From owner-freebsd-hackers Sat Jul 3 6:44:15 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from lamb.sas.com (lamb.sas.com [192.35.83.8]) by hub.freebsd.org (Postfix) with ESMTP id 8F11314C2D for ; Sat, 3 Jul 1999 06:44:10 -0700 (PDT) (envelope-from brdean@unx.sas.com) Received: from mozart (mozart.unx.sas.com [192.58.184.8]) by lamb.sas.com (8.9.3/8.9.1) with SMTP id JAA26548 for ; Sat, 3 Jul 1999 09:44:09 -0400 (EDT) Received: from dean.pc.sas.com by mozart (5.65c/SAS/Domains/5-6-90) id AA22118; Sat, 3 Jul 1999 09:43:38 -0400 Received: (from brdean@localhost) by dean.pc.sas.com (8.9.3/8.9.3) id JAA13822; Sat, 3 Jul 1999 09:43:37 -0400 (EDT) (envelope-from brdean) From: Brian Dean Message-Id: <199907031343.JAA13822@dean.pc.sas.com> Subject: support for i386 hardware debug watch points To: freebsd-hackers@freebsd.org Date: Sat, 3 Jul 1999 09:43:37 -0400 (EDT) X-Mailer: ELM [version 2.4ME+ PL54 (25)] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Hi, After recently debugging a very elusive memory overwrite problem that I was only able to find by setting up a debugger watch point, and suffering through the slowness that this introduced, I began reading up on the ix86 support for hardware watch points. Using this facility of the chip would require OS support, and specifically, loading the debug registers at context switch time. Also, the 'ptrace' system call could easily be extended to provide an interface for doing this from user code. Is there any interest in supporting something like this in FreeBSD? I'm volunteering to spend some cycles on this, but I don't want to go to the effort if there's little chance that the work would be integrated. Thanks, -Brian -- Brian Dean SAS Institute Inc brdean@unx.sas.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message