96 lines
3.3 KiB
C
96 lines
3.3 KiB
C
/*
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* Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
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* The President and Fellows of Harvard College.
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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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* 1. 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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* 2. 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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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _SPINLOCK_H_
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#define _SPINLOCK_H_
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/*
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* Spinlocks. While the guts are machine-dependent, the structure and the
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* basic functions are supposed to be the same across all machines.
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*/
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#include <cdefs.h>
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#include <hangman.h>
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/* Inlining support - for making sure an out-of-line copy gets built */
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#ifndef SPINLOCK_INLINE
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#define SPINLOCK_INLINE INLINE
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#endif
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/* Get the machine-dependent bits. */
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#include <machine/spinlock.h>
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/*
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* Basic spinlock.
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*
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* Note that spinlocks are held by CPUs, not by threads.
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*
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* This structure is made public so spinlocks do not have to be
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* malloc'd; however, code that uses spinlocks should not look inside
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* the structure directly but always use the spinlock API functions.
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*/
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struct spinlock {
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volatile spinlock_data_t splk_lock; /* Memory word where we spin. */
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struct cpu *splk_holder; /* CPU holding this lock. */
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HANGMAN_LOCKABLE(splk_hangman); /* Deadlock detector hook. */
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};
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/*
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* Initializer for cases where a spinlock needs to be static or global.
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*/
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#ifdef OPT_HANGMAN
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#define SPINLOCK_INITIALIZER { SPINLOCK_DATA_INITIALIZER, NULL, \
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HANGMAN_LOCKABLE_INITIALIZER }
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#else
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#define SPINLOCK_INITIALIZER { SPINLOCK_DATA_INITIALIZER, NULL }
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#endif
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/*
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* Spinlock functions.
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*
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* init Initialize the contents of a spinlock.
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* cleanup Opposite of init. Lock must be unlocked.
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*
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* acquire Get the lock, spinning as necessary. Also disables interrupts.
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* release Release the lock. May re-enable interrupts.
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*
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* do_i_hold Check if the current CPU holds the lock.
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*/
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void spinlock_init(struct spinlock *lk);
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void spinlock_cleanup(struct spinlock *lk);
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void spinlock_acquire(struct spinlock *lk);
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void spinlock_release(struct spinlock *lk);
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bool spinlock_do_i_hold(struct spinlock *lk);
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#endif /* _SPINLOCK_H_ */
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