/*      $NetBSD: pthread_spin.c,v 1.11 2023/05/25 14:30:03 riastradh Exp $      */

/*-
* Copyright (c) 2001, 2006, 2007 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Nathan J. Williams and Andrew Doran.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

/*
* Public (POSIX-specified) spinlocks.
*/

#include <sys/cdefs.h>
__RCSID("$NetBSD: pthread_spin.c,v 1.11 2023/05/25 14:30:03 riastradh Exp $");

/* Need to use libc-private names for atomic operations. */
#include "../../common/lib/libc/atomic/atomic_op_namespace.h"

#include <sys/types.h>
#include <sys/ras.h>

#include <machine/lock.h>

#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

#include "pthread.h"
#include "pthread_int.h"

int
pthread_spin_init(pthread_spinlock_t *lock, int pshared)
{

       pthread__error(EINVAL, "Invalid pshared",
           pshared == PTHREAD_PROCESS_PRIVATE ||
           pshared == PTHREAD_PROCESS_SHARED);

       lock->pts_magic = _PT_SPINLOCK_MAGIC;

       /*
        * We don't actually use the pshared flag for anything;
        * CPU simple locks have all the process-shared properties
        * that we want anyway.
        */
       lock->pts_flags = pshared;
       pthread_lockinit(&lock->pts_spin);

       return 0;
}

int
pthread_spin_destroy(pthread_spinlock_t *lock)
{

       pthread__error(EINVAL, "Invalid spinlock",
           lock->pts_magic == _PT_SPINLOCK_MAGIC);

       if (!__SIMPLELOCK_UNLOCKED_P(&lock->pts_spin))
               return EBUSY;

       lock->pts_magic = _PT_SPINLOCK_DEAD;

       return 0;
}

int
pthread_spin_lock(pthread_spinlock_t *lock)
{
       pthread_t self;

       pthread__error(EINVAL, "Invalid spinlock",
           lock->pts_magic == _PT_SPINLOCK_MAGIC);

       self = pthread__self();
       while (pthread__spintrylock(self, &lock->pts_spin) == 0) {
               pthread__smt_wait();
       }

       return 0;
}

int
pthread_spin_trylock(pthread_spinlock_t *lock)
{
       pthread_t self;

       pthread__error(EINVAL, "Invalid spinlock",
           lock->pts_magic == _PT_SPINLOCK_MAGIC);

       self = pthread__self();
       if (pthread__spintrylock(self, &lock->pts_spin) == 0)
               return EBUSY;
       return 0;
}

int
pthread_spin_unlock(pthread_spinlock_t *lock)
{
       pthread_t self;

       pthread__error(EINVAL, "Invalid spinlock",
           lock->pts_magic == _PT_SPINLOCK_MAGIC);

       self = pthread__self();
       pthread__spinunlock(self, &lock->pts_spin);
       pthread__smt_wake();

       return 0;
}