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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E77DDC433F5 for ; Mon, 27 Aug 2018 14:54:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 73FB52087A for ; Mon, 27 Aug 2018 14:54:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=thunk.org header.i=@thunk.org header.b="AEjhaUPS" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 73FB52087A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=mit.edu Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727119AbeH0SlA (ORCPT ); Mon, 27 Aug 2018 14:41:00 -0400 Received: from imap.thunk.org ([74.207.234.97]:48554 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727005AbeH0SlA (ORCPT ); Mon, 27 Aug 2018 14:41:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=thunk.org; s=ef5046eb; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=qjM3kO2OydruLKPNdWoFUDH4AIjaw56WQT90mO97ayM=; b=AEjhaUPSPfNiu6EYlA+t0ccQLM o6aoKfKwPSfT+xiArrv7k1u8A5DKqX8/MnwwsJtfdoL26JtR7g8jU7wB45uqR3bETJ0idtHtbdWuw Ad93YJpfK3LucnOgZ86/aGn1jnNqliQUymVumsM8LF9tK2HAi24dksxNm2ctz2R2s+Ps=; Received: from root (helo=callcc.thunk.org) by imap.thunk.org with local-esmtp (Exim 4.89) (envelope-from ) id 1fuItt-0005u7-Ug; Mon, 27 Aug 2018 14:53:54 +0000 Received: by callcc.thunk.org (Postfix, from userid 15806) id BA1237A4B74; Mon, 27 Aug 2018 10:53:52 -0400 (EDT) Date: Mon, 27 Aug 2018 10:53:52 -0400 From: "Theodore Y. Ts'o" To: Ard Biesheuvel Cc: linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org, will.deacon@arm.com, catalin.marinas@arm.com, herbert@gondor.apana.org.au, ebiggers@google.com, suzuki.poulose@arm.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/4] arm64: wire CRC32 instructions into core crc32 routines Message-ID: <20180827145352.GF2311@thunk.org> Mail-Followup-To: "Theodore Y. Ts'o" , Ard Biesheuvel , linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org, will.deacon@arm.com, catalin.marinas@arm.com, herbert@gondor.apana.org.au, ebiggers@google.com, suzuki.poulose@arm.com, linux-kernel@vger.kernel.org References: <20180827110245.14812-1-ard.biesheuvel@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180827110245.14812-1-ard.biesheuvel@linaro.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 27, 2018 at 01:02:41PM +0200, Ard Biesheuvel wrote: > While this is not known to cause performance issues, calling a table based > time variant implementation with a non-negligible D-cache footprint (8 KB) > is wasteful in any case, and now that the crc32 instructions have been made > mandatory in the architecture, let's wire them up into the core crc routines. Stupid question --- are there any arm64 SOC's out there which do *not* have the crc32 instructions? Presumably there won't be in the future, because it's now mandatory --- but where there any in the past? - Ted