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=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 24BCAC18E7B for ; Wed, 12 May 2021 22:23:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 11EF861417 for ; Wed, 12 May 2021 22:23:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232409AbhELWVB (ORCPT ); Wed, 12 May 2021 18:21:01 -0400 Received: from terminus.zytor.com ([198.137.202.136]:51887 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1387802AbhELWKq (ORCPT ); Wed, 12 May 2021 18:10:46 -0400 Received: from tazenda.hos.anvin.org ([IPv6:2601:646:8602:8be0:7285:c2ff:fefb:fd4]) (authenticated bits=0) by mail.zytor.com (8.16.1/8.15.2) with ESMTPSA id 14CM9D8K2844555 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Wed, 12 May 2021 15:09:14 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 14CM9D8K2844555 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2021042801; t=1620857354; bh=tkwPeG2CvNXmxpgODLd6wDhM+YhWJn9cKsnKBH4qgEg=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=XTqtH4VhAhp5lHa5yBIq6ObWL9qhThr0jLsFquf7m0l+42VXD6vTQx9q/IdOzRN8d P10KujfKJVR4dgJP2Yd2cNDCqHMZefaj8cLFCTQi9iG3OZu/b2xCf1wy54/M5QA5oe iKkbxs0BtMMmRhiYQpZtJQC4rQWLgnLZ6BiQNZAtr3Pn1suxbgxmLUKemtSABoBZ8K GS3Mh7Gfh4UX+oh4efkUac7II8jaTpDVSTfNCC0pDU41b+r+Ia8EzQFAGGWc+cvlRL fUjQd9+XSYHeZkmpv+eoBWxr8+gggHg7iu4sVcayZ+JPSI4X7Y/VV+l3JsPkLa12sr aW7GWFpIcTleg== Subject: Re: [RFC v2 PATCH 7/7] x86/entry: use int for syscall number; handle all invalid syscall nrs To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski Cc: Linux Kernel Mailing List References: <871racf928.ffs@nanos.tec.linutronix.de> <60495dd3-ea68-4db3-47ad-b7b45796bf76@zytor.com> <87o8dfer7k.ffs@nanos.tec.linutronix.de> From: "H. Peter Anvin" Message-ID: Date: Wed, 12 May 2021 15:09:08 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <87o8dfer7k.ffs@nanos.tec.linutronix.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/12/21 11:34 AM, Thomas Gleixner wrote: >> >> That is intentional, as (again) system calls are int. > > They are 'int' kernel internally, but _NOT_ at the user space visible > side. Again: man syscall > > syscall(long number,...); > > So that results in a user ABI change. > >> As stated in my reply to Ingo, I'll clean the various descriptions and >> try to capture the discussion better. > > If we agree to go there then this wants to be a seperate commit which > does nothing else than changing this behaviour. > Good idea. As far as this being a user ABI change, this is actually a revert to the original x86-64 ABI; see my message to Ingo. -hpa