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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 81320C282DE for ; Thu, 13 Mar 2025 10:37:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id: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-Owner; bh=x7zASUItQnpEtXCiku4VqH1IsXtYlinmRro9uTjTIYc=; b=RsMHqa5KPt2vsiWhVQHxil/go7 IT4Q/rtlGOSFKu32GTJGfFuweIbVLDgtT1AVnyzJtwCYmOR244Uh2q6RXK0x3nRTeqKICBWN99U2T hi2ySl8ASNUiKRQVuJ/oqPbizuWMbOw4DQuGjB48Yr8TqnZfUmlwVMFDJAKF4Hhow+Y20CMoL17M/ D8aGD8Kha13V16Z9Qrm4LUtyMwdIKcfhBkOn2fSZnWVznEmV7NG0mqTKMvNwQREC0s3vKzvBrU47B DnVJ7U6ZpwCE8UDCKMw92HQEeklzrziYj3Hbn1QZmJZ42w9hakoxT4sPYarQCo8L8+KdCaMcFPPxd o30qoO8w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tsfwI-0000000AtYk-2Bsd; Thu, 13 Mar 2025 10:37:22 +0000 Received: from nyc.source.kernel.org ([147.75.193.91]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tsfui-0000000AtN8-1MtR for kexec@lists.infradead.org; Thu, 13 Mar 2025 10:35:45 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 85346A46BAB; Thu, 13 Mar 2025 10:30:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E345BC4CEEE; Thu, 13 Mar 2025 10:35:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741862143; bh=HwddNMKoRxMnPfOo1Zy1wl6DJgyF9AKmbUbp/4mYZVM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WPJDy0LysT8DO/IFgRSu1ybIe0REzyyiM7ojFXE5bnQbKp/p/UVi+89gj4xHJ/5xb kNhyCFdLobiFV9uQCVwHo9KnJyt3XVHbChLvmqpQFRFt/ZkMwXWCZ7WUwkPNSp5tZm oyCo4XZ0lea4vWlZctbPFoOdsfZ12Zqxj0a1+fAgOYXpRJPbkjd/MWotqgu/qyiACn Qs2kiUEkSekfypds2s1uzlFZ81ruIW9OzJ2HCYe1hKacasjBiXAGMl92LCfg1yTHqa 9cA7nttj7NKX20MGggXOpDvVt1SPiaCfhIXCNgwz5X3RnhSOzzCOG+EiQ+RqfJ16Zv I5azTI4BnjYnQ== Date: Thu, 13 Mar 2025 11:35:36 +0100 From: Ingo Molnar To: David Woodhouse Cc: kexec@lists.infradead.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , David Woodhouse , "Kirill A . Shutemov" , Kai Huang , Nikolay Borisov , linux-kernel@vger.kernel.org, Simon Horman , Dave Young , Peter Zijlstra , jpoimboe@kernel.org, bsz@amazon.de Subject: Re: [PATCH v7 4/8] x86/kexec: Add 8250 serial port output Message-ID: References: <20250312144257.2348250-1-dwmw2@infradead.org> <20250312144257.2348250-5-dwmw2@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250312144257.2348250-5-dwmw2@infradead.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250313_033544_456836_713392E4 X-CRM114-Status: GOOD ( 11.13 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org * David Woodhouse wrote: > From: David Woodhouse > > If a serial port was configured for early_printk, use it for debug output > from the relocate_kernel exception handler too. Does the early console output something once it's initialized? If not then I'd go one step further here: if early_printk serial debugging was configured, let's output some sort of message as early as it's expected to work. That way if any of this debug codepath regresses for relocate_kernel, the discovery of that regression won't be delayed until something nasty triggers within relocate_kernel that would necessitate a working debug mechanism ... Also, printing something to the early console using these new relocate_kernel printing functions would be an additional bonus as well, for similar reasons. Thanks, Ingo