From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gateway-1237.mvista.com (gateway-1237.mvista.com [63.81.120.158]) by ozlabs.org (Postfix) with ESMTP id 4230DDDFC0 for ; Sat, 28 Apr 2007 02:58:52 +1000 (EST) Message-ID: <46322C76.3060903@mvista.com> Date: Fri, 27 Apr 2007 10:01:42 -0700 From: Dave Jiang MIME-Version: 1.0 To: Kumar Gala , paulus@samba.org Subject: Re: [PATCH] add reg and stack dump to booke WD handler References: <20070413173524.GA17890@blade.az.mvista.com> <461FCB6F.7010504@ru.mvista.com> <20070413200659.GA21588@blade.az.mvista.com> <20070413221657.GA23624@blade.az.mvista.com> In-Reply-To: <20070413221657.GA23624@blade.az.mvista.com> Content-Type: text/plain; charset=ISO-8859-1 Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Paul Mackerras wrote: > Dave Jiang wrote: > > Have the booke watchdog dump some useful information when triggered. > > Hopefully that'll give the user some hint of what happened rather than just a > > mysterious reboot. > > Why not call either die() or panic()? Won't they do what you want? I think the main thing I'm worried about is kexec. Both panic and die handler can potentially call kexec. The watchdog cannot be killed unless a hardware reset happens. So it is possible that during the boot of the kexec'd kernel the watchdog forces a hardware reset. In fact, the watchdog can actually make kdump rather tricky since the current implementation makes it being kept alive via userland. I'm thinking that the only way to get around that is to ping the watchdog consistently in something such as the timer interrupt. But then we probably have to move the initialization of the driver into core kernel code and not a char driver. Do we want to do that? -- ------------------------------------------------------ Dave Jiang Software Engineer MontaVista Software, Inc. http://www.mvista.com ------------------------------------------------------