e58bb1c453
with respect to interrupts on UP systems. (The upgrade from gcc 2.7.x to egcs 1.1.2 produced at least one non-atomic code sequence in swap_pager_getpages.) In addition, the primitives are now SMP-safe, but only on SMPs. (For portability between SMPs and UPs, modules are compiled with the SMP-safe versions.) Submitted by: dillon and myself Reviewed by: bde
79 lines
3.0 KiB
C
79 lines
3.0 KiB
C
/*-
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* Copyright (c) 1998 Doug Rabson
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: atomic.h,v 1.1 1998/08/24 08:39:36 dfr Exp $
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*/
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#ifndef _MACHINE_ATOMIC_H_
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#define _MACHINE_ATOMIC_H_
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/*
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* Various simple arithmetic on memory which is atomic in the presence
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* of interrupts. This code is now SMP safe as well.
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*
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* The assembly is volatilized to demark potential before-and-after side
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* effects if an interrupt or SMP collision were to occurs.
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*/
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#ifdef SMP
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#define ATOMIC_ASM(NAME, TYPE, OP, V) \
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static __inline void \
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NAME(void *p, TYPE v) \
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{ \
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__asm __volatile("lock; " \
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OP : "=m" (*(TYPE *)p) : "ir" (V), "0" (*(TYPE *)p)); \
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}
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#else
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#define ATOMIC_ASM(NAME, TYPE, OP, V) \
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static __inline void \
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NAME(void *p, TYPE v) \
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{ \
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__asm __volatile(OP : "=m" (*(TYPE *)p) : "ir" (V), "0" (*(TYPE *)p)); \
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}
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#endif
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ATOMIC_ASM(atomic_set_char, u_char, "orb %1,%0", v)
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ATOMIC_ASM(atomic_clear_char, u_char, "andb %1,%0", ~v)
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ATOMIC_ASM(atomic_add_char, u_char, "addb %1,%0", v)
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ATOMIC_ASM(atomic_subtract_char,u_char, "subb %1,%0", v)
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ATOMIC_ASM(atomic_set_short, u_short,"orw %1,%0", v)
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ATOMIC_ASM(atomic_clear_short, u_short,"andw %1,%0", ~v)
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ATOMIC_ASM(atomic_add_short, u_short,"addw %1,%0", v)
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ATOMIC_ASM(atomic_subtract_short,u_short,"subw %1,%0", v)
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ATOMIC_ASM(atomic_set_int, u_int, "orl %1,%0", v)
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ATOMIC_ASM(atomic_clear_int, u_int, "andl %1,%0", ~v)
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ATOMIC_ASM(atomic_add_int, u_int, "addl %1,%0", v)
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ATOMIC_ASM(atomic_subtract_int, u_int, "subl %1,%0", v)
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ATOMIC_ASM(atomic_set_long, u_long, "orl %1,%0", v)
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ATOMIC_ASM(atomic_clear_long, u_long, "andl %1,%0", ~v)
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ATOMIC_ASM(atomic_add_long, u_long, "addl %1,%0", v)
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ATOMIC_ASM(atomic_subtract_long,u_long, "subl %1,%0", v)
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#undef ATOMIC_ASM
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#endif /* ! _MACHINE_ATOMIC_H_ */
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