fb: add hooks to handle KDB enter/exit

Add fb ops to handle enter/exit of the kernel debugger.  If present, the
fb core will register them with KGDB and they'll be called when the
debugger is entered and exited.  The new functions are responsible for
switching to an appropriate debug framebuffer and restoring the
interrupted state at exit time.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>

2 files changed, 27 insertions, 0 deletions

diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index b0a3fa00706d..3b3f5749af92 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -2342,6 +2342,30 @@ static int fbcon_blank(struct vc_data *vc, int blank, int mode_switch)
         return 0;
 }
 
+static int fbcon_debug_enter(struct vc_data *vc)
+{
+        struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
+        struct fbcon_ops *ops = info->fbcon_par;
+
+        ops->save_graphics = ops->graphics;
+        ops->graphics = 0;
+        if (info->fbops->fb_debug_enter)
+                info->fbops->fb_debug_enter(info);
+        fbcon_set_palette(vc, color_table);
+        return 0;
+}
+
+static int fbcon_debug_leave(struct vc_data *vc)
+{
+        struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
+        struct fbcon_ops *ops = info->fbcon_par;
+
+        ops->graphics = ops->save_graphics;
+        if (info->fbops->fb_debug_leave)
+                info->fbops->fb_debug_leave(info);
+        return 0;
+}
+
 static int fbcon_get_font(struct vc_data *vc, struct console_font *font)
 {
         u8 *fontdata = vc->vc_font.data;
@@ -3276,6 +3300,8 @@ static const struct consw fb_con = {
         .con_screen_pos         = fbcon_screen_pos,
         .con_getxy              = fbcon_getxy,
         .con_resize             = fbcon_resize,
+        .con_debug_enter        = fbcon_debug_enter,
+        .con_debug_leave        = fbcon_debug_leave,
 };
 
 static struct notifier_block fbcon_event_notifier = {
diff --git a/drivers/video/console/fbcon.h b/drivers/video/console/fbcon.h
index 89a346880ec0..6bd2e0c7f209 100644
--- a/drivers/video/console/fbcon.h
+++ b/drivers/video/console/fbcon.h
@@ -74,6 +74,7 @@ struct fbcon_ops {
         int    cursor_reset;
         int    blank_state;
         int    graphics;
+        int    save_graphics; /* for debug enter/leave */
         int    flags;
         int    rotate;
         int    cur_rotate;