about summary refs log tree commit diff
path: root/nptl/sysdeps/unix/sysv/linux/i386/i486/libc-lowlevellock.S
blob: f246711489ab487c28ea621a97f8e16c50311688 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
/* Copyright (C) 2002, 2003, 2007 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <kernel-features.h>

/* In libc.so we do not unconditionally use the lock prefix.  Only if
   the application is using threads.  */
#ifndef UP
# define LOCK \
	cmpl	$0, %gs:MULTIPLE_THREADS_OFFSET; 			      \
	je	0f;							      \
	lock;								      \
0:
#endif

/* All locks in libc are private.  Use the kernel feature if possible.  */
#define FUTEX_PRIVATE_FLAG	128
#ifdef __ASSUME_PRIVATE_FUTEX
# define FUTEX_WAIT		(0 | FUTEX_PRIVATE_FLAG)
# define FUTEX_WAKE		(1 | FUTEX_PRIVATE_FLAG)
#else
# define LOAD_FUTEX_WAIT(reg) \
	movl	%gs:PRIVATE_FUTEX, reg
# define LOAD_FUTEX_WAKE(reg) \
	movl	%gs:PRIVATE_FUTEX, reg ; \
	orl	$FUTEX_WAKE, reg
#endif

#include "lowlevellock.S"