[PATCH 0/4 POC] Allow executing code and syscalls in another address space

[sbaugh at catern.com]

Just to add to the list of use cases for PROCESS_VM_EXEC_SYSCALL,
another use case is initializing a process from the "outside", instead
of from the "inside" as fork requires.  This can be much easier to work
with.  http://catern.com/rsys21.pdf goes into this use case in some
depth.

It relies heavily on a remote syscall primitive:
https://github.com/catern/rsyscall.  The PROCESS_VM_EXEC_SYSCALL API
proposed in this patch would be a great replacement for the current
implementation, which relies on running code inside the target process.