Re: [PATCH v3 1/3] Documentation: arm: add UEFI support documentation

[Matthew Garrett <mjg59@srcf.ucam.org>]

On Wed, Dec 04, 2013 at 03:06:47PM -0600, Matt Sealey wrote:

> there's no guarantee that the kernel hasn't been decompressed over 
> some important UEFI feature or some memory hasn't been trashed. You 
> can't make that guarantee because by entering the plain zImage, you 
> forfeited that information.

The stub is responsible for ensuring that the compressed kernel is 
loaded at a suitable address. Take a look at efi_relocate_kernel().

> Most of the guessing is ideally not required to be a guess at all, the
> restrictions are purely to deal with the lack of trust for the
> bootloader environment. Why can't we trust UEFI? Or at least hold it
> to a higher standard. If someone ships a broken UEFI, they screw a
> feature or have a horrible bug and ship it, laud the fact Linux
> doesn't boot on it and the fact that it's their fault - over their
> head. It actually works these days, Linux actually has "market share,"
> companies really go out of their way to rescue their "image" and
> resolve the situation when someone blogs about a serious UEFI bug on
> their $1300 laptops, or even $300 tablets.

Yeah, that hasn't actually worked out too well for us.

-- 
Matthew Garrett | mjg59@srcf.ucam.org