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freebsd/sys/i386/include/atomic.h

256 lines
7.1 KiB
C

/*-
* 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_readandclear_int(P) (return *(u_int*)P; *(u_int*)P = 0;)
*
* 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))
* atomic_readandclear_long(P) (return *(u_long*)P; *(u_long*)P = 0;)
*/
/*
* 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) \
void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v);
int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src);
#else /* !KLD_MODULE */
#if defined(SMP)
#if defined(LOCORE)
#define MPLOCKED lock ;
#else
#define MPLOCKED "lock ; "
#endif
#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.
*/
#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ > 9)
/* egcs 1.1.2+ version */
#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)); \
}
/*
* Atomic compare and set, used by the mutex functions
*
* if (*dst == exp) *dst = src (all 32 bit words)
*
* Returns 0 on failure, non-zero on success
*/
#if defined(I386_CPU)
static __inline int
atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
{
int res = exp;
__asm __volatile(
" pushfl ; "
" cli ; "
" cmpl %1,%3 ; "
" jne 1f ; "
" movl %2,%3 ; "
"1: "
" sete %%al; "
" movzbl %%al,%0 ; "
" popfl ; "
"# atomic_cmpset_int"
: "=a" (res) /* 0 (result) */
: "0" (exp), /* 1 */
"r" (src), /* 2 */
"m" (*(dst)) /* 3 */
: "memory");
return (res);
}
#else /* defined(I386_CPU) */
static __inline int
atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
{
int res = exp;
__asm __volatile (
" " MPLOCKED " "
" cmpxchgl %2,%3 ; "
" setz %%al ; "
" movzbl %%al,%0 ; "
"1: "
"# atomic_cmpset_int"
: "=a" (res) /* 0 (result) */
: "0" (exp), /* 1 */
"r" (src), /* 2 */
"m" (*(dst)) /* 3 */
: "memory");
return (res);
}
#endif /* defined(I386_CPU) */
#else
/* gcc <= 2.8 version */
#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) \
: "ir" (V)); \
}
#endif
#endif /* KLD_MODULE */
#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ > 9)
/* egcs 1.1.2+ version */
ATOMIC_ASM(set, char, "orb %b2,%0", v)
ATOMIC_ASM(clear, char, "andb %b2,%0", ~v)
ATOMIC_ASM(add, char, "addb %b2,%0", v)
ATOMIC_ASM(subtract, char, "subb %b2,%0", v)
ATOMIC_ASM(set, short, "orw %w2,%0", v)
ATOMIC_ASM(clear, short, "andw %w2,%0", ~v)
ATOMIC_ASM(add, short, "addw %w2,%0", v)
ATOMIC_ASM(subtract, short, "subw %w2,%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)
#else
/* gcc <= 2.8 version */
ATOMIC_ASM(set, char, "orb %1,%0", v)
ATOMIC_ASM(clear, char, "andb %1,%0", ~v)
ATOMIC_ASM(add, char, "addb %1,%0", v)
ATOMIC_ASM(subtract, char, "subb %1,%0", v)
ATOMIC_ASM(set, short, "orw %1,%0", v)
ATOMIC_ASM(clear, short, "andw %1,%0", ~v)
ATOMIC_ASM(add, short, "addw %1,%0", v)
ATOMIC_ASM(subtract, short, "subw %1,%0", v)
ATOMIC_ASM(set, int, "orl %1,%0", v)
ATOMIC_ASM(clear, int, "andl %1,%0", ~v)
ATOMIC_ASM(add, int, "addl %1,%0", v)
ATOMIC_ASM(subtract, int, "subl %1,%0", v)
ATOMIC_ASM(set, long, "orl %1,%0", v)
ATOMIC_ASM(clear, long, "andl %1,%0", ~v)
ATOMIC_ASM(add, long, "addl %1,%0", v)
ATOMIC_ASM(subtract, long, "subl %1,%0", v)
#endif
#ifndef WANT_FUNCTIONS
static __inline int
atomic_cmpset_ptr(volatile void *dst, void *exp, void *src)
{
return (
atomic_cmpset_int((volatile u_int *)dst, (u_int)exp, (u_int)src));
}
static __inline u_int
atomic_readandclear_int(volatile u_int *addr)
{
u_int result;
__asm __volatile (
" xorl %0,%0 ; "
" xchgl %1,%0 ; "
"# atomic_readandclear_int"
: "=&r" (result) /* 0 (result) */
: "m" (*addr)); /* 1 (addr) */
return (result);
}
static __inline u_long
atomic_readandclear_long(volatile u_long *addr)
{
u_long result;
__asm __volatile (
" xorl %0,%0 ; "
" xchgl %1,%0 ; "
"# atomic_readandclear_int"
: "=&r" (result) /* 0 (result) */
: "m" (*addr)); /* 1 (addr) */
return (result);
}
#endif
#endif /* ! _MACHINE_ATOMIC_H_ */