[coreboot] Request for Help/Information - Booting Linux Kernel(Embedded x86)

Myles Watson mylesgw at gmail.com
Fri Jan 29 00:50:25 CET 2010

Disclaimer: I could easily have botched the answers to your questions.
Maybe someone will know the best way to load Linux from Uboot, but I don't.

I've found that people more readily correct misinformation than volunteer
information, so I hope this gets you somewhere :)

> I suppose I have a couple of questions to start of with that I hope
> someone here can answer:

The best answer to your questions is probably something like: 
It depends on your boot loader.

Coreboot initializes the hardware and then loads its payload.  That payload
could be a BIOS (SeaBIOS), a boot loader (FILO, Grub, Linux-As-Bootloader,
elfboot...), a Linux kernel, memtest, coreinfo, ...

This gives you the flexibility to load the kernel over the network, from a

You can check out buildrom to see how some payloads are built.  It gets out
of date quickly, but it is faster than starting from scratch.
>   0) Is there a good repository of information regarding embedded Linux
>      in the x86 (not PC!!!!) architecture
I would choose a boot loader and go from there.

>   1) The boot-loader (both U-Boot and coreboot) put the x86 staight into
>      Protected Mode - Does the CPU need to be put back into Real Mode
>      before entering the Linux Kernel (in order to allow the Kernel to put
>      the CPU into Protected Mode)
Our terminology is conflicting here, since we don't call Coreboot a
boot-loader, but hopefully what I'm saying still makes sense.  The
boot-loader will do this if it needs to.

>   2) Which Kernel image should I use (vmlinux, vmlinux.bin, bzImage etc)
>   3) Can I copy the compiled Kernel image directly into RAM simply perform
>      a 'Jump' into it
>   5) Can I run x86 Linux without needed any kind of BIOS emulation?
>   4) Are these the right questions to ask? Are there 'better' questions I
>      should be asking?
If you want to use Coreboot, the first question is probably "Which
bootloader do I want to use?"

All the rest will be answered by the documentation for that bootloader.


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