Modifications on gdbserver

[Sérgio Durigan Júnior <sergiodj at linux dot vnet dot ibm dot com>]

Hello guys,

I'm extending gdbserver in order to accept new types of hardware  
breakpoints/watchpoints, and trying to figure out how to do this in the best 
way.  Specifically, right now I'm implementing the support for hardware ranged 
breakpoints (one will be able to specify an address and a range, and GDB will 
stop whenever the inferior executes code within this range), and there are 
some ways to do it:

1) I could extend the remote protocol and include one more type of `Z' packet 
(`Z5', for example) which would represent this type of hardware breakpoint.

2) I could extend the existing `Z1' (hardware breakpoint) packet in order to 
include a "length" (or "range") parameter.  This will be different from the 
existing "size" parameter, because "size" is currently used the size of the 
instruction on the architecture.

What do you think?  Considering that there will be more "special" types of 
hardware breakpoints/watchpoints, probably I should choose (2) and try to 
modify the remote protocol as few as possible.  Do you agree?  Also, do you 
see other option(s) that could be better for this case?

Best regards,

-- 
Sérgio Durigan Júnior
Linux on Power Toolchain - Software Engineer
Linux Technology Center - LTC
IBM Brazil