From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752676AbbIWIGM (ORCPT ); Wed, 23 Sep 2015 04:06:12 -0400 Received: from mail-wi0-f173.google.com ([209.85.212.173]:37213 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751854AbbIWIGB (ORCPT ); Wed, 23 Sep 2015 04:06:01 -0400 Date: Wed, 23 Sep 2015 10:05:58 +0200 From: Ingo Molnar To: Dave Hansen Cc: Thomas Gleixner , x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Peter Zijlstra Subject: Re: [PATCH 10/26] x86, pkeys: notify userspace about protection key faults Message-ID: <20150923080558.GA28876@gmail.com> References: <20150916174903.E112E464@viggo.jf.intel.com> <20150916174906.51062FBC@viggo.jf.intel.com> <5601B82F.6070601@sr71.net> <5601BA44.8080604@sr71.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5601BA44.8080604@sr71.net> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Dave Hansen wrote: > On 09/22/2015 01:27 PM, Thomas Gleixner wrote: > >> > > >> > So I defined all the kernel-internal types as u16 since I *know* the > >> > size of the hardware. > >> > > >> > The user-exposed ones should probably be a bit more generic. I did just > >> > realize that this is an int and my proposed syscall is a long. That I > >> > definitely need to make consistent. > >> > > >> > Does anybody care whether it's an int or a long? > > long is frowned upon due to 32/64bit. Even if that key stuff is only > > available on 64bit for now .... > > Well, it can be used by 32-bit apps on 64-bit kernels. > > Ahh, that's why we don't see any longs in the siginfo. So does that > mean 'int' is still our best bet in siginfo? Use {s|u}{8|16|32|64} integer types in ABI relevant interfaces please, they are our most unambiguous and constant types. Here that would mean s32 or u32? Thanks, Ingo