From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 982C11A5A0; Wed, 3 Jan 2024 14:36:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Pj111nEW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8961AC433C8; Wed, 3 Jan 2024 14:36:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1704292564; bh=is7O5uMKlFnKVd3x+vpOi0jZoWskFl0wA4r7k43/gWY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Pj111nEWhbwtnIBXAmtPTKY07uMZLZalmcUisGEP01x91bzK1WMukhkXdmvcbLiz4 nzjuKfvPLvnFmmJnrLQ3u5SNnbNuN7NK7IuyAO7jqoF0a4BeqbHjaoYV14ky9gjX7u AQMYN2St2mGoLuzjRd+80Ftvu2tbiJmi8zaOAteCnijOw/MGNC+tQiq1/XqiG9txGu R1dqFESMQMMqdCT57+JD8QAZu4Xa5xXNj+LQwbw3REC5LQfR/1AaGwt0+F/MikT/nw bzj0byS0nAt1ZtobKqk3F5og48OWQeWe5VrN+DFCETjFL6EO7F3nQiUlMw5X/4jtnA qAzRUdUnPCWuQ== Date: Wed, 3 Jan 2024 08:35:57 -0600 From: Eric Biggers To: Ard Biesheuvel Cc: linux-crypto@vger.kernel.org, linux-riscv@lists.infradead.org, Jerry Shih , linux-kernel@vger.kernel.org, Heiko Stuebner , Phoebe Chen , hongrong.hsu@sifive.com, Paul Walmsley , Palmer Dabbelt , Albert Ou , Andy Chiu Subject: Re: [RFC PATCH 00/13] RISC-V crypto with reworked asm files Message-ID: <20240103143557.GA773@quark.localdomain> References: <20240102064743.220490-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Jan 03, 2024 at 03:00:29PM +0100, Ard Biesheuvel wrote: > On Tue, 2 Jan 2024 at 07:50, Eric Biggers wrote: > > > > As discussed previously, the proposed use of the so-called perlasm for > > the RISC-V crypto assembly files makes them difficult to read, and these > > files have some other issues such extensively duplicating source code > > for the different AES key lengths and for the unrolled hash functions. > > There is/was a desire to share code with OpenSSL, but many of the files > > have already diverged significantly; also, for most of the algorithms > > the source code can be quite short anyway, due to the native support for > > them in the RISC-V vector crypto extensions combined with the way the > > RISC-V vector extension naturally scales to arbitrary vector lengths. > > > > Since we're still waiting for prerequisite patches to be merged anyway, > > we have a bit more time to get this cleaned up properly. So I've had a > > go at cleaning up the patchset to use standard .S files, with the code > > duplication fixed. I also made some tweaks to make the different > > algorithms consistent with each other and with what exists in the kernel > > already for other architectures, and tried to improve comments. > > > > The result is this series, which passes all tests and is about 2400 > > lines shorter than the latest version with the perlasm > > (https://lore.kernel.org/linux-crypto/20231231152743.6304-1-jerry.shih@sifive.com/). > > All the same functionality and general optimizations are still included, > > except for some minor optimizations in XTS that I dropped since it's not > > clear they are worth the complexity. (Note that almost all users of XTS > > in the kernel only use it with block-aligned messages, so it's not very > > important to optimize the ciphertext stealing case.) > > > > I'd appreciate people's thoughts on this series. Jerry, I hope I'm not > > stepping on your toes too much here, but I think there are some big > > improvements here. > > > > As I have indicated before, I fully agree with Eric here that avoiding > perlasm is preferable: sharing code with OpenSSL is great if we can > simply adopt the exact same code (and track OpenSSL as its upstream) > but this never really worked that well for skciphers, due to API > differences. (The SHA transforms can be reused a bit more easily) > > I will also note that perlasm is not as useful for RISC-V as it is for > other architectures: in OpenSSL, perlasm is also used to abstract > differences in calling conventions between, e.g., x86_64 on Linux vs > Windows, or to support building with outdated [proprietary] > toolchains. > > I do wonder if we could also use .req directives for register aliases > instead of CPP defines? It shouldn't matter for working code, but the > diagnostics tend to be a bit more useful if the aliases are visible to > the assembler. .req unfortunately isn't an option since it is specific to AArch64 and ARM assembly. So we have to use #defines like x86 does. Ultimately, the effect is about the same. - Eric