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path: root/drivers/tty/serial/kgdb_nmi.c
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Diffstat (limited to 'drivers/tty/serial/kgdb_nmi.c')
-rw-r--r--drivers/tty/serial/kgdb_nmi.c59
1 files changed, 27 insertions, 32 deletions
diff --git a/drivers/tty/serial/kgdb_nmi.c b/drivers/tty/serial/kgdb_nmi.c
index 5f673b7ca50e..cfadf2971b12 100644
--- a/drivers/tty/serial/kgdb_nmi.c
+++ b/drivers/tty/serial/kgdb_nmi.c
@@ -44,13 +44,22 @@ MODULE_PARM_DESC(magic, "magic sequence to enter NMI debugger (default $3#33)");
static bool kgdb_nmi_tty_enabled;
+static int kgdb_nmi_console_setup(struct console *co, char *options)
+{
+ /* The NMI console uses the dbg_io_ops to issue console messages. To
+ * avoid duplicate messages during kdb sessions we must inform kdb's
+ * I/O utilities that messages sent to the console will automatically
+ * be displayed on the dbg_io.
+ */
+ dbg_io_ops->is_console = true;
+
+ return 0;
+}
+
static void kgdb_nmi_console_write(struct console *co, const char *s, uint c)
{
int i;
- if (!kgdb_nmi_tty_enabled || atomic_read(&kgdb_active) >= 0)
- return;
-
for (i = 0; i < c; i++)
dbg_io_ops->write_char(s[i]);
}
@@ -65,6 +74,7 @@ static struct tty_driver *kgdb_nmi_console_device(struct console *co, int *idx)
static struct console kgdb_nmi_console = {
.name = "ttyNMI",
+ .setup = kgdb_nmi_console_setup,
.write = kgdb_nmi_console_write,
.device = kgdb_nmi_console_device,
.flags = CON_PRINTBUFFER | CON_ANYTIME | CON_ENABLED,
@@ -80,29 +90,10 @@ static struct console kgdb_nmi_console = {
struct kgdb_nmi_tty_priv {
struct tty_port port;
- struct tasklet_struct tlet;
+ struct timer_list timer;
STRUCT_KFIFO(char, KGDB_NMI_FIFO_SIZE) fifo;
};
-static struct kgdb_nmi_tty_priv *kgdb_nmi_port_to_priv(struct tty_port *port)
-{
- return container_of(port, struct kgdb_nmi_tty_priv, port);
-}
-
-/*
- * Our debugging console is polled in a tasklet, so we'll check for input
- * every tick. In HZ-less mode, we should program the next tick. We have
- * to use the lowlevel stuff as no locks should be grabbed.
- */
-#ifdef CONFIG_HIGH_RES_TIMERS
-static void kgdb_tty_poke(void)
-{
- tick_program_event(ktime_get(), 0);
-}
-#else
-static inline void kgdb_tty_poke(void) {}
-#endif
-
static struct tty_port *kgdb_nmi_port;
static void kgdb_tty_recv(int ch)
@@ -113,14 +104,13 @@ static void kgdb_tty_recv(int ch)
if (!kgdb_nmi_port || ch < 0)
return;
/*
- * Can't use port->tty->driver_data as tty might be not there. Tasklet
+ * Can't use port->tty->driver_data as tty might be not there. Timer
* will check for tty and will get the ref, but here we don't have to
* do that, and actually, we can't: we're in NMI context, no locks are
* possible.
*/
- priv = kgdb_nmi_port_to_priv(kgdb_nmi_port);
+ priv = container_of(kgdb_nmi_port, struct kgdb_nmi_tty_priv, port);
kfifo_in(&priv->fifo, &c, 1);
- kgdb_tty_poke();
}
static int kgdb_nmi_poll_one_knock(void)
@@ -204,7 +194,8 @@ static void kgdb_nmi_tty_receiver(unsigned long data)
struct kgdb_nmi_tty_priv *priv = (void *)data;
char ch;
- tasklet_schedule(&priv->tlet);
+ priv->timer.expires = jiffies + (HZ/100);
+ add_timer(&priv->timer);
if (likely(!kgdb_nmi_tty_enabled || !kfifo_len(&priv->fifo)))
return;
@@ -216,18 +207,22 @@ static void kgdb_nmi_tty_receiver(unsigned long data)
static int kgdb_nmi_tty_activate(struct tty_port *port, struct tty_struct *tty)
{
- struct kgdb_nmi_tty_priv *priv = tty->driver_data;
+ struct kgdb_nmi_tty_priv *priv =
+ container_of(port, struct kgdb_nmi_tty_priv, port);
kgdb_nmi_port = port;
- tasklet_schedule(&priv->tlet);
+ priv->timer.expires = jiffies + (HZ/100);
+ add_timer(&priv->timer);
+
return 0;
}
static void kgdb_nmi_tty_shutdown(struct tty_port *port)
{
- struct kgdb_nmi_tty_priv *priv = port->tty->driver_data;
+ struct kgdb_nmi_tty_priv *priv =
+ container_of(port, struct kgdb_nmi_tty_priv, port);
- tasklet_kill(&priv->tlet);
+ del_timer(&priv->timer);
kgdb_nmi_port = NULL;
}
@@ -246,7 +241,7 @@ static int kgdb_nmi_tty_install(struct tty_driver *drv, struct tty_struct *tty)
return -ENOMEM;
INIT_KFIFO(priv->fifo);
- tasklet_init(&priv->tlet, kgdb_nmi_tty_receiver, (unsigned long)priv);
+ setup_timer(&priv->timer, kgdb_nmi_tty_receiver, (unsigned long)priv);
tty_port_init(&priv->port);
priv->port.ops = &kgdb_nmi_tty_port_ops;
tty->driver_data = priv;