OMAP-L138: Trigger the exception hook manually

Friedrich Sanzi

Part Number: OMAP-L138
Other Parts Discussed in Thread: SYSBIOS

Hello,

is it possible to trigger the exception hook manually?

In principle, I use the following code:

In the application cfg file:
var Exc = xdc.useModule('ti.sysbios.family.c64p.Exception');
Exc.exceptionHook = '&Exception_Hook_Function';
Exc.enablePrint = true;

In the code:
void Exception_Hook_Function( void )
{
// do something ...
}

How can the function Exception_Hook_Function be reached using manually written code?

Thanks in advance.

Regards,
Friedrich

over 5 years ago

0 Aravind Batni over 5 years ago

TI__Expert 8885 points

Hi Friedrich,

you can access a non present memory or access a protected memory from DSP, which DSP has no privileges to access, to trigger the exception (known fault injection) and notice your hook function should be invoked.

Thanks,

Aravind

0 Friedrich Sanzi over 5 years ago in reply to Aravind Batni

Prodigy 185 points

Hello Aravind,

thanks for your response.

I have used two tests:

1. test:
Int32 *pointer_test_ptr = NULL; // generate Null pointer

/* Read Null pointer content */
if( *pointer_test_ptr > 0 )
{
/* Do something */
}

2. test:
Int32 *pointer_test_ptr = NULL; // generate Null pointer

pointer_test_ptr--;
/* Read pointer content */
if( *pointer_test_ptr > 0 )
{
/* Do something */
}
else
{
/* Do something */
}

However, in both cases the hook function is not invoked.

What changes have to be done in order to trigger the hook function?

Thanks in advance.

Regards,

Friedrich

0 Aravind Batni over 5 years ago in reply to Friedrich Sanzi

TI__Expert 8885 points

Hi Friedrich,

>> However, in both cases the hook function is not invoked.

Are you really hitting an exception and not hitting the function or seeing the exception and not hitting the hook function?

Can you try below in the code?

asm (" .word 0x4567f123 "); /* Undefined instruction */

The above should trigger the exception and you can check if it hits the exception function.

Please let me know.

0 Friedrich Sanzi over 5 years ago in reply to Aravind Batni

Prodigy 185 points

Hello Aravind,

thanks for your response.

I will check if the exception hook function is invoked using your test Code.

Regards,

Friedrich

0 Aravind Batni over 5 years ago in reply to Friedrich Sanzi

TI__Expert 8885 points

Friedrich,

Sure..Thanks

0 Friedrich Sanzi over 5 years ago in reply to Aravind Batni

Prodigy 185 points

Hello Aravind,

using your test code the exception hook function is invoked.

Can the exception hook function be triggered if access to a NULL pointer occurs?

Thanks in advance.

Regards,
Friedrich

+1 Aravind Batni over 5 years ago in reply to Friedrich Sanzi

TI__Expert 8885 points

Hi Friedrich,

I do not see it generating exception for access a NULL address (0x0000_0000). For other valid DSP memory addresses, there are MPU that can generate exceptions for invalid access

Please mark the thread as resolved if it answered all of your questions.

0 Friedrich Sanzi over 5 years ago in reply to Aravind Batni

Prodigy 185 points

Hello Aravind,

thanks for your response.

Regards,
Friedrich

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OMAP-L138: Trigger the exception hook manually