Re: [Qemu-devel] vexpress-a9: coreboot is unable to push any data on stack

[Piotr Król]

On Fri, Aug 15, 2014 at 11:54:55PM +0100, Peter Maydell wrote:
> I'm not looking for advocacy, just for an explanation of what it's
> doing, and in particular whether anybody's ever tested this on real
> hardware. (Running guest code only on QEMU is a recipe for bugs,
> because our emulation is often not very accurate and if you only test
> on QEMU you can end up accidentally relying on our bugs.)
> 
Creboot is an open source replacement for BIOS. Almost every supported
board contain its own memory map. According to commit message from
Chromium developer coreboot build for qemu vexpress-a9 was created to
'simplify testing ARM implementation (... and) to verify the boot loader
functionality'. I think that code for real hardware got little in common
with qemu implementation.

I'm trying to use this implementation for pure educational purposes.

Going back to my initial issues with stack, changing stack location to
SRAM improves situation but does not fix booting. It looks like whole
implementation assumes running from RAM.

> The common motherboard docs:
> http://infocenter.arm.com/help/topic/com.arm.doc.dui0447j/index.html
> A9 daughterboard docs:
> http://infocenter.arm.com/help/topic/com.arm.doc.dui0448h/index.html
> A15 daughterboard docs:
> http://infocenter.arm.com/help/topic/com.arm.doc.dui0604e/index.html
> 
Thanks,
Piotr