From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752431AbeBZIhY (ORCPT ); Mon, 26 Feb 2018 03:37:24 -0500 Received: from mail-wm0-f66.google.com ([74.125.82.66]:34728 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752096AbeBZIhT (ORCPT ); Mon, 26 Feb 2018 03:37:19 -0500 X-Google-Smtp-Source: AH8x227ilAP4NIRPJXCFUXz1MsJxnuCTaTraJarAupEx0vTLwamjDSC7I+kOUWL8kco0YsqNzBKC+w== Date: Mon, 26 Feb 2018 11:37:09 +0300 From: "Kirill A. Shutemov" To: Cyrill Gorcunov Cc: Ingo Molnar , Borislav Petkov , tglx@linutronix.de, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, willy@infradead.org, hpa@zytor.com, kirill.shutemov@linux.intel.com, peterz@infradead.org, luto@amacapital.net, linux-tip-commits@vger.kernel.org Subject: Re: [tip:x86/boot] x86/boot/compressed/64: Prepare trampoline memory Message-ID: <20180226083709.al5pvzwzyxuci4qp@node.shutemov.name> References: <20180209142228.21231-4-kirill.shutemov@linux.intel.com> <20180224214818.GD29374@pd.tnic> <20180225105205.xicklkl3n5azdw2j@node.shutemov.name> <20180226073552.xabt55ukp24inut5@gmail.com> <20180226080256.j7jzuxyokx42uytd@node.shutemov.name> <20180226081533.GA5308@uranus.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180226081533.GA5308@uranus.lan> User-Agent: NeoMutt/20171215 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 26, 2018 at 11:15:34AM +0300, Cyrill Gorcunov wrote: > On Mon, Feb 26, 2018 at 11:02:56AM +0300, Kirill A. Shutemov wrote: > ... > > > Also, could do a puts() hexdump of the affected memory area _before_ we overwrite > > > it? Is it empty? Could we add some debug warning that checks that it's all zeroes? > > > > The problem is that we don't really have a way get a message out of there. > > > > http://lkml.kernel.org/r/793b9c55-e85b-97b5-c857-dd8edcda4081@zytor.com > > > > I'm sorry for stepping in (since I didn't follow the series in details) > but can't we use vga memory here and print this early data tere? I have no idea how to do this :/ And what about systems without monitor at all? -- Kirill A. Shutemov