Re: Thread awareness in remote serial protocol Z packet

[Earl Chew <earl_chew at agilent dot com>]

Daniel Jacobowitz wrote:
> Earl wrote:
> > Perhaps extended the Z protocol to allow Zt,addr,length,id
> > (plus the corresponding change in breakpoint.c) would be sufficient
> > to allow this. Old targets presumably would ignore the ,id
> > argument and proceed as before.
> 
> Either that or we'd need to specify a different packet type for
> this... gdbserver doesn't support the Z packet right now, so it
> wouldn't care; it could easily be extended to support the Z packet
> and to support thread-specific breakpoints but I haven't had a chance.

As to whether extending the Z packet is possible, I suppose it
depends on whether targets that support it explicitly check
for end-of-packet after reading the existing length field.

Do you know of any remote agents implementing Z and their behaviours?

Another related question I'm pondering is how to have the remote
agent react when one thread hits a breakpoint. My browsing of
the documentation and source suggests that gdb expects all threads
to stop when any one thread hits a breakpoint.

Is this correct?

I think that this means that mult-threaded embedded targets would
have to suspend related threads when a thread-specific breakpoint hits.

Earl
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