From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sascha Hauer Subject: Re: Early kernel hang with big DTB appended Date: Fri, 11 Jan 2013 17:45:31 +0100 Message-ID: <20130111164531.GC13025@pengutronix.de> References: <7811936.npteFbuYu2@amdc1227> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <7811936.npteFbuYu2@amdc1227> Sender: linux-samsung-soc-owner@vger.kernel.org To: Tomasz Figa Cc: devicetree-discuss@lists.ozlabs.org, linux-samsung-soc@vger.kernel.org, linux@arm.linux.org.uk, nico@linaro.org, kgene.kim@samsung.com, thomas.abraham@linaro.org, bones@secretlab.ca, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org On Thu, Jan 03, 2013 at 04:55:00PM +0100, Tomasz Figa wrote: > Hi, > > I'm observing strange behavior when booting 3.8-rc1 and -rc2 with appended > DTB. The kernel hangs very early when the DTB is bigger than some > threshold somewhere around 24 KiB. With fullest possible low level UART > debugging (and printk patched to use printascii) I'm receiving following > output: > > Uncompressing Linux... done, booting the kernel. > Booting Linux on physical CPU 0xa00 > Linux version 3.8.0-rc1-00073-gdf6efca-dirty (t.figa@amdc1227) (gcc > version 4.5.2 (Gentoo 4.5.2 p1.2, pie-0.4.5) ) #2 SMP PREEMPT Thu Jan 3 > 15:37:35 CET 2013 > CPU: ARMv7 Processor [413fc090] revision 0 (ARMv7), cr=10c53c7d > CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache > > I tested on two Exynos-based boards (exynos4210-trats and one internal > exynos4412-based board) and same happens on both. > > Do you have any ideas? Another thing besides the things already mentioned is that the dtb may not cross a 1MiB boundary. The Kernel uses a single 1Mib section (aligned to 1Mib) to initially map the dtb. Once you cross that boundary parts of the dtb won't be accessible for the Kernel anymore. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |