diff options
Diffstat (limited to 'nptl/sysdeps/unix/sysv/linux/sparc/pthread_once.c')
-rw-r--r-- | nptl/sysdeps/unix/sysv/linux/sparc/pthread_once.c | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/nptl/sysdeps/unix/sysv/linux/sparc/pthread_once.c b/nptl/sysdeps/unix/sysv/linux/sparc/pthread_once.c new file mode 100644 index 0000000000..16f1279f8d --- /dev/null +++ b/nptl/sysdeps/unix/sysv/linux/sparc/pthread_once.c @@ -0,0 +1,94 @@ +/* Copyright (C) 2003 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Jakub Jelinek <jakub@redhat.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 (once_control, init_routine) + pthread_once_t *once_control; + void (*init_routine) (void); +{ + while (1) + { + int oldval, val, newval; + + val = *once_control; + do + { + /* Check if the initialized has already been done. */ + if ((val & 2) != 0) + return 0; + + oldval = val; + newval = (oldval & 3) | __fork_generation | 1; + val = atomic_compare_and_exchange_val_acq (once_control, newval, + oldval); + } + while (__builtin_expect (val != oldval, 0)); + + /* Check if another thread already runs the initializer. */ + if ((oldval & 1) != 0) + { + /* Check whether the initializer execution was interrupted + by a fork. */ + if (((oldval ^ newval) & -4) == 0) + { + /* Same generation, some other thread was faster. Wait. */ + lll_futex_wait (once_control, newval); + continue; + } + } + + /* 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. */ + atomic_exchange_and_add (once_control, 1); + + /* Wake up all other threads. */ + lll_futex_wake (once_control, INT_MAX); + break; + } + + return 0; +} +weak_alias (__pthread_once, pthread_once) +strong_alias (__pthread_once, __pthread_once_internal) |