Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 6 Feb 2002 16:18:03 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 6 Feb 2002 16:17:54 -0500 Received: from neon-gw-l3.transmeta.com ([63.209.4.196]:40456 "EHLO neon-gw.transmeta.com") by vger.kernel.org with ESMTP id ; Wed, 6 Feb 2002 16:17:38 -0500 Message-ID: <3C619D69.6090605@zytor.com> Date: Wed, 06 Feb 2002 13:17:29 -0800 From: "H. Peter Anvin" Organization: Zytor Communications User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.6) Gecko/20011120 X-Accept-Language: en, sv MIME-Version: 1.0 To: Jakub Jelinek CC: linux-kernel@vger.kernel.org Subject: Re: kernel: ldt allocation failed In-Reply-To: <200202061402.g16E2Nt32223@Port.imtp.ilyichevsk.odessa.ua> <20020206101231.X21624@devserv.devel.redhat.com> <20020206161511.D21624@devserv.devel.redhat.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jakub Jelinek wrote: >>> >>x86-64, interestingly, retains vestigial meaning of the %fs and %gs >>registers (but no others) to use as a base pointer for this reason >>alone. > > Well, on x86-64 this is purely x86-64 ABI designers decision, they could > pick one of %r8 - %r15 and use that as thread pointer instead (and were > recommended to do so). > Wasting an architectural register is still bloody expensive, even if 1 among 16 is less than 1 among 8. They'll be using %gs as thread pointer in userspace and CPU pointer in kernel space. -hpa - 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/