From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 679CEC04ABB for ; Wed, 12 Sep 2018 00:15:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 14C0A20866 for ; Wed, 12 Sep 2018 00:15:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 14C0A20866 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=telegraphics.com.au Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726646AbeILFQ5 (ORCPT ); Wed, 12 Sep 2018 01:16:57 -0400 Received: from kvm5.telegraphics.com.au ([98.124.60.144]:51458 "EHLO kvm5.telegraphics.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725738AbeILFQ5 (ORCPT ); Wed, 12 Sep 2018 01:16:57 -0400 Received: from localhost (localhost.localdomain [127.0.0.1]) by kvm5.telegraphics.com.au (Postfix) with ESMTP id CF5352A7CE; Tue, 11 Sep 2018 20:15:07 -0400 (EDT) Date: Wed, 12 Sep 2018 10:15:23 +1000 (AEST) From: Finn Thain cc: Frank Rowand , Stan Johnson , Rob Herring , Benjamin Herrenschmidt , Chintan Pandya , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: v4.17 regression: PowerMac G3 won't boot, was Re: [PATCH v5 1/3] of: cache phandle nodes to reduce cost of of_find_node_by_phandle() In-Reply-To: Message-ID: References: <1520208889-3908-1-git-send-email-frowand.list@gmail.com> <1520208889-3908-2-git-send-email-frowand.list@gmail.com> <0ad5dbfd-08f3-b97d-34b9-70fc9a729921@gmail.com> <7427daf6570d519e6793eb96d2fbaa52714b0cd7.camel@kernel.crashing.org> <20180910125320.GA17028@bogus> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII To: unlisted-recipients:; (no To-header on input) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [The Cc list got pruned so I'm forwarding Stan's reply for the benefit of the list archives and any other interested parties.] On Mon, 10 Sep 2018, Stan Johnson wrote: > On 9/10/18 6:53 AM, Rob Herring wrote: > > > ... > > Can you try this patch (w/o Ben's patch). I think the problem is if > > there are no phandles, then roundup_pow_of_two is passed 0 which is > > documented as undefined result. > > > > Though, if a DT has no properties with phandles, then why are we doing a > > lookup in the first place? > > > > > > 8<---------------------------------------------------------------------- > > > > diff --git a/drivers/of/base.c b/drivers/of/base.c > > index 9095b8290150..74eaedd5b860 100644 > > --- a/drivers/of/base.c > > +++ b/drivers/of/base.c > > @@ -140,6 +140,9 @@ void of_populate_phandle_cache(void) > > if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) > > phandles++; > > > > + if (!phandles) > > + goto out; > > + > > cache_entries = roundup_pow_of_two(phandles); > > phandle_cache_mask = cache_entries - 1; > > > > Using the attached .config file, I first compiled the stock 4.18 > kernel from kernel.org; it hung at the Mac OS background screen > on my Beige G3 Desktop using the BootX extension and the BootX.app > from within MacOS. I then applied the above patch, and it booted > without any problems from both the BootX extension and using the > BootX.app from within MacOS. > > -Stan > >