[PULL][Trusty] arm64: Add EFI stub support

[Luis Henriques]

On Fri, Apr 10, 2015 at 03:11:49PM -0600, Dann Frazier wrote:
> Ubuntu currently provides arm64-efi cloud images, but the 14.04 LTS
> images aren't actually bootable due to the lack of EFI stub support.
> This means there is currently no Ubuntu LTS option for users deploying
> guests on ARM64-based clouds, and that's just not cool, man.
> 
>   git://kernel.ubuntu.com/dannf/trusty-xgene.git@arm64-efi
> 

I believe that "@arm64-efi" means the arm64-efi branch (and that the
arm64 EFI are the 21 patches on top of ca13cad7da7c).

> Prebuilt packages are available in ppa:dannf/arm64efi.
> 
> This is based on an earlier backport from Ming Lei, but modified to
> minimize the changes (read: regression risk) to x86. There are no
> changes under arch/x86, and all of the arch-indep changes are adding
> new interfaces that x86 doesn't use.
> 
> With these changes, the trusty cloud images are now bootable. However,
> they do not have automatic console detection (you have to manually add
> console=ttyAMA0), and do not yet have an EFI RTC driver - that work is
> up next.
> 
> I've regression tested on X-Gene/u-boot and on the QEMU arm64 virt
> model booted w/ -kernel to make sure it doesn't break non-EFI systems.
> Thanks to Rod Smith for regression testing on an EFI-mode mac and
> within virtualbox to confirm I didn't break EFI mode on x86.
> 
> -- 
> kernel-team mailing list
> kernel-team at lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team

I've just started looking at this patchset and I have a few questions.
The 1st one is related with the new configuration options
(CONFIG_EFI_PARAMS_FROM_FDT, CONFIG_GENERIC_EARLY_IOREMAP and
CONFIG_LIBFDT).  I suspect you would want these to be set to 'y' for
arm64; but what about other arches?  Should they be set to 'n'?
Anyway, maybe you could include an extra "UBUNTU: [Config]" patch in
this patchset?

Also, I'm curious about the "cherry picked from..." line, instead of the
more standard "cherry picked from commit...".  You should use '-x'
when doing the cherry-pick.  Also, some of these commits should
actually be replaced by a "backported from commit..." as they are not
clean cherry-picks but backports instead (e.g. the backport of
3c7f255039a2 "arm64: efi: add EFI stub").

Cheers,
--
Luís