Merge branch 'bpf-perf-hw-sw-events'

Alexei Starovoitov says:

====================
perf, bpf: add support for bpf in sw/hw perf_events

this patch set is a follow up to the discussion:
https://lkml.kernel.org/r/20160804142853.GO6862%20()%20twins%20!%20programming%20!%20kicks-ass%20!%20net
It turned out to be simpler than what we discussed.

Patches 1-3 is bpf-side prep for the main patch 4
that adds bpf program as an overflow_handler to sw and hw perf_events.

Patches 5 and 6 are examples from myself and Brendan.

Peter,
to implement your suggestion to add ifdef CONFIG_BPF_SYSCALL
inside struct perf_event, I had to shuffle ifdefs in events/core.c
Please double check whether that is what you wanted to see.

v2->v3: fixed few more minor issues
v1->v2: fixed issues spotted by Peter and Daniel.
====================

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>