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lock.h revision 1.11.18.1 
      1 /* 	$NetBSD: lock.h,v 1.11.18.1 2007/07/18 13:36:17 skrll Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1998, 1999, 2000, 2001 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 of the Numerical Aerospace Simulation Facility,
      9  * NASA Ames Research Center, and Matthew Fredette.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  * 3. All advertising materials mentioning features or use of this software
     20  *    must display the following acknowledgement:
     21  *	This product includes software developed by the NetBSD
     22  *	Foundation, Inc. and its contributors.
     23  * 4. Neither the name of The NetBSD Foundation nor the names of its
     24  *    contributors may be used to endorse or promote products derived
     25  *    from this software without specific prior written permission.
     26  *
     27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     37  * POSSIBILITY OF SUCH DAMAGE.
     38  */
     39 
     40 /*
     41  * Machine-dependent spin lock operations.
     42  */
     43 
     44 #ifndef _HPPA_LOCK_H_
     45 #define	_HPPA_LOCK_H_
     46 
     47 #define HPPA_LDCW_ALIGN	16
     48 
     49 #define __SIMPLELOCK_ALIGN(p) \
     50     (unsigned long *)(((uintptr_t)(p) + HPPA_LDCW_ALIGN - 1) & ~(HPPA_LDCW_ALIGN - 1))
     51 
     52 #define __SIMPLELOCK_RAW_LOCKED		0
     53 #define __SIMPLELOCK_RAW_UNLOCKED	1
     54 
     55 static __inline int
     56 __SIMPLELOCK_LOCKED_P(__cpu_simple_lock_t *__ptr)
     57 {
     58 	return *__SIMPLELOCK_ALIGN(__ptr) == __SIMPLELOCK_RAW_LOCKED;
     59 }
     60 
     61 static __inline int
     62 __SIMPLELOCK_UNLOCKED_P(__cpu_simple_lock_t *__ptr)
     63 {
     64 	return *__SIMPLELOCK_ALIGN(__ptr) == __SIMPLELOCK_RAW_UNLOCKED;
     65 }
     66 
     67 static __inline int
     68 __ldcw(unsigned long *__ptr)
     69 {
     70 	int __val;
     71 
     72 	__asm volatile("ldcw 0(%1), %0"
     73 	    : "=r" (__val) : "r" (__ptr)
     74 	    : "memory");
     75 
     76 	return __val;
     77 }
     78 
     79 static __inline void
     80 __sync(void)
     81 {
     82 
     83 	__asm volatile("sync\n"
     84 		: /* no outputs */
     85 		: /* no inputs */
     86 		: "memory");
     87 }
     88 
     89 static __inline void
     90 __cpu_simple_lock_init(__cpu_simple_lock_t *alp)
     91 {
     92 	__cpu_simple_lock_t ul = __SIMPLELOCK_UNLOCKED;
     93 
     94 	*alp = ul;
     95 	__sync();
     96 }
     97 
     98 static __inline void
     99 __cpu_simple_lock(__cpu_simple_lock_t *alp)
    100 {
    101 	unsigned long *__aptr = __SIMPLELOCK_ALIGN(alp);
    102 
    103 	/*
    104 	 * Note, if we detect that the lock is held when
    105 	 * we do the initial load-clear-word, we spin using
    106 	 * a non-locked load to save the coherency logic
    107 	 * some work.
    108 	 */
    109 
    110 	while (__ldcw(__aptr) == __SIMPLELOCK_RAW_LOCKED)
    111 		while (*__aptr == __SIMPLELOCK_RAW_LOCKED)
    112 			;
    113 }
    114 
    115 static __inline int
    116 __cpu_simple_lock_try(__cpu_simple_lock_t *alp)
    117 {
    118 	unsigned long *__aptr = __SIMPLELOCK_ALIGN(alp);
    119 
    120 	return (__ldcw(__aptr) != __SIMPLELOCK_RAW_LOCKED);
    121 }
    122 
    123 static __inline void
    124 __cpu_simple_unlock(__cpu_simple_lock_t *alp)
    125 {
    126 	unsigned long *__aptr = __SIMPLELOCK_ALIGN(alp);
    127 
    128 	__sync();
    129 	*__aptr = __SIMPLELOCK_RAW_UNLOCKED;
    130 }
    131 
    132 static __inline void
    133 __cpu_simple_lock_set(__cpu_simple_lock_t *alp)
    134 {
    135 	unsigned long *__aptr = __SIMPLELOCK_ALIGN(alp);
    136 
    137 	*__aptr = __SIMPLELOCK_RAW_LOCKED;
    138 }
    139 
    140 static __inline void
    141 __cpu_simple_lock_clear(__cpu_simple_lock_t *alp)
    142 {
    143 	unsigned long *__aptr = __SIMPLELOCK_ALIGN(alp);
    144 
    145 	*__aptr = __SIMPLELOCK_RAW_UNLOCKED;
    146 }
    147 
    148 static __inline void
    149 mb_read(void)
    150 {
    151 	__sync();
    152 }
    153 
    154 static __inline void
    155 mb_write(void)
    156 {
    157 	__sync();
    158 }
    159 
    160 static __inline void
    161 mb_memory(void)
    162 {
    163 	__sync();
    164 }
    165 
    166 #endif /* _HPPA_LOCK_H_ */
    167