From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Engelhardt Subject: Re: [PATCH v4 3/7] x86: put msr-index.h in uapi Date: Mon, 23 Jan 2017 23:24:02 +0100 (CET) Message-ID: References: <1484304406-10820-1-git-send-email-nicolas.dichtel@6wind.com> <1485183521-13002-1-git-send-email-nicolas.dichtel@6wind.com> <1485183521-13002-4-git-send-email-nicolas.dichtel@6wind.com> <20170123165245.7zy7nf3cx5o4vvh3@pd.tnic> <20170123171732.i3qfbcsqzznppe5m@pd.tnic> <20170123172103.GB28446@infradead.org> <20170123172627.32zcbntwo7nmd5rf@pd.tnic> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: <20170123172627.32zcbntwo7nmd5rf@pd.tnic> Sender: linux-kbuild-owner@vger.kernel.org To: Borislav Petkov Cc: Christoph Hellwig , Nicolas Dichtel , arnd@arndb.de, mmarek@suse.com, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, airlied@linux.ie, davem@davemloft.net, linux@armlinux.org.uk, slash.tmp@free.fr, daniel.vetter@ffwll.ch, rmk+kernel@armlinux.org.uk, msalter@redhat.com, tklauser@distanz.ch, mpe@ellerman.id.au, mingo@kernel.org, hpa@zytor.com List-Id: linux-arch.vger.kernel.org On Monday 2017-01-23 18:26, Borislav Petkov wrote: >On Mon, Jan 23, 2017 at 09:21:03AM -0800, Christoph Hellwig wrote: >> Or keep the exported version as-is and never changed it, and use >> a different copy for the kernel itself. > >I guess we'll have to do that if something in userspace has put its >sticky fingers on that file and cannot be fixed. Which I hardly doubt >but we can't break that damn userspace. The importance of uapi headers presence is a bit overrated. If you look at, for example, iptables (and further projects in that area), copies of uapi headers have been made (and this process is likely to continue) because it could be compiled on a variety of vintage systems that do not have all required #defines yet. Similarly, it may be built on a variety of _modern_ systems whose kernels no longer have a particular thing (e.g. ipt_SAME), so it also ships copies of those headers. So if some userspace component depends on that particular msr header (which, unlike ipt_SAME, was not intended for export), is it not reasonable to expect them to make a copy if and when they need it? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ares41.inai.de ([46.4.122.207]:55088 "EHLO ares41.inai.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751183AbdAWWYF (ORCPT ); Mon, 23 Jan 2017 17:24:05 -0500 Date: Mon, 23 Jan 2017 23:24:02 +0100 (CET) From: Jan Engelhardt Subject: Re: [PATCH v4 3/7] x86: put msr-index.h in uapi In-Reply-To: <20170123172627.32zcbntwo7nmd5rf@pd.tnic> Message-ID: References: <1484304406-10820-1-git-send-email-nicolas.dichtel@6wind.com> <1485183521-13002-1-git-send-email-nicolas.dichtel@6wind.com> <1485183521-13002-4-git-send-email-nicolas.dichtel@6wind.com> <20170123165245.7zy7nf3cx5o4vvh3@pd.tnic> <20170123171732.i3qfbcsqzznppe5m@pd.tnic> <20170123172103.GB28446@infradead.org> <20170123172627.32zcbntwo7nmd5rf@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-arch-owner@vger.kernel.org List-ID: To: Borislav Petkov Cc: Christoph Hellwig , Nicolas Dichtel , arnd@arndb.de, mmarek@suse.com, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, airlied@linux.ie, davem@davemloft.net, linux@armlinux.org.uk, slash.tmp@free.fr, daniel.vetter@ffwll.ch, rmk+kernel@armlinux.org.uk, msalter@redhat.com, tklauser@distanz.ch, mpe@ellerman.id.au, mingo@kernel.org, hpa@zytor.com Message-ID: <20170123222402.qKfdJK1Bk5Ve5ZNYGGYwnaEFhO_G35xknFmPztPAsOU@z> On Monday 2017-01-23 18:26, Borislav Petkov wrote: >On Mon, Jan 23, 2017 at 09:21:03AM -0800, Christoph Hellwig wrote: >> Or keep the exported version as-is and never changed it, and use >> a different copy for the kernel itself. > >I guess we'll have to do that if something in userspace has put its >sticky fingers on that file and cannot be fixed. Which I hardly doubt >but we can't break that damn userspace. The importance of uapi headers presence is a bit overrated. If you look at, for example, iptables (and further projects in that area), copies of uapi headers have been made (and this process is likely to continue) because it could be compiled on a variety of vintage systems that do not have all required #defines yet. Similarly, it may be built on a variety of _modern_ systems whose kernels no longer have a particular thing (e.g. ipt_SAME), so it also ships copies of those headers. So if some userspace component depends on that particular msr header (which, unlike ipt_SAME, was not intended for export), is it not reasonable to expect them to make a copy if and when they need it?