On Mon, 27 Jan 1997 16:49:21 -0500 
 "Perry E. Metzger" <perry@piermont.com> wrote:

 > The 4.4 book claimed that most 4.4. ports already had a guard page at
 > the end of the kernel stack -- I was unaware that this was not the
 > case any longer.

So, the hp300 port had this long ago... it was a bit easier to do
in 4.4BSD because of the double-mapping of the kernel stack.  I.e.
the "guard page" address never changed, because the kernel stack
for all processes was mapped to the same address (kstack) upon
context switch.

When kstack went away, the stack checking stuff was garbage-collected.

Jason R. Thorpe                                       thorpej@nas.nasa.gov
NASA Ames Research Center                               Home: 408.866.1912
NAS: M/S 258-6                                          Work: 415.604.0935
Moffett Field, CA 94035                                Pager: 415.428.6939