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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9AEF3C433EF for ; Tue, 8 Mar 2022 17:56:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244279AbiCHR5Q (ORCPT ); Tue, 8 Mar 2022 12:57:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52420 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234578AbiCHR5N (ORCPT ); Tue, 8 Mar 2022 12:57:13 -0500 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9C9075640C for ; Tue, 8 Mar 2022 09:56:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender: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-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=EwNJ6vcuwAWnpkCBLf8tK97j16097dDp2sNIoTQu1C8=; b=Z+Ek8w5ltB58NLWb/l9GyVMPdh 4LxwGXFfcTuBD41J+rysdNoOsKxb7VBvSOFTzAH+7xT5d/t+Jw8kTMGXJEMPOW1z8Y2iHrtEHYlRu n3xjxawu4vo/7fXpi2/sgsyX8Cr7LavLUIbZKhrvbfg1uj6lxHNAw1jDB0Iy76dk6Pqdi7DtVWSl0 oofnaPH3Ws5sb9U6guvX+Z4MEOHanhOriTme74ThaoxAzAK39u65x9VVpV30+4e4F7dZj7bPDBtUS ffNeV6TBRtFYiPCxCKpSN33ONRjHHitWA8RyzicAdjoRiFzRzo+bn8PhL+B+0pQmg5XWw9yoCj5oD Pkwyk8OA==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:57720) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1nRe3y-0000ht-5r; Tue, 08 Mar 2022 17:55:58 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1nRe3u-00074S-4Z; Tue, 08 Mar 2022 17:55:54 +0000 Date: Tue, 8 Mar 2022 17:55:54 +0000 From: "Russell King (Oracle)" To: Arnd Bergmann Cc: Robin Murphy , Marc Zyngier , Rongwei Wang , Catalin Marinas , Will Deacon , joey.gouly@arm.com, Mark Rutland , Andrew Morton , Linux ARM , Linux Kernel Mailing List Subject: Re: [PATCH RFC] arm64: improve display about CPU architecture in cpuinfo Message-ID: References: <20220307030417.22974-1-rongwei.wang@linux.alibaba.com> <87h78a178u.wl-maz@kernel.org> <87bkyi0x53.wl-maz@kernel.org> <1b94af8b-a294-5765-4e1e-896f70db621f@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 07, 2022 at 08:30:07PM +0100, Arnd Bergmann wrote: > On Mon, Mar 7, 2022 at 5:48 PM Robin Murphy wrote: > > > And arguably it's not even too late, because 10 years ago this *did* say > > "AArch64". I don't remember all the exact details behind commit > > 44b82b7700d0 ("arm64: Fix up /proc/cpuinfo") - this just tickled enough > > of a memory to go and look up the git history - but I don't think we > > changed any of those fields without a real reason. > > > > The patch description does state that this was done for compatibility with > 32-bit architectures, which does make some sense. I suppose for similar > reasons, the arch/arm/ version of /proc/cpuinfo is now stuck at > 'CPU architecture: 7', even for ARMv8 or higher in aarch32 mode. > > The part that I find more annoying is how we leave out the one bit > of information that people are generally looking for in /proc/cpuinfo: > the name of the processor. Even though we already know the > exact processor type in order to handle the CPU errata, this is > always "model name\t: ARMv7 Processor rev %d (v7l)" on 32-bit, > and "model name\t: ARMv8 Processor rev %d (%s)" on 64-bit, > with the revision being the least important bit of information here... It would have been nice if one could read the processor name out of the processor itself... but alas that doesn't exist. Then we wouldn't need some way to translate MIDR values to the processor. Sadly, though, some MIDR values are not unique... -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!