1 /* $NetBSD: atomic_init_testset.c,v 1.4 2008/04/28 20:22:53 martin Exp $ */ 2 3 /*- 4 * Copyright (c) 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /* 30 * libc glue for atomic operations where the hardware does not provide 31 * compare-and-swap. It's assumed that this will only be used on 32-bit 32 * platforms. 33 * 34 * This should be compiled with '-fno-reorder-blocks -fomit-frame-pointer' 35 * if using gcc. 36 */ 37 38 #include <sys/cdefs.h> 39 __RCSID("$NetBSD: atomic_init_testset.c,v 1.4 2008/04/28 20:22:53 martin Exp $"); 40 41 #include "atomic_op_namespace.h" 42 43 #include <sys/types.h> 44 #include <sys/atomic.h> 45 #include <sys/lock.h> 46 #include <sys/ras.h> 47 #include <sys/sysctl.h> 48 49 #include <string.h> 50 51 #define I2 __SIMPLELOCK_UNLOCKED, __SIMPLELOCK_UNLOCKED, 52 #define I16 I2 I2 I2 I2 I2 I2 I2 I2 53 #define I128 I16 I16 I16 I16 I16 I16 I16 I16 54 55 static __cpu_simple_lock_t atomic_locks[128] = { I128 }; 56 static uint32_t (*_atomic_cas_fn)(volatile uint32_t *, uint32_t, uint32_t); 57 58 void __libc_atomic_init(void) __attribute__ ((visibility("hidden"))); 59 60 RAS_DECL(_atomic_cas); 61 62 static uint32_t 63 _atomic_cas_up(volatile uint32_t *ptr, uint32_t old, uint32_t new) 64 { 65 uint32_t ret; 66 67 RAS_START(_atomic_cas); 68 ret = *ptr; 69 if (__predict_false(ret != old)) { 70 return ret; 71 } 72 *ptr = new; 73 RAS_END(_atomic_cas); 74 75 return ret; 76 } 77 78 static uint32_t 79 _atomic_cas_mp(volatile uint32_t *ptr, uint32_t old, uint32_t new) 80 { 81 __cpu_simple_lock_t *lock; 82 uint32_t ret; 83 84 lock = &atomic_locks[((uint32_t)ptr >> 3) & 127]; 85 __cpu_simple_lock(lock); 86 ret = *ptr; 87 if (__predict_true(ret == old)) { 88 *ptr = new; 89 } 90 __cpu_simple_unlock(lock); 91 92 return ret; 93 } 94 95 uint32_t 96 _atomic_cas_32(volatile uint32_t *ptr, uint32_t old, uint32_t new) 97 { 98 99 return (*_atomic_cas_fn)(ptr, old, new); 100 } 101 102 void 103 __libc_atomic_init(void) 104 { 105 int ncpu, mib[2]; 106 size_t len; 107 108 _atomic_cas_fn = _atomic_cas_mp; 109 110 mib[0] = CTL_HW; 111 mib[1] = HW_NCPU; 112 len = sizeof(ncpu); 113 if (sysctl(mib, 2, &ncpu, &len, NULL, 0) == -1) 114 return; 115 if (ncpu > 1) 116 return; 117 if (rasctl(RAS_ADDR(_atomic_cas), RAS_SIZE(_atomic_cas), 118 RAS_INSTALL) == 0) { 119 _atomic_cas_fn = _atomic_cas_up; 120 return; 121 } 122 } 123 124 #undef atomic_cas_32 125 #undef atomic_cas_uint 126 #undef atomic_cas_ulong 127 #undef atomic_cas_ptr 128 129 atomic_op_alias(atomic_cas_32,_atomic_cas_32) 130 atomic_op_alias(atomic_cas_uint,_atomic_cas_32) 131 __strong_alias(_atomic_cas_uint,_atomic_cas_32) 132 atomic_op_alias(atomic_cas_ulong,_atomic_cas_32) 133 __strong_alias(_atomic_cas_ulong,_atomic_cas_32) 134 atomic_op_alias(atomic_cas_ptr,_atomic_cas_32) 135 __strong_alias(_atomic_cas_ptr,_atomic_cas_32) 136 137 atomic_op_alias(atomic_cas_32_ni,_atomic_cas_32) 138 __strong_alias(_atomic_cas_32_ni,_atomic_cas_32) 139 atomic_op_alias(atomic_cas_uint_ni,_atomic_cas_32) 140 __strong_alias(_atomic_cas_uint_ni,_atomic_cas_32) 141 atomic_op_alias(atomic_cas_ulong_ni,_atomic_cas_32) 142 __strong_alias(_atomic_cas_ulong_ni,_atomic_cas_32) 143 atomic_op_alias(atomic_cas_ptr_ni,_atomic_cas_32) 144 __strong_alias(_atomic_cas_ptr_ni,_atomic_cas_32) 145