From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932395Ab2CSQDT (ORCPT ); Mon, 19 Mar 2012 12:03:19 -0400 Received: from mga09.intel.com ([134.134.136.24]:55318 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932256Ab2CSQDR (ORCPT ); Mon, 19 Mar 2012 12:03:17 -0400 Subject: Re: EFI Boot Stub Early Console From: Matt Fleming To: Alan Cox Cc: Shea Levy , "H. Peter Anvin" , linux-kernel@vger.kernel.org In-Reply-To: <20120319155639.7cff5df6@pyx> References: <4F5E46EA.7020602@shealevy.com> <4F5E47E4.2070303@shealevy.com> <4F5E74A0.60001@zytor.com> <4F5E761B.7010608@shealevy.com> <4F5E775D.7080702@zytor.com> <4F648DD3.3000405@shealevy.com> <1332069701.4041.42.camel@mfleming-mobl1.ger.corp.intel.com> <4F65D09B.4050807@shealevy.com> <1332146834.4041.46.camel@mfleming-mobl1.ger.corp.intel.com> <20120319155639.7cff5df6@pyx> Content-Type: text/plain; charset="UTF-8" Organization: Intel Corporation (UK) Ltd. - Registered No. 1134945 - Pipers Way, Swindon SN3 1RJ Date: Mon, 19 Mar 2012 16:03:09 +0000 Message-ID: <1332172989.4041.52.camel@mfleming-mobl1.ger.corp.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.32.3 (2.32.3-1.fc14) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2012-03-19 at 15:56 +0000, Alan Cox wrote: > > > any bootloader (including the bootstub) will call ExitBootServices() > > > before any printk'ing actually happens?? Or am I misunderstanding the > > > spec somehow? I suppose I could just try it and see what happens... > > > > Oops. Good point, that isn't going to work. > > Surely it works fine if you are using bootstub directly from EFI ? Yeah, up until the point you call ExitBootServices(), which is very early in the boot process. After that you can't rely on the validity of the console pointers in the system table.