From owner-freebsd-hackers@FreeBSD.ORG Wed Oct 31 16:53:20 2007 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 147AF16A421 for ; Wed, 31 Oct 2007 16:53:20 +0000 (UTC) (envelope-from deathjestr@gmail.com) Received: from py-out-1112.google.com (py-out-1112.google.com [64.233.166.183]) by mx1.freebsd.org (Postfix) with ESMTP id B6EA613C4B7 for ; Wed, 31 Oct 2007 16:53:19 +0000 (UTC) (envelope-from deathjestr@gmail.com) Received: by py-out-1112.google.com with SMTP id u77so414729pyb for ; Wed, 31 Oct 2007 09:52:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; bh=7Y4iQHdWpjll8nmTyxoaXbPKxU2weB7VvIUAMMr2A0M=; b=AXE0cUJTzxrUUuLgX7UkLwVTZTDS+dU2joGvtwZ0C/wq1K1o6lVcWU/obRbuBlt40trnQ9NUEPV9yarirLwRm7Brp8x6os4pfzFS7vGx1r2N84/7AYqhcRXONwasG8+tybr2MUUiW5X6yRYSBP7WHQiZIk+K5b6H2OiOojWmE9g= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=aIVgzkhuEAxZKtBd5+NSvt410/IY6yzMmOjjmfJ/dNyYjfIIaEYRMwiBmK/z8m2NkFQO22uGLs/2blnFjY44TuTtiZZ6CTKiG4urDU/daqAsoBxVUtDMEa9P/NKYMjajx4ql27fZHQiqAK1uP72OR//t6NsBjt2DzKfsdlNMVwQ= Received: by 10.35.115.18 with SMTP id s18mr10336327pym.1193847991424; Wed, 31 Oct 2007 09:26:31 -0700 (PDT) Received: by 10.35.12.15 with HTTP; Wed, 31 Oct 2007 09:26:31 -0700 (PDT) Message-ID: <44b564930710310926m54f74566s104d12808ed5c9cb@mail.gmail.com> Date: Wed, 31 Oct 2007 12:26:31 -0400 From: "Michael M. Press" To: "=?ISO-8859-2?Q?Jaroszewski_=A3ukasz?=" , Maslan In-Reply-To: <319cceca0710301402j48355b54gc572f9c76a39d5a8@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <0862634D7E37134986CB15DF2E4542BA1C1EE5@sbssrv.SALAG.local> <319cceca0710301402j48355b54gc572f9c76a39d5a8@mail.gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: ``Stopping RAM access'' 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: Wed, 31 Oct 2007 16:53:20 -0000 >> Can anyone give me a clue, how one can ``stop'' system from accessing RAM, and then allow it again? > > I think this has no aim, RAM tests should be done during booting, but > u could try to disable interrupts while in kernel mode 'cli' which > will prevent any further context switching, then try to do whatever > you want, finally enable interrupts back 'sti'. > > That's my two cents. I don't whether it will work or not. > Also, keep in mind that 'cli/sti' is just a starting point. You can't just go playing with memory anywhere you want because interrupts are disabled. What if a DMA transfer is in progress? Mike