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

[Peter Zijlstra]

On Wed, Nov 11, 2015 at 07:50:15PM +0100, Daniel Borkmann wrote:
> Well, on that note, it's not like you just change the target to bpf in your
> Makefile and can compile (& load into the kernel) anything you want with it.
> You do have to write small, restricted programs from scratch for a specific
> use-case with the limited set of helper functions and intrinsics that are
> available from the kernel. So I don't think that "Programs that used to work
> will now no longer work." holds if you regard it as such.

So I don't get this argument. If everything is so targeted, then why are
the BPF instructions an ABI.

If OTOH you're expected to be able to transfer these small proglets,
then too I would expect to transfer the source of these proglets.

You cannot argue both ways.