Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 29 Aug 2002 19:15:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 29 Aug 2002 19:15:49 -0400 Received: from pc1-cwma1-5-cust128.swa.cable.ntl.com ([80.5.120.128]:37117 "EHLO irongate.swansea.linux.org.uk") by vger.kernel.org with ESMTP id ; Thu, 29 Aug 2002 19:15:48 -0400 Subject: Re: [PATCH 1 / ...] i386 dynamic fixup/self modifying code From: Alan Cox To: Pavel Machek Cc: Luca Barbieri , Linux-Kernel ML , Linus Torvalds In-Reply-To: <20020828121129.A35@toy.ucw.cz> References: <1030506106.1489.27.camel@ldb> <20020828121129.A35@toy.ucw.cz> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.8 (1.0.8-6) Date: 30 Aug 2002 00:19:52 +0100 Message-Id: <1030663192.1326.20.camel@irongate.swansea.linux.org.uk> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1029 Lines: 22 On Wed, 2002-08-28 at 13:11, Pavel Machek wrote: > > Unfortunately with this patch executing invalid code will cause the > > processor to enter an infinite exception loop rather than panic. Fixing > > this is not trivial for SMP+preempt so it's not done at the moment. > > Using 0xcc for everything should fix that, right? Except you can't do the fixup on SMP without risking hitting the CPU errata. You also break debugging tools that map kernel code pages r/o and people who ROM it. The latter aren't a big problem (they can compile without runtime fixups). For the other fixups though you -have- to do them before you run the code. That isnt hard (eg sparc btfixup). You generate a list of the addresses in a segment, patch them all and let the init freeup blow the table away - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/