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1 jermar 1
/*
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 * Copyright (C) 2001-2004 Jakub Jermar
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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#include <arch.h>
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#include <arch/atomic.h>
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#include <arch/barrier.h>
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#include <synch/spinlock.h>
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#include <print.h>
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#ifdef __SMP__
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void spinlock_initialize(spinlock_t *sl)
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{
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    sl->val = 0;
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}
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#ifdef DEBUG_SPINLOCK
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void spinlock_lock(spinlock_t *sl)
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{
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    int i = 0;
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    __address caller = ((__u32 *) &sl)[-1];
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    while (test_and_set(&sl->val)) {
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        if (i++ > 300000) {
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            printf("cpu%d: looping on spinlock %X, caller=%X\n", CPU->id, sl, caller);
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            i = 0;
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        }
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    }
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    CS_ENTER_BARRIER();
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}
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#else
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void spinlock_lock(spinlock_t *sl)
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{
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    /*
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     * Each architecture has its own efficient/recommended
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     * implementation of spinlock.
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     */
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    spinlock_arch(&sl->val);
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    CS_ENTER_BARRIER();
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}
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#endif
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int spinlock_trylock(spinlock_t *sl)
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{
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    int rc;
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    rc = !test_and_set(&sl->val);
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    CS_ENTER_BARRIER();
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    return rc;
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}
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void spinlock_unlock(spinlock_t *sl)
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{
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    CS_LEAVE_BARRIER();
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    sl->val = 0;
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}
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#endif