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 ESMTP id 9C5D2DDE10 for ; Tue, 22 May 2007 20:05:57 +1000 (EST) Subject: Re: fsl booke MM vs. SMP questions From: Benjamin Herrenschmidt To: Gabriel Paubert In-Reply-To: <20070522100212.GA13225@iram.es> References: <1179731215.32247.659.camel@localhost.localdomain> <1179741447.3660.7.camel@localhost.localdomain> <1179742083.32247.689.camel@localhost.localdomain> <1179747448.3660.22.camel@localhost.localdomain> <1179785273.32247.742.camel@localhost.localdomain> <20070522084645.GA12009@iram.es> <1179825278.32247.827.camel@localhost.localdomain> <20070522100212.GA13225@iram.es> Content-Type: text/plain Date: Tue, 22 May 2007 20:05:42 +1000 Message-Id: <1179828342.32247.832.camel@localhost.localdomain> Mime-Version: 1.0 Cc: ppc-dev , Dave Liu , Paul Mackerras , Kumar Gala List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2007-05-22 at 12:02 +0200, Gabriel Paubert wrote: > > Well, there should always be an stwcx. to clear reservation before > any interrupt return. Otherwise you'll be able to cause hard to > reproduce bugs in the interrupted code. Well, that's the point. The BookE TLB refill exception is a very fast path that doesn't use the normal interrupt return code path. It thus needs to be careful about not leaving dangling reservations. On some CPUs, there are also performance issues with leaving dangling lwarx iirc but I don't have the details off the top of my mind. Cheers, Ben.