From owner-freebsd-hackers Mon Sep 9 4: 2:52 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 72C5A37B400 for ; Mon, 9 Sep 2002 04:02:46 -0700 (PDT) Received: from swan.mail.pas.earthlink.net (swan.mail.pas.earthlink.net [207.217.120.123]) by mx1.FreeBSD.org (Postfix) with ESMTP id 13D2B43E42 for ; Mon, 9 Sep 2002 04:02:46 -0700 (PDT) (envelope-from tlambert2@mindspring.com) Received: from pool0019.cvx21-bradley.dialup.earthlink.net ([209.179.192.19] helo=mindspring.com) by swan.mail.pas.earthlink.net with esmtp (Exim 3.33 #1) id 17oMJW-0001e7-00 for freebsd-hackers@freebsd.org; Mon, 09 Sep 2002 04:02:42 -0700 Message-ID: <3D7C7F96.9032BA7B@mindspring.com> Date: Mon, 09 Sep 2002 04:01:42 -0700 From: Terry Lambert X-Mailer: Mozilla 4.79 [en] (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: freebsd-hackers@freebsd.org Subject: Re: interrupting target kernel using single sio References: <20020909112248.A613@gicco.cablecom.ch> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Hanspeter Roth wrote: > using a single serial cable I can pass control to the remote kgdb > pressing ctl-alt-del at the target host. > I'm looking for a means to interrupt the target kernel from the > remote host. > I got suggestions using a second serial cable or using ipgdb > instead. > Setting remotechat didn't help me. > > Is it intended to be able to interrupt the target kernel from the > remote kgdb by some means at all? Or is this a wrong expectation? You need to send something which sends an interrupt to the driver on the remote host, so that it can be caught, and enter the debugger. Normally, this is done using the "break" signal (250+ms of RS232-C line silence). This is enabled via: options ALT_BREAK_TO_DEBUGGER options BREAK_TO_DEBUGGER See /usr/src/sys/i386/conf/LINT for details. Note that your gdb client program is, AFAIK, too stupid to be able to send this break. But if you can get it to do it, then FreeBSD will do the right thing. Most likely, you will need to hack gdb to make it able to send the break signal in response to a ^C or whatever you define as your "remote break" character. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message