3b35cd045f
PR libgomp/55561 * config/linux/wait.h (do_spin): Use atomic load for addr. * config/linux/ptrlock.c (gomp_ptrlock_get_slow): Use atomic for intptr and ptrlock. * config/linux/ptrlock.h (gomp_ptrlock_get): Use atomic load for ptrlock. Co-Authored-By: Joost VandeVondele <Joost.VandeVondele@mat.ethz.ch> From-SVN: r195618
70 lines
2.4 KiB
C
70 lines
2.4 KiB
C
/* Copyright (C) 2008-2013 Free Software Foundation, Inc.
|
|
Contributed by Jakub Jelinek <jakub@redhat.com>.
|
|
|
|
This file is part of the GNU OpenMP Library (libgomp).
|
|
|
|
Libgomp is free software; you can redistribute it and/or modify it
|
|
under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 3, or (at your option)
|
|
any later version.
|
|
|
|
Libgomp 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 General Public License for
|
|
more details.
|
|
|
|
Under Section 7 of GPL version 3, you are granted additional
|
|
permissions described in the GCC Runtime Library Exception, version
|
|
3.1, as published by the Free Software Foundation.
|
|
|
|
You should have received a copy of the GNU General Public License and
|
|
a copy of the GCC Runtime Library Exception along with this program;
|
|
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
/* This is a Linux specific implementation of a mutex synchronization
|
|
mechanism for libgomp. This type is private to the library. This
|
|
implementation uses atomic instructions and the futex syscall. */
|
|
|
|
#include <endian.h>
|
|
#include <limits.h>
|
|
#include "wait.h"
|
|
|
|
void *
|
|
gomp_ptrlock_get_slow (gomp_ptrlock_t *ptrlock)
|
|
{
|
|
int *intptr;
|
|
uintptr_t oldval = 1;
|
|
|
|
__atomic_compare_exchange_n (ptrlock, &oldval, 2, false,
|
|
MEMMODEL_RELAXED, MEMMODEL_RELAXED);
|
|
|
|
/* futex works on ints, not pointers.
|
|
But a valid work share pointer will be at least
|
|
8 byte aligned, so it is safe to assume the low
|
|
32-bits of the pointer won't contain values 1 or 2. */
|
|
__asm volatile ("" : "=r" (intptr) : "0" (ptrlock));
|
|
#if __BYTE_ORDER == __BIG_ENDIAN
|
|
if (sizeof (*ptrlock) > sizeof (int))
|
|
intptr += (sizeof (*ptrlock) / sizeof (int)) - 1;
|
|
#endif
|
|
do
|
|
do_wait (intptr, 2);
|
|
while (__atomic_load_n (intptr, MEMMODEL_RELAXED) == 2);
|
|
__asm volatile ("" : : : "memory");
|
|
return (void *) __atomic_load_n (ptrlock, MEMMODEL_ACQUIRE);
|
|
}
|
|
|
|
void
|
|
gomp_ptrlock_set_slow (gomp_ptrlock_t *ptrlock)
|
|
{
|
|
int *intptr;
|
|
|
|
__asm volatile ("" : "=r" (intptr) : "0" (ptrlock));
|
|
#if __BYTE_ORDER == __BIG_ENDIAN
|
|
if (sizeof (*ptrlock) > sizeof (int))
|
|
intptr += (sizeof (*ptrlock) / sizeof (int)) - 1;
|
|
#endif
|
|
futex_wake (intptr, INT_MAX);
|
|
}
|