From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760554AbcBYNIn (ORCPT ); Thu, 25 Feb 2016 08:08:43 -0500 Received: from verein.lst.de ([213.95.11.211]:48298 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760178AbcBYNIm (ORCPT ); Thu, 25 Feb 2016 08:08:42 -0500 Date: Thu, 25 Feb 2016 14:08:39 +0100 From: Torsten Duwe To: Michael Ellerman Cc: linuxppc-dev@ozlabs.org, bsingharora@gmail.com, linux-kernel@vger.kernel.org, rostedt@goodmis.org, kamalesh@linux.vnet.ibm.com, pmladek@suse.com, jeyu@redhat.com, jkosina@suse.cz, live-patching@vger.kernel.org, mbenes@suse.cz Subject: Re: [PATCH 01/12] powerpc/module: Only try to generate the ftrace_caller() stub once Message-ID: <20160225130839.GC21932@lst.de> References: <1456324115-21144-1-git-send-email-mpe@ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1456324115-21144-1-git-send-email-mpe@ellerman.id.au> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 25, 2016 at 01:28:24AM +1100, Michael Ellerman wrote: > Currently we generate the module stub for ftrace_caller() at the bottom > of apply_relocate_add(). However apply_relocate_add() is potentially > called more than once per module, which means we will try to generate > the ftrace_caller() stub multiple times. > > Although the current code deals with that correctly, ie. it only > generates a stub the first time, it would be clearer to only try to > generate the stub once. > > Note also on first reading it may appear that we generate a different > stub for each section that requires relocation, but that is not the > case. The code in stub_for_addr() that searches for an existing stub > uses sechdrs[me->arch.stubs_section], ie. the single stub section for > this module. > > A cleaner approach is to only generate the ftrace_caller() stub once, > from module_finalize(). An additional benefit is we can clean the ifdefs > up a little. > > Finally we must propagate the const'ness of some of the pointers passed > to module_finalize(), but that is also an improvement. > > Signed-off-by: Michael Ellerman Reviewed-by: Torsten Duwe Torsten