From owner-freebsd-hackers Sat Oct 31 20:18:20 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id UAA05204 for freebsd-hackers-outgoing; Sat, 31 Oct 1998 20:18:20 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from phoenix (phoenix.aye.net [206.185.8.134]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id UAA05197 for ; Sat, 31 Oct 1998 20:18:15 -0800 (PST) (envelope-from rabtter@aye.net) Received: (qmail 2185 invoked by uid 2784); 1 Nov 1998 04:16:26 -0000 Received: from localhost (sendmail-bs@127.0.0.1) by localhost with SMTP; 1 Nov 1998 04:16:26 -0000 Date: Sat, 31 Oct 1998 23:16:26 -0500 (EST) From: Barrett Richardson To: hackers@FreeBSD.ORG Subject: multistack compiler and VM_MAXUSER_ADDRESS Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG A gentleman recently posted a patch to bugtraq for the egcs compiler from cygnus (actually a linux patch) that allocates a separate stack for each locally declared array. One of the items needed is the address of the stack top. The only thing I could find that looks it may fill the bill is VM_MAXUSER_ADDRESS in vmparam.h. Any hints tips? Also his notes say that there is unaccessable pages between stacks to prevent one stack for overflowing on to another. What exactly happens when you write to an unaccessable page, and what exactly is an "unaccessable" page? - Barrett To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message