MmCommunicationDxe.c

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#include "MmCommunicationDxe.h"
 
//
// PI 1.7 MM Communication Protocol 2 instance
//
EFI_MM_COMMUNICATION2_PROTOCOL  mMmCommunication2 = {
  MmCommunicate2
};
 
//
// PI 1.7 MM Communication Protocol instance
//
EFI_MM_COMMUNICATION_PROTOCOL  mMmCommunication = {
  MmCommunicate
};
 
MM_COMM_BUFFER             mMmCommonBuffer;
EFI_SMM_CONTROL2_PROTOCOL  *mSmmControl2;
EFI_SMM_ACCESS2_PROTOCOL   *mSmmAccess;
BOOLEAN                    mSmmLocked = FALSE;
BOOLEAN                    mEndOfDxe  = FALSE;
 
//
// Table of Protocol notification and GUIDed Event notifications that the Standalone Mm requires
//
MM_EVENT_NOTIFICATION  mMmEvents[] = {
  //
  // Declare protocol notification on DxeMmReadyToLock protocols.  When this notification is established,
  // the associated event is immediately signalled, so the notification function will be executed and the
  // DXE Mm Ready To Lock Protocol will be found if it is already in the handle database.
  //
  { ProtocolNotify, TRUE,  &gEfiDxeMmReadyToLockProtocolGuid,  MmReadyToLockEventNotify,    &gEfiDxeMmReadyToLockProtocolGuid, NULL },
  //
  // Declare event notification on Ready To Boot Event Group.  This is an extra event notification that is
  // used to make sure SMRAM is locked before any boot options are processed.
  //
  { EventNotify,    TRUE,  &gEfiEventReadyToBootGuid,          MmReadyToLockEventNotify,    &gEfiEventReadyToBootGuid,         NULL },
  //
  // Declare event notification on Ready To Boot Event Group.  This is used to inform the MM Core
  // to notify MM driver that system enter ready to boot.
  //
  { EventNotify,    FALSE, &gEfiEventReadyToBootGuid,          MmGuidedEventNotify,         &gEfiEventReadyToBootGuid,         NULL },
  //
  // Declare event notification on EndOfDxe event.  When this notification is established,
  // the associated event is immediately signalled, so the notification function will be executed and the
  // End Of Dxe Protocol will be found if it is already in the handle database.
  //
  { EventNotify,    TRUE,  &gEfiEndOfDxeEventGroupGuid,        MmGuidedEventNotify,         &gEfiEndOfDxeEventGroupGuid,       NULL },
  //
  // Declare event notification on EndOfDxe event.  This is used to set EndOfDxe event signaled flag.
  //
  { EventNotify,    TRUE,  &gEfiEndOfDxeEventGroupGuid,        MmEndOfDxeEventNotify,       &gEfiEndOfDxeEventGroupGuid,       NULL },
  //
  // Declare event notification on Exit Boot Services Event Group.  This is used to inform the MM Core
  // to notify MM driver that system enter exit boot services.
  //
  { EventNotify,    FALSE, &gEfiEventExitBootServicesGuid,     MmGuidedEventNotify,         &gEfiEventExitBootServicesGuid,    NULL },
  //
  // Declare event notification on SetVirtualAddressMap() Event Group.  This is used to convert fixed MM communication buffer
  // and MM_COMM_BUFFER_STATUS in mMmCommonBuffer, mSmmControl2 from physical addresses to virtual addresses.
  //
  { EventNotify,    FALSE, &gEfiEventVirtualAddressChangeGuid, MmVirtualAddressChangeEvent, NULL,                              NULL },
  //
  // Terminate the table of event notifications
  //
  { EndNotify,      FALSE, NULL,                               NULL,                        NULL,                              NULL }
};
 
VOID
EFIAPI
MmGuidedEventNotify (
  IN EFI_EVENT  Event,
  IN VOID       *Context
  )
{
  UINTN                      Size;
  EFI_MM_COMMUNICATE_HEADER  *CommunicateHeader;
 
  CommunicateHeader = (EFI_MM_COMMUNICATE_HEADER *)(UINTN)mMmCommonBuffer.PhysicalStart;
 
  //
  // Use Guid to initialize EFI_MM_COMMUNICATE_HEADER structure
  //
  CopyGuid (&CommunicateHeader->HeaderGuid, (EFI_GUID *)Context);
  CommunicateHeader->MessageLength = 1;
  CommunicateHeader->Data[0]       = 0;
 
  //
  // Generate the Software SMI and return the result
  //
  Size = sizeof (EFI_MM_COMMUNICATE_HEADER);
  MmCommunicate2 (&mMmCommunication2, CommunicateHeader, CommunicateHeader, &Size);
}
 
VOID
EFIAPI
MmReadyToLockEventNotify (
  IN EFI_EVENT  Event,
  IN VOID       *Context
  )
{
  EFI_STATUS  Status;
  VOID        *Interface;
  UINTN       Index;
 
  //
  // See if we are already locked
  //
  if (mSmmLocked) {
    return;
  }
 
  //
  // Make sure this notification is for this handler
  //
  if (CompareGuid ((EFI_GUID *)Context, &gEfiDxeMmReadyToLockProtocolGuid)) {
    Status = gBS->LocateProtocol (&gEfiDxeMmReadyToLockProtocolGuid, NULL, &Interface);
    if (EFI_ERROR (Status)) {
      return;
    }
  } else {
    //
    // If MM is not locked yet and we got here from gEfiEventReadyToBootGuid being
    // signaled, then gEfiDxeMmReadyToLockProtocolGuid was not installed as expected.
    // Print a warning on debug builds.
    //
    DEBUG ((DEBUG_WARN, "DXE Mm Ready To Lock Protocol not installed before Ready To Boot signal\n"));
  }
 
  if (!mEndOfDxe) {
    DEBUG ((DEBUG_ERROR, "EndOfDxe Event must be signaled before DxeSmmReadyToLock Protocol installation!\n"));
    REPORT_STATUS_CODE (
      EFI_ERROR_CODE | EFI_ERROR_UNRECOVERED,
      (EFI_SOFTWARE_SMM_DRIVER | EFI_SW_EC_ILLEGAL_SOFTWARE_STATE)
      );
    ASSERT (FALSE);
  }
 
  //
  // Lock the SMRAM (Note: Locking SMRAM may not be supported on all platforms)
  //
  mSmmAccess->Lock (mSmmAccess);
 
  //
  // Close protocol and event notification events that do not apply after the
  // DXE MM Ready To Lock Protocol has been installed or the Ready To Boot
  // event has been signalled.
  //
  for (Index = 0; mMmEvents[Index].NotifyFunction != NULL; Index++) {
    if (mMmEvents[Index].CloseOnLock) {
      gBS->CloseEvent (mMmEvents[Index].Event);
    }
  }
 
  //
  // Inform MM Core that the DxeSmmReadyToLock protocol was installed
  //
  MmGuidedEventNotify (Event, (VOID *)&gEfiDxeMmReadyToLockProtocolGuid);
 
  //
  // Print debug message that the SMRAM window is now locked.
  //
  DEBUG ((DEBUG_INFO, "MmCommunicationDxe locked SMRAM window\n"));
 
  //
  // Set flag so this operation will not be performed again
  //
  mSmmLocked = TRUE;
}
 
VOID
EFIAPI
MmEndOfDxeEventNotify (
  IN EFI_EVENT  Event,
  IN VOID       *Context
  )
{
  mEndOfDxe = TRUE;
}
 
VOID
EFIAPI
MmVirtualAddressChangeEvent (
  IN EFI_EVENT  Event,
  IN VOID       *Context
  )
{
  EfiConvertPointer (0x0, (VOID **)&mMmCommonBuffer.Status);
  EfiConvertPointer (0x0, (VOID **)&mMmCommonBuffer.PhysicalStart);
  EfiConvertPointer (0x0, (VOID **)&mSmmControl2);
}
 
EFI_STATUS
EFIAPI
ProcessCommunicationBuffer (
  IN OUT VOID   *CommBuffer,
  IN OUT UINTN  *CommSize OPTIONAL
  )
{
  EFI_STATUS                 Status;
  EFI_MM_COMMUNICATE_HEADER  *CommunicateHeader;
  MM_COMM_BUFFER_STATUS      *CommonBufferStatus;
  UINTN                      BufferSize;
 
  //
  // Check parameters
  //
  if (CommBuffer == NULL) {
    return EFI_INVALID_PARAMETER;
  }
 
  CommunicateHeader = (EFI_MM_COMMUNICATE_HEADER *)CommBuffer;
  BufferSize        = OFFSET_OF (EFI_MM_COMMUNICATE_HEADER, Data) + CommunicateHeader->MessageLength;
 
  if (CommSize != NULL) {
    ASSERT (*CommSize == BufferSize);
  }
 
  CommonBufferStatus = (MM_COMM_BUFFER_STATUS *)(UINTN)mMmCommonBuffer.Status;
 
  //
  // Copy the content at input CommBuffer to fixed MM communication buffer
  // if CommBuffer is not equal to fixed MM communication buffer.
  //
  if ((UINTN)CommBuffer != mMmCommonBuffer.PhysicalStart) {
    CopyMem ((VOID *)(UINTN)mMmCommonBuffer.PhysicalStart, CommBuffer, BufferSize);
  }
 
  CommonBufferStatus->IsCommBufferValid = TRUE;
 
  //
  // Generate Software SMI
  //
  Status = mSmmControl2->Trigger (mSmmControl2, NULL, NULL, FALSE, 0);
  if (EFI_ERROR (Status)) {
    return EFI_UNSUPPORTED;
  }
 
  //
  // Copy the returned data to the non-mmram buffer (CommBuffer)
  //
  if ((UINTN)CommBuffer != mMmCommonBuffer.PhysicalStart) {
    CopyMem (CommBuffer, (VOID *)(UINTN)mMmCommonBuffer.PhysicalStart, CommonBufferStatus->ReturnBufferSize);
  }
 
  //
  // Retrieve BufferSize and return status from CommonBufferStatus
  //
  if (CommSize != NULL) {
    *CommSize = CommonBufferStatus->ReturnBufferSize;
  }
 
  CommonBufferStatus->IsCommBufferValid = FALSE;
 
  return CommonBufferStatus->ReturnStatus;
}
 
EFI_STATUS
EFIAPI
MmCommunicate2 (
  IN CONST EFI_MM_COMMUNICATION2_PROTOCOL  *This,
  IN OUT VOID                              *CommBufferPhysical,
  IN OUT VOID                              *CommBufferVirtual,
  IN OUT UINTN                             *CommSize OPTIONAL
  )
{
  return ProcessCommunicationBuffer (CommBufferVirtual, CommSize);
}
 
EFI_STATUS
EFIAPI
MmCommunicate (
  IN CONST EFI_MM_COMMUNICATION_PROTOCOL  *This,
  IN OUT VOID                             *CommBuffer,
  IN OUT UINTN                            *CommSize OPTIONAL
  )
{
  return ProcessCommunicationBuffer (CommBuffer, CommSize);
}
 
EFI_STATUS
EFIAPI
MmCommunicationEntryPoint (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS         Status;
  EFI_HANDLE         Handle;
  EFI_HOB_GUID_TYPE  *GuidHob;
  MM_COMM_BUFFER     *MmCommonBuffer;
  UINTN              Index;
  VOID               *Registration;
 
  //
  // Locate gMmCommBufferHobGuid and cache the content
  //
  GuidHob = GetFirstGuidHob (&gMmCommBufferHobGuid);
  ASSERT (GuidHob != NULL);
  MmCommonBuffer = GET_GUID_HOB_DATA (GuidHob);
  CopyMem (&mMmCommonBuffer, MmCommonBuffer, sizeof (MM_COMM_BUFFER));
 
  //
  // Get SMM Control2 Protocol
  //
  Status = gBS->LocateProtocol (&gEfiSmmControl2ProtocolGuid, NULL, (VOID **)&mSmmControl2);
  ASSERT_EFI_ERROR (Status);
 
  //
  // Get SMM Access Protocol
  //
  Status = gBS->LocateProtocol (&gEfiSmmAccess2ProtocolGuid, NULL, (VOID **)&mSmmAccess);
  ASSERT_EFI_ERROR (Status);
 
  Handle = NULL;
  Status = gBS->InstallProtocolInterface (
                  &Handle,
                  &gEfiMmCommunication2ProtocolGuid,
                  EFI_NATIVE_INTERFACE,
                  &mMmCommunication2
                  );
  ASSERT_EFI_ERROR (Status);
 
  Status = gBS->InstallProtocolInterface (
                  &Handle,
                  &gEfiMmCommunicationProtocolGuid,
                  EFI_NATIVE_INTERFACE,
                  &mMmCommunication
                  );
  ASSERT_EFI_ERROR (Status);
 
  //
  // Create the set of protocol and event notifications that the Standalone Mm requires
  //
  for (Index = 0; mMmEvents[Index].NotificationType != EndNotify; Index++) {
    if (mMmEvents[Index].NotificationType == ProtocolNotify) {
      mMmEvents[Index].Event = EfiCreateProtocolNotifyEvent (
                                 mMmEvents[Index].Guid,
                                 TPL_CALLBACK,
                                 mMmEvents[Index].NotifyFunction,
                                 mMmEvents[Index].NotifyContext,
                                 &Registration
                                 );
    } else {
      Status = gBS->CreateEventEx (
                      EVT_NOTIFY_SIGNAL,
                      TPL_CALLBACK,
                      mMmEvents[Index].NotifyFunction,
                      mMmEvents[Index].NotifyContext,
                      mMmEvents[Index].Guid,
                      &mMmEvents[Index].Event
                      );
      ASSERT_EFI_ERROR (Status);
    }
  }
 
  return EFI_SUCCESS;
}