Subject: Re: [PATCH 1/8] arm64: Import latest version of Cortex Strings' memcmp

From: Szabolcs Nagy <[email-masked]>
Date: Wed, 12 May 2021 15:51:56 +0100

The 05/12/2021 14:38, Robin Murphy wrote:
> [ Dropping Kai Shen who is now bouncing, adding Szabolcs just in case ]
> On 2021-05-12 14:28, Mark Rutland wrote:
> > On Tue, May 11, 2021 at 05:12:31PM +0100, Robin Murphy wrote:
> > > From: Sam Tebbs <[email-masked]>
> > > 
> > > Import the latest version of the former Cortex Strings - now
> > > Arm Optimized Routines - memcmp function based on the upstream
> > > code of string/aarch64/memcmp.S at commit e823e3a from
> > > https://github.com/ARM-software/optimized-routines
> > 
> > What's the licensing/copyright situation here?
> > 
> > Because below...
> > 
> > > 
> > > Signed-off-by: Sam Tebbs <[email-masked]>
> > > [ rm: update attribution and commit message ]
> > > Signed-off-by: Robin Murphy <[email-masked]>
> > > ---
> > >   arch/arm64/lib/memcmp.S | 330 ++++++++++++++--------------------------
> > >   1 file changed, 111 insertions(+), 219 deletions(-)
> > > 
> > > diff --git a/arch/arm64/lib/memcmp.S b/arch/arm64/lib/memcmp.S
> > > index c0671e793ea9..498f0d9941d9 100644
> > > --- a/arch/arm64/lib/memcmp.S
> > > +++ b/arch/arm64/lib/memcmp.S
> > > @@ -1,247 +1,139 @@
> > >   /* SPDX-License-Identifier: GPL-2.0-only */
> > 
> > ... this says GPL-2.0-only ....
> > 
> > >   /*
> > > - * Copyright (C) 2013 ARM Ltd.
> > > - * Copyright (C) 2013 Linaro.
> > > + * Copyright (c) 2013-2020, Arm Limited.
> > >    *
> > > - * This code is based on glibc cortex strings work originally authored by Linaro
> > > - * be found @
> > > - *
> > > - * http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/
> > > - * files/head:/src/aarch64/
> > > + * Adapted from the original at:
> > > + * https://github.com/ARM-software/optimized-routines/blob/master/string/aarch64/memcmp.S
> > >    */
> > 
> > ... but this referenced file says "SPDX-License-Identifier: MIT", and I
> > don't know when this relicensing is legitimate.
> 
> We were told that since the copyright was fully assigned back to Arm in the
> move from Cortex Strings to Arm Optimized Routines, we are free to relicense
> it as we see fit, so a GPLv2 submission to Linux was still fine.

yes, this code is fully owned by arm now, but the
licensing is not clear to an outside observer.

arm optimized-routines uses MIT license since that
seemed to be widely accepted, but then we were asked
to contribute the code under BSD3, LLVM, GPLv2,...
which is a bit of a pain (since then arm has to get
involved, we wanted others to take the code without
us having to do anything).

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