From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Mon, 09 Jan 2006 14:51:53 +0000 (GMT) Received: from extgw-uk.mips.com ([62.254.210.129]:12059 "EHLO bacchus.net.dhis.org") by ftp.linux-mips.org with ESMTP id S8134414AbWAIOvf (ORCPT ); Mon, 9 Jan 2006 14:51:35 +0000 Received: from denk.linux-mips.net (denk.linux-mips.net [127.0.0.1]) by bacchus.net.dhis.org (8.13.4/8.13.4) with ESMTP id k09EsPre005527; Mon, 9 Jan 2006 14:54:26 GMT Received: (from ralf@localhost) by denk.linux-mips.net (8.13.4/8.13.4/Submit) id k09EsP66005526; Mon, 9 Jan 2006 14:54:25 GMT Date: Mon, 9 Jan 2006 14:54:25 +0000 From: Ralf Baechle To: Sathesh Babu Edara Cc: linux-mips-bounce@linux-mips.org, linux-mips@linux-mips.org Subject: Re: LL and SC instruction simulation Message-ID: <20060109145425.GA4286@linux-mips.org> References: <200601090742.k097gYaZ017304@lilac.hdcindia.analog.com> <200601090749.k097nFaZ017891@lilac.hdcindia.analog.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200601090749.k097nFaZ017891@lilac.hdcindia.analog.com> User-Agent: Mutt/1.4.2.1i Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 9811 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Mon, Jan 09, 2006 at 01:19:46PM +0530, Sathesh Babu Edara wrote: > We have ported linux-2.4.18 and linux-2-6.12 kernel (mips.org)onto MIPS > processor (CPU type lx4189). > > We observed that on 2.4 kernel,ll and sc instruction exception handlers > hitting very often. > Where as on linux-2.6.12 this is not happening. > Can anybody have idea why this instructions are hitting on 2.4.18 kernel and > not on 2-6.12 kernel. Only ll/sc instructions in application software can be emulated, so it would seem your application is behaving different on 2.4 and 2.6 kernels. > What is the significance of these instructions?. All sorts of atomic operations. I suggest you read up on them in See MIPS Run or short of that in the MIPS32/64 specification. Ralf