copyin

[amos at instable.UUCP]

When in kernel mode on a VAX, you have both kernel and user spaces mapped,
since they do not overlap virtually. Copyin/copyout do not use special
instructions, but they do sanity checks without which a mistake by a user
might crash the system.

(A side effect of this is that the u struct is accessible from user mode,
although read-only).
-- 
	Amos Shapir
National Semiconductor (Israel)
6 Maskit st. P.O.B. 3007, Herzlia 46104, Israel
(011-972) 52-522261  amos%nsta at nsc.com 34.48'E 32.10'N