From owner-svn-src-head@FreeBSD.ORG  Mon Nov 29 06:50:31 2010
Return-Path: <owner-svn-src-head@FreeBSD.ORG>
Delivered-To: svn-src-head@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 1F3DE1065670;
	Mon, 29 Nov 2010 06:50:31 +0000 (UTC)
	(envelope-from cperciva@FreeBSD.org)
Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c])
	by mx1.freebsd.org (Postfix) with ESMTP id 0DEBD8FC12;
	Mon, 29 Nov 2010 06:50:31 +0000 (UTC)
Received: from svn.freebsd.org (localhost [127.0.0.1])
	by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id oAT6oUmO005297;
	Mon, 29 Nov 2010 06:50:30 GMT
	(envelope-from cperciva@svn.freebsd.org)
Received: (from cperciva@localhost)
	by svn.freebsd.org (8.14.3/8.14.3/Submit) id oAT6oUE2005295;
	Mon, 29 Nov 2010 06:50:30 GMT
	(envelope-from cperciva@svn.freebsd.org)
Message-Id: <201011290650.oAT6oUE2005295@svn.freebsd.org>
From: Colin Percival <cperciva@FreeBSD.org>
Date: Mon, 29 Nov 2010 06:50:30 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
	svn-src-head@freebsd.org
X-SVN-Group: head
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Cc: 
Subject: svn commit: r216041 - head/sys/i386/i386
X-BeenThere: svn-src-head@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: SVN commit messages for the src tree for head/-current
	<svn-src-head.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-head>,
	<mailto:svn-src-head-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-head>
List-Post: <mailto:svn-src-head@freebsd.org>
List-Help: <mailto:svn-src-head-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-head>,
	<mailto:svn-src-head-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 29 Nov 2010 06:50:31 -0000

Author: cperciva
Date: Mon Nov 29 06:50:30 2010
New Revision: 216041
URL: http://svn.freebsd.org/changeset/base/216041

Log:
  Fix bug introduced by r194784: Under XEN, the page(s) allocated to dpcpu
  for CPU #0 weren't being properly reserved.  Under VM pressure this would
  cause problems when the dpcpu structures were overwritten by arbitrary
  data; the most common symptom was a panic when netisr attempted to lock a
  mutex.
  
  For some reason the XEN code keeps track of the start of available memory
  in the variables 'first', 'physfree', and 'init_first'; as far as I can
  tell, we always have first == physfree == init_first * PAGE_SIZE.  The
  earlier commit adjusted 'first' (which, on !XEN, is the only variable
  which tracks this value) but not the other two variables.
  
  Exercise for reader: Eliminate two of these three variables.

Modified:
  head/sys/i386/i386/machdep.c

Modified: head/sys/i386/i386/machdep.c
==============================================================================
--- head/sys/i386/i386/machdep.c	Mon Nov 29 05:50:20 2010	(r216040)
+++ head/sys/i386/i386/machdep.c	Mon Nov 29 06:50:30 2010	(r216041)
@@ -2576,6 +2576,8 @@ init386(first)
 		pmap_kenter(pa + KERNBASE, pa);
 	dpcpu_init((void *)(first + KERNBASE), 0);
 	first += DPCPU_SIZE;
+	physfree += DPCPU_SIZE;
+	init_first += DPCPU_SIZE / PAGE_SIZE;
 
 	PCPU_SET(prvspace, pc);
 	PCPU_SET(curthread, &thread0);