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) 2011-2017 Bart Van Assche <bvanassche@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_core_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 HChar *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    ML_(sema_init)(&p->sema);
55    return p;
56 }
57 
58 static void destroy_sched_lock(struct sched_lock *p)
59 {
60    ML_(sema_deinit)(&p->sema);
61    VG_(free)(p);
62 }
63 
64 static int get_sched_lock_owner(struct sched_lock *p)
65 {
66    return p->sema.owner_lwpid;
67 }
68 
69 static void acquire_sched_lock(struct sched_lock *p)
70 {
71    ML_(sema_down)(&p->sema, False);
72 }
73 
74 static void release_sched_lock(struct sched_lock *p)
75 {
76    ML_(sema_up)(&p->sema, False);
77 }
78 
79 const struct sched_lock_ops ML_(generic_sched_lock_ops) = {
80    .get_sched_lock_name  = get_sched_lock_name,
81    .create_sched_lock    = create_sched_lock,
82    .destroy_sched_lock   = destroy_sched_lock,
83    .get_sched_lock_owner = get_sched_lock_owner,
84    .acquire_sched_lock   = acquire_sched_lock,
85    .release_sched_lock   = release_sched_lock,
86 };
87