From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction abstraction Date: Fri, 20 Jun 2008 12:15:24 -0700 (PDT) Message-ID: References: <1213831403.8011.24.camel@pasglop> <4859A149.9090004@goop.org> <4859A528.1010107@goop.org> <4859AA47.2020903@goop.org> <20080619115832.GM15228@elte.hu> <20080619164708.GA32190@elte.hu> <20080620101028.GA23664@elte.hu> <485BFFC4.3070902@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <485BFFC4.3070902@goop.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Jeremy Fitzhardinge Cc: xen-devel , Peter Zijlstra , kvm-devel , benh@kernel.crashing.org, x86@kernel.org, LKML , Virtualization Mailing List , Hugh Dickins , Ingo Molnar , Thomas Gleixner List-Id: virtualization@lists.linuxfoundation.org On Fri, 20 Jun 2008, Jeremy Fitzhardinge wrote: > > Blows up on "gcc version 3.4.4 20050314 (prerelease) (Debian 3.4.3-13)": Yeah, I was a bit worried about that. Gcc sometimes does insane things. We literally just tested that the asm should only _ever_ be generated with a constant value, but if some gcc dead-code removal thing doesn't work, it will then screw up and try to generate the asm even for a non-constant thing. The fairly trivial fix is probably to just change the "i" to "ir", safe in the knowledge that any _sane_ case will never use the "r" possibility. I suspect even your insane case will end up then killing the bad choice later. Linus