gptboot rewrite, bootonce, etc.

[John Baldwin]

On Friday, September 17, 2010 7:45:42 pm Pawel Jakub Dawidek wrote:
> - Split code shared by almost any boot loader into separate files and
>   clean up most layering violations:

I like this in general.  I worry that the space constraints for boot2 will 
prevent it from using this though as it depends on inlining almost everything 
to fit into its allotted space.  At least it can use the rbx.h header.

> - Introduce three new GPT attributes:
> 
> 	bootme - this is bootable partition
> 	bootonce - try to boot from this partition only once
> 	bootfailed - we failed to boot from this partition

The 'bootme' attribute alone is a boon.  One of the problems with EFI was 
figuring out a sane way to choose the root partition.  EFI on ia64 currently 
uses the 'first partition wins' strategy, and this will be a definite 
improvement.  To that end this should also help with EFI on x86.

-- 
John Baldwin