36e9f877df
syscall path inward. A system call may select whether it needs the MP
lock or not (the default being that it does need it).
A great deal of conditional SMP code for various deadended experiments
has been removed. 'cil' and 'cml' have been removed entirely, and the
locking around the cpl has been removed. The conditional
separately-locked fast-interrupt code has been removed, meaning that
interrupts must hold the CPL now (but they pretty much had to anyway).
Another reason for doing this is that the original separate-lock for
interrupts just doesn't apply to the interrupt thread mechanism being
contemplated.
Modifications to the cpl may now ONLY occur while holding the MP
lock. For example, if an otherwise MP safe syscall needs to mess with
the cpl, it must hold the MP lock for the duration and must (as usual)
save/restore the cpl in a nested fashion.
This is precursor work for the real meat coming later: avoiding having
to hold the MP lock for common syscalls and I/O's and interrupt threads.
It is expected that the spl mechanisms and new interrupt threading
mechanisms will be able to run in tandem, allowing a slow piecemeal
transition to occur.
This patch should result in a moderate performance improvement due to
the considerable amount of code that has been removed from the critical
path, especially the simplification of the spl*() calls. The real
performance gains will come later.
Approved by: jkh
Reviewed by: current, bde (exception.s)
Some work taken from: luoqi's patch
186 lines
4.8 KiB
C
186 lines
4.8 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.
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*/
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#define MP_LOCK call _get_mplock
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#define MP_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 MP_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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#else /* SMP */
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#define MPLOCKED /* NOP */
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#define MP_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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* 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 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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