Hello Punit,
On Wed, Nov 14, 2012 at 8:28 PM, Punit Agrawal punit.agrawal@arm.com wrote:
Hi Arun,
You can think of the trace in the ETB as the raw stream resulting from the multiplexing of different trace streams. So to get to the PTM trace you'll first have to de-multiplex the stream, and then decode the stream based on the source - in this case PTM.
The format of the data stored in the ETB is described in the ETM TRM Section 9.6 (http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0314h/Bgbhhid...). The decoding should give you a trace stream for each active trace source. The ATBID can be used to de-multiplex multiple sources, e.g., the two PTMs associated with the two A9s.
The PTM stream can then be decoded using the Program Flow Trace Protocol described in Program Flow Trace Architecture Specification Section 4 (http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ihi0035b/Chddbbd...).
So do you mean that there is no open source tool which decodes this as of now and I have to write one?
Out of curiosity, may I ask what are you trying to do?
The main intention is to debug freeze issues using PTM traces. When a device is in freeze, my intention is to collect PTM traces from ETB and decode. So that I ll get traces of last few branches and exceptions.
Thanks, Arun
Hope this helps. Feel free to ask for clarification.
Cheers, Punit
On 14/11/12 14:04, Arun KS wrote:
Hello,
I m trying to capture and decode PTM trace from Cortex A9 dual core.
I m successful in configuring the driver(arch/arm/kernel/etm.c) and setting the funnel to get data in ETB. But I don't know how to decode these traces.
Anyone has any pointers?
Thanks, Arun
linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
-- IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.