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 261EE190696; Sun, 1 Jun 2025 23:00:33 +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=1748818836; cv=none; b=Hzi7BbTPXekyFGIG3Y/Hsh85Tlitt3JZN9bO2ffT/k1J/ZAszndm+26nK3jLyGUERuwxyx75nXGJJ4ZeVO+K2Ihzs2gPadu3cFznmq4bTASn8SXYdneJjgKUi5Hi80nfVWTCjZnf18ciFOG02g1C4Ya6evA2h3h309I8BMuG3qE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748818836; c=relaxed/simple; bh=9iuAqFgWuAM8zbaClmJE1PWkDiz9aDszJI49BnUralg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GkV/L9mOeKnECfMVYjcgH2DpCnOQ/iOCbx1SwZHNmPRFVwPfHP0JoJwQ2OmWOUYs6xEMP/BRxXaM5GBKHtFw7MelaX/tgp5ylhkA0yBSTEVHXVSH7TlT8JHQ/JMRonxJTsAtePzc3XSyuznFmz4ThijOhrriVXwoXf3ELvdM4WE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=vHFxc2VE; 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="vHFxc2VE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 14CC5C4CEE7; Sun, 1 Jun 2025 23:00:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1748818833; bh=9iuAqFgWuAM8zbaClmJE1PWkDiz9aDszJI49BnUralg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=vHFxc2VElAHlFA2+p6pUxtFWEe5J4xv+o56KAxPCmT8t7sop9JD+tvRSV5M6+149b 3yslurmUrK9306e+AjqkjU66ZE4+J12qO4pfC9GKOwcLYIKirbFU/Rg2oRbbVA43ns 5uDfSlrlHs9e9hvwYN9GazeDaNtZ3XeMSpkJHQHb3lkfbDihKnyqOzItzJyKZ/V5SA kll91RZkjqNe9evwrPUGhmeKBh/iuKFMYirrTrajg0Qa5HWH48c/p5D7scSRNhf3bP g9JW0K0QMuooWlvxhFXufeAQiYS/ENsn141k7rnLZBFnOMguZuObdXNfv/1/r4saJT S2ckVl3S2NSgA== Date: Sun, 1 Jun 2025 16:00:14 -0700 From: Eric Biggers To: Linus Torvalds Cc: Alex Williamson , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, sparclinux@vger.kernel.org, linux-s390@vger.kernel.org, x86@kernel.org, Ard Biesheuvel , "Jason A . Donenfeld" Subject: Re: [PATCH v4 08/13] crypto: s390/sha256 - implement library instead of shash Message-ID: <20250601230014.GB1228@sol> References: <20250428170040.423825-1-ebiggers@kernel.org> <20250428170040.423825-9-ebiggers@kernel.org> <20250529110526.6d2959a9.alex.williamson@redhat.com> <20250529173702.GA3840196@google.com> <20250529211639.GD23614@sol> <20250530001858.GD3840196@google.com> Precedence: bulk X-Mailing-List: linux-arch@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: <20250530001858.GD3840196@google.com> On Fri, May 30, 2025 at 12:18:58AM +0000, Eric Biggers wrote: > On Thu, May 29, 2025 at 04:54:34PM -0700, Linus Torvalds wrote: > > On Thu, 29 May 2025 at 14:16, Eric Biggers wrote: > > > > > > So using crc32c() + ext4 + x86 as an example (but SHA-256 would be very > > > similar), the current behavior is that ext4.ko depends on the crc32c_arch() > > > symbol. > > > > Yes, I think that's a good example. > > > > I think it's an example of something that "works", but it certainly is > > a bit hacky. > > > > Wouldn't it be nicer if just plain "crc32c()" did the right thing, > > instead of users having to do strange hacks just to get the optimized > > version that they are looking for? > > For crc32c() that's exactly how it works (since v6.14, when I implemented it). > The users call crc32c() which is an inline function, which then calls > crc32c_arch() or crc32c_base() depending on the kconfig. So that's why I said > the symbol dependency is currently on crc32c_arch. Sorry if I wasn't clear. > The SHA-256, ChaCha, and Poly1305 library code now has a similar design too. > > If we merged the arch and generic modules together, then the symbol would become > crc32c. But in either case crc32c() is the API that all the users call. > > - Eric > I implemented my proposal, for lib/crc first, in https://lore.kernel.org/lkml/20250601224441.778374-1-ebiggers@kernel.org. I think it's strictly better than the status quo, and once applied to lib/crypto it will solve some of the problems we've been having there too. But let me know if you still have misgivings. - Eric