From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752487AbaEUQdk (ORCPT ); Wed, 21 May 2014 12:33:40 -0400 Received: from mail.skyhub.de ([78.46.96.112]:54131 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751018AbaEUQdi (ORCPT ); Wed, 21 May 2014 12:33:38 -0400 Date: Wed, 21 May 2014 18:33:15 +0200 From: Borislav Petkov To: Andy Lutomirski Cc: Jiri Kosina , Thomas Gleixner , Linus Torvalds , Steven Rostedt , Andi Kleen , "linux-kernel@vger.kernel.org" , "H. Peter Anvin" , Ingo Molnar Subject: Re: [RFC] x86_64: A real proposal for iret-less return to kernel Message-ID: <20140521163315.GJ21205@pd.tnic> References: <1400639227.9759.21.camel@pippen.local.home> 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 Wed, May 21, 2014 at 08:21:57AM -0700, Andy Lutomirski wrote: > ISTM the do_machine_check code ought to consider any kill-worthy MCE > from kernel space to be non-recoverable, but I want to keep the scope > of these patches under control. MCA has a bit called RIPV which, if set, signals that RIP is valid and it is safe to return provided we've taken proper care of handling even non-correctable errors (memory poisoning, etc). If RIPV is not set, we panic anyway. > That being said, if an MCE that came from CPL0 never tried to return, > this would be simpler. I don't know enough about the machine check > architecture to know whether that's a reasonable thing to do. Yeah, there are cases where MCE can return, see above. -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --