From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755009Ab3GKQqT (ORCPT ); Thu, 11 Jul 2013 12:46:19 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:21900 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752076Ab3GKQqS (ORCPT ); Thu, 11 Jul 2013 12:46:18 -0400 X-Authority-Analysis: v=2.0 cv=Tr1kdUrh c=1 sm=0 a=Sro2XwOs0tJUSHxCKfOySw==:17 a=Drc5e87SC40A:10 a=nbHVgzOhg_YA:10 a=5SG0PmZfjMsA:10 a=IkcTkHD0fZMA:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=QEdfzldPcAgA:10 a=wL381XPGSTaCNMBmk4cA:9 a=QEXdDO2ut3YA:10 a=Sro2XwOs0tJUSHxCKfOySw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 67.255.60.225 Message-ID: <1373561176.17876.44.camel@gandalf.local.home> Subject: Re: [RFC] [PATCH 1/2 v2] x86: introduce int3-based instruction patching From: Steven Rostedt To: "H. Peter Anvin" Cc: Jiri Kosina , Masami Hiramatsu , Jason Baron , Borislav Petkov , linux-kernel@vger.kernel.org Date: Thu, 11 Jul 2013 12:46:16 -0400 In-Reply-To: <51DEDDEF.4060502@linux.intel.com> References: <51DDD3E9.6090601@linux.intel.com> <51DEDDEF.4060502@linux.intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-3 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2013-07-11 at 09:31 -0700, H. Peter Anvin wrote: > The current code assumes that one of the two code sequences is a NOP, > and therefore that jumping over the region is legal. This does not > allow for transitioning one active code sequence to another. Correct, and I think we should keep the two changes separate, as the NOP case is trivial. No need to complicate the trivial and common updates (jump_labels and ftrace). But for things like kprobes, we could do a bit more complex code, but it should probably be separate. Perhaps call this text_poke_nop_bp()? -- Steve