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/** @file
DXE Core library services.
Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "DxeMain.h"
//
// Lock Stuff
//
/**
Initialize a basic mutual exclusion lock. Each lock
provides mutual exclusion access at it's task priority
level. Since there is no-premption (at any TPL) or
multiprocessor support, acquiring the lock only consists
of raising to the locks TPL.
@param Lock The EFI_LOCK structure to initialize
@retval EFI_SUCCESS Lock Owned.
@retval EFI_ACCESS_DENIED Reentrant Lock Acquisition, Lock not Owned.
**/
EFI_STATUS
CoreAcquireLockOrFail (
IN EFI_LOCK *Lock
)
{
ASSERT (Lock != NULL);
ASSERT (Lock->Lock != EfiLockUninitialized);
if (Lock->Lock == EfiLockAcquired) {
//
// Lock is already owned, so bail out
//
return EFI_ACCESS_DENIED;
}
Lock->OwnerTpl = CoreRaiseTpl (Lock->Tpl);
Lock->Lock = EfiLockAcquired;
return EFI_SUCCESS;
}
/**
Raising to the task priority level of the mutual exclusion
lock, and then acquires ownership of the lock.
@param Lock The lock to acquire
@return Lock owned
**/
VOID
CoreAcquireLock (
IN EFI_LOCK *Lock
)
{
ASSERT (Lock != NULL);
ASSERT (Lock->Lock == EfiLockReleased);
Lock->OwnerTpl = CoreRaiseTpl (Lock->Tpl);
Lock->Lock = EfiLockAcquired;
}
/**
Releases ownership of the mutual exclusion lock, and
restores the previous task priority level.
@param Lock The lock to release
@return Lock unowned
**/
VOID
CoreReleaseLock (
IN EFI_LOCK *Lock
)
{
EFI_TPL Tpl;
ASSERT (Lock != NULL);
ASSERT (Lock->Lock == EfiLockAcquired);
Tpl = Lock->OwnerTpl;
Lock->Lock = EfiLockReleased;
CoreRestoreTpl (Tpl);
}
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