2005-01-06 22:18:23 +00:00
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/*-
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2003-10-23 06:41:59 +00:00
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* Copyright (c) 2003 The FreeBSD Project
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2000-09-29 13:46:07 +00:00
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* All rights reserved.
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*
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2003-10-23 06:41:59 +00:00
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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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*
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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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2000-09-29 13:46:07 +00:00
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*
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2003-10-23 06:41:59 +00:00
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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2000-09-29 13:46:07 +00:00
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*
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2003-10-23 06:41:59 +00:00
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* $FreeBSD$
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2000-09-29 13:46:07 +00:00
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*/
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2001-12-06 18:17:02 +00:00
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#ifndef _MACHINE_PROC_H_
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#define _MACHINE_PROC_H_
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2001-09-12 08:38:13 +00:00
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struct mdthread {
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Divorce critical sections from spinlocks. Critical sections as denoted by
critical_enter() and critical_exit() are now solely a mechanism for
deferring kernel preemptions. They no longer have any affect on
interrupts. This means that standalone critical sections are now very
cheap as they are simply unlocked integer increments and decrements for the
common case.
Spin mutexes now use a separate KPI implemented in MD code: spinlock_enter()
and spinlock_exit(). This KPI is responsible for providing whatever MD
guarantees are needed to ensure that a thread holding a spin lock won't
be preempted by any other code that will try to lock the same lock. For
now all archs continue to block interrupts in a "spinlock section" as they
did formerly in all critical sections. Note that I've also taken this
opportunity to push a few things into MD code rather than MI. For example,
critical_fork_exit() no longer exists. Instead, MD code ensures that new
threads have the correct state when they are created. Also, we no longer
try to fixup the idlethreads for APs in MI code. Instead, each arch sets
the initial curthread and adjusts the state of the idle thread it borrows
in order to perform the initial context switch.
This change is largely a big NOP, but the cleaner separation it provides
will allow for more efficient alternative locking schemes in other parts
of the kernel (bare critical sections rather than per-CPU spin mutexes
for per-CPU data for example).
Reviewed by: grehan, cognet, arch@, others
Tested on: i386, alpha, sparc64, powerpc, arm, possibly more
2005-04-04 21:53:56 +00:00
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int md_spinlock_count; /* (k) */
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register_t md_saved_intr; /* (k) */
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2000-09-29 13:46:07 +00:00
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};
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2001-09-12 08:38:13 +00:00
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struct mdproc {
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2003-05-16 21:26:42 +00:00
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int __dummy; /* Avoid having an empty struct. */
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2001-09-12 08:38:13 +00:00
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};
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2001-12-06 18:17:02 +00:00
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#endif /* !_MACHINE_PROC_H_ */
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