Re: [PATCH 1/2] efi: Make 'efi_enabled' a function to query EFI facilities

[Ben Hutchings <ben@decadent.org.uk>]

[-- Attachment #1: Type: text/plain, Size: 1788 bytes --]

On Mon, 2013-01-21 at 21:12 +0000, Matt Fleming wrote:
[...]
> From 92e73f936e40a8c6562e47425d434a4e62d2b8e2 Mon Sep 17 00:00:00 2001
> From: Matt Fleming <matt.fleming@intel.com>
> Date: Wed, 14 Nov 2012 09:42:35 +0000
> Subject: [PATCH] efi: Make 'efi_enabled' a function to query EFI facilities
> 
> 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.
> 
> The immediate motivation for this patch is the bug report at,
> 
>     https://bugs.launchpad.net/ubuntu-cdimage/+bug/1040557
> 
> which details how running a platform driver on an EFI machine that is
> designed to run under BIOS can cause the machine to become
> bricked. Also, the following report,
> 
>     https://bugzilla.kernel.org/show_bug.cgi?id=47121
> 
> details how running said driver can also cause Machine Check
> Exceptions. Drivers need a new means of detecting whether they're
> running on an EFI machine, as sadly the expression,
> 
>     if (!efi_enabled)
> 
> hasn't been a sufficient condition for quite some time.
[...]

This patch maps the old efi_enabled flag to efi_enabled(EFI_BOOT).  Your
second patch adds a test for efi_enabled(EFI_BOOT) to the samsung-laptop
driver.  So the samsung-laptop driver could be fixed by adding a check
for the old flag; it doesn't depend on the addition of new flags at all.
The changes elsewhere may well be important, but the cited motivation
here just doesn't make sense.

Ben.

-- 
Ben Hutchings
Q.  Which is the greater problem in the world today, ignorance or apathy?
A.  I don't know and I couldn't care less.

[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 828 bytes --]