From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755482Ab3IYNMf (ORCPT ); Wed, 25 Sep 2013 09:12:35 -0400 Received: from arkanian.console-pimps.org ([212.110.184.194]:50153 "EHLO arkanian.console-pimps.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755306Ab3IYNMe (ORCPT ); Wed, 25 Sep 2013 09:12:34 -0400 Date: Wed, 25 Sep 2013 14:12:30 +0100 From: Matt Fleming To: Bart Kuivenhoven Cc: matt.fleming@intel.com, hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, x86@kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, jcm@redhat.com, msalter@redhat.com Subject: Re: [PATCH] x86 efi: bugfix interrupt disabling sequence Message-ID: <20130925131230.GL21381@console-pimps.org> References: <1379929528-7534-1-git-send-email-bemk@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1379929528-7534-1-git-send-email-bemk@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 23 Sep, at 11:45:28AM, Bart Kuivenhoven wrote: > The problem in efi_main was that the idt was cleared before the > interrupts were disabled. > > The UEFI spec states that interrupts aren't used so this shouldn't be > too much of a problem. Peripherals however don't necessarily know about > this and thus might cause interrupts to happen anyway. Even if > ExitBootServices() has been called. > > This means there is a risk of an interrupt being triggered while the IDT > register is nullified and the interrupt bit hasn't been cleared, > allowing for a triple fault. > > This patch disables the interrupt flag, while leaving the existing IDT > in place. The CPU won't care about the IDT at all as long as the > interrupt bit is off, so it's safe to leave it in place as nothing will > ever happen to it. > > Signed-off-by: Bart Kuivenhoven > --- > arch/x86/boot/compressed/eboot.c | 15 +-------------- > 1 file changed, 1 insertion(+), 14 deletions(-) Applied, thanks Bart! -- Matt Fleming, Intel Open Source Technology Center