From owner-cvs-src-old@FreeBSD.ORG  Mon Oct 13 18:42:32 2008
Return-Path: <owner-cvs-src-old@FreeBSD.ORG>
Delivered-To: cvs-src-old@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id C66E61065747
	for <cvs-src-old@freebsd.org>; Mon, 13 Oct 2008 18:42:32 +0000 (UTC)
	(envelope-from raj@FreeBSD.org)
Received: from repoman.freebsd.org (repoman.freebsd.org
	[IPv6:2001:4f8:fff6::29])
	by mx1.freebsd.org (Postfix) with ESMTP id B2BAD8FC08
	for <cvs-src-old@freebsd.org>; Mon, 13 Oct 2008 18:42:32 +0000 (UTC)
	(envelope-from raj@FreeBSD.org)
Received: from repoman.freebsd.org (localhost [127.0.0.1])
	by repoman.freebsd.org (8.14.3/8.14.3) with ESMTP id m9DIgWXg055246
	for <cvs-src-old@freebsd.org>; Mon, 13 Oct 2008 18:42:32 GMT
	(envelope-from raj@repoman.freebsd.org)
Received: (from svn2cvs@localhost)
	by repoman.freebsd.org (8.14.3/8.14.3/Submit) id m9DIgWwc055245
	for cvs-src-old@freebsd.org; Mon, 13 Oct 2008 18:42:32 GMT
	(envelope-from raj@repoman.freebsd.org)
Message-Id: <200810131842.m9DIgWwc055245@repoman.freebsd.org>
X-Authentication-Warning: repoman.freebsd.org: svn2cvs set sender to
	raj@repoman.freebsd.org using -f
From: Rafal Jaworowski <raj@FreeBSD.org>
Date: Mon, 13 Oct 2008 18:42:25 +0000 (UTC)
To: cvs-src-old@freebsd.org
X-FreeBSD-CVS-Branch: HEAD
Subject: cvs commit: src/sys/arm/arm pmap.c
X-BeenThere: cvs-src-old@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: **OBSOLETE** CVS commit messages for the src tree
	<cvs-src-old.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-src-old>,
	<mailto:cvs-src-old-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/cvs-src-old>
List-Post: <mailto:cvs-src-old@freebsd.org>
List-Help: <mailto:cvs-src-old-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-src-old>,
	<mailto:cvs-src-old-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 13 Oct 2008 18:42:32 -0000

raj         2008-10-13 18:42:25 UTC

  FreeBSD src repository

  Modified files:
    sys/arm/arm          pmap.c 
  Log:
  SVN rev 183836 on 2008-10-13 18:42:25Z by raj
  
  Do not use cached page for temporary mapping in pmap_zero_page_generic()
  
  The physical page which we clear is accessed via additional temp kernel
  mapping for the period of zeroing operation. However in systems with virtual
  d-cache (most ARMs) when write-allocate feature is enabled, we can have
  modified but unflushed content pertaining to this physical page still in the
  d-cache due to its primary (pre-existing) mapping. In such scenario that
  cached content upon flush is likely to overwrite [portions of] the physical
  page we want to zero here..
  
  This is a general problem with multiple virtual mappings covering the same
  physical page with write-allocate and virtual d-cache: there is inherent
  potential for corruptions of this kind, which are not easily resolved; it is
  best policy that such multiple mappings be not allowed.
  
  Obtained from:  Marvell, Semihalf
  
  Revision  Changes    Path
  1.103     +8 -10     src/sys/arm/arm/pmap.c