From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933128AbZHDVsp (ORCPT ); Tue, 4 Aug 2009 17:48:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932986AbZHDVsp (ORCPT ); Tue, 4 Aug 2009 17:48:45 -0400 Received: from cs20.apochromatic.org ([204.152.189.161]:61266 "EHLO cs20.apochromatic.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932908AbZHDVso (ORCPT ); Tue, 4 Aug 2009 17:48:44 -0400 Date: Tue, 4 Aug 2009 22:48:15 +0100 From: Matt Fleming To: Mathieu Desnoyers Cc: Giuseppe CAVALLARO , ltt-dev@lists.casi.polymtl.ca, Paul Mundt , linux-kernel@vger.kernel.org, Ingo Molnar , rostedt@goodmis.org Subject: Re: sh: Add ftrace syscall tracing support (was: Re: [ltt-dev] [PATCH] sh: added LTT_DUMP_TABLES support) Message-ID: <20090804214815.GC4084@console-pimps.org> References: <1249040606-15402-1-git-send-email-peppe.cavallaro@st.com> <20090731155048.GD8847@Krystal> <4A77F585.2070508@st.com> <20090804133515.GB23807@Krystal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090804133515.GB23807@Krystal> 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 Tue, Aug 04, 2009 at 09:35:15AM -0400, Mathieu Desnoyers wrote: > * Giuseppe CAVALLARO (peppe.cavallaro@st.com) wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > > Hash: SHA1 > > > > Hi Mathieu, > > > > Mathieu Desnoyers wrote: > > > So now we only need to fix entry-common.S to get everything working. > > > > I've just noticed that this has been already done: > > http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Flethal%2Fsh-2.6.git;a=commitdiff_plain;h=c652d780c9cf7f860141de232b37160fe013feca;hp=c1340c053be7a43d837a3acb352d5008be865a55 > > I think it will be necessary to to re-add the _TIF_KERNEL_TRACE against > > this modifications, only. > > > > Hrm, I don't like the approach taken there. It extends the bitmasks for > _TIF_WORK_SYSCALL_MASK and _TIF_ALLWORK_MASK beyond 8 bits, and adds a & > 0xff in the assembly whenever needed. This begs for a bug to be > introduced. > > If we need something like that on SH, we should probably declare a 8-bit > only bitmask for those assembly sites which does not need the > FTRACE_SYSCALL thread flag, and another mask for sites which need to > test the 2 bytes. > If I remember correctly, I originally split TIF_WORK_SYSCALL_MASK into a high 8-bit and low 8-bit chunks. However, I think I remember Paul saying that wasn't the best way to do it. I've no issue with doing it either way.