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 1C1C9C433ED for ; Fri, 14 May 2021 00:38:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D89AA6141F for ; Fri, 14 May 2021 00:38:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231776AbhENAjr (ORCPT ); Thu, 13 May 2021 20:39:47 -0400 Received: from terminus.zytor.com ([198.137.202.136]:54293 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230305AbhENAjq (ORCPT ); Thu, 13 May 2021 20:39:46 -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 14E0c7db3026741 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Thu, 13 May 2021 17:38:08 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 14E0c7db3026741 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2021042801; t=1620952688; bh=tiFWqHXSKNf8T3GK1jvsbQAtN+RbpKZCEkFdNfESs6o=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=D8qCDot95FwhkGSe9LKFTJhYb8a3+mDaEAaGIaZwD9YKq8dAkUvqD9kYeMlHep0t1 h+5smXI19UpJWcybV6z46KHG9RTLy/vBbvgeivmV6Sx+slleNOpoWtr7HyFpSdixwW KHT6rhdZDPLx2lPqzMGrYSUsbT7+Ixoc8Nk0yGCxdAeuYRRV8peuhsTk38ehvRLJc9 uZrLl8pe0kIFBEp0CCpV/tpuMHEVNkKS9750CEBMnzX09T/3mwNn4b9mjDHcI5zSNg tC12AXIiFxG97rm4dOS+v+UO9qhJFfBY+2BEjpp04KiqgvfWL964BnLWPNG86C88bK +cTDEROKwqsZA== 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> <87mtsz619u.ffs@nanos.tec.linutronix.de> From: "H. Peter Anvin" Message-ID: Date: Thu, 13 May 2021 17:38:02 -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: <87mtsz619u.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 3:22 PM, Thomas Gleixner wrote: >> >> 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. > > I'm not against that change, but it has to be well justified and the > reasoning wants to be in the changelog. You know the drill :) > FYI: So in the process of breaking up and better document this patch, I have looked at the syscall_numbering_64 (and have rewritten it to be more complete.) I found that running it under strace fails, as strace (possibly ptrace, possibly the strace binary) causes %rax = 2^32 to be clobbered to zero already... More motivation, I guess. -hpa