Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751715AbWEaRUI (ORCPT ); Wed, 31 May 2006 13:20:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751736AbWEaRUH (ORCPT ); Wed, 31 May 2006 13:20:07 -0400 Received: from e1.ny.us.ibm.com ([32.97.182.141]:21478 "EHLO e1.ny.us.ibm.com") by vger.kernel.org with ESMTP id S1751715AbWEaRUG (ORCPT ); Wed, 31 May 2006 13:20:06 -0400 Date: Wed, 31 May 2006 13:19:34 -0400 From: Vivek Goyal To: "Magnus Damm" Cc: "Eric W. Biederman" , "Magnus Damm" , "Andrew Morton" , fastboot@lists.osdl.org Subject: Re: [Fastboot] [PATCH 03/03] kexec: Avoid overwriting the current pgd (V2, x86_64) Message-ID: <20060531171934.GB8475@in.ibm.com> Reply-To: vgoyal@in.ibm.com References: <20060524044232.14219.68240.sendpatchset@cherry.local> <20060524044247.14219.13579.sendpatchset@cherry.local> <1148545616.5793.180.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1428 Lines: 37 On Mon, May 29, 2006 at 05:40:32PM +0900, Magnus Damm wrote: > > >However while I agree that you need to do this in assembly for > >control I disagree that this code should be part of the > >relocate_new_kernel function. > > > >Please move the code that uses page_table_a to a separate function, > >that when it is done jumps to the control_code page. Then you can > >map this page both virtually and physically with a statically > >allocated page table built a compile time. > > This function, you write "uses page_table_a". Do you mean that the > function allocates it? Or fills it in? Or maybe switches to it? Please > clarify! > > >This is a little simpler as you don't need to build this first > >page table dynamically and a little clearer as you aren't trying to > >get the control code page to serve two different functions. > > But doesn't a static set of pages used for page_table_a just mean that > you are wasting valuable unswappable kernel memory? In your implementation, is control page swappable? >Also, how can you > be sure that the static pages are in a DMA-safe address range? > Why would kernel setup DMA on statically allocated pages? Thanks Vivek - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/