2 * Copyright (c) 2013, 2014 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 /* This header implements atomic operation primitives on GCC 4.x. */
18 #ifndef IN_OVS_ATOMIC_H
19 #error "This header should only be included indirectly via ovs-atomic.h."
22 #include "ovs-atomic-locked.h"
23 #define OVS_ATOMIC_GCC4P_IMPL 1
25 #define ATOMIC(TYPE) TYPE
27 #define ATOMIC_BOOL_LOCK_FREE 2
28 #define ATOMIC_CHAR_LOCK_FREE 2
29 #define ATOMIC_SHORT_LOCK_FREE 2
30 #define ATOMIC_INT_LOCK_FREE 2
31 #define ATOMIC_LONG_LOCK_FREE (ULONG_MAX <= UINTPTR_MAX ? 2 : 0)
32 #define ATOMIC_LLONG_LOCK_FREE (ULLONG_MAX <= UINTPTR_MAX ? 2 : 0)
33 #define ATOMIC_POINTER_LOCK_FREE 2
44 #define IS_LOCKLESS_ATOMIC(OBJECT) (sizeof(OBJECT) <= sizeof(void *))
46 #define ATOMIC_VAR_INIT(VALUE) VALUE
47 #define atomic_init(OBJECT, VALUE) (*(OBJECT) = (VALUE), (void) 0)
48 #define atomic_destroy(OBJECT) ((void) (OBJECT))
51 atomic_thread_fence(memory_order order)
53 if (order != memory_order_relaxed) {
59 atomic_thread_fence_if_seq_cst(memory_order order)
61 if (order == memory_order_seq_cst) {
67 atomic_signal_fence(memory_order order OVS_UNUSED)
69 if (order != memory_order_relaxed) {
70 asm volatile("" : : : "memory");
74 #define atomic_is_lock_free(OBJ) \
76 IF_LOCKLESS_ATOMIC(OBJ, true, false))
78 #define atomic_store(DST, SRC) \
79 atomic_store_explicit(DST, SRC, memory_order_seq_cst)
80 #define atomic_store_explicit(DST, SRC, ORDER) \
82 typeof(DST) dst__ = (DST); \
83 typeof(SRC) src__ = (SRC); \
84 memory_order order__ = (ORDER); \
86 if (IS_LOCKLESS_ATOMIC(*dst__)) { \
87 atomic_thread_fence(order__); \
89 atomic_thread_fence_if_seq_cst(order__); \
91 atomic_store_locked(DST, SRC); \
95 #define atomic_read(SRC, DST) \
96 atomic_read_explicit(SRC, DST, memory_order_seq_cst)
97 #define atomic_read_explicit(SRC, DST, ORDER) \
99 typeof(DST) dst__ = (DST); \
100 typeof(SRC) src__ = (SRC); \
101 memory_order order__ = (ORDER); \
103 if (IS_LOCKLESS_ATOMIC(*src__)) { \
104 atomic_thread_fence_if_seq_cst(order__); \
107 atomic_read_locked(SRC, DST); \
112 #define atomic_op__(RMW, OP, ARG, ORIG) \
114 typeof(RMW) rmw__ = (RMW); \
115 typeof(ARG) arg__ = (ARG); \
116 typeof(ORIG) orig__ = (ORIG); \
118 if (IS_LOCKLESS_ATOMIC(*rmw__)) { \
119 *orig__ = __sync_fetch_and_##OP(rmw__, arg__); \
121 atomic_op_locked(RMW, OP, ARG, ORIG); \
125 #define atomic_add(RMW, ARG, ORIG) atomic_op__(RMW, add, ARG, ORIG)
126 #define atomic_sub(RMW, ARG, ORIG) atomic_op__(RMW, sub, ARG, ORIG)
127 #define atomic_or( RMW, ARG, ORIG) atomic_op__(RMW, or, ARG, ORIG)
128 #define atomic_xor(RMW, ARG, ORIG) atomic_op__(RMW, xor, ARG, ORIG)
129 #define atomic_and(RMW, ARG, ORIG) atomic_op__(RMW, and, ARG, ORIG)
131 #define atomic_add_explicit(RMW, OPERAND, ORIG, ORDER) \
132 ((void) (ORDER), atomic_add(RMW, OPERAND, ORIG))
133 #define atomic_sub_explicit(RMW, OPERAND, ORIG, ORDER) \
134 ((void) (ORDER), atomic_sub(RMW, OPERAND, ORIG))
135 #define atomic_or_explicit(RMW, OPERAND, ORIG, ORDER) \
136 ((void) (ORDER), atomic_or(RMW, OPERAND, ORIG))
137 #define atomic_xor_explicit(RMW, OPERAND, ORIG, ORDER) \
138 ((void) (ORDER), atomic_xor(RMW, OPERAND, ORIG))
139 #define atomic_and_explicit(RMW, OPERAND, ORIG, ORDER) \
140 ((void) (ORDER), atomic_and(RMW, OPERAND, ORIG))
147 #define ATOMIC_FLAG_INIT { false }
150 atomic_flag_init(volatile atomic_flag *object OVS_UNUSED)
156 atomic_flag_destroy(volatile atomic_flag *object OVS_UNUSED)
162 atomic_flag_test_and_set(volatile atomic_flag *object)
164 return __sync_lock_test_and_set(&object->b, 1);
168 atomic_flag_test_and_set_explicit(volatile atomic_flag *object,
169 memory_order order OVS_UNUSED)
171 return atomic_flag_test_and_set(object);
175 atomic_flag_clear(volatile atomic_flag *object)
177 __sync_lock_release(&object->b);
181 atomic_flag_clear_explicit(volatile atomic_flag *object,
182 memory_order order OVS_UNUSED)
184 atomic_flag_clear(object);