Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 10 Nov 2002 14:25:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 10 Nov 2002 14:25:23 -0500 Received: from neon-gw-l3.transmeta.com ([63.209.4.196]:58376 "EHLO neon-gw.transmeta.com") by vger.kernel.org with ESMTP id ; Sun, 10 Nov 2002 14:25:23 -0500 Date: Sun, 10 Nov 2002 11:31:45 -0800 (PST) From: Linus Torvalds To: Pavel Machek cc: vojtech@ucw.cz, Alan Cox , "J.E.J. Bottomley" , john stultz , lkml Subject: Re: Voyager subarchitecture for 2.5.46 In-Reply-To: <20021110191822.GA1237@elf.ucw.cz> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1034 Lines: 25 On Sun, 10 Nov 2002, Pavel Machek wrote: > > I believe you need to *store* last value given to userland. But that's trivially done: it doesn't even have to be thread-specific, so it can be just a global entry anywhere in the process data structures. This is just a random sanity check thing, after all. It doesn't have to be system-global or even per-cpu. The only really important thing is that "gettimeofday()" should return monotonically increasing data - and if it doesn't, the vsyscall would have to ask why (sometimes it's fine, if somebody did a settimeofday, but usually it's a sign of trouble). But yes, it's certainly a lot more complex than just doing it in a controlled system call environment. Which is why I think vsyscalls are eventually not worth it. Linus - 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/