kgdboc,kdb: Allow kdb to work on a non open console port

If kdb is open on a serial port that is not actually a console make
sure to call the poll routines to emit and receive characters.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Martin Hicks <mort@sgi.com>

3 files changed, 33 insertions, 0 deletions

diff --git a/drivers/serial/kgdboc.c b/drivers/serial/kgdboc.c
index ecef6e1a599a..b765ab48dfe7 100644
--- a/drivers/serial/kgdboc.c
+++ b/drivers/serial/kgdboc.c
@@ -16,6 +16,7 @@
 #include <linux/kgdb.h>
 #include <linux/kdb.h>
 #include <linux/tty.h>
+#include <linux/console.h>
 
 #define MAX_CONFIG_LEN          40
 
@@ -93,12 +94,14 @@ static int configure_kgdboc(void)
         int tty_line = 0;
         int err;
         char *cptr = config;
+        struct console *cons;
 
         err = kgdboc_option_setup(config);
         if (err || !strlen(config) || isspace(config[0]))
                 goto noconfig;
 
         err = -ENODEV;
+        kgdboc_io_ops.is_console = 0;
         kgdb_tty_driver = NULL;
 
         if (kgdboc_register_kbd(&cptr))
@@ -108,6 +111,17 @@ static int configure_kgdboc(void)
         if (!p)
                 goto noconfig;
 
+        cons = console_drivers;
+        while (cons) {
+                int idx;
+                if (cons->device && cons->device(cons, &idx) == p &&
+                    idx == tty_line) {
+                        kgdboc_io_ops.is_console = 1;
+                        break;
+                }
+                cons = cons->next;
+        }
+
         kgdb_tty_driver = p;
         kgdb_tty_line = tty_line;
 
diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h
index ee007ea341b8..6c784ab6856a 100644
--- a/include/linux/kgdb.h
+++ b/include/linux/kgdb.h
@@ -247,6 +247,8 @@ struct kgdb_arch {
  * the I/O driver.
  * @post_exception: Pointer to a function that will do any cleanup work
  * for the I/O driver.
+ * @is_console: 1 if the end device is a console 0 if the I/O device is
+ * not a console
  */
 struct kgdb_io {
         const char              *name;
@@ -256,6 +258,7 @@ struct kgdb_io {
         int                     (*init) (void);
         void                    (*pre_exception) (void);
         void                    (*post_exception) (void);
+        int                     is_console;
 };
 
 extern struct kgdb_arch         arch_kgdb_ops;
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 8339b291e8bc..58be7e9c9e95 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -673,6 +673,14 @@ kdb_printit:
         if (!dbg_kdb_mode && kgdb_connected) {
                 gdbstub_msg_write(kdb_buffer, retlen);
         } else {
+                if (!dbg_io_ops->is_console) {
+                        len = strlen(kdb_buffer);
+                        cp = kdb_buffer;
+                        while (len--) {
+                                dbg_io_ops->write_char(*cp);
+                                cp++;
+                        }
+                }
                 while (c) {
                         c->write(c, kdb_buffer, retlen);
                         touch_nmi_watchdog();
@@ -719,6 +727,14 @@ kdb_printit:
                 kdb_input_flush();
                 c = console_drivers;
 
+                if (!dbg_io_ops->is_console) {
+                        len = strlen(moreprompt);
+                        cp = moreprompt;
+                        while (len--) {
+                                dbg_io_ops->write_char(*cp);
+                                cp++;
+                        }
+                }
                 while (c) {
                         c->write(c, moreprompt, strlen(moreprompt));
                         touch_nmi_watchdog();