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=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, 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 04C82C43387 for ; Fri, 11 Jan 2019 11:29:13 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C8D0821783 for ; Fri, 11 Jan 2019 11:29:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="WVm4mLjw"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="kf8vx4Ds" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C8D0821783 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=alien8.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Subject:To:From :Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=LhKrtoQxXNvNI5d44LwLYB2yFq7Z0K63A+o4B2dVV+U=; b=WVm4mLjwvERQ+j tlqPHsEyhrxvoikuPwP38eGj5w84LBOHmRLepZQq5yFonrunstae5EHaLf4SN4hIiWWjQZczTt6qS Zr4prTcRiQfTvehoryCzvV6tl48r5xo1VqC5cxC0FufPbm/2hOQVxTLufvlrsg4cWZo4TS1NuZNMz CBoJC+Rv4gsMD8yJsJLZaW4tcfyPevnknzf5bPQ9JAkd1PzHMEEgHRXG8+tgxnnhukAY05EOgthOp 9kMl2rXPRSLtPPxf/P0aC01xAHQfjmmg42GAnJJzGd8QwBJFlZEY09eTc/AQRB3aIGXXOdsiP8QKm 1IUC6I8T/7UOEUZ1deQw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ghuzu-0007Gf-MX; Fri, 11 Jan 2019 11:29:10 +0000 Received: from mail.skyhub.de ([2a01:4f8:190:11c2::b:1457]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1ghuzf-00072s-9N for linux-arm-kernel@lists.infradead.org; Fri, 11 Jan 2019 11:28:58 +0000 Received: from zn.tnic (p200300EC2BCAC5006CCD8D4D75E662CE.dip0.t-ipconnect.de [IPv6:2003:ec:2bca:c500:6ccd:8d4d:75e6:62ce]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id B4DD91EC03DB; Fri, 11 Jan 2019 12:28:47 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1547206127; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:references; bh=hCfXYtQjUYbpfemdO/BMKeV7KyCEeg9EzgbAR4onQaM=; b=kf8vx4Ds58lhzBpSZx0kkKyt1+ja5ObmR+3a331sGWk1ZqQRce3wBwLmP4y61squ0aHDh9 rUEXhymnTCgkSdcIq5DNNBG7xvUBP4w6EyI1cLe1emdOqjs8HzTGgQZ+Egr2ZZ0cfFArL0 Q14SuAC2zP9ffp8oRxKesLOjxHtsWyM= Date: Fri, 11 Jan 2019 12:28:40 +0100 From: Borislav Petkov To: James Morse , Tony Luck Subject: (ghes|hest)_disable Message-ID: <20190111112840.GB4729@zn.tnic> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190111_032855_632968_9432A661 X-CRM114-Status: GOOD ( 13.89 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Rafael Wysocki , Tony Luck , Fan Wu , linux-mm@kvack.org, Marc Zyngier , Catalin Marinas , Xie XiuQi , Will Deacon , Christoffer Dall , Dongjiu Geng , linux-acpi@vger.kernel.org, Naoya Horiguchi , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, Len Brown Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Ok, lemme split this out into a separate thread and add Tony. On Thu, Jan 10, 2019 at 06:20:35PM +0000, James Morse wrote: > > Grrr, what an effing mess that code is! There's hest_disable *and* > > ghes_disable. Do we really need them both? > > ghes_disable lets you ignore the firmware-first notifications, but still 'use' > the other error sources: > drivers/pci/pcie/aer.c picks out the three AER types, and uses apei_hest_parse() > to know if firmware is controlling AER, even if ghes_disable is set. Ok, that kinda makes sense. But look what our sparse documentation says: hest_disable [ACPI] Disable Hardware Error Source Table (HEST) support; corresponding firmware-first mode error processing logic will be disabled. and from looking at the code, hest_disable is kinda like the master switch because it gets evaluated first. Right? Which sounds to me like we want a generic switch which does: apei=disable_ff_notifications to explicitly do exactly that - disable the firmware-first notification method. And then the master switch will be apei=disable And we'll be able to pass whatever options here instead of all those different _disable switches which need lotsa code staring to figure out what exactly they even do in the first place. > x86's arch_apei_enable_cmcff() looks like it disables MCE to get firmware to > handle them. hest_disable would stop this, but instead ghes_disable keeps that, > and stops the NOTIFY_NMI being registered. Yeah, and when you boot with ghes_disable, that would say: pr_info("HEST: Enabling Firmware First mode for corrected errors.\n"); but there will be no notifications and users will scratch heads. > (do you consider cmdline arguments as ABI, or hard to justify and hard to remove?) I don't, frankly. I guess we will have to have a transition period where we keep them and issue a warning message that users should switch to "apei=xxx" instead and remove them after a lot of time has passed. > I don't think its broken enough to justify ripping them out. A user of > ghes_disable would be someone with broken firmware-first handling of AER. They > need to know firmware is changing the register values behind their back (so need > to parse the HEST), but want to ignore the junk notifications. It doesn't sound > like an unlikely scenario. Yes, that makes sense. But I think we should add a generic cmdline arg with suboptions and document exactly what all those do. Similar to "mce=" on x86 which is nicely documented in Documentation/x86/x86_64/boot-options.txt. Right now, only a few people understand what those do and in some of the cases they do too much/the wrong thing. Thoughts? -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel