IDEA: Linux kernel and pcbios compatibility...

[Joshua Wise]

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> > 1) First stage assembly loader sets up serial and DRAM.
> > 2) First stage loader probes RAM, and sets up tagged list.
> Roughly what LinuxBIOS does.
Right, ok. You can find my code in arch/arm/boot/bootldr-xscale.S.

> Somehow I could write a subapp that would make linux look like a normal
> pcbios, but I can be surprised.
The subapp does run in kernelland, so you can do pretty much anything you 
want. (That's how we can boot another kernel from within LAB land.)

> > LAB for ARM's zImage is currently ~509kbytes for those who care. (We must
> > keep it below 512KB.)
> Ouch!  My x86 images are below that, at least before decompression.
Whine whine whine. :) This is including lots of cruft.

> I probably will.  Doing that stuff inside the kernel does not really feel
> proper to me.   I already have an x86 kernel that can load another kernel
> from user space.  I'm just trying to find a good long term architecture
> for using the kernel as a bootloader.

The design decision was made to do this all from kernelland when LAB started 
off in 2.4. 2.4 did not have initramfs, so that was not even an option. The 
decision stuck as I upported to 2.6.

Yes, you have TKM for x86, but that's not very portable or readable. armboot 
is very readable (and portable) code, despite its name.

Regarding longevity, LAB will be supported for the next forever by 
handhelds.org.

> Eric
/joshua

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Joshua Wise | www.joshuawise.com
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In memoriam | Whiskers the hamster, 2001 - Dec 15, 2003
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