| 1 | /* $NetBSD: atomic.h,v 1.7 2014/07/17 14:30:33 riastradh Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 2013 The NetBSD Foundation, Inc. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to The NetBSD Foundation |
| 8 | * by Taylor R. Campbell. |
| 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 | #ifndef _LINUX_ATOMIC_H_ |
| 33 | #define _LINUX_ATOMIC_H_ |
| 34 | |
| 35 | #include <sys/atomic.h> |
| 36 | |
| 37 | #include <machine/limits.h> |
| 38 | |
| 39 | struct atomic { |
| 40 | union { |
| 41 | volatile int au_int; |
| 42 | volatile unsigned int au_uint; |
| 43 | } a_u; |
| 44 | }; |
| 45 | |
| 46 | #define ATOMIC_INIT(i) { .a_u = { .au_int = (i) } } |
| 47 | |
| 48 | typedef struct atomic atomic_t; |
| 49 | |
| 50 | static inline int |
| 51 | atomic_read(atomic_t *atomic) |
| 52 | { |
| 53 | return atomic->a_u.au_int; |
| 54 | } |
| 55 | |
| 56 | static inline void |
| 57 | atomic_set(atomic_t *atomic, int value) |
| 58 | { |
| 59 | atomic->a_u.au_int = value; |
| 60 | } |
| 61 | |
| 62 | static inline void |
| 63 | atomic_add(int addend, atomic_t *atomic) |
| 64 | { |
| 65 | atomic_add_int(&atomic->a_u.au_uint, addend); |
| 66 | } |
| 67 | |
| 68 | static inline void |
| 69 | atomic_sub(int subtrahend, atomic_t *atomic) |
| 70 | { |
| 71 | atomic_add_int(&atomic->a_u.au_uint, -subtrahend); |
| 72 | } |
| 73 | |
| 74 | static inline int |
| 75 | atomic_add_return(int addend, atomic_t *atomic) |
| 76 | { |
| 77 | return (int)atomic_add_int_nv(&atomic->a_u.au_uint, addend); |
| 78 | } |
| 79 | |
| 80 | static inline void |
| 81 | atomic_inc(atomic_t *atomic) |
| 82 | { |
| 83 | atomic_inc_uint(&atomic->a_u.au_uint); |
| 84 | } |
| 85 | |
| 86 | static inline void |
| 87 | atomic_dec(atomic_t *atomic) |
| 88 | { |
| 89 | atomic_dec_uint(&atomic->a_u.au_uint); |
| 90 | } |
| 91 | |
| 92 | static inline int |
| 93 | atomic_inc_return(atomic_t *atomic) |
| 94 | { |
| 95 | return (int)atomic_inc_uint_nv(&atomic->a_u.au_uint); |
| 96 | } |
| 97 | |
| 98 | static inline int |
| 99 | atomic_dec_return(atomic_t *atomic) |
| 100 | { |
| 101 | return (int)atomic_dec_uint_nv(&atomic->a_u.au_uint); |
| 102 | } |
| 103 | |
| 104 | static inline int |
| 105 | atomic_dec_and_test(atomic_t *atomic) |
| 106 | { |
| 107 | return (0 == (int)atomic_dec_uint_nv(&atomic->a_u.au_uint)); |
| 108 | } |
| 109 | |
| 110 | static inline void |
| 111 | atomic_set_mask(unsigned long mask, atomic_t *atomic) |
| 112 | { |
| 113 | atomic_or_uint(&atomic->a_u.au_uint, mask); |
| 114 | } |
| 115 | |
| 116 | static inline void |
| 117 | atomic_clear_mask(unsigned long mask, atomic_t *atomic) |
| 118 | { |
| 119 | atomic_and_uint(&atomic->a_u.au_uint, ~mask); |
| 120 | } |
| 121 | |
| 122 | static inline int |
| 123 | atomic_add_unless(atomic_t *atomic, int addend, int zero) |
| 124 | { |
| 125 | int value; |
| 126 | |
| 127 | do { |
| 128 | value = atomic->a_u.au_int; |
| 129 | if (value == zero) |
| 130 | return 0; |
| 131 | } while (atomic_cas_uint(&atomic->a_u.au_uint, value, (value + addend)) |
| 132 | != value); |
| 133 | |
| 134 | return 1; |
| 135 | } |
| 136 | |
| 137 | static inline int |
| 138 | atomic_inc_not_zero(atomic_t *atomic) |
| 139 | { |
| 140 | return atomic_add_unless(atomic, 1, 0); |
| 141 | } |
| 142 | |
| 143 | static inline int |
| 144 | atomic_xchg(atomic_t *atomic, int new) |
| 145 | { |
| 146 | return (int)atomic_swap_uint(&atomic->a_u.au_uint, (unsigned)new); |
| 147 | } |
| 148 | |
| 149 | static inline int |
| 150 | atomic_cmpxchg(atomic_t *atomic, int old, int new) |
| 151 | { |
| 152 | return (int)atomic_cas_uint(&atomic->a_u.au_uint, (unsigned)old, |
| 153 | (unsigned)new); |
| 154 | } |
| 155 | |
| 156 | struct atomic64 { |
| 157 | volatile uint64_t a_v; |
| 158 | }; |
| 159 | |
| 160 | typedef struct atomic64 atomic64_t; |
| 161 | |
| 162 | static inline uint64_t |
| 163 | atomic64_read(const struct atomic64 *a) |
| 164 | { |
| 165 | return a->a_v; |
| 166 | } |
| 167 | |
| 168 | static inline void |
| 169 | atomic64_set(struct atomic64 *a, uint64_t v) |
| 170 | { |
| 171 | a->a_v = v; |
| 172 | } |
| 173 | |
| 174 | static inline void |
| 175 | atomic64_add(long long d, struct atomic64 *a) |
| 176 | { |
| 177 | atomic_add_64(&a->a_v, d); |
| 178 | } |
| 179 | |
| 180 | static inline void |
| 181 | atomic64_sub(long long d, struct atomic64 *a) |
| 182 | { |
| 183 | atomic_add_64(&a->a_v, -d); |
| 184 | } |
| 185 | |
| 186 | static inline uint64_t |
| 187 | atomic64_xchg(struct atomic64 *a, uint64_t v) |
| 188 | { |
| 189 | return atomic_swap_64(&a->a_v, v); |
| 190 | } |
| 191 | |
| 192 | static inline void |
| 193 | set_bit(unsigned int bit, volatile unsigned long *ptr) |
| 194 | { |
| 195 | const unsigned int units = (sizeof(*ptr) * CHAR_BIT); |
| 196 | |
| 197 | atomic_or_ulong(&ptr[bit / units], (1UL << (bit % units))); |
| 198 | } |
| 199 | |
| 200 | static inline void |
| 201 | clear_bit(unsigned int bit, volatile unsigned long *ptr) |
| 202 | { |
| 203 | const unsigned int units = (sizeof(*ptr) * CHAR_BIT); |
| 204 | |
| 205 | atomic_and_ulong(&ptr[bit / units], ~(1UL << (bit % units))); |
| 206 | } |
| 207 | |
| 208 | static inline void |
| 209 | change_bit(unsigned int bit, volatile unsigned long *ptr) |
| 210 | { |
| 211 | const unsigned int units = (sizeof(*ptr) * CHAR_BIT); |
| 212 | volatile unsigned long *const p = &ptr[bit / units]; |
| 213 | const unsigned long mask = (1UL << (bit % units)); |
| 214 | unsigned long v; |
| 215 | |
| 216 | do v = *p; while (atomic_cas_ulong(p, v, (v ^ mask)) != v); |
| 217 | } |
| 218 | |
| 219 | static inline unsigned long |
| 220 | test_and_set_bit(unsigned int bit, volatile unsigned long *ptr) |
| 221 | { |
| 222 | const unsigned int units = (sizeof(*ptr) * CHAR_BIT); |
| 223 | volatile unsigned long *const p = &ptr[bit / units]; |
| 224 | const unsigned long mask = (1UL << (bit % units)); |
| 225 | unsigned long v; |
| 226 | |
| 227 | do v = *p; while (atomic_cas_ulong(p, v, (v | mask)) != v); |
| 228 | |
| 229 | return ((v & mask) != 0); |
| 230 | } |
| 231 | |
| 232 | static inline unsigned long |
| 233 | test_and_clear_bit(unsigned int bit, volatile unsigned long *ptr) |
| 234 | { |
| 235 | const unsigned int units = (sizeof(*ptr) * CHAR_BIT); |
| 236 | volatile unsigned long *const p = &ptr[bit / units]; |
| 237 | const unsigned long mask = (1UL << (bit % units)); |
| 238 | unsigned long v; |
| 239 | |
| 240 | do v = *p; while (atomic_cas_ulong(p, v, (v & ~mask)) != v); |
| 241 | |
| 242 | return ((v & mask) != 0); |
| 243 | } |
| 244 | |
| 245 | static inline unsigned long |
| 246 | test_and_change_bit(unsigned int bit, volatile unsigned long *ptr) |
| 247 | { |
| 248 | const unsigned int units = (sizeof(*ptr) * CHAR_BIT); |
| 249 | volatile unsigned long *const p = &ptr[bit / units]; |
| 250 | const unsigned long mask = (1UL << (bit % units)); |
| 251 | unsigned long v; |
| 252 | |
| 253 | do v = *p; while (atomic_cas_ulong(p, v, (v ^ mask)) != v); |
| 254 | |
| 255 | return ((v & mask) != 0); |
| 256 | } |
| 257 | |
| 258 | #if defined(MULTIPROCESSOR) && !defined(__HAVE_ATOMIC_AS_MEMBAR) |
| 259 | /* |
| 260 | * XXX These memory barriers are doubtless overkill, but I am having |
| 261 | * trouble understanding the intent and use of the Linux atomic membar |
| 262 | * API. I think that for reference counting purposes, the sequences |
| 263 | * should be insn/inc/enter and exit/dec/insn, but the use of the |
| 264 | * before/after memory barriers is not consistent throughout Linux. |
| 265 | */ |
| 266 | # define smp_mb__before_atomic_inc() membar_sync() |
| 267 | # define smp_mb__after_atomic_inc() membar_sync() |
| 268 | # define smp_mb__before_atomic_dec() membar_sync() |
| 269 | # define smp_mb__after_atomic_dec() membar_sync() |
| 270 | #else |
| 271 | # define smp_mb__before_atomic_inc() __insn_barrier() |
| 272 | # define smp_mb__after_atomic_inc() __insn_barrier() |
| 273 | # define smp_mb__before_atomic_dec() __insn_barrier() |
| 274 | # define smp_mb__after_atomic_dec() __insn_barrier() |
| 275 | #endif |
| 276 | |
| 277 | #endif /* _LINUX_ATOMIC_H_ */ |
| 278 | |