I'm adding extra documentation to those fields in a new patchset.
On Fri, Oct 4, 2024 at 1:46 PM Alex Bennée <alex.ben...@linaro.org> wrote:
>
> Roque Arcudia Hernandez <roq...@google.com> writes:
>
> > In the context of using the remote gdb with multiple
> > processes/inferiors (multiple cluster machine) a given breakpoint
> > will target an specific inferior. If needed the remote protocol will
> > use the packet 'H op thread-id' with op = 'g' to change focus to the
> > inferior we want to insert/remove the breakpoint to, for instance
> > 'Hgp3.3' and not 'Hcp3.3'.
> >
> > This is supported by the documentation of the H packets:
> >
> > > 'H op thread-id'
> > > Set thread for subsequent operations ('m', 'M', 'g', 'G',
> > > et.al.). Depending on the operation to be performed, op should be
> > > 'c' for step and continue operations (note that this is
> > > deprecated, supporting the 'vCont' command is a better option),
> > > and 'g' for other operations.
>
> Can we better comment:
>
> CPUState *c_cpu; /* current CPU for step/continue ops */
> CPUState *g_cpu; /* current CPU for other ops */
>
> in GDBState?
>
> >
> > This can also be verified in the GDB source code file gdb/remote.c.
> > Functions remote_target::insert_breakpoint and
> > remote_target::remove_breakpoint will eventually call
> > remote_target::set_general_thread if it needs to change the process
> > focus and not remote_target::set_continue_thread.
> >
> > This can be seen around a comment that says:
> >
> > /* Make sure the remote is pointing at the right process, if
> > necessary. */
> >
> > Google-Bug-Id: 355027002
> > Signed-off-by: Roque Arcudia Hernandez <roq...@google.com>
> > ---
> > gdbstub/gdbstub.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c
> > index d08568cea0..98574eba68 100644
> > --- a/gdbstub/gdbstub.c
> > +++ b/gdbstub/gdbstub.c
> > @@ -1148,7 +1148,7 @@ static void handle_insert_bp(GArray *params, void
> > *user_ctx)
> > return;
> > }
> >
> > - res = gdb_breakpoint_insert(gdbserver_state.c_cpu,
> > + res = gdb_breakpoint_insert(gdbserver_state.g_cpu,
> > gdb_get_cmd_param(params, 0)->val_ul,
> > gdb_get_cmd_param(params, 1)->val_ull,
> > gdb_get_cmd_param(params, 2)->val_ull);
> > @@ -1172,7 +1172,7 @@ static void handle_remove_bp(GArray *params, void
> > *user_ctx)
> > return;
> > }
> >
> > - res = gdb_breakpoint_remove(gdbserver_state.c_cpu,
> > + res = gdb_breakpoint_remove(gdbserver_state.g_cpu,
> > gdb_get_cmd_param(params, 0)->val_ul,
> > gdb_get_cmd_param(params, 1)->val_ull,
> > gdb_get_cmd_param(params, 2)->val_ull);
>
> --
> Alex Bennée
> Virtualisation Tech Lead @ Linaro
