From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by oss.sgi.com id ; Fri, 15 Sep 2000 17:03:11 -0700 Received: from gateway-490.mvista.com ([63.192.220.206]:57595 "EHLO hermes.mvista.com") by oss.sgi.com with ESMTP id ; Fri, 15 Sep 2000 17:02:56 -0700 Received: from mvista.com (IDENT:jsun@orion.mvista.com [10.0.0.75]) by hermes.mvista.com (8.9.3/8.9.3) with ESMTP id RAA27427; Fri, 15 Sep 2000 17:02:50 -0700 Message-ID: <39C2B8AA.9B873EF7@mvista.com> Date: Fri, 15 Sep 2000 17:02:50 -0700 From: Jun Sun X-Mailer: Mozilla 4.7 [en] (X11; I; Linux 2.2.12-20b i586) X-Accept-Language: en MIME-Version: 1.0 To: Ralf Baechle CC: linux-mips@oss.sgi.com, linux-mips@fnet.fr Subject: Re: trap handler for unaligned memory read/write References: <39C29018.9389FBCE@mvista.com> <20000916012853.A16047@bacchus.dhis.org> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mips@oss.sgi.com Precedence: bulk Return-Path: X-Orcpt: rfc822;linux-mips-outgoing Ralf Baechle wrote: > > For short-term solutions, we can have trap handler that supports the > > unaligned read/write. Does anybody know if there is such a trap handler > > for MIPS? > > It's right there in your kernel ... > Cool! I found it. > You _really_ _really_ want to avoid relying on the unaligned trap handler. > Performancewise that's equivalent to a swapping on a floppy disk on the > Mars over NFS via avian carriers ... > > However unaligned accesses will result in an address error exception not > bus error therefore I suspect you've got another problem. > I got the error when I use gdb to debug kernel. I suppose the gdb stub intercepted the error and report it as BUS error. We should make gdb-stub a little smarter ... Jun