Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751438AbVJRA7k (ORCPT ); Mon, 17 Oct 2005 20:59:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751441AbVJRA7k (ORCPT ); Mon, 17 Oct 2005 20:59:40 -0400 Received: from sccrmhc14.comcast.net ([204.127.202.59]:27780 "EHLO sccrmhc14.comcast.net") by vger.kernel.org with ESMTP id S1751438AbVJRA7j (ORCPT ); Mon, 17 Oct 2005 20:59:39 -0400 Date: Mon, 17 Oct 2005 18:00:28 -0700 From: Deepak Saxena To: Jeff Garzik Cc: linux-kernel@vger.kernel.org Subject: Re: [RFC] RNG rewrite... Message-ID: <20051018010028.GA16005@plexity.net> Reply-To: dsaxena@plexity.net References: <20051015043120.GA5946@plexity.net> <4350DCB1.7010201@pobox.com> <20051016005341.GB5946@plexity.net> <43543455.4080206@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43543455.4080206@pobox.com> Organization: Plexity Networks User-Agent: Mutt/1.5.10i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1423 Lines: 35 On Oct 17 2005, at 19:31, Jeff Garzik was caught saying: > >PCI devices, but I don't know enough about x86 to say whether msr > >instructions can execute out of userspace (or if we want them to...). > > All of the hot path RNG stuff can and should be moved to userspace. > > Right now the path is > > kernel /dev/hwrandom -> rngd -> add /dev/random entropy > > All three current vendors shown in hw_random.c are doable in userspace. > Intel uses MMIO, AMD uses PIO, and VIA uses a specialized CPU > instruction. As HPA mentioned, you can use the MSR driver for control. > > Patches welcome! http://sf.net/projects/gkernel/ OK...I already did most of a rewrite keeping the driver in user space and added support for IXP4xx and OMAP but will look at the msr driver. However, looking at the MPC85xx and the Alchemy MIPs parts with RNGs, they have interrupt sources for error conditions so those need to be in kernel... ~Deepak -- Deepak Saxena - dsaxena@plexity.net - http://www.plexity.net When law and duty are one, united by religion, you never become fully conscious, fully aware of yourself. You are always a little less than an individual. - Frank Herbert - 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/