1 /* $NetBSD: lock.h,v 1.17 2009/01/12 03:05:10 pooka Exp $ */ 2 3 /*- 4 * Copyright (c) 2001, 2007 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Wayne Knowles and Andrew Doran. 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 for MIPS processors. 34 * 35 * Note: R2000/R3000 doesn't have any atomic update instructions; this 36 * will cause problems for user applications using this header. 37 */ 38 39 #ifndef _MIPS_LOCK_H_ 40 #define _MIPS_LOCK_H_ 41 42 #include <sys/param.h> 43 44 static __inline int 45 __SIMPLELOCK_LOCKED_P(__cpu_simple_lock_t *__ptr) 46 { 47 return *__ptr == __SIMPLELOCK_LOCKED; 48 } 49 50 static __inline int 51 __SIMPLELOCK_UNLOCKED_P(__cpu_simple_lock_t *__ptr) 52 { 53 return *__ptr == __SIMPLELOCK_UNLOCKED; 54 } 55 56 static __inline void 57 __cpu_simple_lock_clear(__cpu_simple_lock_t *__ptr) 58 { 59 *__ptr = __SIMPLELOCK_UNLOCKED; 60 } 61 62 static __inline void 63 __cpu_simple_lock_set(__cpu_simple_lock_t *__ptr) 64 { 65 *__ptr = __SIMPLELOCK_LOCKED; 66 } 67 68 #ifndef _HARDKERNEL 69 70 static __inline int 71 __cpu_simple_lock_try(__cpu_simple_lock_t *lp) 72 { 73 unsigned long t0, v0; 74 75 __asm volatile( 76 "# -- BEGIN __cpu_simple_lock_try\n" 77 " .set push \n" 78 " .set mips2 \n" 79 "1: ll %0, %4 \n" 80 " bnez %0, 2f \n" 81 " nop # BDslot \n" 82 " li %0, %3 \n" 83 " sc %0, %2 \n" 84 " beqz %0, 2f \n" 85 " nop # BDslot \n" 86 " li %1, 1 \n" 87 " sync \n" 88 " j 3f \n" 89 " nop \n" 90 " nop \n" 91 "2: li %1, 0 \n" 92 "3: \n" 93 " .set pop \n" 94 "# -- END __cpu_simple_lock_try \n" 95 : "=r" (t0), "=r" (v0), "+m" (*lp) 96 : "i" (__SIMPLELOCK_LOCKED), "m" (*lp)); 97 98 return (v0 != 0); 99 } 100 101 #ifdef MIPS1 102 static __inline void 103 mb_read(void) 104 { 105 __insn_barrier(); 106 } 107 108 static __inline void 109 mb_write(void) 110 { 111 __insn_barrier(); 112 } 113 114 static __inline void 115 mb_memory(void) 116 { 117 __insn_barrier(); 118 } 119 #else /* MIPS1*/ 120 static __inline void 121 mb_read(void) 122 { 123 __asm volatile( 124 " .set push\n" 125 " .set mips2\n" 126 " sync\n" 127 " .set pop" 128 ::: "memory" 129 ); 130 } 131 132 static __inline void 133 mb_write(void) 134 { 135 mb_read(); 136 } 137 138 static __inline void 139 mb_memory(void) 140 { 141 mb_read(); 142 } 143 #endif /* MIPS1 */ 144 145 #else /* !_HARDKERNEL */ 146 147 unsigned _atomic_cas_uint(volatile unsigned *, unsigned, unsigned); 148 void mb_read(void); 149 void mb_write(void); 150 void mb_memory(void); 151 152 static __inline int 153 __cpu_simple_lock_try(__cpu_simple_lock_t *lp) 154 { 155 156 return _atomic_cas_uint((volatile unsigned *)lp, 157 __SIMPLELOCK_UNLOCKED, __SIMPLELOCK_LOCKED) == 158 __SIMPLELOCK_UNLOCKED; 159 } 160 161 #endif /* _HARDKERNEL */ 162 163 static __inline void 164 __cpu_simple_lock_init(__cpu_simple_lock_t *lp) 165 { 166 167 *lp = __SIMPLELOCK_UNLOCKED; 168 mb_memory(); 169 } 170 171 static __inline void 172 __cpu_simple_lock(__cpu_simple_lock_t *lp) 173 { 174 175 while (!__cpu_simple_lock_try(lp)) 176 while (*lp == __SIMPLELOCK_LOCKED) 177 /* spin */; 178 } 179 180 static __inline void 181 __cpu_simple_unlock(__cpu_simple_lock_t *lp) 182 { 183 184 mb_memory(); 185 *lp = __SIMPLELOCK_UNLOCKED; 186 } 187 188 #endif /* _MIPS_LOCK_H_ */ 189