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author | Roland McGrath <roland@gnu.org> | 2003-03-17 11:22:52 +0000 |
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committer | Roland McGrath <roland@gnu.org> | 2003-03-17 11:22:52 +0000 |
commit | f3c13160fe2f53dd4971fe9772c9c23300a287be (patch) | |
tree | 6dee91780dfa4d4ac75ff1a3775a0047edfd8c3e /nptl/sysdeps/unix/sysv/linux/powerpc/pthread_once.c | |
parent | 5778033ffc5964450a20469a142202b5fdda36da (diff) | |
download | glibc-f3c13160fe2f53dd4971fe9772c9c23300a287be.tar.gz |
2003-03-17 Roland McGrath <roland@redhat.com>
PowerPC port contributed by Paul Mackerras <paulus@samba.org>.
* sysdeps/pthread/pthread_spin_init.c: New file.
* sysdeps/pthread/pthread_spin_unlock.c: New file.
* sysdeps/powerpc/Makefile: New file.
* sysdeps/powerpc/pthread_spin_lock.c: New file.
* sysdeps/powerpc/pthread_spin_trylock.c: New file.
* sysdeps/powerpc/pthreaddef.h: New file.
* sysdeps/powerpc/tcb-offsets.sym: New file.
* sysdeps/powerpc/td_ta_map_lwp2thr.c: New file.
* sysdeps/powerpc/tls.h: New file.
* sysdeps/powerpc/bits/atomic.h: New file.
* sysdeps/unix/sysv/linux/libc-lowlevelmutex.c: New file.
* sysdeps/unix/sysv/linux/libc-lowlevellock.c: New file.
* sysdeps/unix/sysv/linux/lowlevellock.c: New file.
* sysdeps/unix/sysv/linux/sem_post.c: New file.
* sysdeps/unix/sysv/linux/sem_timedwait.c: New file.
* sysdeps/unix/sysv/linux/sem_trywait.c: New file.
* sysdeps/unix/sysv/linux/powerpc/Makefile: New file.
* sysdeps/unix/sysv/linux/powerpc/createthread.c: New file.
* sysdeps/unix/sysv/linux/powerpc/fork.c: New file.
* sysdeps/unix/sysv/linux/powerpc/lowlevellock.h: New file.
* sysdeps/unix/sysv/linux/powerpc/pt-vfork.S: New file.
* sysdeps/unix/sysv/linux/powerpc/pthread_once.c: New file.
* sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h: New file.
* sysdeps/unix/sysv/linux/powerpc/bits/semaphore.h: New file.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep-cancel.h: New file.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep-cancel.h: New file.
Diffstat (limited to 'nptl/sysdeps/unix/sysv/linux/powerpc/pthread_once.c')
-rw-r--r-- | nptl/sysdeps/unix/sysv/linux/powerpc/pthread_once.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/nptl/sysdeps/unix/sysv/linux/powerpc/pthread_once.c b/nptl/sysdeps/unix/sysv/linux/powerpc/pthread_once.c new file mode 100644 index 0000000000..18029e979d --- /dev/null +++ b/nptl/sysdeps/unix/sysv/linux/powerpc/pthread_once.c @@ -0,0 +1,99 @@ +/* Copyright (C) 2003 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003. + + 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 "pthreadP.h" +#include <lowlevellock.h> + + +unsigned long int __fork_generation attribute_hidden; + + +static void +clear_once_control (void *arg) +{ + pthread_once_t *once_control = (pthread_once_t *) arg; + + *once_control = 0; + lll_futex_wake (once_control, INT_MAX); +} + + +int +__pthread_once (pthread_once_t *once_control, void (*init_routine) (void)) +{ + for (;;) + { + int oldval; + int newval; + int tmp; + + /* Pseudo code: + newval = __fork_generation | 1; + oldval = *once_control; + if ((oldval & 2) == 0) + *once_control = newval; + Do this atomically. + */ + newval = __fork_generation | 1; + __asm __volatile ("1: lwarx %0,0,%3\n" + " andi. %1,%0,2\n" + " bne 2f\n" + " stwcx. %4,0,%3\n" + "2: isync" + : "=&r" (oldval), "=&r" (tmp), "=m" (*once_control) + : "r" (once_control), "r" (newval), "m" (*once_control) + : "cr0"); + + /* Check if the initializer has already been done. */ + if ((oldval & 2) != 0) + return 0; + + /* Check if another thread already runs the initializer. */ + if ((oldval & 1) == 0) + break; + + /* Check whether the initializer execution was interrupted by a fork. */ + if (oldval != newval) + break; + + /* Same generation, some other thread was faster. Wait. */ + lll_futex_wait (once_control, oldval); + } + + + /* This thread is the first here. Do the initialization. + Register a cleanup handler so that in case the thread gets + interrupted the initialization can be restarted. */ + pthread_cleanup_push (clear_once_control, once_control); + + init_routine (); + + pthread_cleanup_pop (0); + + + /* Add one to *once_control to take the bottom 2 bits from 01 to 10. */ + __lll_add (once_control, 1); + + /* Wake up all other threads. */ + lll_futex_wake (once_control, INT_MAX); + + return 0; +} +weak_alias (__pthread_once, pthread_once) +strong_alias (__pthread_once, __pthread_once_internal) |