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lock.h revision 1.13 
      1 /* 	$NetBSD: lock.h,v 1.13 2007/09/15 08:05:34 he 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 #include <sys/stdint.h>
     48 
     49 #define HPPA_LDCW_ALIGN	16
     50 
     51 #define __SIMPLELOCK_ALIGN(p) \
     52     (volatile unsigned long *)(((uintptr_t)(p) + HPPA_LDCW_ALIGN - 1) & \
     53     ~(HPPA_LDCW_ALIGN - 1))
     54 
     55 #define __SIMPLELOCK_RAW_LOCKED		0
     56 #define __SIMPLELOCK_RAW_UNLOCKED	1
     57 
     58 static __inline int
     59 __SIMPLELOCK_LOCKED_P(__cpu_simple_lock_t *__ptr)
     60 {
     61 	return *__SIMPLELOCK_ALIGN(__ptr) == __SIMPLELOCK_RAW_LOCKED;
     62 }
     63 
     64 static __inline int
     65 __SIMPLELOCK_UNLOCKED_P(__cpu_simple_lock_t *__ptr)
     66 {
     67 	return *__SIMPLELOCK_ALIGN(__ptr) == __SIMPLELOCK_RAW_UNLOCKED;
     68 }
     69 
     70 static __inline int
     71 __ldcw(volatile unsigned long *__ptr)
     72 {
     73 	int __val;
     74 
     75 	__asm volatile("ldcw 0(%1), %0"
     76 	    : "=r" (__val) : "r" (__ptr)
     77 	    : "memory");
     78 
     79 	return __val;
     80 }
     81 
     82 static __inline void
     83 __sync(void)
     84 {
     85 
     86 	__asm volatile("sync\n"
     87 		: /* no outputs */
     88 		: /* no inputs */
     89 		: "memory");
     90 }
     91 
     92 static __inline void
     93 __cpu_simple_lock_init(__cpu_simple_lock_t *alp)
     94 {
     95 	__cpu_simple_lock_t ul = __SIMPLELOCK_UNLOCKED;
     96 
     97 	*alp = ul;
     98 	__sync();
     99 }
    100 
    101 static __inline void
    102 __cpu_simple_lock(__cpu_simple_lock_t *alp)
    103 {
    104 	volatile unsigned long *__aptr = __SIMPLELOCK_ALIGN(alp);
    105 
    106 	/*
    107 	 * Note, if we detect that the lock is held when
    108 	 * we do the initial load-clear-word, we spin using
    109 	 * a non-locked load to save the coherency logic
    110 	 * some work.
    111 	 */
    112 
    113 	while (__ldcw(__aptr) == __SIMPLELOCK_RAW_LOCKED)
    114 		while (*__aptr == __SIMPLELOCK_RAW_LOCKED)
    115 			;
    116 }
    117 
    118 static __inline int
    119 __cpu_simple_lock_try(__cpu_simple_lock_t *alp)
    120 {
    121 	volatile unsigned long *__aptr = __SIMPLELOCK_ALIGN(alp);
    122 
    123 	return (__ldcw(__aptr) != __SIMPLELOCK_RAW_LOCKED);
    124 }
    125 
    126 static __inline void
    127 __cpu_simple_unlock(__cpu_simple_lock_t *alp)
    128 {
    129 	volatile unsigned long *__aptr = __SIMPLELOCK_ALIGN(alp);
    130 
    131 	__sync();
    132 	*__aptr = __SIMPLELOCK_RAW_UNLOCKED;
    133 }
    134 
    135 static __inline void
    136 __cpu_simple_lock_set(__cpu_simple_lock_t *alp)
    137 {
    138 	volatile unsigned long *__aptr = __SIMPLELOCK_ALIGN(alp);
    139 
    140 	*__aptr = __SIMPLELOCK_RAW_LOCKED;
    141 }
    142 
    143 static __inline void
    144 __cpu_simple_lock_clear(__cpu_simple_lock_t *alp)
    145 {
    146 	volatile unsigned long *__aptr = __SIMPLELOCK_ALIGN(alp);
    147 
    148 	*__aptr = __SIMPLELOCK_RAW_UNLOCKED;
    149 }
    150 
    151 static __inline void
    152 mb_read(void)
    153 {
    154 	__sync();
    155 }
    156 
    157 static __inline void
    158 mb_write(void)
    159 {
    160 	__sync();
    161 }
    162 
    163 static __inline void
    164 mb_memory(void)
    165 {
    166 	__sync();
    167 }
    168 
    169 #endif /* _HPPA_LOCK_H_ */
    170