Hi Julien, > On 20 Aug 2022, at 20:08, Julien Grall <jul...@xen.org> wrote: > > Hi Stefano, > > On 19/08/2022 23:53, Stefano Stabellini wrote: >> On Fri, 19 Aug 2022, Julien Grall wrote: >>> On 18/08/2022 23:03, Stefano Stabellini wrote: >>>> Add SPDX license information to all the *.c files under arch/arm. >>> >>> There are some of the files below that didn't have copyright. It would be >>> worth explaining in the commit message which license you selected and how. >>> AFAICT you assumed they were GPLv2 but I am not sure this is correct at >>> least >>> one of them. >> My goal is not to change the existing license on any of the files, even >> if the existing license is imprecise. By what is written under COPYING, >> everything not explicitly listed is GPL-2.0. I only reflected today's >> reality. I think it is best if we keep mechanical changes separate from >> "smart" changes, especially on a series like this introducing many >> mechanical changes. More on this at the bottom. > > I will answer to this at the bottom. > >>> [...] >>> >>>> diff --git a/xen/arch/arm/decode.c b/xen/arch/arm/decode.c >>>> index f5f6562600..2537dbebc1 100644 >>>> --- a/xen/arch/arm/decode.c >>>> +++ b/xen/arch/arm/decode.c >>>> @@ -1,3 +1,4 @@ >>>> +/* SPDX-License-Identifier: GPL-2.0-or-later */ >>> >>> This license is not part of LICENSES. Was it intended? >> It is: the tag is described as part of LICENSES/GPL-2.0. > > Ah! I was looking as the list of files and didn't look for the tag. Thanks > for the pointer :). > >>> If yes, this should be mentioned in one of the commit message (possible >>> patch >>> #2) and maybe in CONTRIBUTING (to tell user to not use it for new files) >>> because one could expect all the LICENSES to be listed. >> It could make sense to say that: >> /* SPDX-License-Identifier: GPL-2.0 */ >> is recommended for new files. > > So I was reading through xen/COPYING and we already have something like that: > > "Note that the only valid version of the GPL as far as Xen is concerned > is _this_ particular version of the license (i.e., *only* v2, not v2.2 > or v3.x or whatever), unless explicitly otherwise stated." > > So nothing to add here unless you want to tell the contributor which tag > correspond to GPLv2. > >>>> /* >>>> * xen/arch/arm/decode.c >>>> * >>>> @@ -5,16 +6,6 @@ >>>> * >>>> * Julien Grall <julien.gr...@linaro.org> >>>> * Copyright (C) 2013 Linaro Limited. >>>> - * >>>> - * This program is free software; you can redistribute it and/or modify >>>> - * it under the terms of the GNU General Public License as published by >>>> - * the Free Software Foundation; either version 2 of the License, or >>>> - * (at your option) any later version. >>>> - * >>>> - * This program is distributed in the hope that it will be useful, >>>> - * but WITHOUT ANY WARRANTY; without even the implied warranty of >>>> - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >>>> - * GNU General Public License for more details. >>>> */ >>>> #include <xen/guest_access.h> >>> >>> [...] >>> >>>> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c >>>> index 3fd1186b53..b29bdf3aa6 100644 >>>> --- a/xen/arch/arm/domain_build.c >>>> +++ b/xen/arch/arm/domain_build.c >>>> @@ -1,3 +1,4 @@ >>>> +/* SPDX-License-Identifier: GPL-2.0 */ >>> >>> AFAIU, the assumption is all the files with no copyright are GPLv2. That >>> works >>> here. But ... >>> >>>> #include <xen/init.h> >>>> #include <xen/compile.h> >>>> #include <xen/lib.h> >>>> diff --git a/xen/arch/arm/domain_page.c b/xen/arch/arm/domain_page.c >>>> index 71182575f9..47405e0866 100644 >>>> --- a/xen/arch/arm/domain_page.c >>>> +++ b/xen/arch/arm/domain_page.c >>>> @@ -1,3 +1,4 @@ >>>> +/* SPDX-License-Identifier: GPL-2.0 */ >>> >>> .... this file was split from mm.c which is gpl-2.0-or-later. So I don't >>> think >>> we can use GPL-2.0 here. >> Well spotted! Effectively this file is now declared as GPL 2.0 only, >> given what is stated in COPYING. The code in domain_page has lost "or >> later" with the loss of the copyright header. > > Yes. This was an oversight from me when I split the code a few weeks ago. > >> So if there were new contributions to this file after its creation, they >> would have been GPL-2.0 only contributions, and it would have been >> impossible to go back to GPL-2.0-or-later without asking the copyright >> owners of the new changes. >> In this case thankfully there are no new contributions since the split >> of the file, so I can fix it by using the SPDX GPL-2.0-or-later tag >> without problems. I'll do it in the next version of the series. >> Xen is not saying: "if there is no copyright header it might be GPLv2 >> but you need to look it up". Xen is actively saying: "if there is no >> copyright header it is GPLv2". Not up for discussion. Given that as a >> whole Xen is GPLv2, the only possibility is that the file without a >> copyright header used to be: >> - GPLv2 or later >> - dual license GPL and another compatible license (e.g. BSD) >> Either way, with the loss of the copyright header, the file becomes >> immediately GPLv2 only. >> Does it make sense? >> This is why I think it is best to keep copyright discussions out of the >> SPDX patches review and limit ourselves to mechanical changes. > > Yes I agree this series should be mechanical (baring the file that is contain > GPLv2+ code). > > I am putting some thoughts below (they can be split in a separate thread if > you prefer). > > This is not the first time this topic is brought up and probably not the last > as long as we have file using GPLv2+. > > IIRC from past discussion there are two broads concern with GPLv2+: > - We are leaving the choice of which license applies to the person copying > the code. So if a new version is released that is less favorable to the > initial contributor, then we have no leverage. > - Some companies are rather cautious to contribute code that my be licensed > under GPLv3 (would be allowed with GPLv2+). > > The later is particularly a problem because not many people realize that a > fair part of Xen on Arm is GPLv2+. I never really understood why we chose > that (this was before my time) but this got spread as the existing copyright > was added to a new file. Admittely, the contributor should be more cautious. > But I would not say this is trivial to spot the difference. > > I would like to consider to re-license all the GPLv2+ files to GPLv2. AFAIU, > this would mean we would need to ask the permission for every comapany that > contributed to the file. Do you know if this was done before in Xen Project?
If I am understanding right, GPLv2+ means that someone could relicense the files to GPLv3 if he wants which is more restrictive. Why do you want to move those back to GPLv2 ? Cheers Bertrand > > Cheers, > > -- > Julien Grall
