Re: [PATCH 1/3] crypto: X25519 low-level primitives for ppc64le.

Michael Ellerman
2024-05-16T04:53:57Z

Hi Danny,

Danny Tsen <dtsen@linux.ibm.com> writes:
> Use the perl output of x25519-ppc64.pl from CRYPTOGAMs and added three
> supporting functions, x25519_fe51_sqr_times, x25519_fe51_frombytes
> and x25519_fe51_tobytes.

For other algorithms we have checked-in the perl script and generated
the code at runtime. Is there a reason you've done it differently this time?

> Signed-off-by: Danny Tsen <dtsen@linux.ibm.com>
> ---
> arch/powerpc/crypto/curve25519-ppc64le_asm.S | 648 +++++++++++++++++++
> 1 file changed, 648 insertions(+)
> create mode 100644 arch/powerpc/crypto/curve25519-ppc64le_asm.S
>
> diff --git a/arch/powerpc/crypto/curve25519-ppc64le_asm.S b/arch/powerpc/crypto/curve25519-ppc64le_asm.S
> new file mode 100644
> index 000000000000..8a018104838a
> --- /dev/null
> +++ b/arch/powerpc/crypto/curve25519-ppc64le_asm.S
> @@ -0,0 +1,648 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +#
> +# Copyright 2024- IBM Corp. All Rights Reserved.

I'm not a lawyer, but AFAIK "All Rights Reserved" is not required and
can be confusing - because we are not reserving all rights, we are
granting some rights under the GPL.

I also think the IBM copyright should be down below where your
modifications are described.

> +# This code is taken from CRYPTOGAMs[1] and is included here using the option
> +# in the license to distribute the code under the GPL. Therefore this program
> +# is free software; you can redistribute it and/or modify it under the terms of
> +# the GNU General Public License version 2 as published by the Free Software
> +# Foundation.
> +#
> +# [1] https://www.openssl.org/~appro/cryptogams/
> +
> +# Copyright (c) 2006-2017, CRYPTOGAMS by <appro@openssl.org>
> +# All rights reserved.
> +#
> +# Redistribution and use in source and binary forms, with or without
> +# modification, are permitted provided that the following conditions
> +# are met:
> +#
> +# * Redistributions of source code must retain copyright notices,
> +# this list of conditions and the following disclaimer.
> +#
> +# * Redistributions in binary form must reproduce the above
> +# copyright notice, this list of conditions and the following
> +# disclaimer in the documentation and/or other materials
> +# provided with the distribution.
> +#
> +# * Neither the name of the CRYPTOGAMS nor the names of its
> +# copyright holder and contributors may be used to endorse or
> +# promote products derived from this software without specific
> +# prior written permission.
> +#
> +# ALTERNATIVELY, provided that this notice is retained in full, this
> +# product may be distributed under the terms of the GNU General Public
> +# License (GPL), in which case the provisions of the GPL apply INSTEAD OF
> +# those given above.
> +#
> +# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS
> +# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
> +# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
> +# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
> +# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
> +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
> +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
> +# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
> +# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> +# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
> +# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> +
> +# ====================================================================
> +# Written by Andy Polyakov <appro@openssl.org> for the OpenSSL
> +# project. The module is, however, dual licensed under OpenSSL and
> +# CRYPTOGAMS licenses depending on where you obtain it. For further
> +# details see https://www.openssl.org/~appro/cryptogams/.
> +# ====================================================================
> +
> +#
> +# ====================================================================
> +# Written and Modified by Danny Tsen <dtsen@us.ibm.com>
> +# - Added x25519_fe51_sqr_times, x25519_fe51_frombytes, x25519_fe51_tobytes

ie. here.

> +# X25519 lower-level primitives for PPC64.
> +#
> +
> +#include <linux/linkage.h>
> +
> +.machine "any"

Please don't add new .machine directives unless they are required.

> +.abiversion 2

I'd prefer that was left to the compiler flags.

cheers