[aarch64-port-dev ] Aarch64 port for ZGC, so far

[Roland Westrelin]

> However, it may be that the linking of the Acquire as a direct feed of
> the secondary CAS is a problem. That CAS is only executed conditionally
> on the first CAS failing. If the memory flow is not ordered correctly
> then this might risk allowing the first CAS to complete and bypass the
> necessary trailing dmb. I could struggle through this code but it is
> probably best to ask Roland to look at it.

I'll take a look.

Roland.