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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: nop.c,v 1.1.1.1 2002-03-29 14:12:52 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 14:12:52 $
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 ------------
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 Binary Semaphores. see nop.h for more details...
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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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#include <modules/nop.h>
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#include <ll/ll.h>
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#include <ll/stdio.h>
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#include <ll/string.h>
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#include <kernel/const.h>
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#include <sys/types.h>
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#include <modules/codes.h>
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#include <kernel/descr.h>
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#include <kernel/var.h>
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#include <kernel/func.h>
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/* The NOP resource level descriptor */
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typedef struct {
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  mutex_resource_des m;   /*+ the mutex interface +*/
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} NOP_mutex_resource_des;
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/* this is the structure normally pointed by the opt field in the
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   mutex_t structure */
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typedef struct {
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  PID owner;
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  QQUEUE blocked;
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} NOP_mutex_t;
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/* Wait status for this library */
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#define NOP_WAIT LIB_STATUS_BASE
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/*+ print resource protocol statistics...+*/
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static void NOP_resource_status(RLEVEL r)
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{
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  kern_printf("No status for NOP module\n");
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}
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static int NOP_level_accept_resource_model(RLEVEL l, RES_MODEL *r)
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{
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  /* priority inheritance works with all tasks without Resource parameters */
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  return -1;
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}
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static void NOP_res_register(RLEVEL l, PID p, RES_MODEL *r)
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{
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  /* never called!!! */
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}
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static void NOP_res_detach(RLEVEL l, PID p)
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{
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}
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static int NOP_level_accept_mutexattr(RLEVEL l, const mutexattr_t *a)
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{
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  if (a->mclass == NOP_MCLASS || a->mclass == (NOP_MCLASS | l) )
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    return 0;
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  else
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    return -1;
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}
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static int NOP_init(RLEVEL l, mutex_t *m, const mutexattr_t *a)
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{
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  NOP_mutex_t *p;
117
 
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  p = (NOP_mutex_t *) kern_alloc(sizeof(NOP_mutex_t));
119
 
120
  /* control if there is enough memory; no control on init on a
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     non- destroyed mutex */
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123
  if (!p)
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    return (ENOMEM);
125
 
126
  p->owner = NIL;
127
  qq_init(&p->blocked);
128
 
129
  m->mutexlevel = l;
130
  m->opt = (void *)p;
131
 
132
  return 0;
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}
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static int NOP_destroy(RLEVEL l, mutex_t *m)
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{
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//  NOP_mutex_resource_des *lev = (NOP_mutex_resource_des *)(resource_table[l]);
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  if ( ((NOP_mutex_t *)m->opt)->owner != NIL)
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    return (EBUSY);
142
 
143
  kern_cli();
144
  if (m->opt) {
145
    kern_free(m->opt,sizeof(NOP_mutex_t));
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    m->opt = NULL;
147
  }
148
  kern_sti();
149
 
150
  return 0;
151
}
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static int NOP_lock(RLEVEL l, mutex_t *m)
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{
155
  NOP_mutex_t *p;
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157
  kern_cli();
158
 
159
  p = (NOP_mutex_t *)m->opt;
160
  if (!p) {
161
    /* if the mutex is not initialized, initialize it! */
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    NOP_mutexattr_t a;
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    NOP_mutexattr_default(a);
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    NOP_init(l, m, &a);
165
  }
166
 
167
  if (p->owner == exec_shadow) {
168
    /* the task already owns the mutex */
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    kern_sti();
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    return (EDEADLK);
171
  }
172
 
173
  if (p->owner != NIL)  {           /* We must block exec task   */
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       LEVEL l;            /* for readableness only */
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       TIME tx;            /* a dummy TIME for timespec operations */
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       struct timespec ty; /* a dummy timespec for timespec operations */
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       proc_table[exec_shadow].context = kern_context_save();
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       /* SAME AS SCHEDULER... manage the capacity event and the load_info */
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       ll_gettime(TIME_EXACT, &schedule_time);
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       SUBTIMESPEC(&schedule_time, &cap_lasttime, &ty);
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       tx = TIMESPEC2USEC(&ty);
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       proc_table[exec_shadow].avail_time -= tx;
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       jet_update_slice(tx);
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       if (cap_timer != NIL) {
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         event_delete(cap_timer);
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         cap_timer = NIL;
188
       }
189
 
190
       l = proc_table[exec_shadow].task_level;
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       level_table[l]->task_extract(l,exec_shadow);
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       /* we insert the task in the semaphore queue */
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       proc_table[exec_shadow].status = NOP_WAIT;
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       qq_insertlast(exec_shadow,&p->blocked);
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       /* and finally we reschedule */
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       exec = exec_shadow = -1;
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       scheduler();
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       kern_context_load(proc_table[exec_shadow].context);
201
  }
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  else {
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    /* the mutex is free, We can lock it! */
204
    p->owner = exec_shadow;
205
    kern_sti();
206
  }
207
 
208
  return 0;
209
}
210
 
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static int NOP_trylock(RLEVEL l, mutex_t *m)
212
{
213
  NOP_mutex_t *p;
214
 
215
  kern_cli();
216
 
217
  p = (NOP_mutex_t *)m->opt;
218
  if (!p) {
219
    /* if the mutex is not initialized, initialize it! */
220
    NOP_mutexattr_t a;
221
    NOP_mutexattr_default(a);
222
    NOP_init(l, m, &a);
223
  }
224
 
225
  if (p->owner != NIL)  {
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    /* a task already owns the mutex */
227
    kern_sti();
228
    return (EBUSY);
229
  }
230
  else {
231
    /* the mutex is free, We can lock it! */
232
    p->owner = exec_shadow;
233
    kern_sti();
234
  }
235
 
236
  return 0;
237
}
238
 
239
static int NOP_unlock(RLEVEL l, mutex_t *m)
240
{
241
  NOP_mutex_t *p;
242
 
243
  p = (NOP_mutex_t *)m->opt;
244
  if (!p)
245
    return (EINVAL);
246
 
247
  if (p->owner != exec_shadow) {
248
    /* the mutex is owned by another task!!! */
249
    kern_sti();
250
    return (EPERM);
251
  }
252
 
253
  proc_table[exec_shadow].context = kern_context_save();
254
 
255
  /* the mutex is mine, pop the firsttask to extract */
256
  p->owner = qq_getfirst(&p->blocked);
257
  if (p->owner != NIL) {
258
    l = proc_table[p->owner].task_level;
259
    level_table[l]->task_insert(l,p->owner);
260
  }
261
 
262
  scheduler();
263
  kern_context_load(proc_table[exec_shadow].context);
264
 
265
  return 0;
266
}
267
 
268
void NOP_register_module(void)
269
{
270
  RLEVEL l;                  /* the level that we register */
271
  NOP_mutex_resource_des *m;  /* for readableness only */
272
 
273
  printk("NOP_register_module\n");
274
 
275
  /* request an entry in the level_table */
276
  l = resource_alloc_descriptor();
277
 
278
  /* alloc the space needed for the EDF_level_des */
279
  m = (NOP_mutex_resource_des *)kern_alloc(sizeof(NOP_mutex_resource_des));
280
 
281
  /* update the level_table with the new entry */
282
  resource_table[l] = (resource_des *)m;
283
 
284
  /* fill the resource_des descriptor */
285
  strncpy(m->m.r.res_name, NOP_MODULENAME, MAX_MODULENAME);
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  m->m.r.res_code                    = NOP_MODULE_CODE;
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  m->m.r.res_version                 = NOP_MODULE_VERSION;
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289
  m->m.r.rtype                       = MUTEX_RTYPE;
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291
  m->m.r.resource_status             = NOP_resource_status;
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  m->m.r.level_accept_resource_model = NOP_level_accept_resource_model;
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  m->m.r.res_register                = NOP_res_register;
294
 
295
  m->m.r.res_detach                  = NOP_res_detach;
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297
  /* fill the mutex_resource_des descriptor */
298
  m->m.level_accept_mutexattr        = NOP_level_accept_mutexattr;
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  m->m.init                          = NOP_init;
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  m->m.destroy                       = NOP_destroy;
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  m->m.lock                          = NOP_lock;
302
  m->m.trylock                       = NOP_trylock;
303
  m->m.unlock                        = NOP_unlock;
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305
}
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