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/*
* Berkeley Lab Checkpoint/Restart (BLCR) for Linux is Copyright (c)
* 2003, The Regents of the University of California, through Lawrence
* Berkeley National Laboratory (subject to receipt of any required
* approvals from the U.S. Dept. of Energy). All rights reserved.
*
* Portions may be copyrighted by others, as may be noted in specific
* copyright notices within specific files.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* $Id: cr_sig_sync.c,v 1.10 2004/12/10 20:55:05 phargrov Exp $
*
*
* cr_sig_sync.c: routines for signal-safe synchronization
*/
#include "cr_private.h"
#define CRI_SL_DEBUG 0
#define CRI_SL_LOCKED 0x27182818U /* decimal digits of e */
#define CRI_SL_UNLOCKED CR_SPINLOCK_INITIALIZER
void cr_spinlock_init(cr_spinlock_t *x)
{
cri_atomic_t *p = (cri_atomic_t *)x;
cri_atomic_write(p, CRI_SL_UNLOCKED);
}
void cr_spinlock_lock(cr_spinlock_t *x)
{
cri_atomic_t *p = (cri_atomic_t *)x;
if (!cri_cmp_swap(p, CRI_SL_UNLOCKED, CRI_SL_LOCKED)) {
#if CRI_SL_DEBUG
cri_atomic_t tmp = cri_atomic_read(p);
if ((tmp != CRI_SL_LOCKED) && (tmp != CRI_SL_UNLOCKED)) {
CRI_ABORT("Spinlock %p has invalid state %x", p, tmp);
}
#endif
CRI_DO_YIELD_WHILE_COND(!cri_cmp_swap(p, CRI_SL_UNLOCKED, CRI_SL_LOCKED));
}
}
void cr_spinlock_unlock(cr_spinlock_t *x)
{
cri_atomic_t *p = (cri_atomic_t *)x;
#if CRI_SL_DEBUG
if (!cri_cmp_swap(p, CRI_SL_LOCKED, CRI_SL_UNLOCKED)) {
cri_atomic_t tmp = cri_atomic_read(p);
if (tmp == CRI_SL_UNLOCKED) {
CRI_ABORT("Spinlock %p is not locked", p);
} else {
CRI_ABORT("Spinlock %p has invalid state %x", p, tmp);
}
}
#else
cri_atomic_write(p, CRI_SL_UNLOCKED);
#endif
}
int cr_spinlock_trylock(cr_spinlock_t *x)
{
cri_atomic_t *p = (cri_atomic_t *)x;
int retval;
retval = cri_cmp_swap(p, CRI_SL_UNLOCKED, CRI_SL_LOCKED);
#if CRI_SL_DEBUG
if (!retval) {
cri_atomic_t tmp = cri_atomic_read(p);
if ((tmp != CRI_SL_LOCKED) && (tmp != CRI_SL_UNLOCKED)) {
CRI_ABORT("Spinlock %p has invalid state %x", p, tmp);
}
}
#endif
return retval;
}
int cri_barrier_enter(cri_atomic_t *p)
{
int retval;
retval = cri_atomic_dec_and_test(p);
if (!retval) {
CRI_DO_YIELD_WHILE_COND(cri_atomic_read(p));
}
return retval;
}
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