1 /**
2 * Many similar implementations exist. See for example libwsbm
3 * or the linux kernel include/atomic.h
4 *
5 * No copyright claimed on this file.
6 *
7 */
8
9 #include "no_extern_c.h"
10
11 #ifndef U_ATOMIC_H
12 #define U_ATOMIC_H
13
14 #include <stdbool.h>
15 #include <stdint.h>
16
17 /* Favor OS-provided implementations.
18 *
19 * Where no OS-provided implementation is available, fall back to
20 * locally coded assembly, compiler intrinsic or ultimately a
21 * mutex-based implementation.
22 */
23 #if defined(__sun)
24 #define PIPE_ATOMIC_OS_SOLARIS
25 #elif defined(_MSC_VER)
26 #define PIPE_ATOMIC_MSVC_INTRINSIC
27 #elif defined(__GNUC__)
28 #define PIPE_ATOMIC_GCC_INTRINSIC
29 #else
30 #error "Unsupported platform"
31 #endif
32
33
34 /* Implementation using GCC-provided synchronization intrinsics
35 */
36 #if defined(PIPE_ATOMIC_GCC_INTRINSIC)
37
38 #define PIPE_ATOMIC "GCC Sync Intrinsics"
39
40 #if defined(USE_GCC_ATOMIC_BUILTINS)
41
42 /* The builtins with explicit memory model are available since GCC 4.7. */
43 #define p_atomic_set(_v, _i) __atomic_store_n((_v), (_i), __ATOMIC_RELEASE)
44 #define p_atomic_read(_v) __atomic_load_n((_v), __ATOMIC_ACQUIRE)
45 #define p_atomic_read_relaxed(_v) __atomic_load_n((_v), __ATOMIC_RELAXED)
46 #define p_atomic_dec_zero(v) (__atomic_sub_fetch((v), 1, __ATOMIC_ACQ_REL) == 0)
47 #define p_atomic_inc(v) (void) __atomic_add_fetch((v), 1, __ATOMIC_ACQ_REL)
48 #define p_atomic_dec(v) (void) __atomic_sub_fetch((v), 1, __ATOMIC_ACQ_REL)
49 #define p_atomic_add(v, i) (void) __atomic_add_fetch((v), (i), __ATOMIC_ACQ_REL)
50 #define p_atomic_inc_return(v) __atomic_add_fetch((v), 1, __ATOMIC_ACQ_REL)
51 #define p_atomic_dec_return(v) __atomic_sub_fetch((v), 1, __ATOMIC_ACQ_REL)
52 #define p_atomic_add_return(v, i) __atomic_add_fetch((v), (i), __ATOMIC_ACQ_REL)
53 #define p_atomic_fetch_add(v, i) __atomic_fetch_add((v), (i), __ATOMIC_ACQ_REL)
54 #define p_atomic_xchg(v, i) __atomic_exchange_n((v), (i), __ATOMIC_ACQ_REL)
55 #define PIPE_NATIVE_ATOMIC_XCHG
56
57 #else
58
59 #define p_atomic_set(_v, _i) (*(_v) = (_i))
60 #define p_atomic_read(_v) (*(_v))
61 #define p_atomic_read_relaxed(_v) (*(_v))
62 #define p_atomic_dec_zero(v) (__sync_sub_and_fetch((v), 1) == 0)
63 #define p_atomic_inc(v) (void) __sync_add_and_fetch((v), 1)
64 #define p_atomic_dec(v) (void) __sync_sub_and_fetch((v), 1)
65 #define p_atomic_add(v, i) (void) __sync_add_and_fetch((v), (i))
66 #define p_atomic_inc_return(v) __sync_add_and_fetch((v), 1)
67 #define p_atomic_dec_return(v) __sync_sub_and_fetch((v), 1)
68 #define p_atomic_add_return(v, i) __sync_add_and_fetch((v), (i))
69 #define p_atomic_fetch_add(v, i) __sync_fetch_and_add((v), (i))
70
71 #endif
72
73 /* There is no __atomic_* compare and exchange that returns the current value.
74 * Also, GCC 5.4 seems unable to optimize a compound statement expression that
75 * uses an additional stack variable with __atomic_compare_exchange[_n].
76 */
77 #define p_atomic_cmpxchg(v, old, _new) \
78 __sync_val_compare_and_swap((v), (old), (_new))
79 #define p_atomic_cmpxchg_ptr(v, old, _new) p_atomic_cmpxchg(v, old, _new)
80
81 #endif
82
83
84
85 /* Unlocked version for single threaded environments, such as some
86 * windows kernel modules.
87 */
88 #if defined(PIPE_ATOMIC_OS_UNLOCKED)
89
90 #define PIPE_ATOMIC "Unlocked"
91
92 #define p_atomic_set(_v, _i) (*(_v) = (_i))
93 #define p_atomic_read(_v) (*(_v))
94 #define p_atomic_read_relaxed(_v) (*(_v))
95 #define p_atomic_dec_zero(_v) (p_atomic_dec_return(_v) == 0)
96 #define p_atomic_inc(_v) ((void) p_atomic_inc_return(_v))
97 #define p_atomic_dec(_v) ((void) p_atomic_dec_return(_v))
98 #define p_atomic_add(_v, _i) ((void) p_atomic_add_return((_v), (_i)))
99 #define p_atomic_inc_return(_v) (++(*(_v)))
100 #define p_atomic_dec_return(_v) (--(*(_v)))
101 #define p_atomic_add_return(_v, _i) (*(_v) = *(_v) + (_i))
102 #define p_atomic_fetch_add(_v, _i) (*(_v) = *(_v) + (_i), *(_v) - (_i))
103 #define p_atomic_cmpxchg(_v, _old, _new) (*(_v) == (_old) ? (*(_v) = (_new), (_old)) : *(_v))
104 #define p_atomic_cmpxchg_ptr(_v, _old, _new) p_atomic_cmpxchg(_v, _old, _new)
105
106 #endif
107
108
109 #if defined(PIPE_ATOMIC_MSVC_INTRINSIC)
110
111 #define PIPE_ATOMIC "MSVC Intrinsics"
112
113 /* We use the Windows header's Interlocked*64 functions instead of the
114 * _Interlocked*64 intrinsics wherever we can, as support for the latter varies
115 * with target CPU, whereas Windows headers take care of all portability
116 * issues: using intrinsics where available, falling back to library
117 * implementations where not.
118 */
119 #ifndef WIN32_LEAN_AND_MEAN
120 #define WIN32_LEAN_AND_MEAN 1
121 #endif
122 #include <windows.h>
123 #include <intrin.h>
124 #include <assert.h>
125
126 /* MSVC supports decltype keyword, but it's only supported on C++ and doesn't
127 * quite work here; and if a C++-only solution is worthwhile, then it would be
128 * better to use templates / function overloading, instead of decltype magic.
129 * Therefore, we rely on implicit casting to LONGLONG for the functions that return
130 */
131
132 #define p_atomic_set(_v, _i) (*(_v) = (_i))
133 #define p_atomic_read(_v) (*(_v))
134 #define p_atomic_read_relaxed(_v) (*(_v))
135
136 #define p_atomic_dec_zero(_v) \
137 (p_atomic_dec_return(_v) == 0)
138
139 #define p_atomic_inc(_v) \
140 ((void) p_atomic_inc_return(_v))
141
142 #define p_atomic_inc_return(_v) (\
143 sizeof *(_v) == sizeof(short) ? _InterlockedIncrement16((short *) (_v)) : \
144 sizeof *(_v) == sizeof(long) ? _InterlockedIncrement ((long *) (_v)) : \
145 sizeof *(_v) == sizeof(__int64) ? InterlockedIncrement64 ((__int64 *)(_v)) : \
146 (assert(!"should not get here"), 0))
147
148 #define p_atomic_dec(_v) \
149 ((void) p_atomic_dec_return(_v))
150
151 #define p_atomic_dec_return(_v) (\
152 sizeof *(_v) == sizeof(short) ? _InterlockedDecrement16((short *) (_v)) : \
153 sizeof *(_v) == sizeof(long) ? _InterlockedDecrement ((long *) (_v)) : \
154 sizeof *(_v) == sizeof(__int64) ? InterlockedDecrement64 ((__int64 *)(_v)) : \
155 (assert(!"should not get here"), 0))
156
157 #define p_atomic_add(_v, _i) \
158 ((void) p_atomic_fetch_add((_v), (_i)))
159
160 #define p_atomic_add_return(_v, _i) (\
161 sizeof *(_v) == sizeof(long) ? InterlockedAdd ((long *) (_v), (_i)) : \
162 sizeof *(_v) == sizeof(__int64) ? InterlockedAdd64((__int64 *)(_v), (_i)) : \
163 (assert(!"should not get here"), 0))
164
165 #define p_atomic_fetch_add(_v, _i) (\
166 sizeof *(_v) == sizeof(char) ? _InterlockedExchangeAdd8 ((char *) (_v), (_i)) : \
167 sizeof *(_v) == sizeof(short) ? _InterlockedExchangeAdd16((short *) (_v), (_i)) : \
168 sizeof *(_v) == sizeof(long) ? InterlockedExchangeAdd ((long *) (_v), (_i)) : \
169 sizeof *(_v) == sizeof(__int64) ? InterlockedExchangeAdd64((__int64 *)(_v), (_i)) : \
170 (assert(!"should not get here"), 0))
171
172 #define p_atomic_cmpxchg(_v, _old, _new) (\
173 sizeof *(_v) == sizeof(char) ? _InterlockedCompareExchange8 ((char *) (_v), (char) (_new), (char) (_old)) : \
174 sizeof *(_v) == sizeof(short) ? _InterlockedCompareExchange16((short *) (_v), (short) (_new), (short) (_old)) : \
175 sizeof *(_v) == sizeof(long) ? _InterlockedCompareExchange ((long *) (_v), (long) (_new), (long) (_old)) : \
176 sizeof *(_v) == sizeof(__int64) ? InterlockedCompareExchange64 ((__int64 *)(_v), (__int64)(_new), (__int64)(_old)) : \
177 (assert(!"should not get here"), 0))
178
179 #if defined(_WIN64)
180 #define p_atomic_cmpxchg_ptr(_v, _old, _new) (void *)InterlockedCompareExchange64((__int64 *)(_v), (__int64)(_new), (__int64)(_old))
181 #else
182 #define p_atomic_cmpxchg_ptr(_v, _old, _new) (void *)InterlockedCompareExchange((long *)(_v), (long)(_new), (long)(_old))
183 #endif
184
185 #define PIPE_NATIVE_ATOMIC_XCHG
186 #define p_atomic_xchg(_v, _new) (\
187 sizeof *(_v) == sizeof(long) ? InterlockedExchange ((long *) (_v), (long) (_new)) : \
188 sizeof *(_v) == sizeof(__int64) ? InterlockedExchange64((__int64 *)(_v), (__int64)(_new)) : \
189 (assert(!"should not get here"), 0))
190
191 #endif
192
193 #if defined(PIPE_ATOMIC_OS_SOLARIS)
194
195 #define PIPE_ATOMIC "Solaris OS atomic functions"
196
197 #include <atomic.h>
198 #include <assert.h>
199
200 #define p_atomic_set(_v, _i) (*(_v) = (_i))
201 #define p_atomic_read(_v) (*(_v))
202
203 #define p_atomic_dec_zero(v) (\
204 sizeof(*v) == sizeof(uint8_t) ? atomic_dec_8_nv ((uint8_t *)(v)) == 0 : \
205 sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16_nv((uint16_t *)(v)) == 0 : \
206 sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32_nv((uint32_t *)(v)) == 0 : \
207 sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64_nv((uint64_t *)(v)) == 0 : \
208 (assert(!"should not get here"), 0))
209
210 #define p_atomic_inc(v) (void) (\
211 sizeof(*v) == sizeof(uint8_t) ? atomic_inc_8 ((uint8_t *)(v)) : \
212 sizeof(*v) == sizeof(uint16_t) ? atomic_inc_16((uint16_t *)(v)) : \
213 sizeof(*v) == sizeof(uint32_t) ? atomic_inc_32((uint32_t *)(v)) : \
214 sizeof(*v) == sizeof(uint64_t) ? atomic_inc_64((uint64_t *)(v)) : \
215 (assert(!"should not get here"), 0))
216
217 #define p_atomic_inc_return(v) (__typeof(*v))( \
218 sizeof(*v) == sizeof(uint8_t) ? atomic_inc_8_nv ((uint8_t *)(v)) : \
219 sizeof(*v) == sizeof(uint16_t) ? atomic_inc_16_nv((uint16_t *)(v)) : \
220 sizeof(*v) == sizeof(uint32_t) ? atomic_inc_32_nv((uint32_t *)(v)) : \
221 sizeof(*v) == sizeof(uint64_t) ? atomic_inc_64_nv((uint64_t *)(v)) : \
222 (assert(!"should not get here"), 0))
223
224 #define p_atomic_dec(v) (void) ( \
225 sizeof(*v) == sizeof(uint8_t) ? atomic_dec_8 ((uint8_t *)(v)) : \
226 sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16((uint16_t *)(v)) : \
227 sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32((uint32_t *)(v)) : \
228 sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64((uint64_t *)(v)) : \
229 (assert(!"should not get here"), 0))
230
231 #define p_atomic_dec_return(v) (__typeof(*v))( \
232 sizeof(*v) == sizeof(uint8_t) ? atomic_dec_8_nv ((uint8_t *)(v)) : \
233 sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16_nv((uint16_t *)(v)) : \
234 sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32_nv((uint32_t *)(v)) : \
235 sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64_nv((uint64_t *)(v)) : \
236 (assert(!"should not get here"), 0))
237
238 #define p_atomic_add(v, i) (void) ( \
239 sizeof(*v) == sizeof(uint8_t) ? atomic_add_8 ((uint8_t *)(v), (i)) : \
240 sizeof(*v) == sizeof(uint16_t) ? atomic_add_16((uint16_t *)(v), (i)) : \
241 sizeof(*v) == sizeof(uint32_t) ? atomic_add_32((uint32_t *)(v), (i)) : \
242 sizeof(*v) == sizeof(uint64_t) ? atomic_add_64((uint64_t *)(v), (i)) : \
243 (assert(!"should not get here"), 0))
244
245 #define p_atomic_add_return(v, i) (__typeof(*v)) ( \
246 sizeof(*v) == sizeof(uint8_t) ? atomic_add_8_nv ((uint8_t *)(v), (i)) : \
247 sizeof(*v) == sizeof(uint16_t) ? atomic_add_16_nv((uint16_t *)(v), (i)) : \
248 sizeof(*v) == sizeof(uint32_t) ? atomic_add_32_nv((uint32_t *)(v), (i)) : \
249 sizeof(*v) == sizeof(uint64_t) ? atomic_add_64_nv((uint64_t *)(v), (i)) : \
250 (assert(!"should not get here"), 0))
251
252 #define p_atomic_fetch_add(v, i) (__typeof(*v)) ( \
253 sizeof(*v) == sizeof(uint8_t) ? atomic_add_8_nv ((uint8_t *)(v), (i)) - (i) : \
254 sizeof(*v) == sizeof(uint16_t) ? atomic_add_16_nv((uint16_t *)(v), (i)) - (i) : \
255 sizeof(*v) == sizeof(uint32_t) ? atomic_add_32_nv((uint32_t *)(v), (i)) - (i) : \
256 sizeof(*v) == sizeof(uint64_t) ? atomic_add_64_nv((uint64_t *)(v), (i)) - (i) : \
257 (assert(!"should not get here"), 0))
258
259 #define p_atomic_cmpxchg(v, old, _new) (__typeof(*v))( \
260 sizeof(*v) == sizeof(uint8_t) ? atomic_cas_8 ((uint8_t *)(v), (uint8_t )(old), (uint8_t )(_new)) : \
261 sizeof(*v) == sizeof(uint16_t) ? atomic_cas_16((uint16_t *)(v), (uint16_t)(old), (uint16_t)(_new)) : \
262 sizeof(*v) == sizeof(uint32_t) ? atomic_cas_32((uint32_t *)(v), (uint32_t)(old), (uint32_t)(_new)) : \
263 sizeof(*v) == sizeof(uint64_t) ? atomic_cas_64((uint64_t *)(v), (uint64_t)(old), (uint64_t)(_new)) : \
264 (assert(!"should not get here"), 0))
265
266 #if INTPTR_MAX == INT32_MAX
267 #define p_atomic_cmpxchg_ptr(v, old, _new) (__typeof(*v))(atomic_cas_32((uint32_t *)(v), (uint32_t)(old), (uint32_t)(_new)))
268 #else
269 #define p_atomic_cmpxchg_ptr(v, old, _new) (__typeof(*v))(atomic_cas_64((uint64_t *)(v), (uint64_t)(old), (uint64_t)(_new)))
270 #endif
271
272 #endif
273
274 #ifndef PIPE_ATOMIC
275 #error "No pipe_atomic implementation selected"
276 #endif
277
278 #ifndef PIPE_NATIVE_ATOMIC_XCHG
p_atomic_xchg_32(uint32_t * v,uint32_t i)279 static inline uint32_t p_atomic_xchg_32(uint32_t *v, uint32_t i)
280 {
281 uint32_t actual = p_atomic_read(v);
282 uint32_t expected;
283 do {
284 expected = actual;
285 actual = p_atomic_cmpxchg(v, expected, i);
286 } while (expected != actual);
287 return actual;
288 }
289
p_atomic_xchg_64(uint64_t * v,uint64_t i)290 static inline uint64_t p_atomic_xchg_64(uint64_t *v, uint64_t i)
291 {
292 uint64_t actual = p_atomic_read(v);
293 uint64_t expected;
294 do {
295 expected = actual;
296 actual = p_atomic_cmpxchg(v, expected, i);
297 } while (expected != actual);
298 return actual;
299 }
300
301 #define p_atomic_xchg(v, i) (__typeof(*(v)))( \
302 sizeof(*(v)) == sizeof(uint32_t) ? p_atomic_xchg_32((uint32_t *)(v), (uint32_t)(i)) : \
303 sizeof(*(v)) == sizeof(uint64_t) ? p_atomic_xchg_64((uint64_t *)(v), (uint64_t)(i)) : \
304 (assert(!"should not get here"), 0))
305 #endif
306
307 #endif /* U_ATOMIC_H */
308