gdbserver+pthreads requires PTHREACE_SINGLESTEP?

[John Williams <jwilliams@itee.uq.edu.au>]

Hello,

Am I correct in thinking that the thread debug support in gdbserver 
requires the kernel to implement the PTRACE_SINGLESTEP functionality?

I'm slowly coming to grips with the thread debug mechanism - it seems 
that gdbserver inserts "private" breakpoints in the child's thread 
library (e.g. create_thread) - when these breakpoints trigger, gdbserver 
handles them itself as thread events, rather than passing them off to gdb.

The singlestep seems to be necessary because when, say , the 
create_thread BP is hit, gdbserver wants to step over the first 
instruction, reinsert the breakpoint, then continue as before.

This creates a bit of a bind for me, since the CPU I'm targetting has no 
HW single step capability -  ptrace(PTRACE_SINGLESTEP) returns -EIO.

Is there a workaround for non-singlestep targets, short of doing a full 
kernel SW implementation of single stepping (yuck)?

Since it's not really singlestep I need, but rather "continue and 
reinsert", I wonder if that might be a simpler mechanism to implement?

Thanks for any insights,

John