From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751502AbbIFGD0 (ORCPT ); Sun, 6 Sep 2015 02:03:26 -0400 Received: from terminus.zytor.com ([198.137.202.10]:48577 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751075AbbIFGDT (ORCPT ); Sun, 6 Sep 2015 02:03:19 -0400 Subject: Re: [PATCH v2] x86/asm/entry/64: Minor cleanup of conditional compilation To: Nikolay Borisov , mingo@kernel.org References: <1441486423-6997-1-git-send-email-nikolay.b.borisov@gmail.com> Cc: dvlasenk@redhat.com, luto@amacapital.net, linux-kernel@vger.kernel.org, bp@suse.de From: "H. Peter Anvin" Message-ID: <55EBD714.30509@zytor.com> Date: Sat, 5 Sep 2015 23:03:00 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: <1441486423-6997-1-git-send-email-nikolay.b.borisov@gmail.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/05/15 13:53, Nikolay Borisov wrote: > The entry_SYSCALL_64_fastpath was checking the value of __SYSCALL_MASK, > which in turn was being set in arch/x86/include/asm/unistd.h depending on > whether CONFIG_X86_X32_ABI was set or not. This made the intention a bit > cryptic. On the contrary: that instruction can be omitted if and only if the value of the mask is all 1's; it doesn't matter how the mask is set. So you just turned a local constraint into a global constraint. This is both unnecessarily confusing and opens the risk for bugs later. If you feel the need, you could submit a patch to add a comment, but this version is: Nacked-by: H. Peter Anvin