From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760172AbZB0VUB (ORCPT ); Fri, 27 Feb 2009 16:20:01 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756777AbZB0VTx (ORCPT ); Fri, 27 Feb 2009 16:19:53 -0500 Received: from gw.goop.org ([64.81.55.164]:57524 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753576AbZB0VTw (ORCPT ); Fri, 27 Feb 2009 16:19:52 -0500 Message-ID: <49A858E8.3070707@goop.org> Date: Fri, 27 Feb 2009 13:19:36 -0800 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.19 (X11/20090105) MIME-Version: 1.0 To: "H. Peter Anvin" CC: Yinghai Lu , Ingo Molnar , the arch/x86 maintainers , Linux Kernel Mailing List Subject: Re: [PATCH RFC] x86: add brk allocation for very, very early allocations References: <49A829CE.9020509@goop.org> <49A84C5A.3020304@kernel.org> <49A855B7.4090204@zytor.com> In-Reply-To: <49A855B7.4090204@zytor.com> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org H. Peter Anvin wrote: > That would make sense. init_memory_mapping() needs to know what not to > step on, and that would include the brk at this stage. For 64-bit mode, > Xen is the only user of !PSE, and so may be particularly vulnerable to > this issue (because of massively larger direct mapping tables.) > Yep. > This reminds me... is your intent that the BRK is permanent (unless > explicitly freed on a page by page basis) or part of the init memory > that is flushed? > Permanent. I'm using it to allocate things which are the moral equivalent of the kernel pagetables. J