Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751889AbaFEQU7 (ORCPT ); Thu, 5 Jun 2014 12:20:59 -0400 Received: from mail.skyhub.de ([78.46.96.112]:50088 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750853AbaFEQU5 (ORCPT ); Thu, 5 Jun 2014 12:20:57 -0400 Date: Thu, 5 Jun 2014 18:18:34 +0200 From: Borislav Petkov To: Andy Lutomirski Cc: Matt Fleming , "H. Peter Anvin" , "linux-kernel@vger.kernel.org" , Ingo Molnar , Ricardo Neri , "tglx@linutronix.de" , "linux-tip-commits@vger.kernel.org" Subject: Re: [tip:x86/efi] x86/efi: Check for unsafe dealing with FPU state in irq ctxt Message-ID: <20140605161834.GF16642@pd.tnic> References: <20140604224920.GB4126@pd.tnic> <538FB775.8070405@amacapital.net> <20140605071805.GA16647@pd.tnic> <20140605090206.GA16642@pd.tnic> <20140605155307.GD16642@pd.tnic> <20140605160842.GE16642@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 05, 2014 at 09:14:51AM -0700, Andy Lutomirski wrote: > Is this NMI pstore thing done from any context that's supposed to be > recoverable? It's always safe to use the FPU and then panic :) Right :) > Anyway, if we're just talking about EFI, there's an easier solution: > just preallocate a per-cpu FPU context for EFI and make the whole mess > be local to the EFI code. For crypto, that's not so good. This is probably something for Matt to decide but it sounds doable. If I'd have to guess, sooner or later we will need to do proper FPU context handling for EFI as I don't see anything stopping it from using FPU insns. At least we won't. :-) -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/