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 E511FB6EF7 for ; Wed, 30 Jun 2010 02:58:26 +1000 (EST) In-Reply-To: <181804936ABC2349BE503168465576460F272CA4@exchserver.basler.com> References: <181804936ABC2349BE503168465576460F272CA4@exchserver.basler.com> Mime-Version: 1.0 (Apple Message framework v753.1) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: From: Segher Boessenkool Subject: Re: [PATCH] arch/powerpc/lib/copy_32.S: Use alternate memcpy for MPC512x and MPC52xx Date: Tue, 29 Jun 2010 18:58:23 +0200 To: "Steve Deiters" Cc: linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > These processors will corrupt data if accessing the local bus with > unaligned > addresses. This version fixes the typical case of copying from > Flash on > the > local bus by keeping the source address always aligned. On many platforms accessing ROM as RAM simply doesn't work(*). You shouldn't map ROM as if it is RAM, and shouldn't use the same access functions on it. Segher (*) Example: any existing 970 system will checkstop as soon as you try to do any cacheable access to some ROM. Another example of course is unaligned accesses on pretty much any system, no matter whether it's called a bug or a feature on that system :-P