summaryrefslogtreecommitdiff
path: root/include/linux/kgdb.h
diff options
context:
space:
mode:
authorAnton Vorontsov <anton.vorontsov@linaro.org>2012-09-24 14:27:56 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-09-26 13:52:36 -0700
commit0c57dfcc6c1d037243c2f8fbf62eab3633326ec0 (patch)
tree0cbdffff6807949c49b49190188d295d489b0c66 /include/linux/kgdb.h
parent5c8124a0f8f50c5671b028b7a030d893a3a1a539 (diff)
tty/serial: Add kgdb_nmi driver
This special driver makes it possible to temporary use NMI debugger port as a normal console by issuing 'nmi_console' command (assuming that the port is attached to KGDB). Unlike KDB's disable_nmi command, with this driver you are always able to go back to the debugger using KGDB escape sequence ($3#33). This is because this console driver processes the input in NMI context, and thus is able to intercept the magic sequence. Note that since the console interprets input and uses polling communication methods, for things like PPP it is still better to fully detach debugger port from the KGDB NMI (i.e. disable_nmi), and use raw console. Usually, to enter the debugger one have to type the magic sequence, so initially the kernel will print the following prompt on the NMI debugger console: Type $3#33 to enter the debugger> For convenience, there is a kgdb_fiq.knock kernel command line option, when set to 0, this turns the special command to just a return key press, so the kernel will be printing this: Hit <return> to enter the debugger> This is more convenient for long debugging sessions, although it makes nmi_console feature somewhat useless. And for the cases when NMI connected to a dedicated button, the knocking can be disabled altogether by setting kgdb_fiq.knock to -1. Suggested-by: Colin Cross <ccross@android.com> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Acked-by: Alan Cox <alan@linux.intel.com> Acked-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/kgdb.h')
-rw-r--r--include/linux/kgdb.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h
index 7800cce284db..4dff0c6ed58f 100644
--- a/include/linux/kgdb.h
+++ b/include/linux/kgdb.h
@@ -286,6 +286,16 @@ extern struct kgdb_arch arch_kgdb_ops;
extern unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs);
+#ifdef CONFIG_SERIAL_KGDB_NMI
+extern int kgdb_register_nmi_console(void);
+extern int kgdb_unregister_nmi_console(void);
+extern bool kgdb_nmi_poll_knock(void);
+#else
+static inline int kgdb_register_nmi_console(void) { return 0; }
+static inline int kgdb_unregister_nmi_console(void) { return 0; }
+static inline bool kgdb_nmi_poll_knock(void) { return 1; }
+#endif
+
extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops);
extern void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops);
extern struct kgdb_io *dbg_io_ops;