79 lines
3.0 KiB
Groff
79 lines
3.0 KiB
Groff
.\" $NetBSD: i386_iopl.2,v 1.9 2000/07/05 15:45:32 msaitoh Exp $
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.\"
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.\" Copyright (c) 1996 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by John T. Kohl and Charles M. Hannum.
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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. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the NetBSD
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.\" Foundation, Inc. and its contributors.
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.\" 4. Neither the name of The NetBSD Foundation nor the names of its
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.\" contributors may be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd October 14, 1995
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.Dt I386_IOPL 2
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.Os
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.Sh NAME
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.Nm i386_iopl
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.Nd change the i386 I/O privilege level
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.Sh LIBRARY
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.Lb libi386
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.Sh SYNOPSIS
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.Fd #include <sys/types.h>
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.Fd #include <machine/sysarch.h>
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.Ft int
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.Fn i386_iopl "int iopl"
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.Sh DESCRIPTION
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.Fn i386_iopl
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sets the i386 I/O privilege level to the value specified by
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.Ar iopl .
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This call is restricted to the super-user.
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.Sh RETURN VALUES
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Upon successful completion,
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.Fn i386_iopl
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returns 0.
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Otherwise, a value of -1 is returned and the global
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variable
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.Va errno
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is set to indicate the error.
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.Sh ERRORS
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.Fn i386_iopl
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will fail if:
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.Bl -tag -width [EINVAL]
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.It Bq Er EPERM
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The caller was not the super-user, or the operation was not permitted at the
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current security level.
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.El
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.Sh SEE ALSO
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.Xr i386_set_ioperm 2 ,
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.Xr i386_get_ioperm 2
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.Sh REFERENCES
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i386 Microprocessor Programmer's Reference Manual, Intel
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.Sh WARNING
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You can really hose your machine if you enable user-level I/O and
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write to hardware ports without care.
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