From owner-freebsd-ppc@FreeBSD.ORG Wed Apr 16 00:42:43 2008 Return-Path: Delivered-To: freebsd-ppc@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 7BDC7106566B; Wed, 16 Apr 2008 00:42:43 +0000 (UTC) (envelope-from xcllnt@mac.com) Received: from smtpoutm.mac.com (smtpoutm.mac.com [17.148.16.71]) by mx1.freebsd.org (Postfix) with ESMTP id 2CDE68FC13; Wed, 16 Apr 2008 00:42:43 +0000 (UTC) (envelope-from xcllnt@mac.com) Received: from mac.com (asmtp002-s [10.150.69.65]) by smtpoutm.mac.com (Xserve/smtpout008/MantshX 4.0) with ESMTP id m3G0ggs7015909; Tue, 15 Apr 2008 17:42:42 -0700 (PDT) Received: from [192.168.1.100] (209-128-86-226.bayarea.net [209.128.86.226]) (authenticated bits=0) by mac.com (Xserve/asmtp002/MantshX 4.0) with ESMTP id m3G0geBM011122 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO); Tue, 15 Apr 2008 17:42:41 -0700 (PDT) Message-Id: From: Marcel Moolenaar To: grehan@freebsd.org In-Reply-To: <48053E46.4090700@freebsd.org> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v919.2) Date: Tue, 15 Apr 2008 17:42:40 -0700 References: <4804AE13.2060600@uchicago.edu> <4804C9E9.6010303@freebsd.org> <5CC81F06-7B59-4163-9AB8-2ACE4235A5AA@mac.com> <4804DD02.10304@freebsd.org> <058EEFE3-09D7-447A-93AB-3E90EC59ECDC@mac.com> <48053E46.4090700@freebsd.org> X-Mailer: Apple Mail (2.919.2) Cc: freebsd-ppc@freebsd.org Subject: Re: kernel stacks [eas: Re: G5 Bridge-mode MMU] X-BeenThere: freebsd-ppc@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Porting FreeBSD to the PowerPC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 16 Apr 2008 00:42:43 -0000 On Apr 15, 2008, at 4:46 PM, Peter Grehan wrote: > Hi Marcel, > >> the not mapping means that the CPU couldn't find the >> translation in its TLB nor in the hash table. The exception code >> treats >> this as a kernel stack overflow. > > Are you sure it isn't a genuine stack overflow ? Positive. The panic happens after 4KB of stack has been used. > You may be able to tell by bumping the size of tmpstk on a non- > kstack0 boot and see how far up it's been used. The backtrace also shows that. From inner-most to out-most function in the backtrace the stack pointers are roughly 4KB apart. > The stack mappings are put into the hash table, and a panic will be > issues if it can't be placed into the primary or secondary buckets. Hmm, It looks like you're right. Odd... Is it possible that the hash computation we use is not one used by the CPU so that we end up adding PTE where the CPU isn't looking? I'll have to dig deeper, I guess... -- Marcel Moolenaar xcllnt@mac.com