Re: [ECOS] Linux over RedBoot

[Gary Thomas <gthomas at redhat dot com>]

On 12-Jul-2001 Fabrice Gautier wrote:
> 
> On Thu, 12 Jul 2001 06:11:03 -0600 (MDT)
> Gary Thomas <gthomas@redhat.com> wrote:
> 
>> 
>> On 12-Jul-2001 Jesper Skov wrote:
>> >>>>>> "Fabrice" == Fabrice Gautier <gautier@email.enst.fr> writes:
>> > 
>> > Fabrice> Yes, one (for now) Does your linux kernel use Redboots
>> > Fabrice> Virtual Vectors and stuff or is Redboot just wiped from
>> > Fabrice> memory once the kernel is launched?
>> > 
>> > RedBoot is wiped on all platforms. Linux runs directly on the
>> > hardware.
>> > 
>> > However, on SH platforms RedBoot can still be used to debug the Linux
>> > kernel (via serial only though).
>> 
>> This is purely a matter of *cooperation* - if the Linux kernel is willing
>> to cooperate with the debug agent [RedBoot], as with the SH version, then
>> many things are possible.  In most cases, Linux considers itself omnipotent
>> and RedBoot is out of the picture the instant you say 'exec'.
> 
> How come that the SH port of the linux kernel is cooperating with
> Redboot? Is it because the ones who initiated the SH port of the linux
> kernel had choosen redboot as their boot loader? Or has this been added
> afterward?

Hard to say, but the fact that Red Hat has done a lot of work on the Linux/SH
port early on probably helped.

> 
> Do you have any ideas of how dificult it would be to have this same
> cooperation for other linux kernel ports, eg i386 or arm ?
> 

I don't know about the x86, but for the ARM it's not that big a deal,
probably measured in man days instead of weeks or months.

The real problem with such efforts is not to make them available but
rather to get them accepted into the mainline Linux sources.

Note: we (Red Hat) wouldn't have the time or resources to do this 
for any particular platform unless that effort was driven by a customer
contract.