I am trying to get ptrace() working correctly so I can use gdbserver so we can debug with more power than printf()'s.
The kernel is 2.4.21-rc1 with stuff done to it to support some hardware that is under development (the chip has a 603-style core). I can fire up gdbserver, I can attach to it with a gdb on my host. I can watch the little ptrace transactions go by and (after eliminating some false leads) they all do seem to be doing sensible things. But when I try an "si", everything seems OK upto the _switch at which point the kernel SIGSTOPs on a 0x0 instruction at the first instruction of my application (or is it the second instruction?--I am not sure, the address complained about is first+4, maybe one worked). Once this happens my Abatron BDI-2000 is somehow hosed and can no longer write to memory. My next download takes all the time I would expect, but the results are all 0x0 unless I first powercycle the Abatron. The kernel seems to otherwise be working quite well. As this is new hardware, I cannot state that it is certainly working correctly. Obviously I suspect that something is wrong with how some memory management data structure is set up when the ptrace calls are being made by gdbserver, but I am not smart enough to have a clear idea of what to look for. (I don't want to get lost in walking page tables and tracing TBL faulting and whatnot for another week--not if I don't have to.) I have tried changing from our previous gdb and gdbserver to the Denx versions with same results. Suggestions? Thanks, -kb ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
