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Using kgdb on iMX7D  (with official bsp)

Question asked by D. RY on Mar 6, 2019
Latest reply on Apr 18, 2019 by gusarambula

I would like to confirm that kgdb is usable for single-stepping the kernel code.   What I see - on iMX7D, official NXP released kernel (i'm on bsp 4.9.11)  - this does not work (kernel doesnt resume , and some gdb errors, etc..). 


Official mainstream kernel page says, "limited execution stepping" , and I don't see more details on it ((kgdb doc on kernel org) ).  Anyone knows what does this mean, and what kind of single stepping is supported through the kgdb?


I've seen a few page references (sorry i won't give links but you can google..), that seem to suggest, that single stepping with kgdb on ARM (Cortex, Cortex A ) does not work, it's not implemented.  But those pages are few years old.  I didn't find anything newer.


Anyone can provide more details on this? I would appreciate it.


At the moment, after I did set it up, and could connect, and stop / break kernel, and get the threads/processes list, etc. Which is nice, but. One thing it felt quite slow (if not painfully slow). Then stop or break and then continue did not always work (mmm, now I'm not even sure I could stop it from gdb, and resume . .may be only with kgdb command console).  


So before I confirm for myself that it isn't much of use that kgdb, I want to make sure on those break points & single stepping.