source: mainline/kernel/generic/include/barrier.h@ fc0de8c

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since fc0de8c was 7328ff4, checked in by Jiří Zárevúcky <jiri.zarevucky@…>, 7 years ago

Use builtin memory fences for kernel barriers, and convert smp_coherence() into a regular function

  • Property mode set to 100644
File size: 2.2 KB
Line 
1/*
2 * Copyright (c) 2012 Adam Hraska
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#ifndef KERN_COMPILER_BARRIER_H_
30#define KERN_COMPILER_BARRIER_H_
31
32#include <stdatomic.h>
33#include <stddef.h>
34
35static inline void compiler_barrier(void)
36{
37 atomic_signal_fence(memory_order_seq_cst);
38}
39
40static inline void memory_barrier(void)
41{
42 atomic_thread_fence(memory_order_seq_cst);
43}
44
45static inline void read_barrier(void)
46{
47 atomic_thread_fence(memory_order_acquire);
48}
49
50static inline void write_barrier(void)
51{
52 atomic_thread_fence(memory_order_release);
53}
54
55#define CS_ENTER_BARRIER() atomic_thread_fence(memory_order_acquire)
56#define CS_LEAVE_BARRIER() atomic_thread_fence(memory_order_release)
57
58/** Forces the compiler to access (ie load/store) the variable only once. */
59#define ACCESS_ONCE(var) (*((volatile typeof(var)*)&(var)))
60
61extern void smc_coherence(void *, size_t);
62
63#endif /* KERN_COMPILER_BARRIER_H_ */
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