From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750764AbVIZKqO (ORCPT ); Mon, 26 Sep 2005 06:46:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750770AbVIZKqO (ORCPT ); Mon, 26 Sep 2005 06:46:14 -0400 Received: from grendel.sisk.pl ([217.67.200.140]:57776 "HELO grendel.sisk.pl") by vger.kernel.org with SMTP id S1750764AbVIZKqO (ORCPT ); Mon, 26 Sep 2005 06:46:14 -0400 From: "Rafael J. Wysocki" To: Pavel Machek Subject: Re: [PATCH][Fix] Prevent swsusp from corrupting page translation tables during resume on x86-64 Date: Mon, 26 Sep 2005 12:46:18 +0200 User-Agent: KMail/1.8.2 Cc: kernel list , Andi Kleen References: <200509241936.12214.rjw@sisk.pl> <20050925220738.GF2775@elf.ucw.cz> In-Reply-To: <20050925220738.GF2775@elf.ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200509261246.19085.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Monday, 26 of September 2005 00:07, Pavel Machek wrote: > Hi! > > > The following patch fixes Bug #4959. It creates temporary page translation > > tables located in the page frames that are not overwritten by swsusp while copying > > the image. > > > > The temporary page translation tables are generally based on the existing ones > > with the exception that the mappings using 4KB pages are replaced with the > > equivalent mappings that use 2MB pages only. The temporary page tables are > > only used for copying the image. > > Would not it be simpler to create them from scratch? mm/init.c has > some handy functions, they should be applicable. [init_memory_mapping, > phys_pud_init]. Perhaps even initialize only simple direct mapping, > and place virt_to_phys() at strategic places? Perhaps, but the outcome would be very much the same. The problem is to what extent we can use the existing constructs, because I'd rather like to avoid the situation in which any future changes to the initialization code would have to be replicated in the swsusp code. I'll have a look at that, but I'm not sure. Also I don't really know what the Andi's preferences are with this respect. Anyway do you think that creating temporary page tables at the beginning of swsusp_arch_resume() is a good idea? If not, where do you think should they be created? Greetings, Rafael