mirror/freebsd
1
0
Fork 0
mirror of https://git.FreeBSD.org/src.git synced 2024-12-21 11:13:30 +00:00
Code Issues Releases Activity
7e1f6dfe9d
freebsd/sys/i386/include/mutex.h
John Baldwin 7e1f6dfe9d Modify the critical section API as follows: 
- The MD functions critical_enter/exit are renamed to start with a cpu_
  prefix.
- MI wrapper functions critical_enter/exit maintain a per-thread nesting
  count and a per-thread critical section saved state set when entering
  a critical section while at nesting level 0 and restored when exiting
  to nesting level 0.  This moves the saved state out of spin mutexes so
  that interlocking spin mutexes works properly.
- Most low-level MD code that used critical_enter/exit now use
  cpu_critical_enter/exit.  MI code such as device drivers and spin
  mutexes use the MI wrappers.  Note that since the MI wrappers store
  the state in the current thread, they do not have any return values or
  arguments.
- mtx_intr_enable() is replaced with a constant CRITICAL_FORK which is
  assigned to curthread->td_savecrit during fork_exit().

Tested on:	i386, alpha
2001-12-18 00:27:18 +00:00

284 lines
8.4 KiB
C
Raw Blame History

/*-
* 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
/* Global locks */
extern struct mtx clock_lock;
/*
* 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 $0 ; \
pushl $0 ; \
pushl $flags ; \
pushl $lck ; \
call _mtx_lock_spin_flags ; \
addl $0x10, %esp ; \
#define MTX_UNLOCK_SPIN(lck) \
pushl $0 ; \
pushl $0 ; \
pushl $0 ; \
pushl $lck ; \
call _mtx_unlock_spin_flags ; \
addl $0x10, %esp ; \
/*
* 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 */
Reference in New Issue View Git Blame Copy Permalink