Re: kernel crash in fault.c

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Nandakumar NarayanaSwamy wrote:

> Hi Raj,
> Thanks for ur immediate response.
>
> There are about three PCI devices in the board. When the linux boots 
> up, it detects all the three devices and allocates memory. The driver 
> for other 2 devices is built with the kernel. I am trying to load  the 
> driver for the third device.
>
> I am trying to use the memory that is already allocated to this device 
> during bootup. When i try to write a word in this address space, the 
> system crashes. Am i missing somewhere? 



    Probably yes ;)... The PCI address allocated by the boot loader will 
be within the
range which is hardwired or routed by the system controller to the PCI 
controller.
If the value is proper you would not get a page fault. There are two 
possibilities

1)  The address assigned by the boot loader to your device might be 
outside the
PCI address window.  Do a cat /proc/pci and see what is the address 
range allocated for your device.

2) You are doing something wrong when you ioremap the PCI IO address 
range to
KSEG2 space.  Try using the memory address range.

I believe you wouldn't get a page fault if the problem was just not 
enabling PCI IO or MEM
access.

BTW what is the badvaddr when the system faults ?

>> The PCI address you accessed doesn't seem to be within the PCI 
>> address window.
>> Check the address range setup in your systems PCI controller. Or you 
>> might be
>> facing problems in the ioremap of the PCI address. So check both the 
>> ioremap'ed
>> address and the PCI address and see if they are OK.
>>



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