Freescale i.MX 53 SABRE tablet - TrustZone demonstration

Stefan Kalkowski stefan.kalkowski at ...1...
Thu Apr 23 11:05:11 CEST 2015


On 04/20/2015 01:08 PM, Ofer Hasson wrote:
> Hello,
> I'm trying to reproduce the demonstration in the article:
> I've followed the readme instructions
> (
> and also tried to download the pre-built image.
> With both i get the same result. The TrustZone GUI loads nicely, but
> when i turn on the 'normal world' by pressing the 'play' button, the
> android hangs and don't complete the boot, it hangs when the small tux
> (Linux penguin logo) is on the top right corner.
> If I'm connected through the RS-232 debug interface, the android
> underlying linux is responding and i get a shell. The Linux keeps
> 'killing' the netd process over and over again:
> init: untracked pid XXXX exited
> sometimes i also get:
> request_suspend_state: on (0->0) at XXXXXXXXXXXX (1970-01-02
> 3:15:26.3252353422 UTC)
> I loaded the image.elf to sdcard, and plugged it to the SABRE tablet, on
> the u-boot countdown i hit a key and load the image using "ext2load mmc
> ....." and then launching the image using 'go'.
> Also, android libraries are not loaded, so 'svc', 'am' and other android
> commands do not work (could not load
> Is there any modifications need to made to the android / Linux guest for
> the demonstration ?
> Any idea what needs to be changed or why this is happening ?

Indeed the Linux/Android kernel is modified and replaces the one you can
find on the MMC card.

The problem is that the userland part of Android (especially the HAL
layer) is hardly coupled with the kernel version. I have also
experienced problems when the Android userland differentiated just a bit
from the one I used for the demonstration.
Unfortunately, the pre-installed Android of the SABRE tablet as it is
shipped right now seems to differ (we got a second one too) from the the
one we originally used.

If I remember correctly we used the Android images from the
imx-android-r10.4_bundle_BSP.tar.gz BSP package for the scenario, but I
would not bet on it. It is hard to find the BSP package on the Freescale
site, therefore here is a link:

You have to choose: "Runtime software" -> "Operating System Software".
It is the item "IMX5X_R10_4_ANDROID_SOURCECODE". I hardly remember you
need some tool from Freescale to exchange the image of the eMMC card, it
is called MFG tool, and is either part of the BSP, or you have to
download it separately.

To reproduce the scenario if the BSP does not match, I fear the only way
is to find the right Freescale Android sources for the tablet (should be
part of the BSP archive) - at best it should match the kernel
modifications we made, apply them, and compile the whole Android
kernel/userland image.

Good luck, and best regards

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Stefan Kalkowski
Genode Labs ยท

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