From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756188Ab3KVTsT (ORCPT ); Fri, 22 Nov 2013 14:48:19 -0500 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:51503 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755771Ab3KVTsS (ORCPT ); Fri, 22 Nov 2013 14:48:18 -0500 X-Sasl-enc: 873KhqJdbFAE1XUKyAA/WT3j2U9DClREiLHawanL9gzM 1385149695 Date: Fri, 22 Nov 2013 11:48:14 -0800 From: Greg KH To: Vivek Goyal Cc: "Eric W. Biederman" , linux-kernel@vger.kernel.org, kexec@lists.infradead.org, hpa@zytor.com, mjg59@srcf.ucam.org Subject: Re: [PATCH 0/6] kexec: A new system call to allow in kernel loading Message-ID: <20131122194814.GC25105@kroah.com> References: <1384969851-7251-1-git-send-email-vgoyal@redhat.com> <8761rl73s7.fsf@xmission.com> <20131122015518.GA31921@redhat.com> <87txf4y304.fsf@xmission.com> <20131122141945.GE4046@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131122141945.GE4046@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 22, 2013 at 09:19:46AM -0500, Vivek Goyal wrote: > On Fri, Nov 22, 2013 at 05:34:03AM -0800, Eric W. Biederman wrote: > > [..] > > > Why ELF case is so interesting. I have not use kexec to boot ELF > > > images in years and have not seen others using it too. In fact bzImage > > > seems to be the most common kernel image format for x86, most of the distros > > > ship and use. > > > > ELF is interesting because it is the minimal file format that does > > everything you need. So especially for a proof of concept ELF needs to > > come first. There is an extra virtual address field in the ELF segment > > header but otherwise ELF does not have any unnecessary fields. > > > > ELF is interesting because it is the native kernel file format on all > > architectures linux supports including x86. > > > > ELF is interesting because producing an ELF image in practice requires > > a trivial amount of tooling so it is a good general purpose format to > > support. > > Ok. I will have a look at ELF loader too. I was hoping to keep only one > loader in initial patch. But looks like that's not acceptable. I totally disagree. I think what you have done now is fine. If it works for bzImage, it's a good sense that this is usable as-is. And, if someone else cares about signed elf images, hey, let them implement the loader for it :) Either way, the syscall interface wouldn't change, which is the important thing to get right, so you should be fine for now. thanks, greg k-h