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 DCE27B6EED for ; Sat, 7 Aug 2010 08:49:27 +1000 (EST) Subject: Re: Relocating bootwrapper causes kernel panic From: Benjamin Herrenschmidt To: Scott Wood In-Reply-To: <20100805134654.70f8f787@schlenkerla.am.freescale.net> References: <20100805123725.63d009b1@schlenkerla.am.freescale.net> <20100805134654.70f8f787@schlenkerla.am.freescale.net> Content-Type: text/plain; charset="UTF-8" Date: Sat, 07 Aug 2010 08:49:18 +1000 Message-ID: <1281134958.2168.39.camel@pasglop> Mime-Version: 1.0 Cc: ppcdev List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , \ > Probably. You won't have any page tables yet, much less an entry for > the device tree. > > > >> I think the cause is clear now. But how to fix it? Two questions: > > >> 2. If the DTLB miss exception handler is not the right guy to load a > > >> proper TLB entry, how can I set one entry based on the link_address > > >> and the address of the flat dt blob? > > > > > > Given how early in the boot process it is, it's probably going to need > > > to be handled specially. > > > > What APIs can I use to set up DTLBs? > > I don't think there is one that works on 8xx. You'll could hack up > initial_mmu, or else write some C code to insert an 8xx TLB entry. Yup, I think he just ends up getting out of the initial mapping which is smallish on 8xx, no ? Might be worth sticking in one more entry during boot... Ben.