cross-memory-attach-update

cross-memory-attach-update

- Add x86_64 specific wire up

- Change behaviour so process_vm_readv and process_vm_writev return
  the number of bytes successfully read or written even if an error
  occurs

- Add more kernel doc interface comments

- rename some internal functions (process_vm_rw_check_iovecs,
  process_vm_rw) so they make more sense.

- Add licence message

- Fix kernel-doc comment format

Still need to do benchmarking to see if the optimisation for small copies
using a local on-stack array in process_vm_rw_core is worth it.

Signed-off-by: Chris Yeoh <cyeoh@au1.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>