Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964873AbbFJNIY (ORCPT ); Wed, 10 Jun 2015 09:08:24 -0400 Received: from one.firstfloor.org ([193.170.194.197]:39663 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964833AbbFJNIQ (ORCPT ); Wed, 10 Jun 2015 09:08:16 -0400 Date: Wed, 10 Jun 2015 15:08:14 +0200 From: Andi Kleen To: Josh Poimboeuf Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Michal Marek , Peter Zijlstra , Andy Lutomirski , Borislav Petkov , Linus Torvalds , Andi Kleen , x86@kernel.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 00/10] x86/asm: Compile-time asm code validation Message-ID: <20150610130814.GN19417@two.firstfloor.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Content-Length: 764 Lines: 22 > 2. Each callable function must never leave its own bounds (i.e. with a > jump to outside the function) except when returning. That prevents a lot of optimizations with out of line code. In fact even gcc with the right options can generate code that violates this. Standard Linux constructions, such as exception handling, also violate this. If your tool needs that your tool is broken. BTW any other frame pointer requirement should be also optional, as it slows down a number of CPUs, such as Atoms. -Andi -- 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/