This patch fixes some copy_user bugs:

- kernelspace page faults that happen on behalf of a process are now
  correctly handled

- add copy_user treatment so a fault handler which looks at the faulting
  instruction

- added a note to do the same with the ldt stuff some day
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>