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 7FFA32A1BA; Sun, 8 Jun 2025 23:47:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749426428; cv=none; b=eY13bqOt1otnbRfiWTVhhFindziCBaaPJgSxUdXb+kI79h1g9D070YXOEO1+ivv/fTGMQ1GN1DGji25sRfLWS00OI5HT0rNoKGmbJlY9ReD2VjUV+pYWsu0RlUtrv5T2PfVgBrLkNbFjRlyhZtAGsv0MIQ4CJAMhNUE4c9odA1o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749426428; c=relaxed/simple; bh=He/qqF7BxEbAQ+KhVIwOAYIjY3DpawZEJHr+Xte/K6Q=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=h+Ot9BiVeE5ljmtAe79J1zJs6TToDtCY2+e+9UinX7wo/NhU3KvvUcYOe1RSjiGKhkmAThp0HscSwHTA6eV+lseOUELhNknSeTOKRbd1uqR8qWNv06qsSe8pt74CGaXHhrVFmIGYkq4zLvERtVUhpwPKWgw6maqGQlAt5qww9iE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EPyWCyBV; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="EPyWCyBV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8491AC4CEEE; Sun, 8 Jun 2025 23:47:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749426428; bh=He/qqF7BxEbAQ+KhVIwOAYIjY3DpawZEJHr+Xte/K6Q=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EPyWCyBVPXpu72efvExgg8gLAw9penLyFzlo1qRsspsqyd4JZoFxW7hHQvlnEtIIa 1BxGaS04c9RuFEve+dtCt1LEb2SSISR2VgjLm0WYXRDHNt8nXsOorMQAj8PjQpmAB0 F5rfSxl/09kNUJny72FkrWqXDDqrWHkySwoyI3r23w9s9UZxhxYgVcxmIH21znQLYr RAY4VaCbmTRnWUl2bEewz1enz7kzJYX9fFC9W66bUVBifTQ9wgF652vwOiRoE9mHCR SyixTBnJQbaXXeJQKz8gWyl2YRqW1kNgBMYmIhv1mCruOadbFAPFkGtBFHhXGzcMB6 +EWaHxDKp/9YA== Date: Sun, 8 Jun 2025 16:46:46 -0700 From: Eric Biggers To: linux-kernel@vger.kernel.org Cc: linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, x86@kernel.org, linux-arch@vger.kernel.org, Ard Biesheuvel , "Jason A . Donenfeld " , Linus Torvalds Subject: Re: [PATCH 00/13] lib/crc: improve how arch-optimized code is integrated Message-ID: <20250608234646.GE1259@sol> References: <20250601224441.778374-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: sparclinux@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: <20250601224441.778374-1-ebiggers@kernel.org> On Sun, Jun 01, 2025 at 03:44:28PM -0700, Eric Biggers wrote: > This series improves how lib/crc supports arch-optimized code. First, > instead of the arch-optimized CRC code being in arch/$(SRCARCH)/lib/, it > will now be in lib/crc/$(SRCARCH)/. Second, the API functions (e.g. > crc32c()), arch-optimized functions (e.g. crc32c_arch()), and generic > functions (e.g. crc32c_base()) will now be part of a single module for > each CRC type, allowing better inlining and dead code elimination. The > second change is made possible by the first. > > As an example, consider CONFIG_CRC32=m on x86. We'll now have just > crc32.ko instead of both crc32-x86.ko and crc32.ko. The two modules > were already coupled together and always both got loaded together via > direct symbol dependency, so the separation provided no benefit. > > Note: later I'd like to apply the same design to lib/crypto/ too, where > often the API functions are out-of-line so this will work even better. > In those cases, for each algorithm we currently have 3 modules all > coupled together, e.g. libsha256.ko, libsha256-generic.ko, and > sha256-x86.ko. We should have just one, inline things properly, and > rely on the compiler's dead code elimination to decide the inclusion of > the generic code instead of manually setting it via kconfig. > > Having arch-specific code outside arch/ was somewhat controversial when > Zinc proposed it back in 2018. But I don't think the concerns are > warranted. It's better from a technical perspective, as it enables the > improvements mentioned above. This model is already successfully used > in other places in the kernel such as lib/raid6/. The community of each > architecture still remains free to work on the code, even if it's not in > arch/. At the time there was also a desire to put the library code in > the same files as the old-school crypto API, but that was a mistake; now > that the library is separate, that's no longer a constraint either. > > Patches 1 and 2, which I previously sent out by themselves, are > prerequisites because they eliminate the need for the CRC32 library API > to expose the generic functions. > > Eric Biggers (13): > crypto/crc32: register only one shash_alg > crypto/crc32c: register only one shash_alg Applied the first 2 patches to https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git/log/?h=crc-next The remaining patches have new versions in the v2 series. - Eric