Z packet support in Gdbserver?

[Andrew Cagney]

I noticed there's no support for z/Z packets for hardware watchpoints in the gdbserver.  (I searched the archives for this, but came up empty-handed.)  I'd guess that (from looking at ptrace.c for i386, where it accesses the DR_ registers) that the Gdbserver gets to configure the hardware breakpoint mechanism through ptrace (PTRACE_POKEUSR, ...).  But how does it get there in the first place, if not as a result of a z/Z packet?  Through direct register writes (G packet)?
Yep.

There are two ways to implement h/w watchpoints: in the target (as was 
done for remote.c); or in the per-architecture code (as was done for 
native i386).  Both are correct.  The missing bit is code to get the 
per-architecture logic working with a remote target - this would involve 
juggling things so that the h/w watchpoint registers are included in the 
regcache and the target/arch to select either a local/remote mechanism.

More notes:
http://sources.redhat.com/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gdb&pr=735
Andrew