Re: [Xen-devel] Running Xen on Nvidia Jetson-TK1

[Meng Xu <mengxu@xxxxxxxxxxxxx>]

Hi Dushyant,

>>> On Thu, Mar 17, 2016 at 8:22 PM, Julien Grall <julien.grall@xxxxxxx>
>>> wrote:
>>>>
>>>> On 14/03/16 14:19, Dushyant Behl wrote:
>>>>>>
>>>>>> Yes, I have enabled these configuration parameters when compiling linux
>>>>>> -
>>>>
>>>>
>>>> The list of options looks good to me. I guess Linux is crashing before
>>>> setting
>>>> up the console. Can you apply the below to Linux and post the log here?
>>>
>>>
>>> I applied your patch to Linux but still there is no output from the
>>> kernel.
>>>
>>> But I have found location of the problem, I have a debugger attached
>>> to the Jetson board
>>> and using that I was able to find out that Linux is failing while
>>> initializing the Tegra timer.
>>>
>>> The call stack at the time of failing is  -
>>>
>>> -   prefetchw (inline)
>>>      arch_spin_lock (inline)
>>>      do_raw_spin_lock_flags (inline)
>>>      __raw_spin_lock_irqssave (inline)
>>>      raw_spin_lock_irq_save (lock = 0xC0B746F0)
>>> -   of_get_parent (node = 0xA00001D3)
>>> -   of_get_address (dev = 0xDBBABC30, index = 0, size = 0xC0A83F30)
>>> -   of_address_to_resource(dev = 0xDBBABC30, index = 0, r = 0xC0A83F50)
>>> -   of_iomap (np = 0xDBBABC30, index = 0)
>>> -   tegra20_init_timer (np = 0xDBBABC30)
>>> -   clocksource_of_init()
>>> -   start_kernel()
>>>
>>> After this Linux jumps to floating point exception handler and then to
>>> undefined instruction and fails.
>>
>>
>> I don't know why Linux is receiving a floating point exception. However,
>> DOM0 must not use the tegra timer as it doesn't support virtualization.
>>
>> You need to ensure that DOM0 will use the arch timer instead. Xen provides
>> some facilities to blacklist a device tree node (see blacklist dev in
>> arm/platforms/tegra.c).
>
> I have blacklisted the tegra20_timer

I guess you blocked the "tegra20-timer" (which uses "-" instead of
"_") right as shown in the following patch? Am I right?

diff --git a/xen/arch/arm/platforms/tegra.c b/xen/arch/arm/platforms/tegra.c

index 5ec9dda..8477ad1 100644

--- a/xen/arch/arm/platforms/tegra.c

+++ b/xen/arch/arm/platforms/tegra.c

@@ -431,6 +431,7 @@ static const struct dt_device_match
tegra_blacklist_dev[] __initconst =

      * UART to dom0, so don't map any of them.

      */

     DT_MATCH_COMPATIBLE("nvidia,tegra20-uart"),

+    DT_MATCH_COMPATIBLE("nvidia,tegra20-timer"),

     { /* sentinel */ },

 };

Thanks and Best Regards,

Meng
-----------
Meng Xu
PhD Student in Computer and Information Science
University of Pennsylvania
http://www.cis.upenn.edu/~mengxu/

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