/* * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009 * The President and Fellows of Harvard College. * * 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. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY 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 UNIVERSITY 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. */ #ifndef _SPINLOCK_H_ #define _SPINLOCK_H_ /* * Spinlocks. While the guts are machine-dependent, the structure and the * basic functions are supposed to be the same across all machines. */ #include <cdefs.h> /* Inlining support - for making sure an out-of-line copy gets built */ #ifndef SPINLOCK_INLINE #define SPINLOCK_INLINE INLINE #endif /* Get the machine-dependent bits. */ #include <machine/spinlock.h> /* * Basic spinlock. * * Note that spinlocks are held by CPUs, not by threads. * * This structure is made public so spinlocks do not have to be * malloc'd; however, code that uses spinlocks should not look inside * the structure directly but always use the spinlock API functions. */ struct spinlock { volatile spinlock_data_t splk_lock; /* Memory word where we spin. */ struct cpu *splk_holder; /* CPU holding this lock. */ }; /* * Initializer for cases where a spinlock needs to be static or global. */ #define SPINLOCK_INITIALIZER { SPINLOCK_DATA_INITIALIZER, NULL } /* * Spinlock functions. * * init Initialize the contents of a spinlock. * cleanup Opposite of init. Lock must be unlocked. * * acquire Get the lock, spinning as necessary. Also disables interrupts. * release Release the lock. May re-enable interrupts. * * do_i_hold Check if the current CPU holds the lock. */ void spinlock_init(struct spinlock *lk); void spinlock_cleanup(struct spinlock *lk); void spinlock_acquire(struct spinlock *lk); void spinlock_release(struct spinlock *lk); bool spinlock_do_i_hold(struct spinlock *lk); #endif /* _SPINLOCK_H_ */