From e0e6d8b474d8bd146f94d4c2dc67f29edd2861ea Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 14 Sep 2023 20:43:48 +0206 Subject: serial: jsm: Use port lock wrappers When a serial port is used for kernel console output, then all modifications to the UART registers which are done from other contexts, e.g. getty, termios, are interference points for the kernel console. So far this has been ignored and the printk output is based on the principle of hope. The rework of the console infrastructure which aims to support threaded and atomic consoles, requires to mark sections which modify the UART registers as unsafe. This allows the atomic write function to make informed decisions and eventually to restore operational state. It also allows to prevent the regular UART code from modifying UART registers while printk output is in progress. All modifications of UART registers are guarded by the UART port lock, which provides an obvious synchronization point with the console infrastructure. To avoid adding this functionality to all UART drivers, wrap the spin_[un]lock*() invocations for uart_port::lock into helper functions which just contain the spin_[un]lock*() invocations for now. In a subsequent step these helpers will gain the console synchronization mechanisms. Converted with coccinelle. No functional change. Signed-off-by: Thomas Gleixner Signed-off-by: John Ogness Link: https://lore.kernel.org/r/20230914183831.587273-32-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/jsm/jsm_tty.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'drivers/tty/serial/jsm/jsm_tty.c') diff --git a/drivers/tty/serial/jsm/jsm_tty.c b/drivers/tty/serial/jsm/jsm_tty.c index 222afc270c88..ce0fef7e2c66 100644 --- a/drivers/tty/serial/jsm/jsm_tty.c +++ b/drivers/tty/serial/jsm/jsm_tty.c @@ -152,14 +152,14 @@ static void jsm_tty_send_xchar(struct uart_port *port, char ch) container_of(port, struct jsm_channel, uart_port); struct ktermios *termios; - spin_lock_irqsave(&port->lock, lock_flags); + uart_port_lock_irqsave(port, &lock_flags); termios = &port->state->port.tty->termios; if (ch == termios->c_cc[VSTART]) channel->ch_bd->bd_ops->send_start_character(channel); if (ch == termios->c_cc[VSTOP]) channel->ch_bd->bd_ops->send_stop_character(channel); - spin_unlock_irqrestore(&port->lock, lock_flags); + uart_port_unlock_irqrestore(port, lock_flags); } static void jsm_tty_stop_rx(struct uart_port *port) @@ -176,13 +176,13 @@ static void jsm_tty_break(struct uart_port *port, int break_state) struct jsm_channel *channel = container_of(port, struct jsm_channel, uart_port); - spin_lock_irqsave(&port->lock, lock_flags); + uart_port_lock_irqsave(port, &lock_flags); if (break_state == -1) channel->ch_bd->bd_ops->send_break(channel); else channel->ch_bd->bd_ops->clear_break(channel); - spin_unlock_irqrestore(&port->lock, lock_flags); + uart_port_unlock_irqrestore(port, lock_flags); } static int jsm_tty_open(struct uart_port *port) @@ -241,7 +241,7 @@ static int jsm_tty_open(struct uart_port *port) channel->ch_cached_lsr = 0; channel->ch_stops_sent = 0; - spin_lock_irqsave(&port->lock, lock_flags); + uart_port_lock_irqsave(port, &lock_flags); termios = &port->state->port.tty->termios; channel->ch_c_cflag = termios->c_cflag; channel->ch_c_iflag = termios->c_iflag; @@ -261,7 +261,7 @@ static int jsm_tty_open(struct uart_port *port) jsm_carrier(channel); channel->ch_open_count++; - spin_unlock_irqrestore(&port->lock, lock_flags); + uart_port_unlock_irqrestore(port, lock_flags); jsm_dbg(OPEN, &channel->ch_bd->pci_dev, "finish\n"); return 0; @@ -307,7 +307,7 @@ static void jsm_tty_set_termios(struct uart_port *port, struct jsm_channel *channel = container_of(port, struct jsm_channel, uart_port); - spin_lock_irqsave(&port->lock, lock_flags); + uart_port_lock_irqsave(port, &lock_flags); channel->ch_c_cflag = termios->c_cflag; channel->ch_c_iflag = termios->c_iflag; channel->ch_c_oflag = termios->c_oflag; @@ -317,7 +317,7 @@ static void jsm_tty_set_termios(struct uart_port *port, channel->ch_bd->bd_ops->param(channel); jsm_carrier(channel); - spin_unlock_irqrestore(&port->lock, lock_flags); + uart_port_unlock_irqrestore(port, lock_flags); } static const char *jsm_tty_type(struct uart_port *port) -- cgit v1.2.3