Re: [Xen-devel] Fwd: [cros-discuss] Boot in Hyp mode on Samsung ARM Chromebook

[francesco.gringoli@xxxxxxxxxxxx]

On Jan 9, 2014, at 8:36 AM, John Johnson <lausgans@xxxxxxxxx> wrote:

> Meanwhile, i've tried to boot just bare linux-chromebook kernel from
> xen repo to no avail. Same symptoms ("I don't see anything on the
> display")...
> Nothing of these hand't helped:
> 1. Usage of defconfig from kernel repo from chromium.googlesource.com
> 2. Attaching both new exynos5250-snow-rev4 & exynos5250-snow-rev5 fdt
> blobs instead of an old exynos5250-snow one.
> Ideas?
Hello John,

I spent a lot of time back in September/October for debugging this stuff. 
Unfortunately I had to stop, this is what I remember:

1) resetting the chromebook (at least on my hardware revision) turns off power 
to the RAM for a while, so everything in the ram log is lost;

2) to avoid 1) I had to do soft reset before crash, so I started putting 
soft-resets in early code of xen, and magically I started accessing the ram 
log; pay attention, after paging is turned on, you have to map a page at the 
top of the page vector for keeping using soft reset;

3) it turned out that xen boots and it also starts booting linux kernel (btw 
you can raise soft-resets also from within Linux, and you can write from Linux 
in a different ram log); pay attention also in Linux, when paging starts to 
change the address of the soft reset register. I don't remember where the dom0 
boot hangs...

I'm restarting working on this, the first goal is to understand exactly where 
the dom0 kernel boot process crash.

Best regards,
-Francesco

Linux boot process goes fairly beyond 
> 
> ---------- Forwarded message ----------
> From:  <lausgans@>
> Date: 2013/12/17
> Subject: Re: [Xen-devel] [cros-discuss] Boot in Hyp mode on Samsung
> ARM Chromebook
> To: chromium-os-discuss@xxxxxxxxxxxx
> Копия: Anthony PERARD <anthony.perard@>, Mike Frysinger <vapier@>, Ian
> Campbell <Ian.Campbell@>, Xen Devel <xen-devel@xxxxxxxxxxxxx>,
> Francesco Gringoli <francesco.gringoli@>, Chen Baozi <baozich@>
> 
> 
>> 17.12.2013, 13:31, "Ian Campbell" <Ian.Campbell@xxxxxxxx>:
>>> On Tue, 2013-12-17 at 05:37 +0000, Held Bier wrote:
>>> 
>>>>  <francesco.gringoli <at> ing.unibs.it> writes:
>>>>>> ...
>>>>> ...
>>>>> After reboot I don't see anything on the
>>>>> display and this is expected: unfortunately after rebooting into
>>>>>  either linux or chromeos I don't see logs saved in dmesg-ramoops.
>>>>> ...
>>>>> I'm wondering if the hardware could have been changed in the
>>>>> meanwhile: Chen, would you mind please post
>>>>> somewhere the unsigned image that you used to get those interesting
>>>>> dmesg-ramoops messages? so that I can
>>>>> try to see after reboot if I'm getting something similar in /dev/pstore ?
>>>>> ...
>>>> PING!
>>> 
>>> Did you mean to also send this to cros-discuss where it appears the
>>> people you are quoting are subscribed? Very little of this discussion
>>> seems to have happened on xen-devel.
>>> 
>>> You might also want to consider CCing the people/person you are
>>> addressing with your ping directly.
>>> 
>>> Ian.
> 
> 
> Done. Thanks, Ian.
> Though, an original was sent only in xen lists:
> http://lists.xen.org/archives/html/xen-devel/2013-09/msg00912.html
> 
>>>> I'm experiencing exactly the same, though upon natively built tools
>>>> (while Francesco cross-compiles).
> 
> P.S.: Maybe drop current subject of this thread? Though secure mode
> escape hack had removed from recent trees, Chromebook Xen tree still
> has it.
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel


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