7899b79715
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@5883 6f19259b-4bc3-4df7-8a09-765794883524
107 lines
2.2 KiB
C
107 lines
2.2 KiB
C
/** @file
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DXE Core library services.
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Copyright (c) 2006 - 2008, Intel Corporation. <BR>
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All rights reserved. This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include "DxeMain.h"
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//
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// Lock Stuff
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//
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/**
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Initialize a basic mutual exclusion lock. Each lock
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provides mutual exclusion access at it's task priority
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level. Since there is no-premption (at any TPL) or
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multiprocessor support, acquiring the lock only consists
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of raising to the locks TPL.
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@param Lock The EFI_LOCK structure to initialize
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@retval EFI_SUCCESS Lock Owned.
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@retval EFI_ACCESS_DENIED Reentrant Lock Acquisition, Lock not Owned.
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**/
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EFI_STATUS
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CoreAcquireLockOrFail (
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IN EFI_LOCK *Lock
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)
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{
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ASSERT (Lock != NULL);
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ASSERT (Lock->Lock != EfiLockUninitialized);
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if (Lock->Lock == EfiLockAcquired) {
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//
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// Lock is already owned, so bail out
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//
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return EFI_ACCESS_DENIED;
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}
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Lock->OwnerTpl = CoreRaiseTpl (Lock->Tpl);
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Lock->Lock = EfiLockAcquired;
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return EFI_SUCCESS;
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}
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/**
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Raising to the task priority level of the mutual exclusion
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lock, and then acquires ownership of the lock.
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@param Lock The lock to acquire
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@return Lock owned
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**/
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VOID
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CoreAcquireLock (
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IN EFI_LOCK *Lock
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)
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{
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ASSERT (Lock != NULL);
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ASSERT (Lock->Lock == EfiLockReleased);
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Lock->OwnerTpl = CoreRaiseTpl (Lock->Tpl);
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Lock->Lock = EfiLockAcquired;
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}
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/**
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Releases ownership of the mutual exclusion lock, and
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restores the previous task priority level.
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@param Lock The lock to release
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@return Lock unowned
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**/
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VOID
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CoreReleaseLock (
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IN EFI_LOCK *Lock
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)
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{
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EFI_TPL Tpl;
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ASSERT (Lock != NULL);
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ASSERT (Lock->Lock == EfiLockAcquired);
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Tpl = Lock->OwnerTpl;
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Lock->Lock = EfiLockReleased;
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CoreRestoreTpl (Tpl);
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}
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