From: "H. Peter Anvin" Subject: Re: RFC: default CONFIG_EFI_STUB=y Date: Tue, 13 Aug 2013 11:30:32 -0700 Message-ID: <520A7B48.3020304@zytor.com> References: <52050985.9070107@zytor.com> <1376062345.2087.16.camel@dabdike.int.hansenpartnership.com> <52050D03.4030805@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <52050D03.4030805-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: James Bottomley Cc: Ingo Molnar , Thomas Gleixner , Linus Torvalds , "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Linux Kernel Mailing List , Matt Fleming List-Id: linux-efi@vger.kernel.org On 08/09/2013 08:38 AM, H. Peter Anvin wrote: > 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. > James, does this address your concerns? -hpa