From mboxrd@z Thu Jan 1 00:00:00 1970 From: Santosh Shilimkar Subject: RE: 4430SDP boot failure - solved + SPI bug fix Date: Sat, 8 Jan 2011 00:58:49 +0530 Message-ID: References: <86f60bc5418ca1d3e87db960e5e2c48f@mail.gmail.com> <729152acd9ee0c3e3e3cd505e84f8865@mail.gmail.com> <20110107125132.GM1198@n2100.arm.linux.org.uk> <48cbfb338be4d33a8a19e070430d015b@mail.gmail.com> <20110107142432.GO1198@n2100.arm.linux.org.uk> <20110107154920.GQ1198@n2100.arm.linux.org.uk> <20110107185250.GT1198@n2100.arm.linux.org.uk> <04b3a28e12c18714cce8c15c1645cc2d@mail.gmail.com> <20110107191949.GV1198@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: Received: from na3sys009aog105.obsmtp.com ([74.125.149.75]:35723 "EHLO na3sys009aog105.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753934Ab1AGT2w (ORCPT ); Fri, 7 Jan 2011 14:28:52 -0500 Received: by mail-bw0-f53.google.com with SMTP id 12so12231951bwg.26 for ; Fri, 07 Jan 2011 11:28:51 -0800 (PST) In-Reply-To: <20110107191949.GV1198@n2100.arm.linux.org.uk> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Russell King - ARM Linux Cc: linux-omap@vger.kernel.org, Tony Lindgren > -----Original Message----- > From: Russell King - ARM Linux [mailto:linux@arm.linux.org.uk] > Sent: Saturday, January 08, 2011 12:50 AM > To: Santosh Shilimkar > Cc: linux-omap@vger.kernel.org; Tony Lindgren > Subject: Re: 4430SDP boot failure - solved + SPI bug fix > > On Sat, Jan 08, 2011 at 12:35:38AM +0530, Santosh Shilimkar wrote: > > > -----Original Message----- > > > From: Russell King - ARM Linux [mailto:linux@arm.linux.org.uk] > > > Sent: Saturday, January 08, 2011 12:23 AM > > > To: Santosh Shilimkar > > > Cc: linux-omap@vger.kernel.org; Tony Lindgren > > > Subject: Re: 4430SDP boot failure - solved + SPI bug fix > > > > > > On Fri, Jan 07, 2011 at 11:55:10PM +0530, Santosh Shilimkar > wrote: > > > > > And, with one ARM errata disabled, the kernel finally boots. > So > > > the > > > > > "X-Loader hangs" message means that we did something that > non- > > > secure > > > > > mode prevented us from doing. > > > > > > > > > Actually it's not. The error message is quite misleading. > > > Basically in > > > > x-loader exception handlers are setup and all these handlers > > > report > > > > same message ("X-Loader hangs"). This should be fixed so that > it > > > can > > > > report more meaningful info like data abort, prefetch abort > etc. > > > > > > > > Till the vector relocation in the kernel exceptions are not > set up > > > > so code jumps to already installed exceptions in the x-loader > and > > > > hence the messege. > > > > > > I disagree with your "actually it's not". It was errata 742230, > > > which > > > requires access to the CP15, c15, c0, 1 register (a diagnostic > > > register) > > > which I bet provokes an undefined instruction trap from non- > secure > > > mode. > > > > > 742230 errata workaround is not implemented in the x-loader so I > > can surely say it's not the secure violation. > > Precisely. So when we directly read, modify and write this > diagnostic > register in the non-secure world during kernel boot, we end up > faulting. > Comment those instructions out, we don't get a fault, and the kernel > boots normally. I understand now. Was confused last time. So your custom build did have this errata CONFIG_ARM_ERRATA_742230 where there is an access to diagnostic register which is not accessible on OMAP4 from non-secure side. Thanks for clarification. Regards, Santosh