Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 7 Jan 2003 12:39:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 7 Jan 2003 12:39:09 -0500 Received: from neon-gw-l3.transmeta.com ([63.209.4.196]:64011 "EHLO neon-gw.transmeta.com") by vger.kernel.org with ESMTP id ; Tue, 7 Jan 2003 12:39:07 -0500 Date: Tue, 7 Jan 2003 09:42:15 -0800 (PST) From: Linus Torvalds To: Jamie Lokier cc: Zack Weinberg , Subject: Re: [PATCH] Set TIF_IRET in more places In-Reply-To: <20030107111905.GA949@bjl1.asuk.net> 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: 1083 Lines: 25 On Tue, 7 Jan 2003, Jamie Lokier wrote: > > Voila! sigreturn() can be written to avoid entering the kernel. Note > that this is possible _now_, with no changes to the kernel. It only > requires changes to libc. I think it would work on all architectures, > not just i386. (It may also be possible to do it without libc help, > in the vsyscall page). I'd certainly prefer playing these kinds of games _without_ any libc involvement, since making libc play games like this is fragile as hell and works really badly for threaded applications, for example (delivering signals to threads is _hard_ to get right, that's one of the things 2.5.x finally does thanks to Ingo and Uli). But moving the signal trampoline to vsyscall space to prepare for changes like this is a good idea. I'll remove the SA_RESTORER logic too. 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/