mirror of
git://sourceware.org/git/glibc.git
synced 2024-12-09 04:11:27 +08:00
27ee0a5595
* include/sys/wait.h: Add some prototypes. * Rules (dummy.c): Create also prototype to shut up GCC. 2000-12-27 Andreas Jaeger <aj@suse.de>
92 lines
2.8 KiB
C
92 lines
2.8 KiB
C
/* POSIX spinlock implementation. S/390 version.
|
|
Copyright (C) 2000 Free Software Foundation, Inc.
|
|
Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Library General Public License as
|
|
published by the Free Software Foundation; either version 2 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
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
License along with the GNU C Library; see the file COPYING.LIB. If not,
|
|
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
Boston, MA 02111-1307, USA. */
|
|
|
|
#include <errno.h>
|
|
#include <pthread.h>
|
|
#include "internals.h"
|
|
|
|
/* This implementation is similar to the one used in the Linux kernel.
|
|
But the kernel is byte instructions for the memory access. This is
|
|
faster but unusable here. The problem is that only 128
|
|
threads/processes could use the spinlock at the same time. If (by
|
|
a design error in the program) a thread/process would hold the
|
|
spinlock for a time long enough to accumulate 128 waiting
|
|
processes, the next one will find a positive value in the spinlock
|
|
and assume it is unlocked. We cannot accept that. */
|
|
|
|
int
|
|
__pthread_spin_lock (pthread_spinlock_t *lock)
|
|
{
|
|
asm volatile(" basr 1,0\n"
|
|
"0: slr 0,0\n"
|
|
" cs 0,1,%1\n"
|
|
" jl 0b\n"
|
|
: "=m" (*lock)
|
|
: "0" (*lock) : "0", "1", "cc" );
|
|
return 0;
|
|
}
|
|
weak_alias (__pthread_spin_lock, pthread_spin_lock)
|
|
|
|
int
|
|
__pthread_spin_trylock (pthread_spinlock_t *lock)
|
|
{
|
|
int oldval;
|
|
|
|
asm volatile(" slr %1,%1\n"
|
|
" basr 1,0\n"
|
|
"0: cs %1,1,%0"
|
|
: "=m" (*lock), "=&d" (oldval)
|
|
: "0" (*lock) : "1", "cc" );
|
|
return oldval == 0 ? 0 : EBUSY;
|
|
}
|
|
weak_alias (__pthread_spin_trylock, pthread_spin_trylock)
|
|
|
|
|
|
int
|
|
__pthread_spin_unlock (pthread_spinlock_t *lock)
|
|
{
|
|
asm volatile(" xc 0(4,%0),0(%0)\n"
|
|
" bcr 15,0"
|
|
: "=a" (lock) );
|
|
return 0;
|
|
}
|
|
weak_alias (__pthread_spin_unlock, pthread_spin_unlock)
|
|
|
|
|
|
int
|
|
__pthread_spin_init (pthread_spinlock_t *lock, int pshared)
|
|
{
|
|
/* We can ignore the `pshared' parameter. Since we are busy-waiting
|
|
all processes which can access the memory location `lock' points
|
|
to can use the spinlock. */
|
|
*lock = 0;
|
|
return 0;
|
|
}
|
|
weak_alias (__pthread_spin_init, pthread_spin_init)
|
|
|
|
|
|
int
|
|
__pthread_spin_destroy (pthread_spinlock_t *lock)
|
|
{
|
|
/* Nothing to do. */
|
|
return 0;
|
|
}
|
|
weak_alias (__pthread_spin_destroy, pthread_spin_destroy)
|