From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ECCAEC43441 for ; Wed, 14 Nov 2018 11:40:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A9CF521582 for ; Wed, 14 Nov 2018 11:40:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A9CF521582 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728258AbeKNVnu (ORCPT ); Wed, 14 Nov 2018 16:43:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]:51658 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727649AbeKNVnu (ORCPT ); Wed, 14 Nov 2018 16:43:50 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id AFB93306B62A; Wed, 14 Nov 2018 11:40:56 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-117-210.ams2.redhat.com [10.36.117.210]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 50B915D9CC; Wed, 14 Nov 2018 11:40:51 +0000 (UTC) From: Florian Weimer To: Dave Martin Cc: Andy Lutomirski , Daniel Colascione , "Michael Kerrisk \(man-pages\)" , linux-kernel , Joel Fernandes , Linux API , Willy Tarreau , Vlastimil Babka , Carlos O'Donell , "libc-alpha\@sourceware.org" Subject: Re: Official Linux system wrapper library? References: <877ehjx447.fsf@oldenburg.str.redhat.com> <875zx2vhpd.fsf@oldenburg.str.redhat.com> <20181113193859.GJ3505@e103592.cambridge.arm.com> <69B07026-5E8B-47FC-9313-E51E899FAFB0@amacapital.net> <20181114105449.GK3505@e103592.cambridge.arm.com> Date: Wed, 14 Nov 2018 12:40:44 +0100 In-Reply-To: <20181114105449.GK3505@e103592.cambridge.arm.com> (Dave Martin's message of "Wed, 14 Nov 2018 10:54:51 +0000") Message-ID: <877ehfdgzn.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Wed, 14 Nov 2018 11:40:57 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Dave Martin: > Fair points, though this is rather what I meant by "sane essentials". > Because there are strict limits on what can be done in the vDSO, it may > be more bloat-resistant and more conservatively maintained. > > This might provide a way to push some dumb compatibility kludge code > that receives little ongoing maintenance outside the privilege wall, > whereas it has to sit in the kernel proper today. > > In theory we could opt to advertise new syscalls only via vDSO entry > points, and not maintain __NR_xxx values for them (which may or may > not upset ptrace users.) Anyway, I digress... Is the vDSO available across all architectures? (I don't think we use it on all architectures in glibc.) If not, a vDSO-based approach would merely lead to even more variance between architectures, which can't be a good thing. Thanks, Florian