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