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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 18E97C33CAA for ; Tue, 21 Jan 2020 16:31:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EDD4F206A2 for ; Tue, 21 Jan 2020 16:31:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729199AbgAUQbO (ORCPT ); Tue, 21 Jan 2020 11:31:14 -0500 Received: from out01.mta.xmission.com ([166.70.13.231]:56736 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726555AbgAUQbN (ORCPT ); Tue, 21 Jan 2020 11:31:13 -0500 Received: from in02.mta.xmission.com ([166.70.13.52]) by out01.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1itwQq-00024m-HU; Tue, 21 Jan 2020 09:31:12 -0700 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1itwQl-0001Fp-NK; Tue, 21 Jan 2020 09:31:12 -0700 From: ebiederm@xmission.com (Eric W. Biederman) To: Jean Delvare Cc: Andy Shevchenko , Andy Shevchenko , Dave Young , linux-efi , Ard Biesheuvel , Matt Fleming , kexec@lists.infradead.org, Linux Kernel Mailing List , Mika Westerberg References: <20161202195416.58953-1-andriy.shevchenko@linux.intel.com> <20161202195416.58953-3-andriy.shevchenko@linux.intel.com> <20161215122856.7d24b7a8@endymion> <20161216023213.GA4505@dhcp-128-65.nay.redhat.com> <1481890738.9552.70.camel@linux.intel.com> <20161216143330.69e9c8ee@endymion> <20161217105721.GB6922@dhcp-128-65.nay.redhat.com> <20200120121927.GJ32742@smile.fi.intel.com> <87a76i9ksr.fsf@x220.int.ebiederm.org> <20200120224204.4e5cc0df@endymion> <20200121100359.6125498c@endymion> Date: Tue, 21 Jan 2020 10:29:35 -0600 In-Reply-To: <20200121100359.6125498c@endymion> (Jean Delvare's message of "Tue, 21 Jan 2020 10:03:59 +0100") Message-ID: <87zheg93io.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1itwQl-0001Fp-NK;;;mid=<87zheg93io.fsf@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19A1vHjXVSUHLJX23KSD0vshxuGi0OSXWU= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH v1 2/2] firmware: dmi_scan: Pass dmi_entry_point to kexec'ed kernel X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jean Delvare writes: > On Mon, 20 Jan 2020 23:55:43 +0200, Andy Shevchenko wrote: >> On Mon, Jan 20, 2020 at 11:44 PM Jean Delvare wrote: >> > >> > On Mon, 20 Jan 2020 10:04:04 -0600, Eric W. Biederman wrote: >> > > Second. I looked at your test results and they don't directly make >> > > sense. dmidecode bypasses the kernel completely or it did last time >> > > I looked so I don't know why you would be using that to test if >> > > something in the kernel is working. >> > >> > That must have been long ago. A recent version of dmidecode (>= 3.0) >> > running on a recent kernel >> > (>= d7f96f97c4031fa4ffdb7801f9aae23e96170a6f, v4.2) will read the DMI >> > data from /sys/firmware/dmi/tables, so it is very much relying on the >> > kernel doing the right thing. If not, it will still try to fallback to >> > reading from /dev/mem directly on certain architectures. You can force >> > that old method with --no-sysfs. >> > >> > Hope that helps, >> >> I don't understand how it possible can help for in-kernel code, like >> DMI quirks in a drivers. > > OK, just ignore me then, probably I misunderstood the point made by > Eric. No. I just haven't dived into this area of code in a long time. It seems a little indirect to use dmidecode as the test to see if the kernel has the pointer to the dmitables, but with the knowledge you provided it seems like a perfectly valid test. Eric