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/*-
* Copyright (c) 1998 Doug Rabson
* 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, 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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 _MACHINE_ATOMIC_H_
#define _MACHINE_ATOMIC_H_
/*
* Various simple arithmetic on memory which is atomic in the presence
* of interrupts and multiple processors.
*
* atomic_set_char(P, V) (*(u_char*)(P) |= (V))
* atomic_clear_char(P, V) (*(u_char*)(P) &= ~(V))
* atomic_add_char(P, V) (*(u_char*)(P) += (V))
* atomic_subtract_char(P, V) (*(u_char*)(P) -= (V))
*
* atomic_set_short(P, V) (*(u_short*)(P) |= (V))
* atomic_clear_short(P, V) (*(u_short*)(P) &= ~(V))
* atomic_add_short(P, V) (*(u_short*)(P) += (V))
* atomic_subtract_short(P, V) (*(u_short*)(P) -= (V))
*
* atomic_set_int(P, V) (*(u_int*)(P) |= (V))
* atomic_clear_int(P, V) (*(u_int*)(P) &= ~(V))
* atomic_add_int(P, V) (*(u_int*)(P) += (V))
* atomic_subtract_int(P, V) (*(u_int*)(P) -= (V))
*
* atomic_set_long(P, V) (*(u_long*)(P) |= (V))
* atomic_clear_long(P, V) (*(u_long*)(P) &= ~(V))
* atomic_add_long(P, V) (*(u_long*)(P) += (V))
* atomic_subtract_long(P, V) (*(u_long*)(P) -= (V))
*/
/*
* The above functions are expanded inline in the statically-linked
* kernel. Lock prefixes are generated if an SMP kernel is being
* built.
*
* Kernel modules call real functions which are built into the kernel.
* This allows kernel modules to be portable between UP and SMP systems.
*/
#if defined(KLD_MODULE)
#define ATOMIC_ASM(NAME, TYPE, OP, V) \
extern void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v);
#else /* !KLD_MODULE */
#if defined(SMP)
#define MPLOCKED "lock ; "
#else
#define MPLOCKED
#endif
/*
* The assembly is volatilized to demark potential before-and-after side
* effects if an interrupt or SMP collision were to occur.
*/
#define ATOMIC_ASM(NAME, TYPE, OP, V) \
static __inline void \
atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
{ \
__asm __volatile(MPLOCKED OP \
: "=m" (*p) \
: "0" (*p), "ir" (V)); \
}
#endif /* KLD_MODULE */
ATOMIC_ASM(set, char, "orb %2,%0", v)
ATOMIC_ASM(clear, char, "andb %2,%0", ~v)
ATOMIC_ASM(add, char, "addb %2,%0", v)
ATOMIC_ASM(subtract, char, "subb %2,%0", v)
ATOMIC_ASM(set, short, "orw %2,%0", v)
ATOMIC_ASM(clear, short, "andw %2,%0", ~v)
ATOMIC_ASM(add, short, "addw %2,%0", v)
ATOMIC_ASM(subtract, short, "subw %2,%0", v)
ATOMIC_ASM(set, int, "orl %2,%0", v)
ATOMIC_ASM(clear, int, "andl %2,%0", ~v)
ATOMIC_ASM(add, int, "addl %2,%0", v)
ATOMIC_ASM(subtract, int, "subl %2,%0", v)
ATOMIC_ASM(set, long, "orl %2,%0", v)
ATOMIC_ASM(clear, long, "andl %2,%0", ~v)
ATOMIC_ASM(add, long, "addl %2,%0", v)
ATOMIC_ASM(subtract, long, "subl %2,%0", v)
#endif /* ! _MACHINE_ATOMIC_H_ */
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