From owner-freebsd-hackers Mon Sep 9 8:30:40 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 5F34537B400 for ; Mon, 9 Sep 2002 08:30:37 -0700 (PDT) Received: from wall.polstra.com (wall-gw.polstra.com [206.213.73.130]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5BDC543E42 for ; Mon, 9 Sep 2002 08:30:36 -0700 (PDT) (envelope-from jdp@polstra.com) Received: from vashon.polstra.com (vashon.polstra.com [206.213.73.13]) by wall.polstra.com (8.11.3/8.11.3) with ESMTP id g89FUZf45656 for ; Mon, 9 Sep 2002 08:30:35 -0700 (PDT) (envelope-from jdp@vashon.polstra.com) Received: (from jdp@localhost) by vashon.polstra.com (8.12.5/8.12.5/Submit) id g89FUZF4028832; Mon, 9 Sep 2002 08:30:35 -0700 (PDT) (envelope-from jdp) Date: Mon, 9 Sep 2002 08:30:35 -0700 (PDT) Message-Id: <200209091530.g89FUZF4028832@vashon.polstra.com> To: hackers@freebsd.org From: John Polstra Subject: Re: interrupting target kernel using single sio In-Reply-To: <20020909112248.A613@gicco.cablecom.ch> References: <20020909112248.A613@gicco.cablecom.ch> Organization: Polstra & Co., Seattle, WA 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 In article <20020909112248.A613@gicco.cablecom.ch>, 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? BSD/OS has a little state machine in its sio driver which notices if something looking like a kgdb packet comes in and interrupts the target automatically. It's extremely handy. You just type "target remote /dev/tty00" into kgdb and the target breaks into the debugger -- no muss, no fuss. I wish we had this feature too. It should obviously be under the control of a sysctl to protect against accidental entry into the debugger. Another nice thing about BSD/OS is that when you exit kgdb, the target OS automatically starts running again. So you can enter and exit the debugger painlessly, as many times as you'd like. John -- John Polstra John D. Polstra & Co., Inc. Seattle, Washington USA "Disappointment is a good sign of basic intelligence." -- Chögyam Trungpa To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message