vt: expose system-wide UTF-8 default setting via sysfs

Create a variable, default_utf8, that defines the system-wide default UTF-8
setting.  This variable can be altered via sysfs. If the variable is properly
set, this should mimimize breakage of UTF-8 encoded consoles when doing a
reset or echo -e '\033c' and of newly opened/allocated consoles.

This is based from patches by Jan Engelhardt and Paul LeoNerd Evans.
Signed-off-by: NAntonino Daplas <adaplas@gmail.com>
Cc: Jan Engelhardt <jengelh@linux01.gwdg.de>
Cc: Paul LeoNerd Evans <leonerd@leonerd.org.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/char/vt.c

@@ -157,6 +157,8 @@ static void blank_screen_t(unsigned long dummy);
 static void set_palette(struct vc_data *vc);
 
 static int printable;		/* Is console ready for printing? */
+static int default_utf8;
+module_param(default_utf8, int, S_IRUGO | S_IWUSR);
 
 /*
  * ignore_poke: don't unblank the screen when things are typed.  This is
@@ -1517,7 +1519,7 @@ static void reset_terminal(struct vc_data *vc, int do_clear)
 	vc->vc_charset		= 0;
 	vc->vc_need_wrap	= 0;
 	vc->vc_report_mouse	= 0;
-	vc->vc_utf		= 0;
+	vc->vc_utf              = default_utf8;
 	vc->vc_utf_count	= 0;
 
 	vc->vc_disp_ctrl	= 0;