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To: Bruce Evans <bde@zeta.org.au>
Subject: Re: Removing execute privs from stack pages 
Cc: terry@lambert.org, wpaul@skynet.ctr.columbia.edu, hackers@freebsd.org
In-reply-to: Your message of "Tue, 04 Mar 1997 22:32:08 +1100."
		<199703041132.WAA06944@godzilla.zeta.org.au> 
References: <199703041132.WAA06944@godzilla.zeta.org.au>  
Date: Tue, 04 Mar 1997 11:12:43 -0700
From: Warner Losh <imp@village.org>
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In message <199703041132.WAA06944@godzilla.zeta.org.au> Bruce Evans writes:
: >Frankly, I wonder how LISP and FORTH can run on such a system.
: 
: I think they would have to do system calls to map pages for execution.
: Even dynamically linked C code would need this.  There would be some
: security if the mapping were refused for setuid processes.

g++ uses trampoline code on the stack as well for things like nested
scopes and references/pointers to functions inside those scopes.
There was also some traffic that g++ placed other things on the stack
as well with its new exception handling code, but I'm not sure if that
is for x86 or not.

Neat idea, too bad otehr people need the stack to be executable :-(.

Warner