From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754600Ab3JKUrm (ORCPT ); Fri, 11 Oct 2013 16:47:42 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:36113 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752217Ab3JKUrj (ORCPT ); Fri, 11 Oct 2013 16:47:39 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Matthew Garrett Cc: Richard Weinberger , Richard Weinberger , Vivek Goyal , Daniel Kiper , hbabu@us.ibm.com, "H. Peter Anvin" , Kees Cook , kexec@lists.infradead.org, LKML , david.vrabel@citrix.com, jbeulich@suse.com, keir@xen.org, xen-devel@lists.xen.org References: <20131011153727.GA30181@srcf.ucam.org> <20131011154450.GB2772@redhat.com> <20131011154805.GB30181@srcf.ucam.org> <20131011163933.GA31941@srcf.ucam.org> <20131011164400.GA32133@srcf.ucam.org> <52582B97.2060907@nod.at> <20131011165542.GB32133@srcf.ucam.org> <52582E7D.8080909@nod.at> <20131011170138.GA32619@srcf.ucam.org> Date: Fri, 11 Oct 2013 13:44:19 -0700 In-Reply-To: <20131011170138.GA32619@srcf.ucam.org> (Matthew Garrett's message of "Fri, 11 Oct 2013 18:01:39 +0100") Message-ID: <87ob6va670.fsf@tw-ebiederman.twitter.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-AID: U2FsdGVkX18XOgao6hM8rTqYJz8KjnTo6OsOIQ4n1pI= X-SA-Exim-Connect-IP: 98.207.154.105 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.7 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -3.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0003] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa06 1397; Body=1 Fuz1=1 Fuz2=1] X-Spam-DCC: XMission; sa06 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Matthew Garrett X-Spam-Relay-Country: Subject: Re: kexec: Clearing registers just before jumping into purgatory X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Wed, 14 Nov 2012 14:26:46 -0700) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Matthew Garrett writes: > On Fri, Oct 11, 2013 at 06:59:41PM +0200, Richard Weinberger wrote: >> Am 11.10.2013 18:55, schrieb Matthew Garrett: >> > On Fri, Oct 11, 2013 at 06:47:19PM +0200, Richard Weinberger wrote: >> > >> >> But you still need a magic tool which create you this list. >> > >> > I just read /proc/kallsyms. I'm really not doing anything complicated. >> > >> >> If you have a tool which takes two kernel images and create such >> >> a delta, fine. >> > >> > Isn't that ksplice? >> >> So, you have a variant of ksplice which is able to kexec? > > No, I manually look up some addresses from /proc/kallsyms and then > modify them in the second kernel. An interesting approach I think most of the rest of us would have just built a module, or rebuilt our kernels. Now if this is a backwards argument to remove that silly code path it totally fails because now we know the code has not bit-rotted and that there are active users. If you are still pushing the signed-boot agenda I eagerly await your patches to make all of this work in a sensible way with signed binaries. Eric