Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758321Ab3HMTCL (ORCPT ); Tue, 13 Aug 2013 15:02:11 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:58271 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757259Ab3HMTCJ (ORCPT ); Tue, 13 Aug 2013 15:02:09 -0400 Message-ID: <1376420525.3467.70.camel@dabdike.int.hansenpartnership.com> Subject: Re: RFC: default CONFIG_EFI_STUB=y From: James Bottomley To: "H. Peter Anvin" Cc: Ingo Molnar , Thomas Gleixner , Linus Torvalds , "linux-efi@vger.kernel.org" , Linux Kernel Mailing List , Matt Fleming Date: Tue, 13 Aug 2013 12:02:05 -0700 In-Reply-To: <520A8054.1030108@zytor.com> 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> <520A8054.1030108@zytor.com> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.8.3 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1154 Lines: 31 On Tue, 2013-08-13 at 11:52 -0700, H. Peter Anvin wrote: > On 08/13/2013 11:43 AM, 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. > > We can boot with a bootloader in "skip stub" mode; no runtime services > yet. So the bootloader has to do the 64->32 transition? > We are working on making it possible to boot via a EFI stub in > assisted mode (still needing a bootloader, but with the boot stub in the > kernel.) > > Runtime services will be the last piece, obviously, but even that looks > reasonably doable. So why not start with the working case (default to EFI on 64 bit) and add in the mostly non-working case (default to EFI on 32 bit) when it actually mostly works? James -- 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/