Re: [PATCH 3/3] ring-buffer: add design document

Huang Ying
2009-06-12T03:13:48Z

On Thu, 2009-06-11 at 10:38 +0800, Mathieu Desnoyers wrote:
> > > Are these archs without cmpxchg and NMIs, a concern for you?
> >
> > ARM has no cmpxchg until ARM v6, but it has NMI like mechanism named
> > FIQ.
> >
>
> One could probably adapt the cmpxchg for earlier ARM so it disables
> FIQs. Note that the current limitation is that there is only a
> fiq disable, not a fiq save/restore.

Yes. It seems that ARM is OK after FIQ save/restore issue is fixed.
Another machine with NMI but no NMI-safe cmpxchg is "real" 386. That is
very old machine, does that matter?

Best Regards,
Huang Ying