Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758599Ab3HMTHF (ORCPT ); Tue, 13 Aug 2013 15:07:05 -0400 Received: from terminus.zytor.com ([198.137.202.10]:35829 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756677Ab3HMTHC (ORCPT ); Tue, 13 Aug 2013 15:07:02 -0400 Message-ID: <520A83B2.4010003@zytor.com> Date: Tue, 13 Aug 2013 12:06:26 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: James Bottomley CC: 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 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> <1376420525.3467.70.camel@dabdike.int.hansenpartnership.com> In-Reply-To: <1376420525.3467.70.camel@dabdike.int.hansenpartnership.com> X-Enigmail-Version: 1.5.2 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1368 Lines: 37 On 08/13/2013 12:02 PM, James Bottomley wrote: > 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? > Currently, yes. >> 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? We can do that, but I really hate making gratuitous differences between 32 and 64 bits... we have too many of those already. -hpa -- 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/