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/** @file
UEFI Dxe DebugLib constructor that prevent some debug service after ExitBootServices event,
because some pointer is nulled at that phase.
Copyright (c) 2018, Microsoft Corporation
Copyright (c) 2015 - 2019, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Uefi.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
//
// BOOLEAN value to indicate if it is at the post ExitBootServices pahse
//
BOOLEAN mPostEBS = FALSE;
static EFI_EVENT mExitBootServicesEvent;
//
// Pointer to SystemTable
// This library instance may have a cycle consume with UefiBootServicesTableLib
// because of the constructors.
//
EFI_SYSTEM_TABLE *mDebugST;
/**
This routine sets the mPostEBS for exit boot servies true
to prevent DebugPort protocol dereferences when the pointer is nulled.
@param Event Event whose notification function is being invoked.
@param Context Pointer to the notification function's context.
**/
VOID
EFIAPI
ExitBootServicesCallback (
EFI_EVENT Event,
VOID* Context
)
{
mPostEBS = TRUE;
return;
}
/**
The constructor gets the pointers to the system table.
And create a event to indicate it is after ExitBootServices.
@param ImageHandle The firmware allocated handle for the EFI image.
@param SystemTable A pointer to the EFI System Table.
@retval EFI_SUCCESS The constructor always returns EFI_SUCCESS.
**/
EFI_STATUS
EFIAPI
DxeDebugLibConstructor(
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
mDebugST = SystemTable;
SystemTable->BootServices->CreateEventEx (
EVT_NOTIFY_SIGNAL,
TPL_NOTIFY,
ExitBootServicesCallback,
NULL,
&gEfiEventExitBootServicesGuid,
&mExitBootServicesEvent
);
return EFI_SUCCESS;
}
/**
The destructor closes Exit Boot Services Event.
@param ImageHandle The firmware allocated handle for the EFI image.
@param SystemTable A pointer to the EFI System Table.
@retval EFI_SUCCESS The destructor always returns EFI_SUCCESS.
**/
EFI_STATUS
EFIAPI
DxeDebugLibDestructor(
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
if (mExitBootServicesEvent != NULL) {
SystemTable->BootServices->CloseEvent (mExitBootServicesEvent);
}
return EFI_SUCCESS;
}
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