1/* 2 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28/* 29 * Copyright (c) 1998 Apple Computer, Inc. All rights reserved. 30 * 31 * HISTORY 32 * 33 */ 34 35/* Copyright (c) 1992 NeXT Computer, Inc. All rights reserved. 36 * 37 * EventShmemLock.h - Shared memory area locks for use between the 38 * WindowServer and the Event Driver. 39 * 40 * HISTORY 41 * 30 Nov 1992 Ben Fathi (benf@next.com) 42 * Ported to m98k. 43 * 44 * 29 April 1992 Mike Paquette at NeXT 45 * Created. 46 * 47 * Multiprocessor locks used within the shared memory area between the 48 * kernel and event system. These must work in both user and kernel mode. 49 * The locks are defined in an include file so they get exported to the local 50 * include file area. 51 */ 52 53 54#ifndef _IOKIT_IOSHAREDLOCKIMP_H 55#define _IOKIT_IOSHAREDLOCKIMP_H 56 57#include <architecture/ppc/asm_help.h> 58#ifdef KERNEL 59#undef END 60#include <mach/ppc/asm.h> 61#endif 62 63/* 64 * void 65 * ev_lock(p) 66 * register int *p; 67 * 68 * Lock the lock pointed to by p. Spin (possibly forever) until 69 * the lock is available. Test and test and set logic used. 70 */ 71 TEXT 72 73#ifndef KERNEL 74LEAF(_ev_lock) 75 76 li a6,1 // lock value 77 788: lwz a7,0(a0) // Get lock word 79 mr. a7,a7 // Is it held? 80 bne-- 8b // Yup... 81 829: lwarx a7,0,a0 // read the lock 83 mr. a7,a7 // Is it held? 84 bne-- 7f // yes, kill reservation 85 stwcx. a6,0,a0 // try to get the lock 86 bne-- 9b // failed, try again 87 isync 88 blr // got it, return 89 907: li a7,-4 // Point to a spot in the red zone 91 stwcx. a7,a7,r1 // Kill reservation 92 b 8b // Go wait some more... 93 94 95END(_ev_lock) 96 97LEAF(_IOSpinLock) 98 99 li a6,1 // lock value 100 1018: lwz a7,0(a0) // Get lock word 102 mr. a7,a7 // Is it held? 103 bne-- 8b // Yup... 104 1059: lwarx a7,0,a0 // read the lock 106 mr. a7,a7 // Is it held? 107 bne-- 7f // yes, kill reservation 108 stwcx. a6,0,a0 // try to get the lock 109 bne-- 9b // failed, try again 110 isync 111 blr // got it, return 112 1137: li a7,-4 // Point to a spot in the red zone 114 stwcx. a7,a7,r1 // Kill reservation 115 b 8b // Go wait some more... 116END(_IOSpinLock) 117#endif 118 119/* 120 * void 121 * spin_unlock(p) 122 * int *p; 123 * 124 * Unlock the lock pointed to by p. 125 */ 126 127LEAF(_ev_unlock) 128 sync 129 li a7,0 130 stw a7,0(a0) 131 blr 132END(_ev_unlock) 133 134LEAF(_IOSpinUnlock) 135 sync 136 li a7,0 137 stw a7,0(a0) 138 blr 139END(_IOSpinUnlock) 140 141 142/* 143 * ev_try_lock(p) 144 * int *p; 145 * 146 * Try to lock p. Return TRUE if successful in obtaining lock. 147 */ 148 149LEAF(_ev_try_lock) 150 li a6,1 // lock value 151 152 lwz a7,0(a0) // Get lock word 153 mr. a7,a7 // Is it held? 154 bne-- 6f // Yup... 155 1569: lwarx a7,0,a0 // read the lock 157 mr. a7,a7 // Is it held? 158 bne-- 7f // yes, kill reservation 159 stwcx. a6,0,a0 // try to get the lock 160 bne-- 9b // failed, try again 161 li a0,1 // return TRUE 162 isync 163 blr // got it, return 164 1657: li a7,-4 // Point to a spot in the red zone 166 stwcx. a7,a7,r1 // Kill reservation 167 1686: 169 li a0,0 // return FALSE 170 blr 171 172END(_ev_try_lock) 173 174LEAF(_IOTrySpinLock) 175 li a6,1 // lock value 176 177 lwz a7,0(a0) // Get lock word 178 mr. a7,a7 // Is it held? 179 bne-- 6f // Yup... 180 1819: lwarx a7,0,a0 // read the lock 182 mr. a7,a7 // Is it held? 183 bne-- 7f // yes, kill reservation 184 stwcx. a6,0,a0 // try to get the lock 185 bne-- 9b // failed, try again 186 li a0,1 // return TRUE 187 isync 188 blr // got it, return 189 1907: li a7,-4 // Point to a spot in the red zone 191 stwcx. a7,a7,r1 // Kill reservation 192 1936: 194 li a0,0 // return FALSE 195 blr 196 197END(_IOTrySpinLock) 198 199#endif /* ! _IOKIT_IOSHAREDLOCKIMP_H */ 200