1 /* $NetBSD: lock.h,v 1.1 2002/06/05 01:04:22 fredette 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 #ifdef MULTIPROCESSOR 48 49 /* 50 * Semaphores must be aligned on 16-byte boundaries on the PA-RISC. 51 */ 52 typedef __volatile struct { 53 int32_t sem __attribute__ ((aligned (16))); 54 } __cpu_simple_lock_t; 55 56 57 static __inline void 58 __cpu_simple_lock_init(__cpu_simple_lock_t *alp) 59 { 60 __asm __volatile( 61 " ; BEGIN __cpu_simple_lock_init\n" 62 " stw %1, %0 \n" 63 " sync \n" 64 " ; END __cpu_simple_lock_init" 65 : "=m" (*alp->sem) 66 : "r" (__SIMPLELOCK_UNLOCKED)); 67 } 68 69 static __inline void 70 __cpu_simple_lock(__cpu_simple_lock_t *alp) 71 { 72 int32_t t0; 73 74 /* 75 * Note, if we detect that the lock is held when 76 * we do the initial load-clear-word, we spin using 77 * a non-locked load to save the coherency logic 78 * some work. 79 */ 80 81 __asm __volatile( 82 " ; BEGIN __cpu_simple_lock\n" 83 " ldcw %1, %0 \n" 84 " comb,<>,n %%r0,%0, 2f \n" 85 "1: comb,=,n %%r0,%0, 1b \n" 86 " ldw %1, %0 \n" 87 " ldcw %1, %0 \n" 88 " comb,=,n %%r0,%0, 1b \n" 89 " ldw %1, %0 \n" 90 "2: sync \n" 91 " ; END __cpu_simple_lock\n" 92 : "=r" (t0), "+m" (*alp->sem)); 93 } 94 95 static __inline int 96 __cpu_simple_lock_try(__cpu_simple_lock_t *alp) 97 { 98 int32_t t0; 99 100 __asm __volatile( 101 " ; BEGIN __cpu_simple_lock_try\n" 102 " ldcw %1, %0 \n" 103 " sync \n" 104 " ; END __cpu_simple_lock_try" 105 : "=r" (t0), "+m" (*alp->sem)); 106 return (t0 != 0); 107 } 108 109 static __inline void 110 __cpu_simple_unlock(__cpu_simple_lock_t *alp) 111 { 112 __asm __volatile( 113 " ; BEGIN __cpu_simple_unlock\n" 114 " sync \n" 115 " stw %1, %0 \n" 116 " ; END __cpu_simple_unlock" 117 : "+m" (*alp->sem) 118 : "r" (__SIMPLELOCK_UNLOCKED)); 119 } 120 121 #else /* !MULTIPROCESSOR */ 122 123 typedef __volatile int __cpu_simple_lock_t; 124 125 #define __SIMPLELOCK_LOCKED 1 126 #define __SIMPLELOCK_UNLOCKED 0 127 128 #endif /* !MULTIPROCESSOR */ 129 130 #endif /* _HPPA_LOCK_H_ */ 131