104 lines
3.2 KiB
Groff
104 lines
3.2 KiB
Groff
.\" $NetBSD: splraiseipl.9,v 1.6 2007/12/05 04:50:49 ad Exp $
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.\"
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.\" Copyright (c)2006 YAMAMOTO Takashi,
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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. 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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.\"
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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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.\" ------------------------------------------------------------
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.Dd February 11, 2007
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.Dt SPLRAISEIPL 9
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.Os
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.\" ------------------------------------------------------------
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.Sh NAME
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.Nm splraiseipl
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.Nd raise the system priority level
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.\" ------------------------------------------------------------
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.Sh SYNOPSIS
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.In sys/param.h
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.\" - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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.Ft int
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.Fn splraiseipl \
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"ipl_cookie_t icookie"
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.\" ------------------------------------------------------------
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.Sh DESCRIPTION
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.Fn splraiseipl
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raises the system priority level to the level specified by
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.Fa icookie .
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.Fa icookie
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should be a value returned by
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.Fn makeiplcookie .
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.Pp
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In general, device drivers should not make use of this interface.
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To ensure correct synchronization, device drivers should use the
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.Xr condvar 9 ,
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.Xr mutex 9 ,
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and
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.Xr rwlock 9
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interfaces.
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.Pp
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See the
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.Xr spl 9
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manual page for a description of interrupt priority levels.
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.\" ------------------------------------------------------------
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.Sh RETURN VALUES
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.Fn splraiseipl
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returns saved priority level which can be used for
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.Fn splx .
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.\" ------------------------------------------------------------
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.Sh EXAMPLES
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The following two lines are functional equivalents.
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.Bd -literal
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s = splraiseipl(makeiplcookie(IPL_VM));
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.Ed
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.Bd -literal
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s = splvm();
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.Ed
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.Pp
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Because
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.Fn makeiplcookie
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can be slow and is not expected to be used in a perfomance critical path,
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it's better to do it beforehand.
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.Bd -literal
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initialization_code(ipl_t ipl)
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{
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ourcookie = makeiplcookie(ipl);
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}
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performance_critical_code()
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{
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int s;
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s = splraiseipl(ourcookie);
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do_something();
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splx(s);
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}
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.Ed
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.\" ------------------------------------------------------------
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.Sh SEE ALSO
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.Xr condvar 9 ,
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.Xr makeiplcookie 9 ,
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.Xr mutex 9 ,
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.Xr rwlock 9 ,
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.Xr spl 9
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