ovs-atomic: New library for atomic operations.

This library should prove useful for the threading changes coming up.
The following commit introduces one (very simple) user.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Ethan Jackson <ethan@nicira.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/lib/ovs-atomic-c11.h b/lib/ovs-atomic-c11.h
new file mode 100644
index 00000000..9dc687c0
--- /dev/null
+++ b/lib/ovs-atomic-c11.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2013 Nicira, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* This header implements atomic operation primitives on compilers that
+ * have built-in support for C11 <stdatomic.h>  */
+#ifndef IN_OVS_ATOMIC_H
+#error "This header should only be included indirectly via ovs-atomic.h."
+#endif
+
+#include <stdatomic.h>
+
+/* Nonstandard atomic types. */
+typedef _Atomic(uint8_t)   atomic_uint8_t;
+typedef _Atomic(uint16_t)  atomic_uint16_t;
+typedef _Atomic(uint32_t)  atomic_uint32_t;
+typedef _Atomic(uint64_t)  atomic_uint64_t;
+
+typedef _Atomic(int8_t)    atomic_int8_t;
+typedef _Atomic(int16_t)   atomic_int16_t;
+typedef _Atomic(int32_t)   atomic_int32_t;
+typedef _Atomic(int64_t)   atomic_int64_t;
+
+#define atomic_read(SRC, DST) \
+    atomic_read_explicit(SRC, DST, memory_order_seq_cst)
+#define atomic_read_explicit(SRC, DST, ORDER)   \
+    (*(DST) = atomic_load_explicit(SRC, ORDER), \
+     (void) 0)
+
+#define atomic_add(RMW, ARG, ORIG) \
+    atomic_add_explicit(RMW, ARG, ORIG, memory_order_seq_cst)
+#define atomic_sub(RMW, ARG, ORIG) \
+    atomic_sub_explicit(RMW, ARG, ORIG, memory_order_seq_cst)
+#define atomic_or(RMW, ARG, ORIG) \
+    atomic_or_explicit(RMW, ARG, ORIG, memory_order_seq_cst)
+#define atomic_xor(RMW, ARG, ORIG) \
+    atomic_xor_explicit(RMW, ARG, ORIG, memory_order_seq_cst)
+#define atomic_and(RMW, ARG, ORIG) \
+    atomic_and_explicit(RMW, ARG, ORIG, memory_order_seq_cst)
+
+#define atomic_add_explicit(RMW, ARG, ORIG, ORDER) \
+    (*(ORIG) = atomic_fetch_add_explicit(RMW, ARG, ORDER), (void) 0)
+#define atomic_sub_explicit(RMW, ARG, ORIG, ORDER) \
+    (*(ORIG) = atomic_fetch_sub_explicit(RMW, ARG, ORDER), (void) 0)
+#define atomic_or_explicit(RMW, ARG, ORIG, ORDER) \
+    (*(ORIG) = atomic_fetch_or_explicit(RMW, ARG, ORDER), (void) 0)
+#define atomic_xor_explicit(RMW, ARG, ORIG, ORDER) \
+    (*(ORIG) = atomic_fetch_xor_explicit(RMW, ARG, ORDER), (void) 0)
+#define atomic_and_explicit(RMW, ARG, ORIG, ORDER) \
+    (*(ORIG) = atomic_fetch_and_explicit(RMW, ARG, ORDER), (void) 0)