f94f8efc61
to use a locked cmpexg when unlocking a lock that we already hold, since
nobody else can touch the lock while we hold it. Second, it is not
necessary to use a locked cmpexg when locking a lock that we already
hold, for the same reason. These changes will allow MP locks to be used
recursively without impacting performance.
Modify two procedures that are called only by assembly and are already
NOPROF entries to pass a critical argument in %edx instead of on the
stack, removing a significant amount of code from the critical path
as a consequence.
Reviewed by: Alfred Perlstein <bright@wintelcom.net>, Peter Wemm <peter@netplex.com.au>
254 lines
6.4 KiB
C
254 lines
6.4 KiB
C
/*
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* Copyright (c) 1997, by Steve Passe
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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. The name of the developer may NOT be used to endorse or promote products
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* derived from this software without specific prior written permission.
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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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* $FreeBSD$
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*/
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#ifndef _MACHINE_LOCK_H_
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#define _MACHINE_LOCK_H_
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#ifdef LOCORE
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#ifdef SMP
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#define MPLOCKED lock ;
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/*
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* Some handy macros to allow logical organization and
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* convenient reassignment of various locks.
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*/
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#define FPU_LOCK call _get_fpu_lock
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#define ALIGN_LOCK call _get_align_lock
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#define SYSCALL_LOCK call _get_syscall_lock
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#define ALTSYSCALL_LOCK call _get_altsyscall_lock
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/*
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* Protects INTR() ISRs.
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*/
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#define ISR_TRYLOCK \
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pushl $_mp_lock ; /* GIANT_LOCK */ \
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call _MPtrylock ; /* try to get lock */ \
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add $4, %esp
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#define ISR_RELLOCK \
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movl $_mp_lock,%edx ; /* GIANT_LOCK */ \
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call _MPrellock_edx
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/*
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* Protects the IO APIC and apic_imen as a critical region.
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*/
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#define IMASK_LOCK \
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pushl $_imen_lock ; /* address of lock */ \
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call _s_lock ; /* MP-safe */ \
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addl $4, %esp
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#define IMASK_UNLOCK \
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movl $0, _imen_lock
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/*
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* Variations of CPL_LOCK protect spl updates as a critical region.
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* Items within this 'region' include:
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* cpl
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* cml
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* cil
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* ipending
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*/
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/*
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* Bottom half routines, ie. those already protected from INTs.
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*
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* Used in:
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* sys/i386/isa/ipl.s: _doreti
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* sys/i386/isa/apic_vector.s: _Xintr0, ..., _Xintr23
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*/
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#define CPL_LOCK \
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pushl $_cpl_lock ; /* address of lock */ \
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call _s_lock ; /* MP-safe */ \
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addl $4, %esp
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#define CPL_UNLOCK \
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movl $0, _cpl_lock
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/*
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* INT safe version for top half of kernel.
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*
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* Used in:
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* sys/i386/i386/exception.s: _Xfpu, _Xalign, _Xsyscall, _Xint0x80_syscall
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* sys/i386/isa/apic_ipl.s: splz()
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*/
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#define SCPL_LOCK \
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pushl $_cpl_lock ; \
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call _ss_lock ; \
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addl $4, %esp
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#define SCPL_UNLOCK \
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pushl $_cpl_lock ; \
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call _ss_unlock ; \
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addl $4, %esp
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#else /* SMP */
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#define MPLOCKED /* NOP */
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#define FPU_LOCK /* NOP */
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#define ALIGN_LOCK /* NOP */
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#define SYSCALL_LOCK /* NOP */
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#define ALTSYSCALL_LOCK /* NOP */
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#endif /* SMP */
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#else /* LOCORE */
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#ifdef SMP
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#include <machine/smptests.h> /** xxx_LOCK */
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/*
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* Locks regions protected in UP kernel via cli/sti.
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*/
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#ifdef USE_MPINTRLOCK
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#define MPINTR_LOCK() s_lock(&mpintr_lock)
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#define MPINTR_UNLOCK() s_unlock(&mpintr_lock)
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#else
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#define MPINTR_LOCK()
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#define MPINTR_UNLOCK()
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#endif /* USE_MPINTRLOCK */
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/*
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* Protects cpl/cml/cil/ipending data as a critical region.
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*
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* Used in:
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* sys/i386/isa/ipl_funcs.c: DO_SETBITS, softclockpending(), GENSPL,
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* spl0(), splx(), splq()
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*/
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#define CPL_LOCK() s_lock(&cpl_lock) /* Bottom end */
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#define CPL_UNLOCK() s_unlock(&cpl_lock)
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#define SCPL_LOCK() ss_lock(&cpl_lock) /* INT safe: top end */
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#define SCPL_UNLOCK() ss_unlock(&cpl_lock)
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/*
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* sio/cy lock.
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* XXX should rc (RISCom/8) use this?
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*/
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#ifdef USE_COMLOCK
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#define COM_LOCK() s_lock(&com_lock)
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#define COM_UNLOCK() s_unlock(&com_lock)
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#define COM_DISABLE_INTR() \
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{ __asm __volatile("cli" : : : "memory"); COM_LOCK(); }
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#define COM_ENABLE_INTR() \
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{ COM_UNLOCK(); __asm __volatile("sti"); }
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#else
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#define COM_LOCK()
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#define COM_UNLOCK()
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#define COM_DISABLE_INTR() disable_intr()
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#define COM_ENABLE_INTR() enable_intr()
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#endif /* USE_COMLOCK */
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/*
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* Clock hardware/struct lock.
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* XXX pcaudio and friends still need this lock installed.
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*/
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#ifdef USE_CLOCKLOCK
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#define CLOCK_LOCK() s_lock(&clock_lock)
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#define CLOCK_UNLOCK() s_unlock(&clock_lock)
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#define CLOCK_DISABLE_INTR() \
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{ __asm __volatile("cli" : : : "memory"); CLOCK_LOCK(); }
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#define CLOCK_ENABLE_INTR() \
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{ CLOCK_UNLOCK(); __asm __volatile("sti"); }
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#else
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#define CLOCK_LOCK()
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#define CLOCK_UNLOCK()
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#define CLOCK_DISABLE_INTR() disable_intr()
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#define CLOCK_ENABLE_INTR() enable_intr()
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#endif /* USE_CLOCKLOCK */
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#else /* SMP */
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#define MPINTR_LOCK()
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#define MPINTR_UNLOCK()
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#define CPL_LOCK()
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#define CPL_UNLOCK()
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#define SCPL_LOCK()
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#define SCPL_UNLOCK()
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#define COM_LOCK()
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#define COM_UNLOCK()
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#define CLOCK_LOCK()
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#define CLOCK_UNLOCK()
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#endif /* SMP */
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/*
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* Simple spin lock.
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* It is an error to hold one of these locks while a process is sleeping.
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*/
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struct simplelock {
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volatile int lock_data;
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};
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/* functions in simplelock.s */
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void s_lock_init __P((struct simplelock *));
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void s_lock __P((struct simplelock *));
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int s_lock_try __P((struct simplelock *));
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void ss_lock __P((struct simplelock *));
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void ss_unlock __P((struct simplelock *));
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void s_lock_np __P((struct simplelock *));
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void s_unlock_np __P((struct simplelock *));
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/* inline simplelock functions */
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static __inline void
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s_unlock(struct simplelock *lkp)
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{
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lkp->lock_data = 0;
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}
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/* global data in mp_machdep.c */
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extern struct simplelock imen_lock;
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extern struct simplelock cpl_lock;
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extern struct simplelock fast_intr_lock;
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extern struct simplelock intr_lock;
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extern struct simplelock clock_lock;
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extern struct simplelock com_lock;
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extern struct simplelock mpintr_lock;
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extern struct simplelock mcount_lock;
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#if !defined(SIMPLELOCK_DEBUG) && NCPUS > 1
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/*
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* This set of defines turns on the real functions in i386/isa/apic_ipl.s.
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*/
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#define simple_lock_init(alp) s_lock_init(alp)
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#define simple_lock(alp) s_lock(alp)
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#define simple_lock_try(alp) s_lock_try(alp)
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#define simple_unlock(alp) s_unlock(alp)
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#endif /* !SIMPLELOCK_DEBUG && NCPUS > 1 */
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#endif /* LOCORE */
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#endif /* !_MACHINE_LOCK_H_ */
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