1/*
2 Copyright 2005-2013 Intel Corporation. All Rights Reserved.
3
4 This file is part of Threading Building Blocks.
5
6 Threading Building Blocks is free software; you can redistribute it
7 and/or modify it under the terms of the GNU General Public License
8 version 2 as published by the Free Software Foundation.
9
10 Threading Building Blocks is distributed in the hope that it will be
11 useful, but WITHOUT ANY WARRANTY; without even the implied warranty
12 of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with Threading Building Blocks; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18
19 As a special exception, you may use this file as part of a free software
20 library without restriction. Specifically, if other files instantiate
21 templates or use macros or inline functions from this file, or you compile
22 this file and link it with other files to produce an executable, this
23 file does not by itself cause the resulting executable to be covered by
24 the GNU General Public License. This exception does not however
25 invalidate any other reasons why the executable file might be covered by
26 the GNU General Public License.
27*/
28
29#ifndef __TBB_machine_H
30#error Do not #include this internal file directly; use public TBB headers instead.
31#endif
32
33#include <sched.h>
34#define __TBB_Yield() sched_yield()
35
36#include <unistd.h>
37/* Futex definitions */
38#include <sys/syscall.h>
39
40#if defined(SYS_futex)
41
42#define __TBB_USE_FUTEX 1
43#include <limits.h>
44#include <errno.h>
45// Unfortunately, some versions of Linux do not have a header that defines FUTEX_WAIT and FUTEX_WAKE.
46
47#ifdef FUTEX_WAIT
48#define __TBB_FUTEX_WAIT FUTEX_WAIT
49#else
50#define __TBB_FUTEX_WAIT 0
51#endif
52
53#ifdef FUTEX_WAKE
54#define __TBB_FUTEX_WAKE FUTEX_WAKE
55#else
56#define __TBB_FUTEX_WAKE 1
57#endif
58
59#ifndef __TBB_ASSERT
60#error machine specific headers must be included after tbb_stddef.h
61#endif
62
63namespace tbb {
64
65namespace internal {
66
67inline int futex_wait( void *futex, int comparand ) {
68 int r = syscall( SYS_futex,futex,__TBB_FUTEX_WAIT,comparand,NULL,NULL,0 );
69#if TBB_USE_ASSERT
70 int e = errno;
71 __TBB_ASSERT( r==0||r==EWOULDBLOCK||(r==-1&&(e==EAGAIN||e==EINTR)), "futex_wait failed." );
72#endif /* TBB_USE_ASSERT */
73 return r;
74}
75
76inline int futex_wakeup_one( void *futex ) {
77 int r = ::syscall( SYS_futex,futex,__TBB_FUTEX_WAKE,1,NULL,NULL,0 );
78 __TBB_ASSERT( r==0||r==1, "futex_wakeup_one: more than one thread woken up?" );
79 return r;
80}
81
82inline int futex_wakeup_all( void *futex ) {
83 int r = ::syscall( SYS_futex,futex,__TBB_FUTEX_WAKE,INT_MAX,NULL,NULL,0 );
84 __TBB_ASSERT( r>=0, "futex_wakeup_all: error in waking up threads" );
85 return r;
86}
87
88} /* namespace internal */
89
90} /* namespace tbb */
91
92#endif /* SYS_futex */
93