Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422883AbWJFTDY (ORCPT ); Fri, 6 Oct 2006 15:03:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422884AbWJFTDY (ORCPT ); Fri, 6 Oct 2006 15:03:24 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:49589 "EHLO ebiederm.dsl.xmission.com") by vger.kernel.org with ESMTP id S1422883AbWJFTDW (ORCPT ); Fri, 6 Oct 2006 15:03:22 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: vgoyal@in.ibm.com Cc: Andrew Morton , linux kernel mailing list , Reloc Kernel List , ak@suse.de, horms@verge.net.au, lace@jankratochvil.net, hpa@zytor.com, magnus.damm@gmail.com, lwang@redhat.com, dzickus@redhat.com, maneesh@in.ibm.com Subject: Re: [PATCH 12/12] i386 boot: Add an ELF header to bzImage References: <20061003170032.GA30036@in.ibm.com> <20061003172511.GL3164@in.ibm.com> <20061003201340.afa7bfce.akpm@osdl.org> <20061004214403.e7d9f23b.akpm@osdl.org> <20061004233137.97451b73.akpm@osdl.org> <20061005235909.75178c09.akpm@osdl.org> <20061006183846.GF19756@in.ibm.com> Date: Fri, 06 Oct 2006 13:01:28 -0600 In-Reply-To: <20061006183846.GF19756@in.ibm.com> (Vivek Goyal's message of "Fri, 6 Oct 2006 14:38:46 -0400") Message-ID: User-Agent: Gnus/5.110004 (No Gnus v0.4) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2383 Lines: 73 Vivek Goyal writes: > Hi Eric, > > I have added cld in the regenerated patch below. > > Also one more minor nit. stosb relies on being %es set properly. By the > time control reaches loader_ok, i could not find %es being set explicitly > hence I am assuming we are relying on bootloader to set it up for us. No my bad. I was thinking it was %ds, like everything else. > Maybe we can be little more paranoid and setup the %es before stosb. I > have done this change too in the attached patch. Pleaese have a look. > I know little about assembly code. Looks good to me. Signed-off-by: Eric W. Biederman > In the lazy programmer school of fixes. > > I haven't really tested this in any configuration. > But reading video.S it does use variable in the bootsector. > It does seem to initialize the variables before use. > But obviously something is missed. > > By zeroing the uninteresting parts of the bootsector just after we > have determined we are loaded ok. We should ensure we are > always in a known state the entire time. > > Andrew if I am right about the cause of your video not working > when you set an enhanced video mode this should fix your boot > problem. > > Singed-off-by: Eric Biederman > > Signed-off-by: Vivek Goyal > --- > > arch/i386/boot/setup.S | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff -puN arch/i386/boot/setup.S~i386-set-bootset-to-zero-fix > arch/i386/boot/setup.S > --- linux-2.6.18-git17/arch/i386/boot/setup.S~i386-set-bootset-to-zero-fix > 2006-10-06 12:42:19.000000000 -0400 > +++ linux-2.6.18-git17-root/arch/i386/boot/setup.S 2006-10-06 12:49:37.000000000 > -0400 > @@ -287,6 +287,17 @@ good_sig: > loader_panic_mess: .string "Wrong loader, giving up..." > > loader_ok: > +# Zero initialize the variables we keep in the bootsector > + movw %cs, %ax # aka SETUPSEG > + subw $DELTA_INITSEG, %ax # aka INITSEG > + movw %ax, %es > + xorw %di, %di > + xorb %al, %al > + movw $497, %cx > + cld > + rep > + stosb > + > # Get memory size (extended mem, kB) > > xorl %eax, %eax > _ - 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/