On Fri, 26 Mar 1999 18:26:21 -0800 (PST) 
 "Eduardo E. Horvath" <eeh@one-o.com> wrote:

 > Pardon me if I'm a bit dense, but what does `access_type' mean and how
 > does it relate to `prot'?

When the page fault occured, it was either a read fault or a write fault.
This information is already passed from machdep to MI code when a fault
occurs.  This is basically useful when you have mod/ref emulation in your
pmap.

It happens that vm_prot_t is a convenient already-existent type for
expressing "read" or "write".

        -- Jason R. Thorpe <thorpej@nas.nasa.gov>