[PATCH] fix gettimeofday vs. update_gtod race

[Nathan Lynch]

Nathan Lynch wrote:
> Benjamin Herrenschmidt wrote:
> > On Wed, 2006-08-16 at 19:18 -0500, Nathan Lynch wrote:
> > 
> > > No?  I didn't find anything about mftb having synchronizing
> > > behavior.  How should we ensure that temp_varp is assigned before
> > > reading the timebase?
> > 
> > I sync an isync would be enough.
> 
> I see, thanks.

Actually, after checking Book 2 and discussing with some other folks
I'm not so sure -- isync "may complete before storage accesses
associated with instructions preceding the isync instruction have been
performed."