Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753131AbbGBQeM (ORCPT ); Thu, 2 Jul 2015 12:34:12 -0400 Received: from mail.skyhub.de ([78.46.96.112]:54392 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753736AbbGBQeE (ORCPT ); Thu, 2 Jul 2015 12:34:04 -0400 Date: Thu, 2 Jul 2015 18:33:39 +0200 From: Borislav Petkov To: Andy Lutomirski Cc: Andy Lutomirski , X86 ML , "linux-kernel@vger.kernel.org" , =?utf-8?B?RnLDqWTDqXJpYw==?= Weisbecker , Rik van Riel , Oleg Nesterov , Denys Vlasenko , Kees Cook , Brian Gerst , Paul McKenney Subject: Re: [PATCH v4 14/17] x86/asm/entry/64: Migrate error and interrupt exit work to C Message-ID: <20150702163339.GM4001@pd.tnic> References: <1a5858d079609a3e293123c9ee45de433a4e9c44.1435602481.git.luto@kernel.org> <20150702120932.GH4001@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 Content-Length: 1154 Lines: 34 On Thu, Jul 02, 2015 at 09:09:23AM -0700, Andy Lutomirski wrote: > You mean link-time asm optimizations? Turning off frame pointers in > leaf functions as long as rbp is still preserved might not be so > terrible either. Is there a gcc switch for that? > I'm torn on this one. In principle, you're right, or we could have a > macro CALL_ENTER_FROM_USER_MODE that does nothing if context tracking > is off. OTOH, that's also kind of messy. Yeah, I'm torn too. If you have something better, cool. Otherwise it is a judgement call for tip people. > If we move even more of this stuff into C, then this problem goes > away. "call enter_from_user_mode" turns into "enter_from_user_mode()" > or similar. ... and that should be optimized away, I'd guess, if the body's empty. Something like empty body removal or whatever... -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- -- 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/