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/*
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 * Project: S.Ha.R.K.
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 *
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 * Coordinators:
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 *   Giorgio Buttazzo    <giorgio@sssup.it>
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 *   Paolo Gai           <pj@gandalf.sssup.it>
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 *
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 * Authors     :
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 *   Paolo Gai           <pj@gandalf.sssup.it>
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 *   Massimiliano Giorgi <massy@gandalf.sssup.it>
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 *   Luca Abeni          <luca@gandalf.sssup.it>
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 *   (see the web pages for full authors list)
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 *
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 * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)
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 *
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 * http://www.sssup.it
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 * http://retis.sssup.it
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 * http://shark.sssup.it
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 */
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/**
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 ------------
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 CVS :        $Id: pc.h,v 1.1.1.1 2002-03-29 14:12:51 pj Exp $
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 File:        $File$
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 Revision:    $Revision: 1.1.1.1 $
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 Last update: $Date: 2002-03-29 14:12:51 $
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 ------------
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 This file contains the Priority Ceiling (PC) Protocol
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 Title:
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   PC (Priority Ceiling protocol)
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 Resource Models Accepted:
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   PC_RES_MODEL
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     This model is used to tell a PC level the priority of a task.
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 Description:
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   This module implement the Priority Ceiling Protocol.
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   The priority inheritance is made using the shadow field of the
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   task descriptor. No difference is made upon the task model of the
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   tasks that use PC mutexes.
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   This module is directly derived from the PI one.
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   A PC mutex is created passing the PC_mutexattr structure to mutex_init.
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   When a task is created, a priority must be assigned to the task. This
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   priority is specified using a PC_RES_MODEL resource model.
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 Exceptions raised:
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   XMUTEX_OWNER_KILLED
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     This exception is raised when a task ends and it owns one or more
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     mutexes
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 Restrictions & special features:
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   - This module is NOT Posix compliant
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   - This module can manage any number of PC mutexes.
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   - If a task ends (because it reaches the end of the body or because it
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     is killed by someone) and it owns some mutex, an exception is raised.
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   - if a mutex unlock is called on a mutex not previously
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     locked or previously locked by another task an exception is raised
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   - A PC mutex can't be statically allocated.
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**/
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/*
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 * Copyright (C) 2000 Paolo Gai
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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 *
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 */
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#ifndef __PC_H__
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#define __PC_H__
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#include <kernel/types.h>
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#include <kernel/descr.h>
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void PC_register_module(void);
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/*+ This function gets the ceiling of a PC mutex, and it have to be called
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    only by a task that owns the mutex.
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    Returns -1 if the mutex is not a PC mutex, 0 otherwise +*/
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int PC_get_mutex_ceiling(const mutex_t *mutex, DWORD *ceiling);
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/*+ This function sets the ceiling of a PC mutex, and it have to be called
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    only by a task that owns the mutex.
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    Returns -1 if the mutex is not a PC mutex, 0 otherwise +*/
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int PC_set_mutex_ceiling(mutex_t *mutex, DWORD ceiling, DWORD *old_ceiling);
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/*+ This function sets the ceiling of a task +*/
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void PC_set_task_ceiling(RLEVEL r, PID p, DWORD priority);
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#endif