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.\" $NetBSD: vslock.9,v 1.1 1996/06/15 20:47:29 pk Exp $
.\"
.\" Copyright (c) 1996 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Paul Kranenburg.
.\"
.\" 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 NETBSD FOUNDATION, INC. 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 REGENTS 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 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd August 29, 2012
.Dt VSLOCK 9
.Os
.Sh NAME
.Nm vslock ,
.Nm vsunlock
.Nd lock/unlock user space addresses in memory
.Sh SYNOPSIS
.In sys/param.h
.In sys/proc.h
.In vm/vm.h
.In vm/vm_extern.h
.Ft int
.Fn vslock "void *addr" "size_t len"
.Ft void
.Fn vsunlock "void *addr" "size_t len"
.Sh DESCRIPTION
The
.Fn vslock
and
.Fn vsunlock
functions respectively lock and unlock a range of
addresses belonging to the currently running process into memory.
The actual amount of memory locked is a multiple of the machine's page size.
The starting page number is computed by truncating
.Fa addr
to the nearest preceding page boundary, and by rounding up
.Fa addr +
.Fa len
to the next page boundary.
The process context to use for this operation is taken from the
global variable
.Va curproc .
.Sh RETURN VALUES
The
.Fn vslock
function will return 0 on success, otherwise it will return
one of the errors listed below.
.Sh ERRORS
The
.Fn vslock
function will fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The
.Fa addr
and
.Fa len
parameters specify a memory range that wraps around the end of the
machine address space.
.It Bq Er ENOMEM
The size of the specified address range exceeds the system
limit on locked memory.
.It Bq Er EFAULT
Some portion of the indicated address range is not allocated.
There was an error faulting/mapping a page.
.El
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