[coreboot] v3 printk on SMP
c-d.hailfinger.devel.2006 at gmx.net
Sat Feb 21 23:45:07 CET 2009
On 21.02.2009 21:49, Stefan Reinauer wrote:
> On 21.02.2009 21:39 Uhr, Carl-Daniel Hailfinger wrote:
>> On 21.02.2009 21:31, ron minnich wrote:
>>> Also I guess it's time to make printk smp-safe.
>> Cool! The big problem here is that you need locking and for that you
>> need something which is shared between CPUs. IIRC this means storing the
>> lock in CAR is a no-go on some processors.
> Yes. the locking mechanisms are all there but can not be used. (or they
> were, at some point)
> The simplest way would be to use a scratchpad register of the chipset as
> a semaphore. That's rather safe but unless on PCIe it can not be done
What about scratchpad registers in the CPU which are guaranteed to be
cache-coherent across multiple cores and processors?
More information about the coreboot