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lock.h revision 1.1.74.1 
      1 /*	$NetBSD: lock.h,v 1.1.74.1 2008/04/03 12:42:19 mjf Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2000 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Jason R. Thorpe.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the NetBSD
     21  *	Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 /*
     40  * Machine-dependent spin lock operations.
     41  */
     42 
     43 #ifndef _IA64_LOCK_H_
     44 #define	_IA64_LOCK_H_
     45 
     46 static __inline int
     47 __SIMPLELOCK_LOCKED_P(__cpu_simple_lock_t *__ptr)
     48 {
     49 	return *__ptr == __SIMPLELOCK_LOCKED;
     50 }
     51 
     52 static __inline int
     53 __SIMPLELOCK_UNLOCKED_P(__cpu_simple_lock_t *__ptr)
     54 {
     55 	return *__ptr == __SIMPLELOCK_UNLOCKED;
     56 }
     57 
     58 static __inline void
     59 __cpu_simple_lock_set(__cpu_simple_lock_t *__ptr)
     60 {
     61 
     62 	*__ptr = __SIMPLELOCK_LOCKED;
     63 }
     64 
     65 static __inline void
     66 __cpu_simple_lock_clear(__cpu_simple_lock_t *__ptr)
     67 {
     68 
     69 	*__ptr = __SIMPLELOCK_UNLOCKED;
     70 }
     71 
     72 #ifdef _KERNEL
     73 
     74 #define	SPINLOCK_SPIN_HOOK	/* nothing */
     75 #define	SPINLOCK_BACKOFF_HOOK	/* XXX(kochi): hint@pause */
     76 
     77 #endif
     78 
     79 static __inline void __cpu_simple_lock_init(__cpu_simple_lock_t *)
     80 	__unused;
     81 static __inline void __cpu_simple_lock(__cpu_simple_lock_t *)
     82 	__unused;
     83 static __inline int __cpu_simple_lock_try(__cpu_simple_lock_t *)
     84 	__unused;
     85 static __inline void __cpu_simple_unlock(__cpu_simple_lock_t *)
     86 	__unused;
     87 
     88 static __inline void
     89 __cpu_simple_lock_init(__cpu_simple_lock_t *lockp)
     90 {
     91 
     92 	*lockp = __SIMPLELOCK_UNLOCKED;
     93 	__insn_barrier();
     94 }
     95 
     96 static __inline int
     97 __cpu_simple_lock_try(__cpu_simple_lock_t *lockp)
     98 {
     99 	uint8_t val;
    100 
    101 	val = __SIMPLELOCK_LOCKED;
    102 /*	__asm volatile ("xchgb %0,(%2)" :
    103 	    "=r" (val)
    104 	    :"0" (val), "r" (lockp)); */
    105 	__insn_barrier();
    106 	return val == __SIMPLELOCK_UNLOCKED;
    107 }
    108 
    109 static __inline void
    110 __cpu_simple_lock(__cpu_simple_lock_t *lockp)
    111 {
    112 
    113 	while (!__cpu_simple_lock_try(lockp))
    114 		/* nothing */;
    115 	__insn_barrier();
    116 }
    117 
    118 static __inline void
    119 __cpu_simple_unlock(__cpu_simple_lock_t *lockp)
    120 {
    121 
    122 	__insn_barrier();
    123 	*lockp = __SIMPLELOCK_UNLOCKED;
    124 }
    125 
    126 #endif /* _IA64_LOCK_H_ */
    127