8.9 DXE SAL Driver

The module type of DXE SAL Driver is only available to the IPF architecture. This module type is used by DXE Drivers that can be called in physical mode before SetVirtualAddressMap() is called, and either physical mode or virtual mode after SetVirtualAddressMap() is called. This means the services that these modules produce are available after ExitBootServices().

A DXE SAL driver defines MODULE_TYPE as DXE_SAL_DRIVER in the INF file. In addition, a DXE SAL driver registers SAL Services for the system.

Because a DXE SAL Driver is available after ExitBootServices(), it may also need to register an event handler for EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE.

8.9.1 INF File

Following is the example of a [Defines] section for a driver named

SampleDriverDxeSal. For DXE SAL driver, the MODULE_TYPE entry should be as follows:

  DXE_SAL_DRIVER

[Defines]
  INF_VERSION = 0x00010005
  BASE_NAME   = SampleDriverDxeSal
  FILE_GUID   = XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
  MODULE_TYPE = DXE_SAL_DRIVER
  ENTRY_POINT = SampleDxeSalDriverEntryPoint

[Depex]
  gSampleProtocolGuid

8.9.2 Entry Point

The entry point of DXE SAL Driver must register the SAL services it produces. The template code is as follows.

Note: EDK II does not specify a detailed way for DXE SAL Drivers to produce and register SAL services.

EFI_STATUS
EFIAPI
SampleDxeSalDriverEntryPoint (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  //
  // More initialization can be added here.
  //
  //
  // Event creation for EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE can be added
  // here.
  //
  //
  // Register SAL services
  //
  return EFI_SUCCESS;
}