These are the minimum changes to the kgdb core in order to enable an API to connect a new front end (kdb) to the debug core. This patch introduces the dbg_kdb_mode variable controls where the user level I/O is routed. It will be routed to the gdbstub (kgdb) or to the kdb front end which is a simple shell available over the kgdboc connection. You can switch back and forth between kdb or the gdb stub mode of operation dynamically. From gdb stub mode you can blindly type "$3#33", or from the kdb mode you can enter "kgdb" to switch to the gdb stub. The logic in the debug core depends on kdb to look for the typical gdb connection sequences and return immediately with KGDB_PASS_EVENT if a gdb serial command sequence is detected. That should allow a reasonably seamless transition between kdb -> gdb without leaving the kernel exception state. The two gdb serial queries that kdb is responsible for detecting are the "?" and "qSupported" packets.
Showing the changes to kernel/debug/debug_core.h (1 of 9 files). Show all
Unified · Split
| @@ -38,6 +38,8 @@ struct debuggerinfo_struct { · 37 unmodified lines | ||
| 38 | 38 | void *debuggerinfo; |
| 39 | 39 | struct task_struct *task; |
| 40 | 40 | int exception_state; |
| 41 | + int ret_state; | |
| 42 | + int irq_depth; | |
| 41 | 43 | }; |
| 42 | 44 | |
| 43 | 45 | extern struct debuggerinfo_struct kgdb_info[]; |
| @@ -47,9 +49,31 @@ extern int dbg_remove_all_break(void); · 3 unmodified lines | ||
| 47 | 49 | extern int dbg_set_sw_break(unsigned long addr); |
| 48 | 50 | extern int dbg_remove_sw_break(unsigned long addr); |
| 49 | 51 | extern int dbg_activate_sw_breakpoints(void); |
| 52 | +extern int dbg_deactivate_sw_breakpoints(void); | |
| 53 | + | |
| 54 | +/* polled character access to i/o module */ | |
| 55 | +extern int dbg_io_get_char(void); | |
| 56 | + | |
| 57 | +/* stub return value for switching between the gdbstub and kdb */ | |
| 58 | +#define DBG_PASS_EVENT -12345 | |
| 59 | +/* Switch from one cpu to another */ | |
| 60 | +#define DBG_SWITCH_CPU_EVENT -123456 | |
| 61 | +extern int dbg_switch_cpu; | |
| 50 | 62 | |
| 51 | 63 | /* gdbstub interface functions */ |
| 52 | 64 | extern int gdb_serial_stub(struct kgdb_state *ks); |
| 53 | 65 | extern void gdbstub_msg_write(const char *s, int len); |
| 54 | 66 | |
| 67 | +/* gdbstub functions used for kdb <-> gdbstub transition */ | |
| 68 | +extern int gdbstub_state(struct kgdb_state *ks, char *cmd); | |
| 69 | + | |
| 70 | +#ifdef CONFIG_KGDB_KDB | |
| 71 | +extern int kdb_stub(struct kgdb_state *ks); | |
| 72 | +#else /* ! CONFIG_KGDB_KDB */ | |
| 73 | +static inline int kdb_stub(struct kgdb_state *ks) | |
| 74 | +{ | |
| 75 | + return DBG_PASS_EVENT; | |
| 76 | +} | |
| 77 | +#endif /* CONFIG_KGDB_KDB */ | |
| 78 | + | |
| 55 | 79 | #endif /* _DEBUG_CORE_H_ */ |