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freebsd/sys/i386/include/mutex.h

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/*-
* Copyright (c) 1997 Berkeley Software Design, Inc. 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.
* 3. Berkeley Software Design Inc's name may not be used to endorse or
* promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``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 BERKELEY SOFTWARE DESIGN INC 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.
*
* from BSDI $Id: mutex.h,v 2.7.2.35 2000/04/27 03:10:26 cp Exp $
* $FreeBSD$
*/
#ifndef _MACHINE_MUTEX_H_
#define _MACHINE_MUTEX_H_
#ifndef LOCORE
#ifdef _KERNEL
#include <machine/psl.h>
/* Global locks */
extern struct mtx clock_lock;
#define mtx_intr_enable(mutex) do (mutex)->mtx_savecrit |= PSL_I; while (0)
/*
* Assembly macros (for internal use only)
*------------------------------------------------------------------------------
*/
#define _V(x) __STRING(x)
#if 0
/* #ifndef I386_CPU */
/*
* For 486 and newer processors.
*/
/* Get a sleep lock, deal with recursion inline. */
#define _getlock_sleep(mtxp, tid, type) ({ \
int _res = MTX_UNOWNED; \
\
__asm __volatile ( \
" " MPLOCKED "" \
" cmpxchgl %3,%1;" /* Try */ \
" jz 1f;" /* Got it */ \
" andl $" _V(MTX_FLAGMASK) ",%0;" /* turn off spec bits */ \
" cmpl %0,%3;" /* already have it? */ \
" je 2f;" /* yes, recurse */ \
" pushl %4;" \
" pushl %5;" \
" call mtx_enter_hard;" \
" addl $8,%%esp;" \
" jmp 1f;" \
"2:" \
" " MPLOCKED "" \
" orl $" _V(MTX_RECURSE) ",%1;" \
" incl %2;" \
"1:" \
"# getlock_sleep" \
: "+a" (_res), /* 0 */ \
"+m" (mtxp->mtx_lock), /* 1 */ \
"+m" (mtxp->mtx_recurse) /* 2 */ \
: "r" (tid), /* 3 (input) */ \
"gi" (type), /* 4 */ \
"g" (mtxp) /* 5 */ \
: "cc", "memory", "ecx", "edx" /* used */ ); \
})
/* Get a spin lock, handle recursion inline (as the less common case) */
#define _getlock_spin_block(mtxp, tid, type) ({ \
int _res = MTX_UNOWNED; \
\
__asm __volatile ( \
" pushfl;" \
" cli;" \
" " MPLOCKED "" \
" cmpxchgl %3,%1;" /* Try */ \
" jz 2f;" /* got it */ \
" pushl %4;" \
" pushl %5;" \
" call mtx_enter_hard;" /* mtx_enter_hard(mtxp, type, oflags) */ \
" addl $12,%%esp;" \
" jmp 1f;" \
"2: popl %2;" /* save flags */ \
"1:" \
"# getlock_spin_block" \
: "+a" (_res), /* 0 */ \
"+m" (mtxp->mtx_lock), /* 1 */ \
"=m" (mtxp->mtx_savecrit) /* 2 */ \
: "r" (tid), /* 3 (input) */ \
"gi" (type), /* 4 */ \
"g" (mtxp) /* 5 */ \
: "cc", "memory", "ecx", "edx" /* used */ ); \
})
/*
* Get a lock without any recursion handling. Calls the hard enter function if
* we can't get it inline.
*/
#define _getlock_norecurse(mtxp, tid, type) ({ \
int _res = MTX_UNOWNED; \
\
__asm __volatile ( \
" " MPLOCKED "" \
" cmpxchgl %2,%1;" /* Try */ \
" jz 1f;" /* got it */ \
" pushl %3;" \
" pushl %4;" \
" call mtx_enter_hard;" /* mtx_enter_hard(mtxp, type) */ \
" addl $8,%%esp;" \
"1:" \
"# getlock_norecurse" \
: "+a" (_res), /* 0 */ \
"+m" (mtxp->mtx_lock) /* 1 */ \
: "r" (tid), /* 2 (input) */ \
"gi" (type), /* 3 */ \
"g" (mtxp) /* 4 */ \
: "cc", "memory", "ecx", "edx" /* used */ ); \
})
/*
* Release a sleep lock assuming we haven't recursed on it, recursion is handled
* in the hard function.
*/
#define _exitlock_norecurse(mtxp, tid, type) ({ \
int _tid = (int)(tid); \
\
__asm __volatile ( \
" " MPLOCKED "" \
" cmpxchgl %4,%0;" /* try easy rel */ \
" jz 1f;" /* released! */ \
" pushl %2;" \
" pushl %3;" \
" call mtx_exit_hard;" \
" addl $8,%%esp;" \
"1:" \
"# exitlock_norecurse" \
: "+m" (mtxp->mtx_lock), /* 0 */ \
"+a" (_tid) /* 1 */ \
: "gi" (type), /* 2 (input) */ \
"g" (mtxp), /* 3 */ \
"r" (MTX_UNOWNED) /* 4 */ \
: "cc", "memory", "ecx", "edx" /* used */ ); \
})
/*
* Release a sleep lock when its likely we recursed (the code to
* deal with simple recursion is inline).
*/
#define _exitlock(mtxp, tid, type) ({ \
int _tid = (int)(tid); \
\
__asm __volatile ( \
" " MPLOCKED "" \
" cmpxchgl %5,%0;" /* try easy rel */ \
" jz 1f;" /* released! */ \
" testl $" _V(MTX_RECURSE) ",%%eax;" /* recursed? */ \
" jnz 3f;" /* handle recursion */ \
/* Lock not recursed and contested: do the hard way */ \
" pushl %3;" \
" pushl %4;" \
" call mtx_exit_hard;" /* mtx_exit_hard(mtxp,type) */ \
" addl $8,%%esp;" \
" jmp 1f;" \
/* lock recursed, lower recursion level */ \
"3: decl %1;" /* one less level */ \
" jnz 1f;" /* still recursed, done */ \
" lock; andl $~" _V(MTX_RECURSE) ",%0;" /* turn off recurse flag */ \
"1:" \
"# exitlock" \
: "+m" (mtxp->mtx_lock), /* 0 */ \
"+m" (mtxp->mtx_recurse), /* 1 */ \
"+a" (_tid) /* 2 */ \
: "gi" (type), /* 3 (input) */ \
"g" (mtxp), /* 4 */ \
"r" (MTX_UNOWNED) /* 5 */ \
: "cc", "memory", "ecx", "edx" /* used */ ); \
})
/*
* Release a spin lock (with possible recursion).
*
* We use xchgl to clear lock (instead of simple store) to flush posting
* buffers and make the change visible to other CPU's.
*/
#define _exitlock_spin(mtxp) ({ \
int _res; \
\
__asm __volatile ( \
" movl %1,%2;" \
" decl %2;" \
" js 1f;" \
" movl %2,%1;" \
" jmp 2f;" \
"1: movl $ " _V(MTX_UNOWNED) ",%2;" \
" pushl %3;" \
" xchgl %2,%0;" \
" popfl;" \
"2:" \
"# exitlock_spin" \
: "+m" (mtxp->mtx_lock), /* 0 */ \
"+m" (mtxp->mtx_recurse), /* 1 */ \
"=r" (_res) /* 2 */ \
: "g" (mtxp->mtx_savecrit) /* 3 */ \
: "cc", "memory", "ecx" /* used */ ); \
})
#endif /* I386_CPU */
#undef _V
#endif /* _KERNEL */
#else /* !LOCORE */
/*
* Simple assembly macros to get and release mutexes.
*
* Note: All of these macros accept a "flags" argument and are analoguous
* to the mtx_lock_flags and mtx_unlock_flags general macros. If one
* desires to not pass a flag, the value 0 may be passed as second
* argument.
*
* XXX: We only have MTX_LOCK_SPIN and MTX_UNLOCK_SPIN for now, since that's
* all we use right now. We should add MTX_LOCK and MTX_UNLOCK (for sleep
* locks) in the near future, however.
*/
#define MTX_LOCK_SPIN(lck, flags) \
pushl %eax ; \
pushl %ecx ; \
pushl %ebx ; \
movl $(MTX_UNOWNED) , %eax ; \
movl PCPU(CURPROC), %ebx ; \
pushfl ; \
popl %ecx ; \
cli ; \
MPLOCKED cmpxchgl %ebx, lck+MTX_LOCK ; \
jz 2f ; \
cmpl lck+MTX_LOCK, %ebx ; \
je 3f ; \
pushl $0 ; \
pushl $0 ; \
pushl %ecx ; \
pushl $flags ; \
pushl $lck ; \
call _mtx_lock_spin ; \
addl $0x14, %esp ; \
jmp 1f ; \
3: movl lck+MTX_RECURSECNT, %ebx ; \
incl %ebx ; \
movl %ebx, lck+MTX_RECURSECNT ; \
jmp 1f ; \
2: movl %ecx, lck+MTX_SAVECRIT ; \
1: popl %ebx ; \
popl %ecx ; \
popl %eax
#define MTX_UNLOCK_SPIN(lck) \
pushl %edx ; \
pushl %eax ; \
movl lck+MTX_SAVECRIT, %edx ; \
movl lck+MTX_RECURSECNT, %eax ; \
testl %eax, %eax ; \
jne 2f ; \
movl $(MTX_UNOWNED), %eax ; \
xchgl %eax, lck+MTX_LOCK ; \
pushl %edx ; \
popfl ; \
jmp 1f ; \
2: decl %eax ; \
movl %eax, lck+MTX_RECURSECNT ; \
1: popl %eax ; \
popl %edx
/*
* XXX: These two are broken right now and need to be made to work for
* XXX: sleep locks, as the above two work for spin locks. We're not in
* XXX: too much of a rush to do these as we do not use them right now.
*/
#define MTX_ENTER(lck, type) \
pushl $0 ; /* dummy __LINE__ */ \
pushl $0 ; /* dummy __FILE__ */ \
pushl $type ; \
pushl $lck ; \
call _mtx_lock_XXX ; \
addl $16,%esp
#define MTX_EXIT(lck, type) \
pushl $0 ; /* dummy __LINE__ */ \
pushl $0 ; /* dummy __FILE__ */ \
pushl $type ; \
pushl $lck ; \
call _mtx_unlock_XXX ; \
addl $16,%esp
#endif /* !LOCORE */
#endif /* __MACHINE_MUTEX_H */
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