From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15160 invoked by alias); 16 Jul 2011 18:21:19 -0000 Received: (qmail 15151 invoked by uid 22791); 16 Jul 2011 18:21:18 -0000 X-SWARE-Spam-Status: No, hits=-1.2 required=5.0 tests=AWL,BAYES_05,RP_MATCHES_RCVD,SPF_HELO_PASS X-Spam-Check-By: sourceware.org Received: from www.meduna.org (HELO meduna.org) (92.240.244.38) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Sat, 16 Jul 2011 18:21:03 +0000 Received: from dial-95-105-188-244-orange.orange.sk ([95.105.188.244] helo=[192.168.130.27]) by meduna.org with esmtpsa (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.69) (envelope-from ) id 1Qi9Ty-0006Kp-6w; Sat, 16 Jul 2011 20:21:00 +0200 Message-ID: <4E21D683.9090001@meduna.org> Date: Sat, 16 Jul 2011 18:21:00 -0000 From: Stanislav Meduna User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.18) Gecko/20110616 Lightning/1.0b2 Thunderbird/3.1.11 MIME-Version: 1.0 To: Pierre-Marie Boyer CC: ecos-discuss@ecos.sourceware.org References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Authenticated-User: stano@meduna.org X-Authenticator: dovecot_plain X-Spam-Score: -8.2 X-Spam-Score-Int: -81 X-Exim-Version: 4.69 (build at 30-Jan-2011 20:48:48) X-Date: 2011-07-16 20:21:00 X-Connected-IP: 95.105.188.244:3195 X-Message-Linecount: 47 X-Body-Linecount: 34 X-Message-Size: 1783 X-Body-Size: 1180 X-Received-Count: 1 X-Recipient-Count: 2 X-Local-Recipient-Count: 2 X-Local-Recipient-Defer-Count: 0 X-Local-Recipient-Fail-Count: 0 X-IsSubscribed: yes Mailing-List: contact ecos-discuss-help@ecos.sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: ecos-discuss-owner@ecos.sourceware.org Subject: Re: [ECOS] data access fron an interrupt handler X-SW-Source: 2011-07/txt/msg00030.txt.bz2 On 16.07.2011 12:27, Pierre-Marie Boyer wrote: > Because in this case the task context is not the same, and I think that no > changing context is performed by the OS before running the interrupt. > > I think this can be a problem when we are in virtual memory system (uC with > MMU ). > > Could you give me some information? > > (I know this is not a specific question of eCos, but I have not found were > to ask this question. sory, and thank you in advance) eCos does not use MMU (or at least not in this way), so this is really wrong forum to ask. Directly accessing user data from kernel space is no trivial task. The address translation is one thing, but on a system with real virtual memory the data are maybe not her at all - they can be swapped out. The other way round is much easier - the kernel just allocates you a virtual memory pointing into kernel space (on unix-like systems see mmap()). What exactly are you trying to accomplish? I'd recommend to get a good book describing the linux kernel and study kernel space - user space interfacing there (copy_to/from_user, ideas behind the mmap() call etc). -- Stano -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss