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 F34F8C433F5 for ; Mon, 7 Mar 2022 12:14:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240487AbiCGMOy (ORCPT ); Mon, 7 Mar 2022 07:14:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60148 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235118AbiCGMOu (ORCPT ); Mon, 7 Mar 2022 07:14:50 -0500 Received: from out30-44.freemail.mail.aliyun.com (out30-44.freemail.mail.aliyun.com [115.124.30.44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CC7524D9F4 for ; Mon, 7 Mar 2022 04:13:55 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R201e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04407;MF=rongwei.wang@linux.alibaba.com;NM=1;PH=DS;RN=8;SR=0;TI=SMTPD_---0V6VlUYF_1646655231; Received: from 30.240.98.128(mailfrom:rongwei.wang@linux.alibaba.com fp:SMTPD_---0V6VlUYF_1646655231) by smtp.aliyun-inc.com(127.0.0.1); Mon, 07 Mar 2022 20:13:52 +0800 Message-ID: Date: Mon, 7 Mar 2022 20:13:50 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:98.0) Gecko/20100101 Thunderbird/98.0 Subject: Re: [PATCH RFC] arm64: improve display about CPU architecture in cpuinfo Content-Language: en-US To: Marc Zyngier Cc: catalin.marinas@arm.com, will@kernel.org, joey.gouly@arm.com, mark.rutland@arm.com, akpm@linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20220307030417.22974-1-rongwei.wang@linux.alibaba.com> <87h78a178u.wl-maz@kernel.org> From: Rongwei Wang In-Reply-To: <87h78a178u.wl-maz@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/7/22 4:45 PM, Marc Zyngier wrote: > On Mon, 07 Mar 2022 03:04:17 +0000, > Rongwei Wang wrote: >> >> Now, it is unsuitable for both ARMv8 and ARMv9 to show a >> fixed string "CPU architecture: 8" in /proc/cpuinfo. > > Please read the various threads that have been going on over the past > 10+ years about *why* we don't allow this sort of change (TL;DR: it > breaks userspace, and we don't do that). > > Also, there is no material difference between v8 and v9 that would be > observable from userspace outside of the "Features:" line. And if that > doesn't convince you, just think of '8' as the number of bytes used byI got your point. It seems that we can regard '8' as the number of bytes. But what make me do this is that 'CPU architecture: 8' is confusing, especially those responsible for testing. And I believe that most people regard this '8' as ARMv8, maybe not. In fact, I'm not sure it has potential ABI implications, so seek your advice. Thanks! > a virtual address. You can't make that a '9'. Yet. > > M. >