(toppers-users 4451) Re: FMP Programming Model

[Pieter Maene]

Hi Daniel,

The exception is triggered in a piece of code that is very 
loop-intensive. However, the same piece of code runs without any 
problems earlier during the program execution, so I don't think it's a 
problem with unsupported instructions. I've also found out that the 
second entry from the _kernel_prc1_exch_table is triggered, but it's not 
clear to me how I can determine the exact type of exception.

Finally, I was wondering whether there are any further instructions on 
how to enable the logtrace functionality. I have found some 
documentation, but couldn't get any output over UART.

Thank you in advance!

Kind regards,

Pieter Maene

On 11/07/2015 04:30 AM, Daniel Sangorrin wrote:
> Hi Pieter,
>
> It's a bit hard to answer with so little information.
> You should start by isolating the problem. For example:
>
> - Does the problem exist when running FMP alone, or only when FMP runs on SafeG?
> - What type of exception is it?
> - Which part of the code is generating the exception?
> - Are your functions using some instructions not supported by your
> processor (in case of
>    an undefined instruction exception) ?
> - Do they require some coprocessor (VFP, SIMD) that is not supported
> by the SoC or by FMP itself?
>
> Regards,
> Daniel
>
>
>
>
>
>
>
> On Sat, Nov 7, 2015 at 1:32 AM, Pieter Maene
> <pieter.maene ＠ esat.kuleuven.be> wrote:
>> Hi,
>>
>> We are currently building a TrustZone application for a course at the
>> University of Leuven. We use SafeG, with FMP in the secure world and Linux
>> as the untrusted OS. A signature module is running in the trusted world and
>> can be invoked to sign a message sent by the untrusted OS. The communication
>> between the OSs works perfectly, but when a complicated function is invoked
>> (e.g. the signing operation or deriving the public/private keypair), the CPU
>> crashes with an "unregistered exception".
>>
>> I think I am missing a key concept of programming for FMP, or maybe
>> misconfigured a setting for the kernel.
>> Do you have an idea of what might be going wrong?
>>
>> Thanks in advance!
>>
>> Kind regards,
>>
>> Pieter Maene