[PATCH 2/2] arm64: bpf: add BPF XADD instruction

[Eric Dumazet]

On Tue, 2015-11-10 at 14:41 -0800, Yang Shi wrote:
> aarch64 doesn't have native support for XADD instruction, implement it by
> the below instruction sequence:
> 
> Load (dst + off) to a register
> Add src to it
> Store it back to (dst + off)

Not really what is needed ?

See this BPF_XADD as an atomic_add() equivalent.