From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 56C03DDECF for ; Fri, 17 Oct 2008 11:52:20 +1100 (EST) Subject: Re: [PATCH] ftrace: powerpc: remove startup functions from tracing From: Benjamin Herrenschmidt To: Steven Rostedt In-Reply-To: References: <20080906050602.409299112@goodmis.org> <20080906120346.GA30964@elte.hu> <20081016181452.GA29739@yoda.jdub.homelinux.org> Content-Type: text/plain Date: Fri, 17 Oct 2008 11:50:46 +1100 Message-Id: <1224204646.7654.52.camel@pasglop> Mime-Version: 1.0 Cc: Thomas Gleixner , Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, Andrew Morton , David Miller Reply-To: benh@kernel.crashing.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 2008-10-16 at 20:48 -0400, Steven Rostedt wrote: > > The early init code in PowerPC is not mapped to their final locations > and all jumps and memory references must be done with relative jumps > and accesses. > > The lib files in the powerpc directory are called in early boot, and > since mcount will perform direct access to memory, the lib files need > not be traced. This is annoying though, because that means things like memcpy, copy_to_from_user etc... can't be traced. On the other hand a lot of that is asm and already doesn't call mcount. Cheers, Ben.