From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B7A3D10F9302 for ; Tue, 31 Mar 2026 22:33:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=0C+/wWU1UaeRij4GshH92j601u74eU2k9j4h7bdT23g=; b=vxXv7UnMfWLHXpy7FoqYCm2ccH onRCLRr868YkoYZknh+NTtQsGNAzspjb+vYsxEN6rE/6AuyOQA9VT9FKTw8stbRqRimSStYw2bxwH jBWcCZg7viCNpwz0zZRqorrVVWRt5s5Wig1rvI2rr0tMDDu4jt6rgojynBVexHg1wCWD0XdQ8lGkB o4kdREU4NsQ3VT1c7P/rrxzKZyW/3bvzjZfu9IGC9FcdBgpOl1oFKu3ypPZ1+FqZF74SWMRPhEXQT uL+FD+H509U9HWPmjdu2VjlYo7vYBQL1CT14yZ0+g7m9OdgWOXKyV4OFJjo5HmHi3Vmkrlyo8t7kR dJZNL4wg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w7hdx-0000000DdaD-1ftg; Tue, 31 Mar 2026 22:33:05 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w7hdv-0000000Dda1-26ph for linux-arm-kernel@lists.infradead.org; Tue, 31 Mar 2026 22:33:03 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 9F312600CB; Tue, 31 Mar 2026 22:33:02 +0000 (UTC) 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260330144630.33026-8-ardb@kernel.org> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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