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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: srp.h,v 1.3 2003-03-13 13:39:05 pj Exp $
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 File:        $File$
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 Revision:    $Revision: 1.3 $
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 Last update: $Date: 2003-03-13 13:39:05 $
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 ------------
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 This file contains the Stack Resource Policy (SRP) Protocol
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 Title:
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   SRP (Stack Resource Policy)
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 Resource Models Accepted:
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   None
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 Description:
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   This module implement the Stack Resource policy using the shadow field
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   of the task descriptor. No difference is made upon the task model of the
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   tasks that use SRP mutexes.
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   A SRP mutex is created passing the SRP_mutexattr structure to mutex_init.
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   In effect, this module doesn't work correctly if it is
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   used, for example, with a Round Robin Module; in this case we
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   can have a task B that preempts A, but when B finishes his timeslice, A
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   can be scheduled by the RR module, and the SRP can't block it, because
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   the SRP module can not control preemptions (it works only using the shadow
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   field at lock and unlock time!!!).
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   Note that this problen not affect the EDF, RM & co. algorithms... because
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   if B preempts A, A will never preempts on B...
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   A task that want to use the SRP protocol MUST declare it using a
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   SRP_RES_MODEL in the task_create. Only the first SRP_RES_MODEL is
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   considered.
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   A task that want to use a SRP mutex have to declare it with the
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   SRP_usemutex function as last parameter of a task_create call, AFTER
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   the specification of the preemption level.
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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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   XSRP_UNVALID_LOCK
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     This exception is raised when a task try to lock a srp mutex but
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     it don't have the provilege.
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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 SRP 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 SRP mutex can not be statically allocated
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   - The module is incompatible with the primitive TASK_JOIN, so the tasks
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     that uses SRP can NOT call task_join.
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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 __SRP_H__
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#define __SRP_H__
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#include <kernel/model.h>
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#include <kernel/descr.h>
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#include "ll/sys/cdefs.h"
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__BEGIN_DECLS
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RLEVEL SRP_register_module(void);
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extern __inline__ RES_MODEL *SRP_usemutex(mutex_t *m) {
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  return (RES_MODEL *)m->opt;
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};
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__END_DECLS
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#endif