[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
disk...
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 It gets out
of date quickly, but it is faster than starting from scratch.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.
Thanks,
Myles
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