dde96c9933
all the debugging code into the function versions of the mutex operations
in kern_mutex.c. This reduced the __mtx_* macros to simply wrappers of
the _{get,rel}_lock_* macros, so the __mtx_* macros were also abolished in
favor of just calling the _{get,rel}_lock_* macros. The tangled hairy mass
of macros calling macros is at least a bit more sane now.
351 lines
12 KiB
C
351 lines
12 KiB
C
/*-
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* Copyright (c) 1997 Berkeley Software Design, Inc. 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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* 3. Berkeley Software Design Inc's name may not be used to endorse or
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* promote products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``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 BERKELEY SOFTWARE DESIGN INC 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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* from BSDI $Id: mutex.h,v 2.7.2.35 2000/04/27 03:10:26 cp Exp $
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* $FreeBSD$
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*/
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#ifndef _SYS_MUTEX_H_
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#define _SYS_MUTEX_H_
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#ifndef LOCORE
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#include <sys/queue.h>
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#include <sys/_lock.h>
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#include <sys/_mutex.h>
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#ifdef _KERNEL
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#include <sys/ktr.h>
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#include <machine/atomic.h>
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#include <machine/cpufunc.h>
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#include <machine/globals.h>
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#endif /* _KERNEL_ */
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#endif /* !LOCORE */
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#include <machine/mutex.h>
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#ifdef _KERNEL
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/*
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* Mutex types and options passed to mtx_init(). MTX_QUIET can also be
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* passed in.
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*/
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#define MTX_DEF 0x00000000 /* DEFAULT (sleep) lock */
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#define MTX_SPIN 0x00000001 /* Spin lock (disables interrupts) */
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#define MTX_RECURSE 0x00000004 /* Option: lock allowed to recurse */
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#define MTX_NOWITNESS 0x00000008 /* Don't do any witness checking. */
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#define MTX_SLEEPABLE 0x00000010 /* We can sleep with this lock. */
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/*
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* Option flags passed to certain lock/unlock routines, through the use
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* of corresponding mtx_{lock,unlock}_flags() interface macros.
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*/
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#define MTX_NOSWITCH LOP_NOSWITCH /* Do not switch on release */
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#define MTX_QUIET LOP_QUIET /* Don't log a mutex event */
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/*
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* State bits kept in mutex->mtx_lock, for the DEFAULT lock type. None of this,
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* with the exception of MTX_UNOWNED, applies to spin locks.
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*/
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#define MTX_RECURSED 0x00000001 /* lock recursed (for MTX_DEF only) */
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#define MTX_CONTESTED 0x00000002 /* lock contested (for MTX_DEF only) */
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#define MTX_UNOWNED 0x00000004 /* Cookie for free mutex */
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#define MTX_FLAGMASK ~(MTX_RECURSED | MTX_CONTESTED)
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#endif /* _KERNEL */
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#ifndef LOCORE
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/*
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* XXX: Friendly reminder to fix things in MP code that is presently being
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* XXX: worked on.
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*/
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#define mp_fixme(string)
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#ifdef _KERNEL
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/*
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* Prototypes
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*
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* NOTE: Functions prepended with `_' (underscore) are exported to other parts
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* of the kernel via macros, thus allowing us to use the cpp LOCK_FILE
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* and LOCK_LINE. These functions should not be called directly by any
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* code using the API. Their macros cover their functionality.
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*
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* [See below for descriptions]
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*
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*/
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void mtx_init(struct mtx *m, const char *description, int opts);
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void mtx_destroy(struct mtx *m);
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void _mtx_lock_sleep(struct mtx *m, int opts, const char *file, int line);
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void _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line);
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void _mtx_lock_spin(struct mtx *m, int opts, critical_t mtx_crit,
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const char *file, int line);
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void _mtx_unlock_spin(struct mtx *m, int opts, const char *file, int line);
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int _mtx_trylock(struct mtx *m, int opts, const char *file, int line);
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void _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line);
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void _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line);
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void _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file,
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int line);
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void _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file,
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int line);
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#ifdef INVARIANT_SUPPORT
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void _mtx_assert(struct mtx *m, int what, const char *file, int line);
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#endif
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/*
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* We define our machine-independent (unoptimized) mutex micro-operations
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* here, if they are not already defined in the machine-dependent mutex.h
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*/
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/* Actually obtain mtx_lock */
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#ifndef _obtain_lock
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#define _obtain_lock(mp, tid) \
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atomic_cmpset_acq_ptr(&(mp)->mtx_lock, (void *)MTX_UNOWNED, (tid))
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#endif
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/* Actually release mtx_lock */
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#ifndef _release_lock
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#define _release_lock(mp, tid) \
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atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), (void *)MTX_UNOWNED)
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#endif
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/* Actually release mtx_lock quickly, assuming we own it. */
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#ifndef _release_lock_quick
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#define _release_lock_quick(mp) \
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atomic_store_rel_ptr(&(mp)->mtx_lock, (void *)MTX_UNOWNED)
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#endif
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/*
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* Obtain a sleep lock inline, or call the "hard" function if we can't get it
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* easy.
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*/
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#ifndef _get_sleep_lock
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#define _get_sleep_lock(mp, tid, opts, file, line) do { \
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if (!_obtain_lock((mp), (tid))) \
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_mtx_lock_sleep((mp), (opts), (file), (line)); \
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} while (0)
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#endif
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/*
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* Obtain a spin lock inline, or call the "hard" function if we can't get it
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* easy. For spinlocks, we handle recursion inline (it turns out that function
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* calls can be significantly expensive on some architectures).
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* Since spin locks are not _too_ common, inlining this code is not too big
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* a deal.
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*/
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#ifndef _get_spin_lock
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#define _get_spin_lock(mp, tid, opts, file, line) do { \
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critical_t _mtx_crit; \
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_mtx_crit = critical_enter(); \
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if (!_obtain_lock((mp), (tid))) { \
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if ((mp)->mtx_lock == (uintptr_t)(tid)) \
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(mp)->mtx_recurse++; \
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else \
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_mtx_lock_spin((mp), (opts), _mtx_crit, (file), \
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(line)); \
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} else \
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(mp)->mtx_savecrit = _mtx_crit; \
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} while (0)
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#endif
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/*
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* Release a sleep lock inline, or call the "hard" function if we can't do it
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* easy.
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*/
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#ifndef _rel_sleep_lock
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#define _rel_sleep_lock(mp, tid, opts, file, line) do { \
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if (!_release_lock((mp), (tid))) \
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_mtx_unlock_sleep((mp), (opts), (file), (line)); \
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} while (0)
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#endif
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/*
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* For spinlocks, we can handle everything inline, as it's pretty simple and
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* a function call would be too expensive (at least on some architectures).
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* Since spin locks are not _too_ common, inlining this code is not too big
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* a deal.
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*/
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#ifndef _rel_spin_lock
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#define _rel_spin_lock(mp) do { \
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critical_t _mtx_crit = (mp)->mtx_savecrit; \
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if (mtx_recursed((mp))) \
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(mp)->mtx_recurse--; \
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else { \
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_release_lock_quick((mp)); \
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critical_exit(_mtx_crit); \
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} \
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} while (0)
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#endif
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/*
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* Exported lock manipulation interface.
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*
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* mtx_lock(m) locks MTX_DEF mutex `m'
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*
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* mtx_lock_spin(m) locks MTX_SPIN mutex `m'
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*
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* mtx_unlock(m) unlocks MTX_DEF mutex `m'
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*
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* mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m'
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*
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* mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m'
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* and passes option flags `opts' to the "hard" function, if required.
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* With these routines, it is possible to pass flags such as MTX_QUIET
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* and/or MTX_NOSWITCH to the appropriate lock manipulation routines.
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*
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* mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if
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* it cannot. Rather, it returns 0 on failure and non-zero on success.
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* It does NOT handle recursion as we assume that if a caller is properly
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* using this part of the interface, he will know that the lock in question
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* is _not_ recursed.
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*
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* mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts
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* relevant option flags `opts.'
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*
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* mtx_initialized(m) returns non-zero if the lock `m' has been initialized.
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*
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* mtx_owned(m) returns non-zero if the current thread owns the lock `m'
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*
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* mtx_recursed(m) returns non-zero if the lock `m' is presently recursed.
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*/
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#define mtx_lock(m) mtx_lock_flags((m), 0)
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#define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0)
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#define mtx_trylock(m) mtx_trylock_flags((m), 0)
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#define mtx_unlock(m) mtx_unlock_flags((m), 0)
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#define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0)
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#ifdef LOCK_DEBUG
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#define mtx_lock_flags(m, opts) \
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_mtx_lock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
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#define mtx_unlock_flags(m, opts) \
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_mtx_unlock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
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#define mtx_lock_spin_flags(m, opts) \
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_mtx_lock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
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#define mtx_unlock_spin_flags(m, opts) \
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_mtx_unlock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
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#else
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#define mtx_lock_flags(m, opts) \
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_get_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
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#define mtx_unlock_flags(m, opts) \
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_rel_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
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#define mtx_lock_spin_flags(m, opts) \
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_get_spin_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
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#define mtx_unlock_spin_flags(m, opts) \
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_rel_spin_lock((m))
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#endif
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#define mtx_trylock_flags(m, opts) \
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_mtx_trylock((m), (opts), LOCK_FILE, LOCK_LINE)
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#define mtx_initialized(m) ((m)->mtx_object.lo_flags & LO_INITIALIZED)
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#define mtx_owned(m) (((m)->mtx_lock & MTX_FLAGMASK) == (uintptr_t)curthread)
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#define mtx_recursed(m) ((m)->mtx_recurse != 0)
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/*
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* Global locks.
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*/
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extern struct mtx sched_lock;
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extern struct mtx Giant;
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/*
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* Giant lock manipulation and clean exit macros.
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* Used to replace return with an exit Giant and return.
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*
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* Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT()
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*/
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#define DROP_GIANT_NOSWITCH() \
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do { \
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int _giantcnt; \
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WITNESS_SAVE_DECL(Giant); \
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\
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if (mtx_owned(&Giant)) \
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WITNESS_SAVE(&Giant.mtx_object, Giant); \
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for (_giantcnt = 0; mtx_owned(&Giant); _giantcnt++) \
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mtx_unlock_flags(&Giant, MTX_NOSWITCH)
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#define DROP_GIANT() \
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do { \
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int _giantcnt; \
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WITNESS_SAVE_DECL(Giant); \
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\
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if (mtx_owned(&Giant)) \
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WITNESS_SAVE(&Giant.mtx_object, Giant); \
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for (_giantcnt = 0; mtx_owned(&Giant); _giantcnt++) \
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mtx_unlock(&Giant)
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#define PICKUP_GIANT() \
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mtx_assert(&Giant, MA_NOTOWNED); \
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while (_giantcnt--) \
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mtx_lock(&Giant); \
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if (mtx_owned(&Giant)) \
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WITNESS_RESTORE(&Giant.mtx_object, Giant); \
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} while (0)
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#define PARTIAL_PICKUP_GIANT() \
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mtx_assert(&Giant, MA_NOTOWNED); \
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while (_giantcnt--) \
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mtx_lock(&Giant); \
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if (mtx_owned(&Giant)) \
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WITNESS_RESTORE(&Giant.mtx_object, Giant)
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#define UGAR(rval) do { \
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int _val = (rval); \
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mtx_unlock(&Giant); \
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return (_val); \
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} while (0)
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/*
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* The INVARIANTS-enabled mtx_assert() functionality.
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*
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* The constants need to be defined for INVARIANT_SUPPORT infrastructure
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* support as _mtx_assert() itself uses them and the latter implies that
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* _mtx_assert() must build.
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*/
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#ifdef INVARIANT_SUPPORT
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#define MA_OWNED 0x01
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#define MA_NOTOWNED 0x02
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#define MA_RECURSED 0x04
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#define MA_NOTRECURSED 0x08
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#endif /* INVARIANT_SUPPORT */
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#ifdef INVARIANTS
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#define mtx_assert(m, what) \
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_mtx_assert((m), (what), __FILE__, __LINE__)
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#define GIANT_REQUIRED mtx_assert(&Giant, MA_OWNED)
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#else /* INVARIANTS */
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#define mtx_assert(m, what)
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#define GIANT_REQUIRED
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#endif /* INVARIANTS */
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#endif /* _KERNEL */
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#endif /* !LOCORE */
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#endif /* _SYS_MUTEX_H_ */
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