dispatcher.c

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/*++

Copyright (c) 2004 - 2006, Intel Corporation                                                         
All rights reserved. This program and the accompanying materials                          
are licensed and made available under the terms and conditions of the BSD License         
which accompanies this distribution.  The full text of the license may be found at        
http://opensource.org/licenses/bsd-license.php                                            
                                                                                          
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.             

Module Name:

  Dispatcher.c

Abstract:

  Tiano DXE Dispatcher.

  Step #1 - When a FV protocol is added to the system every driver in the FV
            is added to the mDiscoveredList. The SOR, Before, and After Depex are 
            pre-processed as drivers are added to the mDiscoveredList. If an Apriori 
            file exists in the FV those drivers are addeded to the 
            mScheduledQueue. The mFvHandleList is used to make sure a 
            FV is only processed once.

  Step #2 - Dispatch. Remove driver from the mScheduledQueue and load and
            start it. After mScheduledQueue is drained check the 
            mDiscoveredList to see if any item has a Depex that is ready to 
            be placed on the mScheduledQueue.

  Step #3 - Adding to the mScheduledQueue requires that you process Before 
            and After dependencies. This is done recursively as the call to add
            to the mScheduledQueue checks for Before and recursively adds 
            all Befores. It then addes the item that was passed in and then 
            processess the After dependecies by recursively calling the routine.

  Dispatcher Rules:
  The rules for the dispatcher are in chapter 10 of the DXE CIS. Figure 10-3 
  is the state diagram for the DXE dispatcher

  Depex - Dependency Expresion.
  SOR   - Schedule On Request - Don't schedule if this bit is set.

--*/

#include "Tiano.h"
#include "DxeCore.h"
#include "FwVolBlock.h"
#include EFI_GUID_DEFINITION (Apriori)

//
// The Driver List contains one copy of every driver that has been discovered.
// Items are never removed from the driver list. List of EFI_CORE_DRIVER_ENTRY
//
EFI_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_CORE_DRIVER_ENTRY.
//
EFI_LIST_ENTRY  mScheduledQueue = INITIALIZE_LIST_HEAD_VARIABLE (mScheduledQueue);

//
// List of handles who's Fv's have been parsed and added to the mFwDriverList.
//
EFI_LIST_ENTRY  mFvHandleList = INITIALIZE_LIST_HEAD_VARIABLE (mFvHandleList);           // list of KNOWN_HANDLE

//
// Lock for mDiscoveredList, mScheduledQueue, mDispatcherRunning.
//
EFI_LOCK  mDispatcherLock = EFI_INITIALIZE_LOCK_VARIABLE (EFI_TPL_HIGH_LEVEL);


//
// Flag for the DXE Dispacher.  TRUE if dispatcher is execuing.
//
BOOLEAN  mDispatcherRunning = FALSE;

//
// Module globals to manage the FwVol registration notification event
//
EFI_EVENT       mFwVolEvent;
VOID            *mFwVolEventRegistration;

//
// List of file types supported by dispatcher
//
static EFI_FV_FILETYPE mDxeFileTypes[] = { 
  EFI_FV_FILETYPE_DRIVER, 
  EFI_FV_FILETYPE_COMBINED_PEIM_DRIVER, 
  EFI_FV_FILETYPE_DXE_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;
//
// Function Prototypes
//
VOID
CoreInsertOnScheduledQueueWhileProcessingBeforeAndAfter (
  IN  EFI_CORE_DRIVER_ENTRY   *InsertedDriverEntry
  );
 
VOID
EFIAPI
CoreFwVolEventProtocolNotify (
  IN  EFI_EVENT       Event,
  IN  VOID            *Context
  );

EFI_DEVICE_PATH_PROTOCOL *
CoreFvToDevicePath (
  IN  EFI_FIRMWARE_VOLUME_PROTOCOL    *Fv,
  IN  EFI_HANDLE                      FvHandle,
  IN  EFI_GUID                        *DriverName
  );

STATIC 
EFI_STATUS
CoreAddToDriverList (
  IN  EFI_FIRMWARE_VOLUME_PROTOCOL  *Fv,
  IN  EFI_HANDLE                    FvHandle,
  IN  EFI_GUID                      *DriverName
  );

STATIC
EFI_STATUS 
CoreProcessFvImageFile (
  IN  EFI_FIRMWARE_VOLUME_PROTOCOL    *Fv,
  IN  EFI_HANDLE                      FvHandle,
  IN  EFI_GUID                        *DriverName
  );


VOID
CoreAcquireDispatcherLock (
  VOID
  )
/*++

Routine Description:

  Enter critical section by gaining lock on mDispatcherLock

Arguments:

  None

Returns:

  None

--*/

{
  CoreAcquireLock (&mDispatcherLock);
}

VOID
CoreReleaseDispatcherLock (
  VOID
  )
/*++

Routine Description:

  Exit critical section by releasing lock on mDispatcherLock

Arguments:

  None

Returns:

  None

--*/
{
  CoreReleaseLock (&mDispatcherLock);
}


EFI_STATUS
CoreGetDepexSectionAndPreProccess (
  IN  EFI_CORE_DRIVER_ENTRY   *DriverEntry
  )
/*++

Routine Description:

  Read Depex and pre-process the Depex for Before and After. If Section Extraction
  protocol returns an error via ReadSection defer the reading of the Depex.

Arguments:

  DriverEntry - Driver to work on.
  
Returns:

  EFI_SUCCESS - Depex read and preprossesed 

  EFI_PROTOCOL_ERROR - The section extraction protocol returned an error and 
                        Depex reading needs to be retried.

  Other Error - DEPEX not found.

--*/
{
  EFI_STATUS                    Status;
  EFI_SECTION_TYPE              SectionType;
  UINT32                        AuthenticationStatus;
  EFI_FIRMWARE_VOLUME_PROTOCOL  *Fv;

  
  Fv = DriverEntry->Fv;

  //
  // Grab Depex info, it will never be free'ed.
  //
  SectionType         = EFI_SECTION_DXE_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 EFI 1.1 driver model
      //
      DriverEntry->Depex = NULL;
      DriverEntry->Dependent = TRUE;
      DriverEntry->DepexProtocolError = FALSE;
    }
  } else {
    //
    // Set Before, After, and Unrequested state information based on Depex
    // Driver will be put in Dependent or Unrequested state
    //
    CorePreProcessDepex (DriverEntry);
    DriverEntry->DepexProtocolError = FALSE;
  }  

  return Status;
}

EFI_DXESERVICE
EFI_STATUS
EFIAPI
CoreSchedule (
  IN  EFI_HANDLE  FirmwareVolumeHandle,
  IN  EFI_GUID    *DriverName
  )
/*++

Routine Description:

  Check every driver and locate a matching one. If the driver is found, the Unrequested
  state flag is cleared.

Arguments:

  FirmwareVolumeHandle - The handle of the Firmware Volume that contains the firmware 
                         file specified by DriverName.

  DriverName           - The Driver name to put in the Dependent state.

Returns:

  EFI_SUCCESS   - The DriverName was found and it's SOR bit was cleared

  EFI_NOT_FOUND - The DriverName does not exist or it's SOR bit was not set.

--*/
{
  EFI_LIST_ENTRY        *Link;
  EFI_CORE_DRIVER_ENTRY *DriverEntry;

  //
  // Check every driver
  //
  for (Link = mDiscoveredList.ForwardLink; Link != &mDiscoveredList; Link = Link->ForwardLink) {
    DriverEntry = CR(Link, EFI_CORE_DRIVER_ENTRY, Link, EFI_CORE_DRIVER_ENTRY_SIGNATURE);
    if (DriverEntry->FvHandle == FirmwareVolumeHandle &&
        DriverEntry->Unrequested && 
        EfiCompareGuid (DriverName, &DriverEntry->FileName)) {
      //
      // Move the driver from the Unrequested to the Dependent state
      //
      CoreAcquireDispatcherLock ();
      DriverEntry->Unrequested  = FALSE;
      DriverEntry->Dependent    = TRUE;
      CoreReleaseDispatcherLock ();
    
      return EFI_SUCCESS;
    }
  }
  return EFI_NOT_FOUND;  
}


EFI_DXESERVICE
EFI_STATUS
EFIAPI
CoreTrust (
  IN  EFI_HANDLE  FirmwareVolumeHandle,
  IN  EFI_GUID    *DriverName
  )
/*++

Routine Description:

  Convert a driver from the Untrused back to the Scheduled state

Arguments:

  FirmwareVolumeHandle - The handle of the Firmware Volume that contains the firmware 
                         file specified by DriverName.

  DriverName           - The Driver name to put in the Scheduled state

Returns:

  EFI_SUCCESS   - The file was found in the untrusted state, and it was promoted 
                  to the trusted state.

  EFI_NOT_FOUND - The file was not found in the untrusted state.

--*/
{
  EFI_LIST_ENTRY        *Link;
  EFI_CORE_DRIVER_ENTRY *DriverEntry;

  //
  // Check every driver
  //
  for (Link = mDiscoveredList.ForwardLink; Link != &mDiscoveredList; Link = Link->ForwardLink) {
    DriverEntry = CR(Link, EFI_CORE_DRIVER_ENTRY, Link, EFI_CORE_DRIVER_ENTRY_SIGNATURE);
    if (DriverEntry->FvHandle == FirmwareVolumeHandle &&
        DriverEntry->Untrusted && 
        EfiCompareGuid (DriverName, &DriverEntry->FileName)) {
      //
      // Transition driver from Untrusted to Scheduled state.
      //
      CoreAcquireDispatcherLock ();
      DriverEntry->Untrusted = FALSE;
      DriverEntry->Scheduled = TRUE;
      InsertTailList (&mScheduledQueue, &DriverEntry->ScheduledLink);
      CoreReleaseDispatcherLock ();
    
      return EFI_SUCCESS;
    }
  }
  return EFI_NOT_FOUND;  
}


EFI_DXESERVICE
EFI_STATUS
EFIAPI
CoreDispatcher (
  VOID
  )
/*++

Routine Description:

  This is the main Dispatcher for DXE and it exits when there are no more 
  drivers to run. Drain the mScheduledQueue and load and start a PE
  image for each driver. Search the mDiscoveredList to see if any driver can 
  be placed on the mScheduledQueue. If no drivers are placed on the
  mScheduledQueue exit the function. On exit it is assumed the Bds()
  will be called, and when the Bds() exits the Dispatcher will be called 
  again.

Arguments:

  NONE

Returns:

  EFI_ALREADY_STARTED - The DXE Dispatcher is already running