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      1 /*	$NetBSD: lock.h,v 1.10 2023/10/06 11:45:37 skrll 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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * Machine-dependent spin lock operations.
     34  */
     35 
     36 #ifndef _IA64_LOCK_H_
     37 #define	_IA64_LOCK_H_
     38 
     39 static __inline int
     40 __SIMPLELOCK_LOCKED_P(const __cpu_simple_lock_t *__ptr)
     41 {
     42 	return *__ptr == __SIMPLELOCK_LOCKED;
     43 }
     44 
     45 static __inline int
     46 __SIMPLELOCK_UNLOCKED_P(const __cpu_simple_lock_t *__ptr)
     47 {
     48 	return *__ptr == __SIMPLELOCK_UNLOCKED;
     49 }
     50 
     51 static __inline void
     52 __cpu_simple_lock_set(__cpu_simple_lock_t *__ptr)
     53 {
     54 
     55 	*__ptr = __SIMPLELOCK_LOCKED;
     56 }
     57 
     58 static __inline void
     59 __cpu_simple_lock_clear(__cpu_simple_lock_t *__ptr)
     60 {
     61 
     62 	*__ptr = __SIMPLELOCK_UNLOCKED;
     63 }
     64 
     65 #ifdef _KERNEL
     66 
     67 #define	SPINLOCK_SPIN_HOOK	/* nothing */
     68 #define	SPINLOCK_BACKOFF_HOOK	/* XXX ia64_pause() */
     69 
     70 #endif
     71 
     72 static __inline void __cpu_simple_lock_init(__cpu_simple_lock_t *)
     73 	__unused;
     74 static __inline void __cpu_simple_lock(__cpu_simple_lock_t *)
     75 	__unused;
     76 static __inline int __cpu_simple_lock_try(__cpu_simple_lock_t *)
     77 	__unused;
     78 static __inline void __cpu_simple_unlock(__cpu_simple_lock_t *)
     79 	__unused;
     80 
     81 static __inline void
     82 __cpu_simple_lock_init(__cpu_simple_lock_t *lockp)
     83 {
     84 
     85 	*lockp = __SIMPLELOCK_UNLOCKED;
     86 }
     87 
     88 static __inline int
     89 __cpu_simple_lock_try(__cpu_simple_lock_t *lockp)
     90 {
     91 	uint8_t val;
     92 
     93 	val = __SIMPLELOCK_LOCKED;
     94 	__asm volatile ("xchg1 %0=[%1],%2" :
     95 	    "=r" (val)
     96 	    :"r" (lockp), "r" (val)
     97 	    :"memory");
     98 	return val == __SIMPLELOCK_UNLOCKED;
     99 }
    100 
    101 static __inline void
    102 __cpu_simple_lock(__cpu_simple_lock_t *lockp)
    103 {
    104 
    105 	while (!__cpu_simple_lock_try(lockp))
    106 		/* nothing */;
    107 	__insn_barrier();
    108 }
    109 
    110 static __inline void
    111 __cpu_simple_unlock(__cpu_simple_lock_t *lockp)
    112 {
    113 
    114 	__insn_barrier();
    115 	*lockp = __SIMPLELOCK_UNLOCKED;
    116 }
    117 
    118 static __inline void
    119 ia64_pause(void)
    120 {
    121 	__asm __volatile("hint @pause" ::: "memory");
    122 }
    123 
    124 #endif /* _IA64_LOCK_H_ */
    125