.\" $OpenBSD: memconfig.8,v 1.6 2001/08/17 11:13:58 mpech Exp $
.\"
.\" Copyright (c) 1999 Chris Costello
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" SUCH DAMAGE.
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.\" $FreeBSD: src/usr.sbin/memcontrol/memcontrol.8,v 1.2 1999/10/09 16:37:37 chris Exp $
.\"
.Dd November 14, 1999
.Dt MEMCONFIG 8
.Os
.Sh NAME
.Nm memconfig
.Nd "control system cache behaviour with respect to memory"
.Sh SYNOPSIS
.Nm memconfig
.Ar list
.Op Fl a
.Nm memconfig
.Ar set
.Fl b Ar base
.Fl l Ar length
.Fl o Ar owner
.Ar attribute
.Nm memconfig
.Ar clear
.Fl o Ar owner
.Nm memconfig
.Ar clear
.Fl b Ar base
.Fl l Ar length
.Sh DESCRIPTION
A number of supported system architectures allow the behaviour of the CPU
cache to be programmed to behave differently depending on the region being
written.
.Pp
.Nm
provides an interface to this facility, allowing CPU cache behavior to
be altered for ranges of system physical memory.
.Pp
These ranges are typically power-of-2 aligned and sized, however the specific
rules governing their layout vary between architectures.
The
.Nm
program does not attempt to enforce these rules, however the system will
reject any attempt to set an illegal combination.
.Pp
The operands and their options are as follows:
.Bl -tag -width clear
.It Ar list
List range slots.
.Bl -tag -width xxxxxx
.It Op Fl a
List all range slots, even those that are inactive.
.El
.It Ar set
Set memory range attributes.
.Bl -tag -width xxxxxx
.It Fl b Ar base
Memory range base address.
.It Fl l Ar length
Length of memory range in bytes, power of 2.
.It Fl o Ar owner
Text identifier for this setting (7 char max).
.It Ar attribute
Attributes applied to this range; one of
.Ar uncacheable ,
.Ar write-combine ,
.Ar write-through ,
.Ar write-back ,
or
.Ar write-protect .
.El
.It Ar clear
Clear memory range attributes.
Ranges may be cleared by owner or by base/length combination.
.Pp
To clear based on ownership:
.Bl -tag -width xxxxxx
.It Fl o Ar owner
All ranges with this owner will be cleared.
.El
.Pp
To clear based on the base/length combination:
.Bl -tag -width xxxxxx
.It Fl b Ar base
Memory range base address.
.It Fl l Ar length
Length of memory range in bytes, power of 2.
.El
.Pp
Base and length must exactly match an existing range.
.El
.Sh SEE ALSO
.Xr mtrr 4
.Sh HISTORY
.Nm
was originally introduced in
.Fx 3.3
as
.Xr memcontrol 8 .