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/* Copyright (C) 2003-2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Martin Schwidefsky <schwidefsky@de.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, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <sysdep.h>
#include <lowlevellock.h>
#include <pthreadP.h>
#include <sparc-nptl.h>
#include <futex-internal.h>
/* Wait on barrier. */
int
__pthread_barrier_wait (pthread_barrier_t *barrier)
{
union sparc_pthread_barrier *ibarrier
= (union sparc_pthread_barrier *) barrier;
int result = 0;
int private = ibarrier->s.pshared ? LLL_SHARED : LLL_PRIVATE;
int futex_private = ibarrier->s.pshared ? FUTEX_SHARED : FUTEX_PRIVATE;
/* Make sure we are alone. */
lll_lock (ibarrier->b.lock, private);
/* One more arrival. */
--ibarrier->b.left;
/* Are these all? */
if (ibarrier->b.left == 0)
{
/* Yes. Increment the event counter to avoid invalid wake-ups and
tell the current waiters that it is their turn. */
++ibarrier->b.curr_event;
/* Wake up everybody. */
futex_wake (&ibarrier->b.curr_event, INT_MAX, futex_private);
/* This is the thread which finished the serialization. */
result = PTHREAD_BARRIER_SERIAL_THREAD;
}
else
{
/* The number of the event we are waiting for. The barrier's event
number must be bumped before we continue. */
unsigned int event = ibarrier->b.curr_event;
/* Before suspending, make the barrier available to others. */
lll_unlock (ibarrier->b.lock, private);
/* Wait for the event counter of the barrier to change. */
do
futex_wait_simple (&ibarrier->b.curr_event, event, futex_private);
while (event == ibarrier->b.curr_event);
}
/* Make sure the init_count is stored locally or in a register. */
unsigned int init_count = ibarrier->b.init_count;
/* If this was the last woken thread, unlock. */
if (__atomic_is_v9 || ibarrier->s.pshared == 0)
{
if (atomic_increment_val (&ibarrier->b.left) == init_count)
/* We are done. */
lll_unlock (ibarrier->b.lock, private);
}
else
{
unsigned int left;
/* Slightly more complicated. On pre-v9 CPUs, atomic_increment_val
is only atomic for threads within the same process, not for
multiple processes. */
__sparc32_atomic_do_lock24 (&ibarrier->s.left_lock);
left = ++ibarrier->b.left;
__sparc32_atomic_do_unlock24 (&ibarrier->s.left_lock);
if (left == init_count)
/* We are done. */
lll_unlock (ibarrier->b.lock, private);
}
return result;
}
weak_alias (__pthread_barrier_wait, pthread_barrier_wait)
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