   NameGuid,
                   EFI_SECTION_TE,
                   0,
                   &Buffer,
                   &Size,
                   &AuthenticationStatus
                   );
  }
 
  if (EFI_ERROR (Status)) {
    if (Buffer != NULL) {
      gBS->FreePool (Buffer);
    }
 
    return Status;
  }
 
  //
  // Verify File Authentication through the Security2 Architectural Protocol
  //
  if (mSecurity2 != NULL) {
    SecurityStatus = mSecurity2->FileAuthentication (
                                   mSecurity2,
                                   OriginalFilePath,
                                   Buffer,
                                   Size,
                                   FALSE
                                   );
  }
 
  //
  // Verify the Authentication Status through the Security Architectural Protocol
  // Only on images that have been read using Firmware Volume protocol.
  // All SMM images are from FV protocol.
  //
  if (!EFI_ERROR (SecurityStatus) && (mSecurity != NULL)) {
    SecurityStatus = mSecurity->FileAuthenticationState (
                                  mSecurity,
                                  AuthenticationStatus,
                                  OriginalFilePath
                                  );
  }
 
  if (EFI_ERROR (SecurityStatus) && (SecurityStatus != EFI_SECURITY_VIOLATION)) {
    Status = SecurityStatus;
    return Status;
  }
 
  //
  // Initialize ImageContext
  //
  ImageContext.Handle    = Buffer;
  ImageContext.ImageRead = PeCoffLoaderImageReadFromMemory;
 
  //
  // Get information about the image being loaded
  //
  Status = PeCoffLoaderGetImageInfo (&ImageContext);
  if (EFI_ERROR (Status)) {
    if (Buffer != NULL) {
      gBS->FreePool (Buffer);
    }
 
    return Status;
  }
 
  //
  // if Loading module at Fixed Address feature is enabled, then  cut out a memory range started from TESG BASE
  // to hold the Smm driver code
  //
  if (PcdGet64 (PcdLoadModuleAtFixAddressEnable) != 0) {
    //
    // Get the fixed loading address assigned by Build tool
    //
    Status = GetPeCoffImageFixLoadingAssignedAddress (&ImageContext);
    if (!EFI_ERROR (Status)) {
      //
      // Since the memory range to load Smm core already been cut out, so no need to allocate and free this range
      // following statements is to bypass SmmFreePages
      //
      PageCount = 0;
      DstBuffer = (UINTN)gLoadModuleAtFixAddressSmramBase;
    } else {
      DEBUG ((DEBUG_INFO|DEBUG_LOAD, "LOADING MODULE FIXED ERROR: Failed to load module at fixed address. \n"));
      //
      // allocate the memory to load the SMM driver
      //
      PageCount = (UINTN)EFI_SIZE_TO_PAGES ((UINTN)ImageContext.ImageSize + ImageContext.SectionAlignment);
      DstBuffer = (UINTN)(-1);
 
      Status = SmmAllocatePages (
                 AllocateMaxAddress,
                 EfiRuntimeServicesCode,
                 PageCount,
                 &DstBuffer
                 );
      if (EFI_ERROR (Status)) {
        if (Buffer != NULL) {
          gBS->FreePool (Buffer);
        }
 
        return Status;
      }
 
      ImageContext.ImageAddress = (EFI_PHYSICAL_ADDRESS)DstBuffer;
    }
  } else {
    PageCount = (UINTN)EFI_SIZE_TO_PAGES ((UINTN)ImageContext.ImageSize + ImageContext.SectionAlignment);
    DstBuffer = (UINTN)(-1);
 
    Status = SmmAllocatePages (
               AllocateMaxAddress,
               EfiRuntimeServicesCode,
               PageCount,
               &DstBuffer
               );
    if (EFI_ERROR (Status)) {
      if (Buffer != NULL) {
        gBS->FreePool (Buffer);
      }
 
      return Status;
    }
 
    ImageContext.ImageAddress = (EFI_PHYSICAL_ADDRESS)DstBuffer;
  }
 
  //
  // Align buffer on section boundary
  //
  ImageContext.ImageAddress += ImageContext.SectionAlignment - 1;
  ImageContext.ImageAddress &= ~((EFI_PHYSICAL_ADDRESS)ImageContext.SectionAlignment - 1);
 
  //
  // Load the image to our new buffer
  //
  Status = PeCoffLoaderLoadImage (&ImageContext);
  if (EFI_ERROR (Status)) {
    if (Buffer != NULL) {
      gBS->FreePool (Buffer);
    }
 
    SmmFreePages (DstBuffer, PageCount);
    return Status;
  }
 
  //
  // Relocate the image in our new buffer
  //
  Status = PeCoffLoaderRelocateImage (&ImageContext);
  if (EFI_ERROR (Status)) {
    if (Buffer != NULL) {
      gBS->FreePool (Buffer);
    }
 
    SmmFreePages (DstBuffer, PageCount);
    return Status;
  }
 
  //
  // Flush the instruction cache so the image data are written before we execute it
  //
  InvalidateInstructionCacheRange ((VOID *)(UINTN)ImageContext.ImageAddress, (UINTN)ImageContext.ImageSize);
 
  //
  // Save Image EntryPoint in DriverEntry
  //
  DriverEntry->ImageEntryPoint = ImageContext.EntryPoint;
  DriverEntry->ImageBuffer     = DstBuffer;
  DriverEntry->NumberOfPage    = PageCount;
 
  //
  // Allocate a Loaded Image Protocol in EfiBootServicesData
  //
  Status = gBS->AllocatePool (EfiBootServicesData, sizeof (EFI_LOADED_IMAGE_PROTOCOL), (VOID **)&DriverEntry->LoadedImage);
  if (EFI_ERROR (Status)) {
    if (Buffer != NULL) {
      gBS->FreePool (Buffer);
    }
 
    SmmFreePages (DstBuffer, PageCount);
    return Status;
  }
 
  ZeroMem (DriverEntry->LoadedImage, sizeof (EFI_LOADED_IMAGE_PROTOCOL));
  //
  // Fill in the remaining fields of the Loaded Image Protocol instance.
  // Note: ImageBase is an SMRAM address that can not be accessed outside of SMRAM if SMRAM window is closed.
  //
  DriverEntry->LoadedImage->Revision     = EFI_LOADED_IMAGE_PROTOCOL_REVISION;
  DriverEntry->LoadedImage->ParentHandle = gSmmCorePrivate->SmmIplImageHandle;
  DriverEntry->LoadedImage->SystemTable  = gST;
  DriverEntry->LoadedImage->DeviceHandle = DeviceHandle;
 
  DriverEntry->SmmLoadedImage.Revision     = EFI_LOADED_IMAGE_PROTOCOL_REVISION;
  DriverEntry->SmmLoadedImage.ParentHandle = gSmmCorePrivate->SmmIplImageHandle;
  DriverEntry->SmmLoadedImage.SystemTable  = gST;
  DriverEntry->SmmLoadedImage.DeviceHandle = DeviceHandle;
 
  //
  // Make an EfiBootServicesData buffer copy of FilePath
  //
  Status = gBS->AllocatePool (EfiBootServicesData, GetDevicePathSize (FilePath), (VOID **)&DriverEntry->LoadedImage->FilePath);
  if (EFI_ERROR (Status)) {
    if (Buffer != NULL) {
      gBS->FreePool (Buffer);
    }
 
    SmmFreePages (DstBuffer, PageCount);
    return Status;
  }
 
  CopyMem (DriverEntry->LoadedImage->FilePath, FilePath, GetDevicePathSize (FilePath));
 
  DriverEntry->LoadedImage->ImageBase     = (VOID *)(UINTN)ImageContext.ImageAddress;
  DriverEntry->LoadedImage->ImageSize     = ImageContext.ImageSize;
  DriverEntry->LoadedImage->ImageCodeType = EfiRuntimeServicesCode;
  DriverEntry->LoadedImage->ImageDataType = EfiRuntimeServicesData;
 
  //
  // Make a buffer copy of FilePath
  //
  Status = SmmAllocatePool (EfiRuntimeServicesData, GetDevicePathSize (FilePath), (VOID **)&DriverEntry->SmmLoadedImage.FilePath);
  if (EFI_ERROR (Status)) {
    if (Buffer != NULL) {
      gBS->FreePool (Buffer);
    }
 
    gBS->FreePool (DriverEntry->LoadedImage->FilePath);
    SmmFreePages (DstBuffer, PageCount);
    return Status;
  }
 
  CopyMem (DriverEntry->SmmLoadedImage.FilePath, FilePath, GetDevicePathSize (FilePath));
 
  DriverEntry->SmmLoadedImage.ImageBase     = (VOID *)(UINTN)ImageContext.ImageAddress;
  DriverEntry->SmmLoadedImage.ImageSize     = ImageContext.ImageSize;
  DriverEntry->SmmLoadedImage.ImageCodeType = EfiRuntimeServicesCode;
  DriverEntry->SmmLoadedImage.ImageDataType = EfiRuntimeServicesData;
 
  //
  // Create a new image handle in the UEFI handle database for the SMM Driver
  //
  DriverEntry->ImageHandle = NULL;
  Status                   = gBS->InstallMultipleProtocolInterfaces (
                                    &DriverEntry->ImageHandle,
                                    &gEfiLoadedImageProtocolGuid,
                                    DriverEntry->LoadedImage,
                                    NULL
                                    );
 
  //
  // Create a new image handle in the SMM handle database for the SMM Driver
  //
  DriverEntry->SmmImageHandle = NULL;
  Status                      = SmmInstallProtocolInterface (
                                  &DriverEntry->SmmImageHandle,
                                  &gEfiLoadedImageProtocolGuid,
                                  EFI_NATIVE_INTERFACE,
                                  &DriverEntry->SmmLoadedImage
                                  );
 
  PERF_LOAD_IMAGE_END (DriverEntry->ImageHandle);
 
  //
  // Print the load address and the PDB file name if it is available
  //
 
  DEBUG ((
    DEBUG_INFO | DEBUG_LOAD,
    "Loading SMM driver at 0x%11p EntryPoint=0x%11p ",
    (VOID *)(UINTN)ImageContext.ImageAddress,
    FUNCTION_ENTRY_POINT (ImageContext.EntryPoint)
    ));
 
  //
  // Print Module Name by Pdb file path.
  // Windows and Unix style file path are all trimmed correctly.
  //
  if (ImageContext.PdbPointer != NULL) {
    StartIndex = 0;
    for (Index = 0; ImageContext.PdbPointer[Index] != 0; Index++) {
      if ((ImageContext.PdbPointer[Index] == '\\') || (ImageContext.PdbPointer[Index] == '/')) {
        StartIndex = Index + 1;
      }
    }
 
    //
    // Copy the PDB file name to our temporary string, and replace .pdb with .efi
    // The PDB file name is limited in the range of 0~255.
    // If the length is bigger than 255, trim the redundant characters to avoid overflow in array boundary.
    //
    for (Index = 0; Index < sizeof (EfiFileName) - 4; Index++) {
      EfiFileName[Index] = ImageContext.PdbPointer[Index + StartIndex];
      if (EfiFileName[Index] == 0) {
        EfiFileName[Index] = '.';
      }
 
      if (EfiFileName[Index] == '.') {
        EfiFileName[Index + 1] = 'e';
        EfiFileName[Index + 2] = 'f';
        EfiFileName[Index + 3] = 'i';
        EfiFileName[Index + 4] = 0;
        break;
      }
    }
 
    if (Index == sizeof (EfiFileName) - 4) {
      EfiFileName[Index] = 0;
    }
 
    DEBUG ((DEBUG_INFO | DEBUG_LOAD, "%a", EfiFileName));   // &Image->ImageContext.PdbPointer[StartIndex]));
  }
 
  DEBUG ((DEBUG_INFO | DEBUG_LOAD, "\n"));
 
  //
  // Free buffer allocated by Fv->ReadSection.
  //
  // The UEFI Boot Services FreePool() function must be used because Fv->ReadSection
  // used the UEFI Boot Services AllocatePool() function
  //
  Status = gBS->FreePool (Buffer);
  if (!EFI_ERROR (Status) && EFI_ERROR (SecurityStatus)) {
    Status = SecurityStatus;
  }
 
  return Status;
}
 
EFI_STATUS
SmmPreProcessDepex (
  IN EFI_SMM_DRIVER_ENTRY  *DriverEntry
  )
{
  UINT8  *Iterator;
 
  Iterator               = DriverEntry->Depex;
  DriverEntry->Dependent = TRUE;
 
  if (*Iterator == EFI_DEP_BEFORE) {
    DriverEntry->Before = TRUE;
  } else if (*Iterator == EFI_DEP_AFTER) {
    DriverEntry->After = TRUE;
  }
 
  if (DriverEntry->Before || DriverEntry->After) {
    CopyMem (&DriverEntry->BeforeAfterGuid, Iterator + 1, sizeof (EFI_GUID));
  }
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
SmmGetDepexSectionAndPreProccess (
  IN EFI_SMM_DRIVER_ENTRY  *DriverEntry
  )
{
  EFI_STATUS                     Status;
  EFI_SECTION_TYPE               SectionType;
  UINT32                         AuthenticationStatus;
  EFI_FIRMWARE_VOLUME2_PROTOCOL  *Fv;
 
  Fv = DriverEntry->Fv;
 
  //
  // Grab Depex info, it will never be free'ed.
  // (Note: DriverEntry->Depex is in DXE memory)
  //
  SectionType = EFI_SECTION_SMM_DEPEX;
  Status      = Fv->ReadSection (
                      DriverEntry->Fv,
                      &DriverEntry->FileName,
                      SectionType,
                      0,
                      &DriverEntry->Depex,
                      (UINTN *)&DriverEntry->DepexSize,
                      &AuthenticationStatus
                      );
  if (EFI_ERROR (Status)) {
    if (Status == EFI_PROTOCOL_ERROR) {
      //
      // The section extraction protocol failed so set protocol error flag
      //
      DriverEntry->DepexProtocolError = TRUE;
    } else {
      //
      // If no Depex assume depend on all architectural protocols
      //
      DriverEntry->Depex              = NULL;
      DriverEntry->Dependent          = TRUE;
      DriverEntry->DepexProtocolError = FALSE;
    }
  } else {
    //
    // Set Before and After state information based on Depex
    // Driver will be put in Dependent state
    //
    SmmPreProcessDepex (DriverEntry);
    DriverEntry->DepexProtocolError = FALSE;
  }
 
  return Status;
}
 
EFI_STATUS
SmmDispatcher (
  VOID
  )
{
  EFI_STATUS            Status;
  LIST_ENTRY            *Link;
  EFI_SMM_DRIVER_ENTRY  *DriverEntry;
  BOOLEAN               ReadyToRun;
  BOOLEAN               PreviousSmmEntryPointRegistered;
 
  if (!gRequestDispatch) {
    return EFI_NOT_FOUND;
  }
 
  if (gDispatcherRunning) {
    //
    // If the dispatcher is running don't let it be restarted.
    //
    return EFI_ALREADY_STARTED;
  }
 
  gDispatcherRunning = TRUE;
 
  do {
    //
    // Drain the Scheduled Queue
    //
    while (!IsListEmpty (&mScheduledQueue)) {
      DriverEntry = CR (
                      mScheduledQueue.ForwardLink,
                      EFI_SMM_DRIVER_ENTRY,
                      ScheduledLink,
                      EFI_SMM_DRIVER_ENTRY_SIGNATURE
                      );
 
      //
      // Load the SMM Driver image into memory. If the Driver was transitioned from
      // Untrused to Scheduled it would have already been loaded so we may need to
      // skip the LoadImage
      //
      if (DriverEntry->ImageHandle == NULL) {
        Status = SmmLoadImage (DriverEntry);
 
        //
        // Update the driver state to reflect that it's been loaded
        //
        if (EFI_ERROR (Status)) {
          //
          // The SMM Driver could not be loaded, and do not attempt to load or start it again.
          // Take driver from Scheduled to Initialized.
          //
          DriverEntry->Initialized = TRUE;
          DriverEntry->Scheduled   = FALSE;
          RemoveEntryList (&DriverEntry->ScheduledLink);
 
          //
          // If it's an error don't try the StartImage
          //
          continue;
        }
      }
 
      DriverEntry->Scheduled   = FALSE;
      DriverEntry->Initialized = TRUE;
      RemoveEntryList (&DriverEntry->ScheduledLink);
 
      REPORT_STATUS_CODE_WITH_EXTENDED_DATA (
        EFI_PROGRESS_CODE,
        EFI_SOFTWARE_SMM_DRIVER | EFI_SW_PC_INIT_BEGIN,
        &DriverEntry->ImageHandle,
        sizeof (DriverEntry->ImageHandle)
        );
 
      //
      // Cache state of SmmEntryPointRegistered before calling entry point
      //
      PreviousSmmEntryPointRegistered = gSmmCorePrivate->SmmEntryPointRegistered;
 
      //
      // For each SMM driver, pass NULL as ImageHandle
      //
      RegisterSmramProfileImage (DriverEntry, TRUE);
      PERF_START_IMAGE_BEGIN (DriverEntry->ImageHandle);
      Status = ((EFI_IMAGE_ENTRY_POINT)(UINTN)DriverEntry->ImageEntryPoint)(DriverEntry->ImageHandle, gST);
      PERF_START_IMAGE_END (DriverEntry->ImageHandle);
      if (EFI_ERROR (Status)) {
        DEBUG ((
          DEBUG_ERROR,
          "Error: SMM image at %11p start failed: %r\n",
          DriverEntry->SmmLoadedImage.ImageBase,
          Status
          ));
        UnregisterSmramProfileImage (DriverEntry, TRUE);
        SmmFreePages (DriverEntry->ImageBuffer, DriverEntry->NumberOfPage);
        //
        // Uninstall LoadedImage
        //
        Status = gBS->UninstallProtocolInterface (
                        DriverEntry->ImageHandle,
                        &gEfiLoadedImageProtocolGuid,
                        DriverEntry->LoadedImage
                        );
        if (!EFI_ERROR (Status)) {
          if (DriverEntry->LoadedImage->FilePath != NULL) {
            gBS->FreePool (DriverEntry->LoadedImage->FilePath);
          }
 
          gBS->FreePool (DriverEntry->LoadedImage);
        }
 
        Status = SmmUninstallProtocolInterface (
                   DriverEntry->SmmImageHandle,
                   &gEfiLoadedImageProtocolGuid,
                   &DriverEntry->SmmLoadedImage
                   );
        if (!EFI_ERROR (Status)) {
          if (DriverEntry->SmmLoadedImage.FilePath != NULL) {
            SmmFreePool (DriverEntry->SmmLoadedImage.FilePath);
          }
        }
      }
 
      REPORT_STATUS_CODE_WITH_EXTENDED_DATA (
        EFI_PROGRESS_CODE,
        EFI_SOFTWARE_SMM_DRIVER | EFI_SW_PC_INIT_END,
        &DriverEntry->ImageHandle,
        sizeof (DriverEntry->ImageHandle)
        );
 
      if (!PreviousSmmEntryPointRegistered && gSmmCorePrivate->SmmEntryPointRegistered) {
        //
        // Return immediately if the SMM Entry Point was registered by the SMM
        // Driver that was just dispatched.  The SMM IPL will reinvoke the SMM
        // Core Dispatcher.  This is required so SMM Mode may be enabled as soon
        // as all the dependent SMM Drivers for SMM Mode have been dispatched.
        // Once the SMM Entry Point has been registered, then SMM Mode will be
        // used.
        //
        gRequestDispatch   = TRUE;
        gDispatcherRunning = FALSE;
        return EFI_NOT_READY;
      }
    }
 
    //
    // Search DriverList for items to place on Scheduled Queue
    //
    ReadyToRun = FALSE;
    for (Link = mDiscoveredList.ForwardLink; Link != &mDiscoveredList; Link = Link->ForwardLink) {
      DriverEntry = CR (Link, EFI_SMM_DRIVER_ENTRY, Link, EFI_SMM_DRIVER_ENTRY_SIGNATURE);
 
      if (DriverEntry->DepexProtocolError) {
        //
        // If Section Extraction Protocol did not let the Depex be read before retry the read
        //
        Status = SmmGetDepexSectionAndPreProccess (DriverEntry);
      }
 
      if (DriverEntry->Dependent) {
        if (SmmIsSchedulable (DriverEntry)) {
          SmmInsertOnScheduledQueueWhileProcessingBeforeAndAfter (DriverEntry);
          ReadyToRun = TRUE;
        }
      }
    }
  } while (ReadyToRun);
 
  //
  // If there is no more SMM driver to dispatch, stop the dispatch request
  //
  gRequestDispatch = FALSE;
  for (Link = mDiscoveredList.ForwardLink; Link != &mDiscoveredList; Link = Link->ForwardLink) {
    DriverEntry = CR (Link, EFI_SMM_DRIVER_ENTRY, Link, EFI_SMM_DRIVER_ENTRY_SIGNATURE);
 
    if (!DriverEntry->Initialized) {
      //
      // We have SMM driver pending to dispatch
      //
      gRequestDispatch = TRUE;
      break;
    }
  }
 
  gDispatcherRunning = FALSE;
 
  return EFI_SUCCESS;
}
 
VOID
SmmInsertOnScheduledQueueWhileProcessingBeforeAndAfter (
  IN  EFI_SMM_DRIVER_ENTRY  *InsertedDriverEntry
  )
{
  LIST_ENTRY            *Link;
  EFI_SMM_DRIVER_ENTRY  *DriverEntry;
 
  //
  // Process Before Dependency
  //
  for (Link = mDiscoveredList.ForwardLink; Link != &mDiscoveredList; Link = Link->ForwardLink) {
    DriverEntry = CR (Link, EFI_SMM_DRIVER_ENTRY, Link, EFI_SMM_DRIVER_ENTRY_SIGNATURE);
    if (DriverEntry->Before && DriverEntry->Dependent && (DriverEntry != InsertedDriverEntry)) {
      DEBUG ((DEBUG_DISPATCH, "Evaluate SMM DEPEX for FFS(%g)\n", &DriverEntry->FileName));
      DEBUG ((DEBUG_DISPATCH, "  BEFORE FFS(%g) = ", &DriverEntry->BeforeAfterGuid));
      if (CompareGuid (&InsertedDriverEntry->FileName, &DriverEntry->BeforeAfterGuid)) {
        //
        // Recursively process BEFORE
        //
        DEBUG ((DEBUG_DISPATCH, "TRUE\n  END\n  RESULT = TRUE\n"));
        SmmInsertOnScheduledQueueWhileProcessingBeforeAndAfter (DriverEntry);
      } else {
        DEBUG ((DEBUG_DISPATCH, "FALSE\n  END\n  RESULT = FALSE\n"));
      }
    }
  }
 
  //
  // Convert driver from Dependent to Scheduled state
  //
 
  InsertedDriverEntry->Dependent = FALSE;
  InsertedDriverEntry->Scheduled = TRUE;
  InsertTailList (&mScheduledQueue, &InsertedDriverEntry->ScheduledLink);
 
  //
  // Process After Dependency
  //
  for (Link = mDiscoveredList.ForwardLink; Link != &mDiscoveredList; Link = Link->ForwardLink) {
    DriverEntry = CR (Link, EFI_SMM_DRIVER_ENTRY, Link, EFI_SMM_DRIVER_ENTRY_SIGNATURE);
    if (DriverEntry->After && DriverEntry->Dependent && (DriverEntry != InsertedDriverEntry)) {
      DEBUG ((DEBUG_DISPATCH, "Evaluate SMM DEPEX for FFS(%g)\n", &DriverEntry->FileName));
      DEBUG ((DEBUG_DISPATCH, "  AFTER FFS(%g) = ", &DriverEntry->BeforeAfterGuid));
      if (CompareGuid (&InsertedDriverEntry->FileName, &DriverEntry->BeforeAfterGuid)) {
        //
        // Recursively process AFTER
        //
        DEBUG ((DEBUG_DISPATCH, "TRUE\n  END\n  RESULT = TRUE\n"));
        SmmInsertOnScheduledQueueWhileProcessingBeforeAndAfter (DriverEntry);
      } else {
        DEBUG ((DEBUG_DISPATCH, "FALSE\n  END\n  RESULT = FALSE\n"));
      }
    }
  }
}
 
BOOLEAN
FvHasBeenProcessed (
  IN EFI_HANDLE  FvHandle
  )
{
  LIST_ENTRY    *Link;
  KNOWN_HANDLE  *KnownHandle;
 
  for (Link = mFvHandleList.ForwardLink; Link != &mFvHandleList; Link = Link->ForwardLink) {
    KnownHandle = CR (Link, KNOWN_HANDLE, Link, KNOWN_HANDLE_SIGNATURE);
    if (KnownHandle->Handle == FvHandle) {
      return TRUE;
    }
  }
 
  return FALSE;
}
 
VOID
FvIsBeingProcessed (
  IN EFI_HANDLE  FvHandle
  )
{
  KNOWN_HANDLE  *KnownHandle;
 
  KnownHandle = AllocatePool (sizeof (KNOWN_HANDLE));
  ASSERT (KnownHandle != NULL);
 
  KnownHandle->Signature = KNOWN_HANDLE_SIGNATURE;
  KnownHandle->Handle    = FvHandle;
  InsertTailList (&mFvHandleList, &KnownHandle->Link);
}
 
EFI_DEVICE_PATH_PROTOCOL *
SmmFvToDevicePath (
  IN  EFI_FIRMWARE_VOLUME2_PROTOCOL  *Fv,
  IN  EFI_HANDLE                     FvHandle,
  IN  EFI_GUID                       *DriverName
  )
{
  EFI_STATUS                Status;
  EFI_DEVICE_PATH_PROTOCOL  *FvDevicePath;
  EFI_DEVICE_PATH_PROTOCOL  *FileNameDevicePath;
 
  //
  // Remember the device path of the FV
  //
  Status = gBS->HandleProtocol (FvHandle, &gEfiDevicePathProtocolGuid, (VOID **)&FvDevicePath);
  if (EFI_ERROR (Status)) {
    FileNameDevicePath = NULL;
  } else {
    //
    // Build a device path to the file in the FV to pass into gBS->LoadImage
    //
    EfiInitializeFwVolDevicepathNode (&mFvDevicePath.File, DriverName);
    SetDevicePathEndNode (&mFvDevicePath.End);
 
    //
    // Note: FileNameDevicePath is in DXE memory
    //
    FileNameDevicePath = AppendDevicePath (
                           FvDevicePath,
                           (EFI_DEVICE_PATH_PROTOCOL *)&mFvDevicePath
                           );
  }
 
  return FileNameDevicePath;
}
 
EFI_STATUS
SmmAddToDriverList (
  IN EFI_FIRMWARE_VOLUME2_PROTOCOL  *Fv,
  IN EFI_HANDLE                     FvHandle,
  IN EFI_GUID                       *DriverName
  )
{
  EFI_SMM_DRIVER_ENTRY  *DriverEntry;
 
  //
  // Create the Driver Entry for the list. ZeroPool initializes lots of variables to
  // NULL or FALSE.
  //
  DriverEntry = AllocateZeroPool (sizeof (EFI_SMM_DRIVER_ENTRY));
  ASSERT (DriverEntry != NULL);
 
  DriverEntry->Signature = EFI_SMM_DRIVER_ENTRY_SIGNATURE;
  CopyGuid (&DriverEntry->FileName, DriverName);
  DriverEntry->FvHandle         = FvHandle;
  DriverEntry->Fv               = Fv;
  DriverEntry->FvFileDevicePath = SmmFvToDevicePath (Fv, FvHandle, DriverName);
 
  SmmGetDepexSectionAndPreProccess (DriverEntry);
 
  InsertTailList (&mDiscoveredList, &DriverEntry->Link);
  gRequestDispatch = TRUE;
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
EFIAPI
SmmDriverDispatchHandler (
  IN     EFI_HANDLE  DispatchHandle,
  IN     CONST VOID  *Context         OPTIONAL,
  IN OUT VOID        *CommBuffer      OPTIONAL,
  IN OUT UINTN       *CommBufferSize  OPTIONAL
  )
{
  EFI_STATUS                     Status;
  UINTN                          HandleCount;
  EFI_HANDLE                     *HandleBuffer;
  EFI_STATUS                     GetNextFileStatus;
  EFI_FIRMWARE_VOLUME2_PROTOCOL  *Fv;
  EFI_DEVICE_PATH_PROTOCOL       *FvDevicePath;
  EFI_HANDLE                     FvHandle;
  EFI_GUID                       NameGuid;
  UINTN                          Key;
  EFI_FV_FILETYPE                Type;
  EFI_FV_FILE_ATTRIBUTES         Attributes;
  UINTN                          Size;
  EFI_SMM_DRIVER_ENTRY           *DriverEntry;
  EFI_GUID                       *AprioriFile;
  UINTN                          AprioriEntryCount;
  UINTN                          HandleIndex;
  UINTN                          SmmTypeIndex;
  UINTN                          AprioriIndex;
  LIST_ENTRY                     *Link;
  UINT32                         AuthenticationStatus;
  UINTN                          SizeOfBuffer;
 
  HandleBuffer = NULL;
  Status       = gBS->LocateHandleBuffer (
                        ByProtocol,
                        &gEfiFirmwareVolume2ProtocolGuid,
                        NULL,
                        &HandleCount,
                        &HandleBuffer
                        );
  if (EFI_ERROR (Status)) {
    return EFI_NOT_FOUND;
  }
 
  PERF_CALLBACK_BEGIN (&gEfiEventDxeDispatchGuid);
 
  for (HandleIndex = 0; HandleIndex < HandleCount; HandleIndex++) {
    FvHandle = HandleBuffer[HandleIndex];
 
    if (FvHasBeenProcessed (FvHandle)) {
      //
      // This Fv has already been processed so lets skip it!
      //
      continue;
    }
 
    //
    // Since we are about to process this Fv mark it as processed.
    //
    FvIsBeingProcessed (FvHandle);
 
    Status = gBS->HandleProtocol (FvHandle, &gEfiFirmwareVolume2ProtocolGuid, (VOID **)&Fv);
    if (EFI_ERROR (Status)) {
      //
      // FvHandle must have a Firmware Volume2 Protocol thus we should never get here.
      //
      ASSERT (FALSE);
      continue;
    }
 
    Status = gBS->HandleProtocol (FvHandle, &gEfiDevicePathProtocolGuid, (VOID **)&FvDevicePath);
    if (EFI_ERROR (Status)) {
      //
      // The Firmware volume doesn't have device path, can't be dispatched.
      //
      continue;
    }
 
    //
    // Discover Drivers in FV and add them to the Discovered Driver List.
    // Process EFI_FV_FILETYPE_SMM type and then EFI_FV_FILETYPE_COMBINED_SMM_DXE
    //  EFI_FV_FILETYPE_SMM_CORE is processed to produce a Loaded Image protocol for the core
    //
    for (SmmTypeIndex = 0; SmmTypeIndex < sizeof (mSmmFileTypes)/sizeof (EFI_FV_FILETYPE); SmmTypeIndex++) {
      //
      // Initialize the search key
      //
      Key = 0;
      do {
        Type              = mSmmFileTypes[SmmTypeIndex];
        GetNextFileStatus = Fv->GetNextFile (
                                  Fv,
                                  &Key,
                                  &Type,
                                  &NameGuid,
                                  &Attributes,
                                  &Size
                                  );
        if (!EFI_ERROR (GetNextFileStatus)) {
          if (Type == EFI_FV_FILETYPE_SMM_CORE) {
            //
            // If this is the SMM core fill in it's DevicePath & DeviceHandle
            //
            if (mSmmCoreLoadedImage->FilePath == NULL) {
              //
              // Maybe one special FV contains only one SMM_CORE module, so its device path must
              // be initialized completely.
              //
              EfiInitializeFwVolDevicepathNode (&mFvDevicePath.File, &NameGuid);
              SetDevicePathEndNode (&mFvDevicePath.End);
 
              //
              // Make an EfiBootServicesData buffer copy of FilePath
              //
              Status = gBS->AllocatePool (
                              EfiBootServicesData,
                              GetDevicePathSize ((EFI_DEVICE_PATH_PROTOCOL *)&mFvDevicePath),
                              (VOID **)&mSmmCoreLoadedImage->FilePath
                              );
              ASSERT_EFI_ERROR (Status);
              CopyMem (mSmmCoreLoadedImage->FilePath, &mFvDevicePath, GetDevicePathSize ((EFI_DEVICE_PATH_PROTOCOL *)&mFvDevicePath));
 
              mSmmCoreLoadedImage->DeviceHandle = FvHandle;
            }
 
            if (mSmmCoreDriverEntry->SmmLoadedImage.FilePath == NULL) {
              //
              // Maybe one special FV contains only one SMM_CORE module, so its device path must
              // be initialized completely.
              //
              EfiInitializeFwVolDevicepathNode (&mFvDevicePath.File, &NameGuid);
              SetDevicePathEndNode (&mFvDevicePath.End);
 
              //
              // Make a buffer copy FilePath
              //
              Status = SmmAllocatePool (
                         EfiRuntimeServicesData,
                         GetDevicePathSize ((EFI_DEVICE_PATH_PROTOCOL *)&mFvDevicePath),
                         (VOID **)&mSmmCoreDriverEntry->SmmLoadedImage.FilePath
                         );
              ASSERT_EFI_ERROR (Status);
              CopyMem (mSmmCoreDriverEntry->SmmLoadedImage.FilePath, &mFvDevicePath, GetDevicePathSize ((EFI_DEVICE_PATH_PROTOCOL *)&mFvDevicePath));
 
              mSmmCoreDriverEntry->SmmLoadedImage.DeviceHandle = FvHandle;
            }
          } else {
            SmmAddToDriverList (Fv, FvHandle, &NameGuid);
          }
        }
      } while (!EFI_ERROR (GetNextFileStatus));
    }
 
    //
    // Read the array of GUIDs from the Apriori file if it is present in the firmware volume
    // (Note: AprioriFile is in DXE memory)
    //
    AprioriFile = NULL;
    Status      = Fv->ReadSection (
                        Fv,
                        &gAprioriGuid,
                        EFI_SECTION_RAW,
                        0,
                        (VOID **)&AprioriFile,
                        &SizeOfBuffer,
                        &AuthenticationStatus
                        );
    if (!EFI_ERROR (Status)) {
      AprioriEntryCount = SizeOfBuffer / sizeof (EFI_GUID);
    } else {
      AprioriEntryCount = 0;
    }
 
    //
    // Put drivers on Apriori List on the Scheduled queue. The Discovered List includes
    // drivers not in the current FV and these must be skipped since the a priori list
    // is only valid for the FV that it resided in.
    //
 
    for (AprioriIndex = 0; AprioriIndex < AprioriEntryCount; AprioriIndex++) {
      for (Link = mDiscoveredList.ForwardLink; Link != &mDiscoveredList; Link = Link->ForwardLink) {
        DriverEntry = CR (Link, EFI_SMM_DRIVER_ENTRY, Link, EFI_SMM_DRIVER_ENTRY_SIGNATURE);
        if (CompareGuid (&DriverEntry->FileName, &AprioriFile[AprioriIndex]) &&
            (FvHandle == DriverEntry->FvHandle))
        {
          DriverEntry->Dependent = FALSE;
          DriverEntry->Scheduled = TRUE;
          InsertTailList (&mScheduledQueue, &DriverEntry->ScheduledLink);
          DEBUG ((DEBUG_DISPATCH, "Evaluate SMM DEPEX for FFS(%g)\n", &DriverEntry->FileName));
          DEBUG ((DEBUG_DISPATCH, "  RESULT = TRUE (Apriori)\n"));
          break;
        }
      }
    }
 
    //
    // Free data allocated by Fv->ReadSection ()
    //
    // The UEFI Boot Services FreePool() function must be used because Fv->ReadSection
    // used the UEFI Boot Services AllocatePool() function
    //
    gBS->FreePool (AprioriFile);
  }
 
  //
  // Execute the SMM Dispatcher on any newly discovered FVs and previously
  // discovered SMM drivers that have been discovered but not dispatched.
  //
  Status = SmmDispatcher ();
 
  //
  // Check to see if CommBuffer and CommBufferSize are valid
  //
  if ((CommBuffer != NULL) && (CommBufferSize != NULL)) {
    if (*CommBufferSize > 0) {
      if (Status == EFI_NOT_READY) {
        //
        // If a the SMM Core Entry Point was just registered, then set flag to
        // request the SMM Dispatcher to be restarted.
        //
        *(UINT8 *)CommBuffer = COMM_BUFFER_SMM_DISPATCH_RESTART;
      } else if (!EFI_ERROR (Status)) {
        //
        // Set the flag to show that the SMM Dispatcher executed without errors
        //
        *(UINT8 *)CommBuffer = COMM_BUFFER_SMM_DISPATCH_SUCCESS;
      } else {
        //
        // Set the flag to show that the SMM Dispatcher encountered an error
        //
        *(UINT8 *)CommBuffer = COMM_BUFFER_SMM_DISPATCH_ERROR;
      }
    }
  }
 
  PERF_CALLBACK_END (&gEfiEventDxeDispatchGuid);
  return EFI_SUCCESS;
}
 
VOID
SmmDisplayDiscoveredNotDispatched (
  VOID
  )
{
  LIST_ENTRY            *Link;
  EFI_SMM_DRIVER_ENTRY  *DriverEntry;
 
  for (Link = mDiscoveredList.ForwardLink; Link != &mDiscoveredList; Link = Link->ForwardLink) {
    DriverEntry = CR (Link, EFI_SMM_DRIVER_ENTRY, Link, EFI_SMM_DRIVER_ENTRY_SIGNATURE);
    if (DriverEntry->Dependent) {
      DEBUG ((DEBUG_LOAD, "SMM Driver %g was discovered but not loaded!!\n", &DriverEntry->FileName));
    }
  }
}