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 CCCE92AD0C for ; Tue, 31 Mar 2026 22:33:02 +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=1774996382; cv=none; b=W+j8418XlFQg5+x9Jd/dgbnIxkAILpOhVIXpQC8Nuy8GnT1GiASAduZgBKG1EVv0gT+xSaWSJkevDN/xC0b+S8J24OBK3dsnH7kbBI2Mq52nftAKWAA9dpCasHQSEuH0XQeTJLerIZX5X3CtVixtbrDayUlJqkcmEruDYZyxYBU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774996382; c=relaxed/simple; bh=RJQkS8bUU8ttoMMCwjfNIsTwajwii9xgzqJ9jw17VAE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZOzUSgqNx39wRDpmKOfbUurFN8fL5vbpzbydL8q3ooJXbjM/PSzB7lvOZy/S/EhLEl51QnC8Bzq/teF8pCqhu0H+SP+/+M+z/apRILrZzEK+rm80GM5fuKb0pEH2HJKTiJmTAedKBZ9ZFo+w8YttYmv0s8aBNGPhYnPGiOg4JhU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cbHRqBeS; 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="cbHRqBeS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2879BC2BC9E; Tue, 31 Mar 2026 22:33:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774996382; bh=RJQkS8bUU8ttoMMCwjfNIsTwajwii9xgzqJ9jw17VAE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cbHRqBeSoYgfTE3DFt478XB2sAGrHwnP3pluE0g7KfKYO5IyjPKzQKNda8WfNYPdP T74vQZvwx/hci0GdiDSYVGQymjvfK7uYKFnMwhgoXGdG6Spc6TRT1wTRuk/iGUsjvp 6EV+s9GR0S4JBMhefTroJ3sQtMZWBRlTurBSwI9WMsnYvcPoUuFlsBkye/a2184IYF p/hB8wfG7lNzS/bZ2nSURnlrRK7Z/5M7nX6xBoZ37fuenrMGxRqLJG0MbKNGQcLWlW fmoXHS1x03HVb7OYB49waYYKROPVWmDvPovBlXEV86XsxnN8kK54+C9GMaj1vHLJeU ka5cwaAPBkakw== Date: Tue, 31 Mar 2026 15:33:00 -0700 From: Eric Biggers To: Ard Biesheuvel Cc: linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Demian Shulhan Subject: Re: [PATCH 1/5] lib/crc: arm64: Drop unnecessary chunking logic from crc64 Message-ID: <20260331223300.GA45047@quark> References: <20260330144630.33026-7-ardb@kernel.org> <20260330144630.33026-8-ardb@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: <20260330144630.33026-8-ardb@kernel.org> On Mon, Mar 30, 2026 at 04:46:32PM +0200, Ard Biesheuvel wrote: > On arm64, kernel mode NEON executes with preemption enabled, so there is > no need to chunk the input by hand. > > Signed-off-by: Ard Biesheuvel There's still similar "chunking" in other arm64 code: $ git grep -E 'SZ_4K|cond_yield' lib/crypto/arm64 lib/crypto/arm64/chacha.h: unsigned int todo = min_t(unsigned int, bytes, SZ_4K); lib/crypto/arm64/poly1305.h: unsigned int todo = min_t(unsigned int, len, SZ_4K); lib/crypto/arm64/sha1-ce-core.S: cond_yield 1f, x5, x6 lib/crypto/arm64/sha256-ce.S: cond_yield 1f, x5, x6 lib/crypto/arm64/sha3-ce-core.S: cond_yield 4f, x8, x9 lib/crypto/arm64/sha512-ce-core.S: cond_yield 3f, x4, x5 I thought it was still sticking around, despite kernel-mode NEON now being preemptible on arm64, because of CONFIG_PREEMPT_VOLUNTARY. However, I see that support for CONFIG_PREEMPT_VOLUNTARY was recently removed on arm64. So that's what finally makes this no longer needed, and we can now clean up these other cases too, right? (Though, I can't find where the voluntary preemption points actually were. So maybe they weren't actually there anyway.) - Eric