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 atomic.
What about scratchpad registers in the CPU which are guaranteed to be cache-coherent across multiple cores and processors?
Regards, Carl-Daniel