Re: [Etherboot-developers] Porting question

[<ebi...@ln...>]

Yannis Mitsos <gm...@te...> writes:

> Hi all,
> 
> I will try to strip-down the etherboot source code in order to make it work in
> an evaluation board of a RISC processor.

Etherboot needs to be stripped down?

It should be possible to take the 5.1.x source and to do a real port.

The tricky bits I see are the self decompresser, which is a screen
Some support code like setjmp and longjmp.
And whatever you need for platform support.
Any big endian issues that may come with your RISC processor.
Any firmware/hardware interfacing issues you may have.

Etherboot is already running on the Itanium so 64bit issues, and
alignment issues are already sorted out.  Though not all of the
drivers have been tested.

>  The GNU tools that I have produce coff
> executable file format. From a first look inside the etherboot code I noticed
> that you support both ELF and a.out.

For building etherboot it should be pretty much of a non-issue.
 
> Since you do not use the bfd library, do you have estimation how difficult would
> be to modify the bootloader accordingly?

It would not be hard.  Maybe a days work including debugging.

The challenge with COFF and a.out there are several variants and you
would need to track down which variant you are using.  For a format to
loader over the network COFF bootloader format ELF is nicer as it is a
stable format. 

I would recommend writing a mkelf for your platform that packages
kernels ramdisks and everything together, instead of adding a COFF
handler.  But it is your port...

Eric