From owner-freebsd-hackers@FreeBSD.ORG Mon Aug 14 14:17:09 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org 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 D66BA16A4DA for ; Mon, 14 Aug 2006 14:17:09 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from server.baldwin.cx (66-23-211-162.clients.speedfactory.net [66.23.211.162]) by mx1.FreeBSD.org (Postfix) with ESMTP id EEF1643D5C for ; Mon, 14 Aug 2006 14:17:02 +0000 (GMT) (envelope-from jhb@freebsd.org) Received: from zion.baldwin.cx (zion.baldwin.cx [192.168.0.7]) (authenticated bits=0) by server.baldwin.cx (8.13.6/8.13.6) with ESMTP id k7EEGn9k013497; Mon, 14 Aug 2006 10:17:00 -0400 (EDT) (envelope-from jhb@freebsd.org) From: John Baldwin To: freebsd-hackers@freebsd.org Date: Mon, 14 Aug 2006 09:32:57 -0400 User-Agent: KMail/1.9.1 References: <20060814124658.1d416cbe@localhost> In-Reply-To: <20060814124658.1d416cbe@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200608140932.57875.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH authentication, not delayed by milter-greylist-2.0.2 (server.baldwin.cx [192.168.0.1]); Mon, 14 Aug 2006 10:17:01 -0400 (EDT) X-Virus-Scanned: ClamAV 0.88.3/1659/Mon Aug 14 04:44:22 2006 on server.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-4.4 required=4.2 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.1.3 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on server.baldwin.cx Cc: Stanislav Sedov Subject: Re: exception handling in kernel code X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 14 Aug 2006 14:17:09 -0000 On Monday 14 August 2006 02:46, Stanislav Sedov wrote: > Hi! > > I'm trying to write kernel code where exceptions are unavoidable. > To clarify , I need to recover after GP (general protection) exception > on i386 cpu and return an error in that case. > Unfortunately, looking in trap.c kernel code I can't find any exception > handling mechanism except inserting hooks into trap.c. > > So, the question is: how can one recover after exception in kernel > code? AFAIK, linux build special exception table from various __ex_table > sections to allow placing recover code into .fixup section. Does any such > mechanism exists in freebsd? > > Thanks! You can make use of pcb_onfault to recover from a page fault, but that's about it. Kernel code is expected to not generate exceptions. :) -- John Baldwin