[syslinux] Booting Embedded x86 - Looking for Information

[Graeme Russ]

On Mon, Feb 1, 2010 at 2:48 PM, H. Peter Anvin <hpa at zytor.com> wrote:
> On 01/31/2010 05:51 PM, Graeme Russ wrote:
>>
>> The problem with going the BIOS route is that I am having extreme
>> difficulty debugging the boot process. I can't even guarantee that
>> the INT calls I am trapping are indeed issued by code in bzImage (let
>> alone the right place in bzImage)
>>
>
> If you can trap INT calls you can just look at the stack contents at
> that point.
>

Hmm, true - But not trivial. My only output is raw writes to the
serial port using outb.

And how does the bzImage boot process work in a 100% disk less
environment? The kernel image I have will be loaded into NOR Flash
and copied directly into RAM by the bootloader. I assume the whole
Boot Sector bootstrap is skipped in this scenario?

I assume this would be the same scenario as something like Loadlin/
GRUB. I have looked at the Loadlin source but must admit I was
completely dumbfounded by it. Haven't looked at GRUB yet, but by the
sounds of it, they don't do things 'the right way'(tm)

Should I look at putting some outb's in arch/x86/boot/compressed/head_32.S
i.e. is this the earliest point that I can check that control has
passed into Linux kernel source or is there an even earlier point?

And lastly, is there a more appropriate mailing list for me to ask
these questions on?

Regards,

Graeme