1.\" 2.\" Copyright (c) 2003 Bruce M Simpson <bms@spc.org> 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd July 21, 2003 29.Dt PMAP_EXTRACT 9 30.Os 31.Sh NAME 32.Nm pmap_extract , 33.Nm pmap_extract_and_hold 34.Nd map a virtual address to a physical page 35.Sh SYNOPSIS 36.In sys/param.h 37.In vm/vm.h 38.In vm/pmap.h 39.Ft vm_paddr_t 40.Fn pmap_extract "pmap_t pmap" "vm_offset_t va" 41.Ft vm_paddr_t 42.Fn pmap_extract_and_hold "pmap_t pmap" "vm_offset_t va" "vm_prot_t prot" 43.Sh DESCRIPTION 44The 45.Fn pmap_extract 46function maps a virtual address to a physical page. 47In certain situations, callers may use 48.Fn pmap_extract_and_hold 49instead, to ensure that the returned page is held. 50.Pp 51The 52.Fn pmap_extract_and_hold 53function maps a virtual address to a physical page, and atomically holds 54the returned page for use by the caller, only if the mapping permits 55the given page protection. 56.Sh IMPLEMENTATION NOTES 57Currently, the page protection requested by the caller is not verified. 58.Sh RETURN VALUES 59The 60.Fn pmap_extract 61function will return the physical page address associated with the 62virtual address 63.Fa va 64inside the physical map 65.Fa pmap . 66If the mapping does not exist, or if the 67.Fa pmap 68parameter is 69.Dv NULL , 70then 71.Dv NULL 72will be returned. 73.Pp 74The 75.Fn pmap_extract_and_hold 76function will return the physical page address associated with the 77virtual address 78.Fa va 79inside the physical map 80.Fa pmap . 81If the mapping does not exist, the result is a no-op, and 82.Dv NULL 83will 84be returned. 85.Sh SEE ALSO 86.Xr mutex 9 , 87.Xr pmap 9 88.Sh AUTHORS 89.An -nosplit 90The 91.Fn pmap_extract_and_hold 92function was implemented by 93.An Alan L. Cox Aq alc@imimic.com . 94This manual page was written by 95.An Bruce M Simpson Aq bms@spc.org . 96