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.\"
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.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. 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(s), this list of conditions and the following disclaimer as
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.\" the first lines of this file unmodified other than the possible
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.\" addition of one or more copyright notices.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice(s), 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 COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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.\" DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
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.\" DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd July 14, 2001
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.Dt VM_PAGE_PROTECT 9
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.Os
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.Sh NAME
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.Nm vm_page_protect
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.Nd "lower a page's protection"
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.Sh SYNOPSIS
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.In sys/param.h
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.In vm/vm.h
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.In vm/vm_page.h
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.Ft void
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.Fn vm_page_protect "vm_page_t mem" "int prot"
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.Sh DESCRIPTION
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The
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.Fn vm_page_protect
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function lowers a page's protection.
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The protection is never raised by this function; therefore, if the page is
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already at
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.Dv VM_PROT_NONE ,
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the function does nothing.
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.Pp
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Its arguments are:
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.Bl -tag -width ".Fa prot"
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.It Fa mem
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The page whose protection is lowered.
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.It Fa prot
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The protection the page should be reduced to.
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If
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.Dv VM_PROT_NONE
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is specified, then the
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.Dv PG_WRITABLE
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and
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.Dv PG_MAPPED
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flags are cleared and the pmap_page's protection is set to
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.Dv VM_PROT_NONE .
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If
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.Dv VM_PROT_READ
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is specified, then the
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.Dv PG_WRITABLE
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flag is cleared and the pmap_page's protection is set to
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.Dv VM_PROT_READ .
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.El
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.Pp
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Higher protection requests are ignored.
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.Sh AUTHORS
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This man page was written by
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.An Chad David Aq davidc@acns.ab.ca .
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