From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964818AbWGYTKA (ORCPT ); Tue, 25 Jul 2006 15:10:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964819AbWGYTKA (ORCPT ); Tue, 25 Jul 2006 15:10:00 -0400 Received: from terminus.zytor.com ([192.83.249.54]:18073 "EHLO terminus.zytor.com") by vger.kernel.org with ESMTP id S964818AbWGYTJ7 (ORCPT ); Tue, 25 Jul 2006 15:09:59 -0400 Message-ID: <44C66C36.2010600@zytor.com> Date: Tue, 25 Jul 2006 12:08:38 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 1.5.0.4 (X11/20060614) MIME-Version: 1.0 To: Arjan van de Ven CC: Neil Horman , linux-kernel@vger.kernel.org, a.zummo@towertech.it, jg@freedesktop.org Subject: Re: [PATCH] RTC: Add mmap method to rtc character driver References: <20060725174100.GA4608@hmsreliant.homelinux.net> <1153850139.8932.40.camel@laptopd505.fenrus.org> <20060725182208.GD4608@hmsreliant.homelinux.net> <1153852375.8932.41.camel@laptopd505.fenrus.org> <20060725184328.GF4608@hmsreliant.homelinux.net> <1153853596.8932.44.camel@laptopd505.fenrus.org> In-Reply-To: <1153853596.8932.44.camel@laptopd505.fenrus.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Arjan van de Ven wrote: > > well the idea that has been tossed about a few times is using a vsyscall > function that either calls into the kernel, or directly uses the hpet > page (which can be user mapped) to get time information that way... > or even would use rdtsc in a way the kernel knows is safe (eg corrected > for the local cpu's speed and offset etc etc). > x86-64 already does that, IIRC. -hpa