TMS320C6657: Invalid Access to L1D External Exception

Kim Steiner

Part Number: TMS320C6657
Other Parts Discussed in Thread: CCSTUDIO

Hi. I am running a c6657 dsp and am running into an External Exception.

I have looked at this wiki describing memory protection errors, which I think I am hitting:
http://processors.wiki.ti.com/index.php/MemoryProtectionOnKeystoneDevices?keyMatch=SMPFSR&tisearch=Search-EN-Everything

The L1DMPFAR register (0x0184ac00) shows the address (00C37BCB).

Looking at the event registers (EVTFLAG0-3) this is what I see:

I think EVTFLAG3 shows an event 122 which is how I came to the conclusion that this is a memory protection fault on the DSP.
Looking at the wiki page from above, it seems event 122 is a "core to L1D invalid access".

I then used the information in the RTOS Object View to put the PC, SP, and B3 into registers in CCStudio so that I could see more helpful information. The disassembly shows these instructions as the location of an External Exception:

Does anything look suspicious to you? What can I do to find this L1D invalid access problem?

The External Exception seems to occur in Release and not Debug.

Thanks,
Kim

over 8 years ago

0 Yordan Kovachev over 8 years ago

TI__Guru**** 161600 points

Hi,

Which SDK & CCS version are you using?

Best Regards,
Yordan

0 Kim Steiner over 8 years ago in reply to Yordan Kovachev

Intellectual 770 points

Hi Yordan,

I am using CCS 5.4.0 and EZSDK 5.05.02.00.

Thanks,

Kim

0 Yordan Kovachev over 8 years ago in reply to Kim Steiner

TI__Guru**** 161600 points

Hi Kim,

Could you share under what circumstances did you hit this invalid access? Summarize what were you trying to do to get to this error?

Besides the wiki you've found there is a C66x Core Pack User Guide:
www.ti.com/.../sprugw0c.pdf
Have a look at it for further description of memory accesses & protection.

Best Regards,
Yordan

0 Kim Steiner over 8 years ago in reply to Yordan Kovachev

Intellectual 770 points

Hi Yordan,

I added a hardware breakpoint to an exception handler. Then I looked at these registers and see that there was an invalid access to L1D. The exception points to code that is using some intrinsic functions (_dotp, _loll, _mem8, _mem4) when the exception occurs. The exception is sometimes an external exception and other times and internal exception:

Any ideas

Thanks,

Kim

0 Yordan Kovachev over 8 years ago in reply to Kim Steiner

TI__Guru**** 161600 points

Hi Kim,

I am out of ideas. I've asked the factory team for help. Their feedback will be posted here.

Best Regards,
Yordan

0 lding over 8 years ago in reply to Yordan Kovachev

TI__Guru* 95265 points

Hi,

"I am using CCS 5.4.0 and EZSDK 5.05.02.00." ====> Can you explain what EZSDK software is? Is this one software-dl.ti.com/.../index_FDS.html But it runs on DM814/6x SOC, you used in C6657. I don't know how you application code looks like, is it for some C6657 driver? Can you program migrate to any code base in Processor SDK RTOS for C6657? software-dl.ti.com/.../index_FDS.html.

Regards, Eric

0 Kim Steiner over 8 years ago in reply to lding

Intellectual 770 points

Hi Eric,

I am running a DM8148 and C6657. The EZSDK is forthe ARM side (linux). The C6657 DSP is using SYS/BIOS 6.35.1.29. Sorry if this confused you. The issue I am seeing is on the DSP side. I get an External Exception and the images in the original post shows the disassembly I see when the exception occurs. Do you see anything in the disassembly which would cause the external exception? I sometimes get an Internal Exception as well, but I filed a new ticket for that issue:

https://e2e.ti.com/support/dsp/c6000_multi-core_dsps/f/639/p/633214/2336181#2336181

I am using CGtools 7.4.2 but have also tried 7.4.20 and see the same issue with External exception. If you could please help explain the external exception and why I see the L1D (core to L1D) invalid access code, that would also be great.

Thanks,

Kim

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TMS320C6657: Invalid Access to L1D External Exception