Fix a leak of the wired pages when unwiring of the PROT_NONE-mapped

wired region.  Rework the handling of unwire to do the it in batch,
both at pmap and object level.

All commits below are by alc.

MFC r268327:
Introduce pmap_unwire().

MFC r268591:
Implement pmap_unwire() for powerpc.

MFC r268776:
Implement pmap_unwire() for arm.

MFC r268806:
pmap_unwire(9) man page.

MFC r269134:
When unwiring a region of an address space, do not assume that the
underlying physical pages are mapped by the pmap.  This fixes a leak
of the wired pages on the unwiring of the region mapped with no access
allowed.

MFC r269339:
In the implementation of the new function pmap_unwire(), the call to
MOEA64_PVO_TO_PTE() must be performed before any changes are made to the
PVO. Otherwise, MOEA64_PVO_TO_PTE() will panic.

MFC r269365:
Correct a long-standing problem in moea{,64}_pvo_enter() that was revealed
by the combination of r268591 and r269134: When we attempt to add the
wired attribute to an existing mapping, moea{,64}_pvo_enter() do nothing.
(They only set the wired attribute on newly created mappings.)

MFC r269433:
Handle wiring failures in vm_map_wire() with the new functions
pmap_unwire() and vm_object_unwire().
Retire vm_fault_{un,}wire(), since they are no longer used.

MFC r269438:
Rewrite a loop in vm_map_wire() so that gcc doesn't think that the variable
"rv" is uninitialized.

MFC r269485:
Retire pmap_change_wiring().

Reviewed by:	alc

3 files changed, 69 insertions, 3 deletions

diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile
index 8cf5a5f..b7c7589 100644
--- a/share/man/man9/Makefile
+++ b/share/man/man9/Makefile
@@ -197,7 +197,6 @@ MAN=	accept_filter.9 \
 	physio.9 \
 	pmap.9 \
 	pmap_activate.9 \
-	pmap_change_wiring.9 \
 	pmap_clear_modify.9 \
 	pmap_copy.9 \
 	pmap_enter.9 \
@@ -217,6 +216,7 @@ MAN=	accept_filter.9 \
 	pmap_release.9 \
 	pmap_remove.9 \
 	pmap_resident_count.9 \
+	pmap_unwire.9 \
 	pmap_zero_page.9 \
 	printf.9 \
 	prison_check.9 \
diff --git a/share/man/man9/pmap.9 b/share/man/man9/pmap.9
index aa6d4a3..5cf5b7e 100644
--- a/share/man/man9/pmap.9
+++ b/share/man/man9/pmap.9
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 21, 2003
+.Dd July 18, 2014
 .Dt PMAP 9
 .Os
 .Sh NAME
@@ -89,7 +89,6 @@ operation.
 .Sh SEE ALSO
 .Xr pmap 9 ,
 .Xr pmap_activate 9 ,
-.Xr pmap_change_wiring 9 ,
 .Xr pmap_clear_modify 9 ,
 .Xr pmap_clear_reference 9 ,
 .Xr pmap_copy 9 ,
@@ -120,6 +119,7 @@ operation.
 .Xr pmap_remove_pages 9 ,
 .Xr pmap_resident_count 9 ,
 .Xr pmap_ts_modified 9 ,
+.Xr pmap_unwire 9 ,
 .Xr pmap_wired_count 9 ,
 .Xr pmap_zero_area 9 ,
 .Xr pmap_zero_idle 9 ,
diff --git a/share/man/man9/pmap_unwire.9 b/share/man/man9/pmap_unwire.9
new file mode 100644
index 0000000..8451383
--- /dev/null
+++ b/share/man/man9/pmap_unwire.9
@@ -0,0 +1,66 @@
+.\"
+.\" Copyright (c) 2014 Alan L. Cox <alc@rice.edu>
+.\" 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
+.\" 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 July 17, 2014
+.Dt PMAP_UNWIRE 9
+.Os
+.Sh NAME
+.Nm pmap_unwire
+.Nd unwire a range of virtual pages
+.Sh SYNOPSIS
+.In sys/param.h
+.In vm/vm.h
+.In vm/pmap.h
+.Ft void
+.Fo pmap_unwire
+.Fa "pmap_t pmap" "vm_offset_t start" "vm_offset_t end"
+.Fc
+.Sh DESCRIPTION
+.Pp
+The function
+.Fn pmap_unwire
+removes the wired attribute from each of the virtual-to-physical page mappings
+within the virtual address range from
+.Fa start
+to
+.Fa end
+of the physical map
+.Fa pmap .
+Every valid mapping within that range is required to have the wired attribute
+set.
+Invalid mappings are ignored, since they cannot have the wired attribute set.
+.Sh NOTES
+Only the function
+.Xr pmap_enter 9
+can be used to set the wired attribute of a virtual-to-physical page mapping.
+.Sh SEE ALSO
+.Xr pmap 9 ,
+.Xr pmap_enter 9 ,
+.Xr pmap_wired_count 9
+.Sh AUTHORS
+This manual page was written by
+.An Alan L. Cox Aq alc@rice.edu .