xref: /freebsd/sys/compat/linuxkpi/common/include/linux/smp.h (revision 95ee2897e98f5d444f26ed2334cc7c439f9c16c6)
1 /*-
2  * Copyright (c) 2017 Mark Johnston <markj@FreeBSD.org>
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions are
6  * met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in
11  *    the documentation and/or other materials provided with the
12  *    distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #ifndef _LINUXKPI_LINUX_SMP_H_
28 #define	_LINUXKPI_LINUX_SMP_H_
29 
30 #include <asm/smp.h>
31 
32 /*
33  * Important note about the use of the function provided below:
34  *
35  * The callback function passed to on_each_cpu() is called from a
36  * so-called critical section, and if you need a mutex you will have
37  * to rewrite the code to use native FreeBSD mtx spinlocks instead of
38  * the spinlocks provided by the LinuxKPI! Be very careful to not call
39  * any LinuxKPI functions inside the on_each_cpu()'s callback
40  * function, because they may sleep, unlike in native Linux.
41  *
42  * Enabling witness(4) when testing, can catch such issues.
43  */
44 #define	on_each_cpu(cb, data, wait) ({				\
45 	CTASSERT(wait);						\
46 	linux_on_each_cpu(cb, data);				\
47 })
48 
49 extern int	linux_on_each_cpu(void (*)(void *), void *);
50 
51 #endif /* _LINUXKPI_LINUX_SMP_H_ */
52