gdb_server: avoid gdb server for virtual targets

Virtual targets, like mem_ap, do not or cannot implement the required
functionality to accept a GDB connection. In the case of mem_ap, the
method get_gdb_reg_list() is missing and a following connection from
gdb causes OpenOCD to segfault.
OpenOCD opens a GDB port for each target; it's always possible to
connect, by mistake, GDB to one virtual target.

Add a method to check if the target supports GDB connections (for the
moment just checking if get_gdb_reg_list is implemented).
Skip opening a gdb server for every targets that don't support GDB
connections.

Change-Id: Ia439a43efe1a9adbb1771cd9d252db8ffa32eb9d
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/4676
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>
bscan_tunnel
Antonio Borneo 2018-08-28 12:29:09 +02:00 committed by Matthias Welwarsky
parent 6823a97beb
commit 24654759d5
3 changed files with 23 additions and 0 deletions

View File

@ -3404,6 +3404,12 @@ static int gdb_target_add_one(struct target *target)
if ((target->smp) && (target->gdb_service)) if ((target->smp) && (target->gdb_service))
return ERROR_OK; return ERROR_OK;
/* skip targets that cannot handle a gdb connections (e.g. mem_ap) */
if (!target_supports_gdb_connection(target)) {
LOG_DEBUG("skip gdb server for target %s", target_name(target));
return ERROR_OK;
}
if (target->gdb_port_override) { if (target->gdb_port_override) {
if (strcmp(target->gdb_port_override, "disabled") == 0) { if (strcmp(target->gdb_port_override, "disabled") == 0) {
LOG_INFO("gdb port disabled"); LOG_INFO("gdb port disabled");

View File

@ -1205,6 +1205,16 @@ int target_get_gdb_reg_list(struct target *target,
{ {
return target->type->get_gdb_reg_list(target, reg_list, reg_list_size, reg_class); return target->type->get_gdb_reg_list(target, reg_list, reg_list_size, reg_class);
} }
bool target_supports_gdb_connection(struct target *target)
{
/*
* based on current code, we can simply exclude all the targets that
* don't provide get_gdb_reg_list; this could change with new targets.
*/
return !!target->type->get_gdb_reg_list;
}
int target_step(struct target *target, int target_step(struct target *target,
int current, target_addr_t address, int handle_breakpoints) int current, target_addr_t address, int handle_breakpoints)
{ {

View File

@ -481,6 +481,13 @@ int target_get_gdb_reg_list(struct target *target,
struct reg **reg_list[], int *reg_list_size, struct reg **reg_list[], int *reg_list_size,
enum target_register_class reg_class); enum target_register_class reg_class);
/**
* Check if @a target allows GDB connections.
*
* Some target do not implement the necessary code required by GDB.
*/
bool target_supports_gdb_connection(struct target *target);
/** /**
* Step the target. * Step the target.
* *