From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967977Ab3HIPj2 (ORCPT ); Fri, 9 Aug 2013 11:39:28 -0400 Received: from terminus.zytor.com ([198.137.202.10]:49055 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965056Ab3HIPj0 (ORCPT ); Fri, 9 Aug 2013 11:39:26 -0400 Message-ID: <52050D03.4030805@zytor.com> Date: Fri, 09 Aug 2013 08:38:43 -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> In-Reply-To: <1376062345.2087.16.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 On 08/09/2013 08:32 AM, James Bottomley wrote: > On Fri, 2013-08-09 at 08:23 -0700, H. Peter Anvin wrote: >> I would like to change the defaults for CONFIG_EFI and CONFIG_EFI_STUB >> to y. There is little reason to omit this since EFI now is a >> significant percentage of all systems. > > You didn't actually attach the patch, but I presume this is for 64 bit > compiles on x86 only? We still have significant problems getting 64 bit > EFI to interact with 32 bit kernels, so I don't believe we should enable > CONFIG_EFI globally for all of x86. > Well, it doesn't *solve* the problem with cross-mode, but it should work as-is for EFI32->32-bit kernel and EFI64->64-bit kernel. For the cross-mode kernels they will simply not do anything. Either way, nothing bad should come from it. The worst thing that will happen is that the kernel says "I don't have any EFI that I recognize." Cross-mode support will always require a secondary bootloader (since as far as I know there is no concept of "fat binaries" for EFI), but Matt Fleming is working on genuine cross-mode support for both the boot stub and (eventually) run time support. -hpa