From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <50FDA81B.9090602@zytor.com> Date: Mon, 21 Jan 2013 14:42:03 -0600 From: "H. Peter Anvin" MIME-Version: 1.0 To: Matt Fleming CC: linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, Tim Gardner , Matthew Garrett , Olof Johansson , Tony Luck , Steve Langasek , Colin Ian King , Matt Fleming , David Airlie , Corentin Chary , Dave Jiang , Peter Jones , Konrad Rzeszutek Wilk , "Rafael J. Wysocki" , stable@vger.kernel.org Subject: Re: [PATCH 1/2] efi: Make 'efi_enabled' a function to query EFI facilities References: <1358800838-10459-1-git-send-email-matt@console-pimps.org> <1358800838-10459-2-git-send-email-matt@console-pimps.org> In-Reply-To: <1358800838-10459-2-git-send-email-matt@console-pimps.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: On 01/21/2013 02:40 PM, Matt Fleming wrote: > From: Matt Fleming > > Originally 'efi_enabled' indicated whether a kernel was booted from > EFI firmware. Over time its semantics have changed, and it now > indicates whether or not we are booted on an EFI machine with > bit-native firmware, e.g. 64-bit kernel with 64-bit firmware. > > But users actually want to query 'efi_enabled' for different reasons - > what they really want access to is the list of available EFI > facilities. > > For instance, the x86 reboot code needs to know whether it can invoke > the ResetSystem() function provided by the EFI runtime services, while > the ACPI OSL code wants to know whether the EFI config tables were > mapped successfully. There are also checks in some of the platform > driver code to simply see if they're running on an EFI machine (which > would make it a bad idea to do BIOS-y things). > Could you please explain as part of the checkin comment why this is needed for urgent/stable? I.e. what breaks *now*, as opposed to this being a cleanup for the next merge window. -hpa