[okl4-developer] unhandled page fault - please help

[Carl van Schaik]

Very quickly,


Nelson Tam wrote:
> Hi Gabi,
>
> On 06/03/2008, at 12:23 PM, Gabi Voiculescu wrote:
>
>   
>> Hello again and sorry for being so pushy.
>>
>> I have made a stub driver for LCD under PXA in two ways: with my own  
>> h file and with a dx file. My current goal is to trigger the LCD to  
>> appear in Skyeye.
>>     
>
> I'd be very careful here - we don't know how much of an LCD peripheral  
> Skyeye supports, if at all, and the answer is not apparent from their  
> SourceForge wiki.  If anything, I'd be inclined to say that skyeye  
> doesn't support LCD on the pxa platforms:
>
> http://skyeye.wiki.sourceforge.net/Linux
>
> Notice how the lcd: config line is commented out.
>
>   
>> I have edited device_core.c for platform/pxa/iguana/devicecore/src/  
>> in the scan_devices function to include the following:
>>
>> <snip>
>>
>> Unhandled page fault:
>>   addr=0x4/??? priv=R
>>   ip=0x8040317c, sp=80048ea0
>>   pd=0x800271d8 thread=0x1e8001
>>     
That looks like a null pointer deferenece at program address 0x8040317c
I would disassemble the corresponding image and see where this is happening.
>> I can't figure out what I did wrong. Where could this page fault be  
>> generated from?
>>     
>
> Hit ESC to enter KDB, 't' to show TCBs, and enter 1e8001 as the tid.   
> It will show you which thread faulted, and sometimes the name is  
> descriptive enough to help you pinpoint the problem.
>
> Then you want to find out where the faulting IP (0x8040317c) is.
>
>   # readelf -a build/images/image.elf
>
> will tell you which ELF binary the faulting IP comes from.  Let's just  
> say it's "ig_server".
>
>   # find build -name "ig_server"
>   build/iguana_server/include/ig_server
>   build/iguana_server/ig_server
>   build/iguana_server/bin/ig_server <- this is the one you want
>
>   # arm-linux-objdump -dx ./build/iguana_server/bin/ig_server
>
> will help you pinpoint the exact instruction that causes the fault.
>
> --
> (nt)
>
> Nelson Tam
> nelson at ok-labs.com
>
>
>
>
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