[RFC PATCH 0/5] earlycon hang under some conditions

[RFC PATCH 0/5] earlycon hang under some conditions

[Jeffy Chen]

I was testing earlycon with 8250 dw serial console. And it hangs in
these cases:
1/ kernel hang when calling early write function after free_initmem:
a) the earlycon not disabled after the init code(due to keep_bootcon or
   not specify a real console to switch to)
b) the early write func is marked as __init, for example 8250_early.

2/ kernel hang when calling early write function after disable unused
clks/pm domain:
a) the earlycon not disabled after the init code
b) the disable unused clks/pm domain kill the requiered clks/pm
   domain, since they are not referenced by the earlycon.

3/ kernel hang when calling early write function after the serial
   console driver runtime suspended:
a) the earlycon not disabled after the init code
b) the serial console driver's runtime suspend kills the requiered
   clks/pm domain, since they are not referenced by the earlycon.

This serial fix 1/ case only.



Jeffy Chen (5):
  serial: arc: Remove __init marking from early write
  serial: omap: Remove __init marking from early write
  serial: xuartps: Remove __init marking from early write
  serial: 8250_ingenic: Remove __init marking from early write
  serial: 8250_early: Remove __init marking from early write

 drivers/tty/serial/8250/8250_early.c   |  8 ++++----
 drivers/tty/serial/8250/8250_ingenic.c |  8 ++++----
 drivers/tty/serial/arc_uart.c          |  4 ++--
 drivers/tty/serial/omap-serial.c       | 13 ++++++-------
 drivers/tty/serial/xilinx_uartps.c     |  2 +-
 5 files changed, 17 insertions(+), 18 deletions(-)

-- 
2.1.4

[RFC PATCH 3/5] serial: xuartps: Remove __init marking from early write

[Jeffy Chen]

The earlycon would be alive outside the init code in these cases:
1/ we have keep_bootcon in cmdline.
2/ we don't have a real console to switch to.

So remove the __init marking to avoid invalid memory access.

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
---

 drivers/tty/serial/xilinx_uartps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index fde55dc..31a630a 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1163,7 +1163,7 @@ static void cdns_uart_console_putchar(struct uart_port *port, int ch)
 	writel(ch, port->membase + CDNS_UART_FIFO);
 }
 
-static void __init cdns_early_write(struct console *con, const char *s,
+static void cdns_early_write(struct console *con, const char *s,
 				    unsigned n)
 {
 	struct earlycon_device *dev = con->data;
-- 
2.1.4