Re: [Qemu-devel] [PATCH v2] arm: add device tree support

[Anthony Liguori]

On 02/01/2012 07:10 AM, Peter Maydell wrote:
> On 1 February 2012 13:04, Anthony Liguori<address@hidden>  wrote:
> > How does it race?  Devices normally never touch memory so a loader device
> > will be the only thing mucking with memory.
>
> The obvious one is "loader reset function wants to set starting PC to
> entry point of kernel/etc" vs "CPU device reset wants to set starting
> PC to hardware-mandated reset vector". We have this at the moment, of
> course, and I think we implicitly rely on reset handlers being called
> in order of registration...

I'm a bit confused, why can't the kernel loader be implemented in terms of a 
firmware blob?

This is what we do for x86 and it solves this problem robustly.  Isn't it just a 
matter of a few instructions to do a jmp to a known location?

Regards,

Anthony Liguori

> (The other irritating case is where the CPU device reset wants
> to read the starting PC out of memory, like the Cortex-M3, but
> really that one is because we don't distinguish "going into reset"
> from "coming out of reset".)
>
> -- PMM