From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ACC2B1D5154 for ; Thu, 13 Mar 2025 10:35:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741862143; cv=none; b=bRIT+CkfTUyr4ed3QQrQkMzO8JQe0D5mzRYKCRf1el4sGO+V93B9dVZRgaKJkI15fMfyGo5CopWmRcnv2KLjzSY0RBaC94d+X7kvOPTh9phbcJChU2HLKf0VNSC6HSCSh/lextj56tu5biintn9XW+Pg5aPhTOLbzBXL8VWyGX8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741862143; c=relaxed/simple; bh=HwddNMKoRxMnPfOo1Zy1wl6DJgyF9AKmbUbp/4mYZVM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AB5/YTcQv3ATC7xGBproBMa1l753gHzTlnum6rFAYsJVvNm6qKkcZd9oMwJoczlAaVQOzIoTItRCBqrvw2hkUTHSwyA5D17FWHidFwYpHrsL7Nh+js37D03D+RdSD9X0MxFp1cJzn2nk6cEMKYuGtorju8f6pJH3pD/AfjjWn64= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WPJDy0Ly; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WPJDy0Ly" 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250312144257.2348250-5-dwmw2@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