Re: RFC: default CONFIG_EFI_STUB=y

["H. Peter Anvin" <hpa@zytor.com>]

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