Merge branch 'bpf-improvements-and-fixes'

Merge branch 'bpf-improvements-and-fixes'

Daniel Borkmann says:

====================
This set contains a small cleanup in cBPF prologue generation and
otherwise fixes an outstanding issue related to BPF to BPF calls
and exception handling. For details please see related patches.
Last but not least, BPF selftests is extended with several new
test cases.

Thanks!
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>