[ECOS] Re: remote debugging

[Mark Salter <msalter@redhat.com>]

>>>>> Vinayak P Risbud writes:

>         Hi,
>             I am trying to use remote debugging using LAN (Tcp/Ip) on
> Redboot
>             What I understood till now is,
>                     1.  the main polls net_io_test function during idle
> time
>                     2.  The function net_io_test checks for
>                                         tcp_sock.state == _ESTABLISHED
>                     3.   If established, the control calls
> net_io_assume_console
>                          to setup debug channel.

>                 But,  after this, how the flow goes,  I am not able to
> trace.

The above happens during TCP connection establishment and not for
debugging per se.

>                 my gdb client on remote PC sends $Hc-1#09 command,
>                 over tcp/ip link.
>                 I am not able to trace, where and how exactly this gdb
>                 command is read and processed (i.e trap is generated ?)

When RedBoot sees the '$' character in the input stream, it executes
a breakpoint instruction which in turn gives control to the GDB stub.

See the interpreter loop in main.c where there is a test:

            if (res == _GETS_GDB) {
               ...
            }

--Mark



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