From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mo-p00-ob.rzone.de (mo-p00-ob.rzone.de [81.169.146.162]) (using TLSv1 with cipher EDH-RSA-DES-CBC3-SHA (168/168 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id EACF4B70D9 for ; Thu, 14 Apr 2011 01:21:43 +1000 (EST) From: Stefan Roese To: Joakim Tjernlund Subject: Re: FTrace on MPC8xx Date: Wed, 13 Apr 2011 17:21:33 +0200 References: <201104131632.21350.ml@stefan-roese.de> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Message-Id: <201104131721.34123.ml@stefan-roese.de> Cc: Scott Wood , linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Joakim, On Wednesday 13 April 2011 16:58:21 Joakim Tjernlund wrote: > > This is on a 2.6.38 kernel (2.6.32 fails too). Debugging shows that > > __copy_tofrom_user() fails with return code 4 (called via > > ftrace_modify_code()). > > > > Before digging deeper: Has anybody tried/tested ftrace on MPC8xx? Any > > ideas what going wrong here? > > Just an idea, remove the usage of dcbX insn, these has been problematic > before. I originally tested with 2.6.32. Same problem there. And your 8xx patches with the dcbX changes are not included in 2.6.32 yet. > How big was the size to copy_tofrom_user()? Did it mange to copy > any bytes? The size in __copy_tofrom_user is 4. And its the first call in ftrace_modify_code() that fails directly. This works just fine on a PPC440EPx board. Best regards, Stefan