Re: [PATCH 3/5] lib/mpi: Fix for building for MIPS32 with Clang

From: Nathan Chancellor <natechancellor@gmail.com>
To: Jussi Kivilinna <jussi.kivilinna@iki.fi>
Cc: Ralf Baechle <ralf@linux-mips.org>,
	Paul Burton <paul.burton@mips.com>,
	James Hogan <jhogan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
	clang-built-linux@googlegroups.com,
	Vladimir Serbinenko <phcoder@gmail.com>
Subject: Re: [PATCH 3/5] lib/mpi: Fix for building for MIPS32 with Clang
Date: Mon, 12 Aug 2019 10:14:48 -0700	[thread overview]
Message-ID: <20190812171448.GA10039@archlinux-threadripper> (raw)
In-Reply-To: <ec4666a6-c7db-247b-de81-bb784bb9d649@iki.fi>

On Mon, Aug 12, 2019 at 10:35:53AM +0300, Jussi Kivilinna wrote:
> Hello,
> 
> On 12.8.2019 6.31, Nathan Chancellor wrote:
> > From: Vladimir Serbinenko <phcoder@gmail.com>
> > 
> > clang doesn't recognise =l / =h assembly operand specifiers but apparently
> > handles C version well.
> > 
> > lib/mpi/generic_mpih-mul1.c:37:24: error: invalid use of a cast in a
> > inline asm context requiring an l-value: remove the cast or build with
> > -fheinous-gnu-extensions
> >                 umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb);
> >                 ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > lib/mpi/longlong.h:652:20: note: expanded from macro 'umul_ppmm'
> >         : "=l" ((USItype)(w0)), \
> >                 ~~~~~~~~~~^~~
> > lib/mpi/generic_mpih-mul1.c:37:3: error: invalid output constraint '=h'
> > in asm
> >                 umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb);
> >                 ^
> > lib/mpi/longlong.h:653:7: note: expanded from macro 'umul_ppmm'
> >              "=h" ((USItype)(w1)) \
> >              ^
> > 2 errors generated.
> > 
> > Fixes: 5ce3e312ec5c ("crypto: GnuPG based MPI lib - header files (part 2)")
> > Link: https://github.com/ClangBuiltLinux/linux/issues/605
> > Link: https://github.com/gpg/libgcrypt/commit/1ecbd0bca31d462719a2a6590c1d03244e76ef89
> > Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
> > [jk: add changelog, rebase on libgcrypt repository, reformat changed
> >  line so it does not go over 80 characters]
> > Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>
> 
> This is my signed-off-by for libgcrypt project, not kernel. I do not think
> signed-offs can be passed from other projects in this way.
> 
> -Jussi

Hi Jussi,

I am no signoff expert but if I am reading the developer certificate of
origin in the libgcrypt repo correctly [1], your signoff on this commit
falls under:

(d) I understand and agree that this project and the contribution
    are public and that a record of the contribution (including all
    personal information I submit with it, including my sign-off) is
    maintained indefinitely and may be redistributed consistent with
    this project or the open source license(s) involved.

This file is maintained under the LGPL because it was taken straight
from the libgcrypr repo and per (b), I can submit this commit here
with everything intact.

However, I don't want to upset you in any way though so if you are not
comfortable with that, I suppose I can remove it as if Vladimir
submitted this fix to me directly (as I got permission for his signoff).
I need to resubmit this fix to an appropriate maintainer so let me know
what you think.

[1]: https://github.com/gpg/libgcrypt/blob/3bb858551cd5d84e43b800edfa2b07d1529718a9/doc/DCO

Cheers,
Nathan