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      1 
      2 /*--------------------------------------------------------------------*/
      3 /*--- Generic scheduler lock implementation   sched-lock-generic.c ---*/
      4 /*---                                                              ---*/
      5 /*--- This implementation does not guarantee fair scheduling on    ---*/
      6 /*--- multicore systems but is sufficient to make the Valgrind     ---*/
      7 /*--- scheduler work reasonably.                                   ---*/
      8 /*--------------------------------------------------------------------*/
      9 
     10 /*
     11    This file is part of Valgrind, a dynamic binary instrumentation
     12    framework.
     13 
     14    Copyright (C) 2011 Bart Van Assche <bvanassche (at) acm.org>.
     15 
     16    This program is free software; you can redistribute it and/or
     17    modify it under the terms of the GNU General Public License as
     18    published by the Free Software Foundation; either version 2 of the
     19    License, or (at your option) any later version.
     20 
     21    This program is distributed in the hope that it will be useful, but
     22    WITHOUT ANY WARRANTY; without even the implied warranty of
     23    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     24    General Public License for more details.
     25 
     26    You should have received a copy of the GNU General Public License
     27    along with this program; if not, write to the Free Software
     28    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
     29    02111-1307, USA.
     30 
     31    The GNU General Public License is contained in the file COPYING.
     32 */
     33 
     34 #include "pub_core_basics.h"
     35 #include "pub_tool_mallocfree.h"
     36 #include "priv_sema.h"
     37 #include "priv_sched-lock.h"
     38 #include "priv_sched-lock-impl.h"
     39 
     40 struct sched_lock {
     41    vg_sema_t sema;
     42 };
     43 
     44 static const Char *get_sched_lock_name(void)
     45 {
     46    return "generic";
     47 }
     48 
     49 static struct sched_lock *create_sched_lock(void)
     50 {
     51    struct sched_lock *p;
     52 
     53    p = VG_(malloc)("sched_lock", sizeof(*p));
     54    if (p)
     55       ML_(sema_init)(&p->sema);
     56    return p;
     57 }
     58 
     59 static void destroy_sched_lock(struct sched_lock *p)
     60 {
     61    ML_(sema_deinit)(&p->sema);
     62    VG_(free)(p);
     63 }
     64 
     65 static int get_sched_lock_owner(struct sched_lock *p)
     66 {
     67    return p->sema.owner_lwpid;
     68 }
     69 
     70 static void acquire_sched_lock(struct sched_lock *p)
     71 {
     72    ML_(sema_down)(&p->sema, False);
     73 }
     74 
     75 static void release_sched_lock(struct sched_lock *p)
     76 {
     77    ML_(sema_up)(&p->sema, False);
     78 }
     79 
     80 const struct sched_lock_ops ML_(generic_sched_lock_ops) = {
     81    .get_sched_lock_name  = get_sched_lock_name,
     82    .create_sched_lock    = create_sched_lock,
     83    .destroy_sched_lock   = destroy_sched_lock,
     84    .get_sched_lock_owner = get_sched_lock_owner,
     85    .acquire_sched_lock   = acquire_sched_lock,
     86    .release_sched_lock   = release_sched_lock,
     87 };
     88