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authorMike Frysinger <vapier@gentoo.org>2006-01-31 05:05:15 +0000
committerMike Frysinger <vapier@gentoo.org>2006-01-31 05:05:15 +0000
commitcccc549ced940c85039c8ce263c8bb571f244afd (patch)
treeef77a870db7211ad6f511867fc56ee1a1a8b4c18 /libpthread/linuxthreads/sysdeps/s390/pspinlock.c
parente73b1211737842732951f9b9049294ef732e1ef0 (diff)
initial import of latest linuxthreads
Diffstat (limited to 'libpthread/linuxthreads/sysdeps/s390/pspinlock.c')
-rw-r--r--libpthread/linuxthreads/sysdeps/s390/pspinlock.c91
1 files changed, 91 insertions, 0 deletions
diff --git a/libpthread/linuxthreads/sysdeps/s390/pspinlock.c b/libpthread/linuxthreads/sysdeps/s390/pspinlock.c
new file mode 100644
index 000000000..f963f3537
--- /dev/null
+++ b/libpthread/linuxthreads/sysdeps/s390/pspinlock.c
@@ -0,0 +1,91 @@
+/* POSIX spinlock implementation. S/390 version.
+ Copyright (C) 2000, 2004 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 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; 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)
+ : "m" (*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)
+ : "m" (*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) : "memory" );
+ 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)