RE: [lwip-users] lwip + sam7x = udef exception

[B B]

Hi,
 
Ok it seems that i have jumped to a conclusion on the stack overflow.
Now i searched the memory area, and started with the end of the memory area, which triggered me
to write the mail below. But now i have found that it just seemed to have been mirrored there.
Because the 0xa5 values also appears from address 0x0020024C to 0x002006BC.
 
Which leaves me still with one question, why do i end up in the undef_handler.
My call stack as i described in an earlier mail seems weird.
But i am running dry of ideas to what could be the cause of this.
 
regards,
Martin

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From: address@hidden
To: address@hidden
Subject: RE: [lwip-users] lwip + sam7x = udef exception
Date: Fri, 16 Feb 2007 08:46:04 +0000

Hi again Caglar,
 
I am able to see the 0xa5 values, but they appear on a weird address.
On the sam7x256 the SRAM area goes from 0x00200000 to 0x00210000 (64kb).
 
I am no expert on this part, but the values appear from address 0x0021024C to 0x002106BC,
which to me indicates that the SRAM has been overshot.
 
So am I correct in the assumption that, the memory area has been overflown, and i should
look at measures to keep my memory usage low on the other tasks ?

regards,
Martin

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> Date: Thu, 15 Feb 2007 17:34:49 +0200
> From: address@hidden
> To: address@hidden
> Subject: Re: [lwip-users] lwip + sam7x = udef exception
>
> B B wrote:
> >
> > Hi Caglar and everyone else :)
> >
> > I am using FreeRTOS v4.1.3 + lwip 1.2.0 + Rowley CrossWorks.
>
> Hi,
>
> As I said before, I'm using also this configuration and it is working in
> a perfect harmony for me.
>
> >
> > Upon further investigation, it actually seems to be a stack overflow,
> > which is
> > the root for my problem
> > I have increased the value for lwipTCP_STACK_SIZE from 600 to 800,
> > and now the application has run straight for over an hour.
>
> I think this stack size is well suited for most kind of operation.
> However, since you are encountering a
> stack overflow issue, it is strongly probable that there is something
> wrong with the code. How do you handle ethernet
> tasks. Sockets api , raw api ? If you can post your ethernet task, then
> you may find better support than me :)
>
> >
> > I read up on the undef exception handling in the ARM archtecture
> > reference manual.
> > Which says that the instruction pointed to by LR is the instruction
> > after the instruction that caused
> > the exception.
> > I thought as per the Atmel datasheet that the failing address would be
> > present in the MC_AASR,
> > but the value in LR - offset, doesn't match the value in MC_AASR.
>
> I think there is nothing important to be concern of this mis-alingment
> error. Since there is a fact like stack overflow
> you should concentrate on it.
>
> Can you investigate your stack when you face the undef exception. If you
> don't see 0xa5 values at the end your stack,then you
> have a stack problem. If you can't debug your stack, you can try
> avaliable options in the FreeRtos code.
>
> Kind Regards,
> Caglar AKYUZ
>
>
> _______________________________________________
> lwip-users mailing list
> address@hidden
> http://lists.nongnu.org/mailman/listinfo/lwip-users

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