When I started working for Red Hat I got a list of packages in RHEL 7.0 which did not built for AArch64. Some time later I worked on merging those fixes in Fedora and upstream. Red Hat Enterprise Linux 7.0 got released. Then 7.1 followed. Then CentOS developers added AArch64 target based on work we did in RHEL.
Yesterday Red Hat Enterprise Linux 7.2 got released. What makes this version special is one paragraph:
Red Hat is also making available Red Hat Enterprise Linux Server for ARM 7.2 Development Preview, which was first made available to partners and their customers in June 2015. This Development Preview enables new partner hardware and additional features for the ARM architecture.
Which means AArch64 port. Working out of box on SBSA/SBBR compliant hardware.