Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751331AbWHNTnt (ORCPT ); Mon, 14 Aug 2006 15:43:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751426AbWHNTnt (ORCPT ); Mon, 14 Aug 2006 15:43:49 -0400 Received: from e3.ny.us.ibm.com ([32.97.182.143]:33474 "EHLO e3.ny.us.ibm.com") by vger.kernel.org with ESMTP id S1751331AbWHNTns (ORCPT ); Mon, 14 Aug 2006 15:43:48 -0400 Date: Mon, 14 Aug 2006 15:42:53 -0400 From: Vivek Goyal To: "H. Peter Anvin" Cc: "Eric W. Biederman" , Don Zickus , fastboot@osdl.org, Horms , Jan Kratochvil , Magnus Damm , linux-kernel@vger.kernel.org Subject: Re: [Fastboot] [CFT] ELF Relocatable x86 and x86_64 bzImages Message-ID: <20060814194252.GC2519@in.ibm.com> Reply-To: vgoyal@in.ibm.com References: <20060809200642.GD7861@redhat.com> <20060810131323.GB9888@in.ibm.com> <20060810181825.GD14732@in.ibm.com> <20060814165150.GA2519@in.ibm.com> <44E0AD1D.1040408@zytor.com> <20060814181118.GB2519@in.ibm.com> <44E0CFD0.3060506@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <44E0CFD0.3060506@zytor.com> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2244 Lines: 51 On Mon, Aug 14, 2006 at 12:32:32PM -0700, H. Peter Anvin wrote: > Vivek Goyal wrote: > >On Mon, Aug 14, 2006 at 10:04:29AM -0700, H. Peter Anvin wrote: > >>Vivek Goyal wrote: > >>>On Thu, Aug 10, 2006 at 02:09:58PM -0600, Eric W. Biederman wrote: > >>>>>I just reserved memory at non 2MB aligned location 65MB@15MB so that > >>>>>kernel is loaded at 16MB and other smaller segments below the > >>>>>compressed > >>>>>image, then I can successfully booted into the kdump kernel. > >>>>:) > >>>> > >>>>>So basically kexec on panic path seems to be clean except stomping > >>>>>issue. > >>>>>May be bzImage program header should reflect right "MemSize" which > >>>>>takes into account extra memory space calculations. > >>>>Yes. That sounds like the right thing to do. > >>>> > >>>>I remember trying to compute a good memsize when I created the bzImage > >>>>header but it is completely possible I missed some part of the > >>>>calculation or assumed that the kernels .bss section would always be > >>>>larger than what I needed for decompression. > >>>> > >>Could someone please describe the intended semantics of this MemSize > >>header, *and* its intended usage? > >> > > > >Now and ELF header(attached to bzImage) is being used to describe > >the kernel executable. One program header of PT_LOAD type is being > >created. The "p_filesz" field of program header is basically > >describing the vmlinux file size and "p_memsz" is giving how > >much memory will be consumed by kernel image at load time. > > > >Ideally "p_memsz" should be "p_memsz" summation of all the program > >headers of vmlinux file but I guess in this case we are stretching the > >ELF specification a little bit and also taking into the account the > >additional memory which will be used by decompressor and decompression > >logic by the time execution is transferred to the actual kernel. > > > > What about once the kernel is booted? > Sorry did not understand the question. Few more lines will help. 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/