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 7F65BC04A68 for ; Thu, 28 Jul 2022 06:59:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234388AbiG1G7z (ORCPT ); Thu, 28 Jul 2022 02:59:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59994 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232715AbiG1G7x (ORCPT ); Thu, 28 Jul 2022 02:59:53 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C7D07558CC for ; Wed, 27 Jul 2022 23:59:52 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6737B617BB for ; Thu, 28 Jul 2022 06:59:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 693F0C433C1; Thu, 28 Jul 2022 06:59:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658991591; bh=H6JnRUnyiByJJ0baf07rcz3QNGmBvJEdeFetwFaIrt8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oMccGIc1VNSGBXBfJ4t4ZMe2sWl5Xli8a6ddC4m2Dc0QeqDnwk3QkUXasHTPj2c/T Cn0kVDBvFQCWWgw2NjRAtzNJCQkFJFrCC1rqHySwCEXAnn2PWY6sGozCCG7DfcAaYY e4973Viozw117ESscA56ECU0US4l9WW9BSpJSeW8= Date: Thu, 28 Jul 2022 08:59:49 +0200 From: Greg Kroah-Hartman To: Petr Vorel Cc: linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , David Sterba Subject: Re: [PATCH 1/1] drivers/base/cpu: Print kernel arch Message-ID: References: <20220727161135.24531-1-pvorel@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 28, 2022 at 12:22:05AM +0200, Petr Vorel wrote: > Hi Greg, > > thanks for your review! > > > On Wed, Jul 27, 2022 at 06:11:35PM +0200, Petr Vorel wrote: > > > Print kernel architecture in /sys/devices/system/cpu/arch > > > using UTS_MACHINE, i.e. member of struct uts_namespace.machine. > > > > This helps people who debug kernel with initramfs with minimal > > > environment (i.e. without coreutils or even busybox) or allow to open > > > sysfs file instead of run uname -m in high level languages. > > > > Signed-off-by: Petr Vorel > > > --- > > > drivers/base/cpu.c | 9 +++++++++ > > > 1 file changed, 9 insertions(+) > > > You can't add a new sysfs file without a Documentation/ABI/ update as > > well. Please fix that up. > I'm sorry. Yes, I realized it later on (once I got offline). > Sure, I'll fix this in v2. But the main question is whether this feature is > acceptable and what is the best place for the file. > > > > > diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c > > > index 4c98849577d4..7c8032e3ff10 100644 > > > --- a/drivers/base/cpu.c > > > +++ b/drivers/base/cpu.c > > > @@ -3,6 +3,7 @@ > > > * CPU subsystem support > > > */ > > > > +#include > > > #include > > > #include > > > #include > > > @@ -232,6 +233,13 @@ static ssize_t print_cpus_kernel_max(struct device *dev, > > > } > > > static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL); > > > > +static ssize_t print_cpus_arch(struct device *dev, > > > + struct device_attribute *attr, char *buf) > > > +{ > > > + return sysfs_emit(buf, "%s\n", UTS_MACHINE); > > > +} > > > +static DEVICE_ATTR(arch, 0444, print_cpus_arch, NULL); > > > why just UTS_MACHINE? Doesn't 'uname' show this already? And I thought > > this was in /proc/cpuinfo but odd, it isn't... > Sure, this info is in uname(). But for certain cases is really easier to read > file from /proc or /sys than run create custom C bindings or a binary which > calls uname(2) libc wrapper or run uname binary via execve(2). > > Yes, I also expected /proc/cpuinfo would have it but it does not have it. I > don't think it's a good idea to add 'arch : foo' line to it, but I can do if > there is consensus that it's the best place. > > > Also what about the other things in compile.h? > UTS_VERSION is in /proc/version. > LINUX_COMPILE_BY (e.g. "user"), LINUX_COMPILE_HOST (e.g. "host") and > LINUX_COMPILER (e.g. "aarch64-alpine-linux-musl-gcc (Alpine 11.2.1_git20220219) > ...") are IMHO useless, but I can add it if you wish. > > Well, there is hostname in /proc/sys/kernel/hostname, there are also ostype and > osrelease.. Thinking about it twice /proc/sys/kernel/ looks to me a better place > for arch file than current /sys/devices/system/cpu/. WDYT? Yeah, I think /proc/sys/kernel/ makes sense, good idea. greg k-h