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From: Sascha Hauer <s.hauer@pengutronix.de>
To: Tomasz Figa <t.figa@samsung.com>
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
Subject: Re: Early kernel hang with big DTB appended
Date: Fri, 11 Jan 2013 17:45:31 +0100	[thread overview]
Message-ID: <20130111164531.GC13025@pengutronix.de> (raw)
In-Reply-To: <7811936.npteFbuYu2@amdc1227>

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

-- 
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  parent reply	other threads:[~2013-01-11 16:45 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-03 15:55 Early kernel hang with big DTB appended Tomasz Figa
2013-01-03 18:40 ` Bryan Evenson
2013-01-04 10:26   ` Tomasz Figa
2013-01-04  2:48 ` Nicolas Pitre
2013-01-04 10:18   ` Tomasz Figa
2013-01-14  8:45     ` $(make uImage) is stupid [Was: Re: Early kernel hang with big DTB appended] Uwe Kleine-König
2013-01-11 16:45 ` Sascha Hauer [this message]
2013-01-14 22:13   ` Early kernel hang with big DTB appended Nicolas Pitre
2013-01-15 10:53     ` Sascha Hauer
2013-01-15 11:26     ` Tomasz Figa
2013-01-15 18:12       ` Nicolas Pitre

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