From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753203Ab3HOFPg (ORCPT ); Thu, 15 Aug 2013 01:15:36 -0400 Received: from cavan.codon.org.uk ([93.93.128.6]:48058 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751174Ab3HOFPe (ORCPT ); Thu, 15 Aug 2013 01:15:34 -0400 Date: Thu, 15 Aug 2013 06:15:09 +0100 From: Matthew Garrett To: James Bottomley Cc: "H. Peter Anvin" , Ingo Molnar , Thomas Gleixner , Linus Torvalds , "linux-efi@vger.kernel.org" , Linux Kernel Mailing List , Matt Fleming Subject: Re: RFC: default CONFIG_EFI_STUB=y Message-ID: <20130815051509.GB1933@srcf.ucam.org> References: <52050985.9070107@zytor.com> <1376062345.2087.16.camel@dabdike.int.hansenpartnership.com> <52050D03.4030805@zytor.com> <520A7B48.3020304@zytor.com> <1376419410.3467.67.camel@dabdike.int.hansenpartnership.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1376419410.3467.67.camel@dabdike.int.hansenpartnership.com> User-Agent: Mutt/1.5.20 (2009-06-14) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: mjg59@cavan.codon.org.uk X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 13, 2013 at 11:43:30AM -0700, James Bottomley wrote: > Can we actually boot a 32 bit kernel on an EFI64 system? The last time > I tried on my Secure Boot SDV it wouldn't work; the problem is getting > someting in the transfer of control path to boot the processor back to > 32 bit mode. In theory, as long as you jump to the 32-bit entry point having already set the cpu to that mode. The linux command in grub2 ought to do that. -- Matthew Garrett | mjg59@srcf.ucam.org