CloverBootloader/OvmfPkg/Library/UefiDriverEntryPointFwCfgOverrideLib/UefiDriverEntryPointFwCfgOverrideLib.c

149 lines
4.1 KiB
C

/** @file
Entry point to a EFI/DXE driver. This version is specific to QEMU, and ties
dispatch of the driver in question on the value of a QEMU fw_cfg boolean
variable which is referenced by name via a fixed pointer PCD.
Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
Copyright (c) 2022, Google LLC. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Uefi.h>
#include <Protocol/LoadedImage.h>
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/QemuFwCfgSimpleParserLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiDriverEntryPoint.h>
/**
Unloads an image from memory.
This function is a callback that a driver registers to do cleanup
when the UnloadImage boot service function is called.
@param ImageHandle The handle to the image to unload.
@return Status returned by all unload().
**/
STATIC
EFI_STATUS
EFIAPI
_DriverUnloadHandler (
EFI_HANDLE ImageHandle
)
{
EFI_STATUS Status;
//
// If an UnloadImage() handler is specified, then call it
//
Status = ProcessModuleUnloadList (ImageHandle);
//
// If the driver specific unload handler does not return an error, then call
// all of the library destructors. If the unload handler returned an error,
// then the driver can not be unloaded, and the library destructors should
// not be called
//
if (!EFI_ERROR (Status)) {
ProcessLibraryDestructorList (ImageHandle, gST);
}
//
// Return the status from the driver specific unload handler
//
return Status;
}
/**
The entry point of PE/COFF Image for a DXE Driver, DXE Runtime Driver, or
UEFI Driver.
@param ImageHandle The image handle of the DXE Driver, DXE
Runtime Driver, or UEFI Driver.
@param SystemTable A pointer to the EFI System Table.
@retval EFI_SUCCESS The DXE Driver, DXE Runtime Driver, or
UEFI Driver exited normally.
@retval EFI_INCOMPATIBLE_VERSION _gUefiDriverRevision is greater than
SystemTable->Hdr.Revision.
@retval Other Return value from
ProcessModuleEntryPointList().
**/
EFI_STATUS
EFIAPI
_ModuleEntryPoint (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
EFI_STATUS Status;
EFI_LOADED_IMAGE_PROTOCOL *LoadedImage;
RETURN_STATUS RetStatus;
BOOLEAN Enabled;
if (_gUefiDriverRevision != 0) {
//
// Make sure that the EFI/UEFI spec revision of the platform is >= EFI/UEFI
// spec revision of the driver
//
if (SystemTable->Hdr.Revision < _gUefiDriverRevision) {
return EFI_INCOMPATIBLE_VERSION;
}
}
//
// Call constructor for all libraries
//
ProcessLibraryConstructorList (ImageHandle, SystemTable);
//
// Install unload handler...
//
if (_gDriverUnloadImageCount != 0) {
Status = gBS->HandleProtocol (
ImageHandle,
&gEfiLoadedImageProtocolGuid,
(VOID **)&LoadedImage
);
ASSERT_EFI_ERROR (Status);
LoadedImage->Unload = _DriverUnloadHandler;
}
RetStatus = QemuFwCfgParseBool (
FixedPcdGetPtr (PcdEntryPointOverrideFwCfgVarName),
&Enabled
);
if (!RETURN_ERROR (RetStatus) && !Enabled) {
//
// The QEMU fw_cfg variable tells us not to load this image. So abort.
//
Status = EFI_ABORTED;
} else {
//
// Call the driver entry point
//
Status = ProcessModuleEntryPointList (ImageHandle, SystemTable);
}
//
// If all of the drivers returned errors, or we if are aborting, then invoke
// all of the library destructors
//
if (EFI_ERROR (Status)) {
ProcessLibraryDestructorList (ImageHandle, SystemTable);
}
//
// Return the cumulative return status code from all of the driver entry
// points
//
return Status;
}