freebsd-dev/sys/compat/linuxkpi/common/include/linux/compiler.h
Mateusz Guzik 21b737495b Introduce __read_mostly and __exclusive_cache_line macros.
The intended use is to annotate frequently used globals which either rarely
change (and thus can be grouped in the same cacheline) or are an atomic counter
(which means it may benefit from being the only variable in the cacheline).

Linker script support is provided only for amd64. Architectures without it risk
having other variables put in, i.e. as if they were not annotated. This is
harmless from correctness point of view.

Reviewed by:	bde (previous version)
MFC after:	1 month
2017-01-27 14:53:09 +00:00

101 lines
3.0 KiB
C

/*-
* Copyright (c) 2010 Isilon Systems, Inc.
* Copyright (c) 2010 iX Systems, Inc.
* Copyright (c) 2010 Panasas, Inc.
* Copyright (c) 2013-2016 Mellanox Technologies, Ltd.
* Copyright (c) 2015 François Tigeot
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _LINUX_COMPILER_H_
#define _LINUX_COMPILER_H_
#include <sys/cdefs.h>
#define __user
#define __kernel
#define __safe
#define __force
#define __nocast
#define __iomem
#define __chk_user_ptr(x) 0
#define __chk_io_ptr(x) 0
#define __builtin_warning(x, y...) (1)
#define __acquires(x)
#define __releases(x)
#define __acquire(x) 0
#define __release(x) 0
#define __cond_lock(x,c) (c)
#define __bitwise
#define __devinitdata
#define __deprecated
#define __init
#define __devinit
#define __devexit
#define __exit
#define __rcu
#define __stringify(x) #x
#define __attribute_const__ __attribute__((__const__))
#undef __always_inline
#define __always_inline inline
#define ____cacheline_aligned __aligned(CACHE_LINE_SIZE)
#define likely(x) __builtin_expect(!!(x), 1)
#define unlikely(x) __builtin_expect(!!(x), 0)
#define typeof(x) __typeof(x)
#define uninitialized_var(x) x = x
#define __always_unused __unused
#define __must_check __result_use_check
#define __printf(a,b) __printflike(a,b)
#define barrier() __asm__ __volatile__("": : :"memory")
#define ___PASTE(a,b) a##b
#define __PASTE(a,b) ___PASTE(a,b)
#define ACCESS_ONCE(x) (*(volatile __typeof(x) *)&(x))
#define WRITE_ONCE(x,v) do { \
barrier(); \
ACCESS_ONCE(x) = (v); \
barrier(); \
} while (0)
#define READ_ONCE(x) ({ \
__typeof(x) __var; \
barrier(); \
__var = ACCESS_ONCE(x); \
barrier(); \
__var; \
})
#define lockless_dereference(p) READ_ONCE(p)
#define _AT(T,X) ((T)(X))
#endif /* _LINUX_COMPILER_H_ */