[$] Bringing BPF to binfmt_misc

The kernel is able to run a few types of executable files, including native
binaries in the ELF format and interpreted programs that begin with the
#! marker. It also, however, has a mechanism, called binfmt_misc,
that can be configured from user space to enable the transparent execution
of programs in just about any format. This feature has been relatively
static for years, but it seems likely to receive some significant updates
in the near future, including the ability to load BPF programs that can
decide how to run a given program.