AT_HWCAP support on aarch64

[John Baldwin]

On Thursday, October 19, 2017 02:04:46 AM Jan Beich wrote:
> armv6 and armv7 recently gained support to check NEON or VFP* at runtime.
> However, some ports want to take advantage of AES, CRC32, SHA1, SHA256
> acceleration on aarch64 as well.
> 
> Do you plan to support any HWCAP_* for AT_HWCAP on aarch64?
> 
> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=223016
> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=223019 (ditto Chromium)
> http://elixir.free-electrons.com/linux/latest/source/arch/arm64/include/uapi/asm/hwcap.h

I think there is certainly a desire to do so, it should just be a matter of
populating a hwcap variable and setting it in sysentvec.

-- 
John Baldwin