[coreboot] v3 printk on SMP

Stefan Reinauer stepan at coresystems.de
Sat Feb 21 21:49:23 CET 2009

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

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