From: Thomas Gleixner Date: Thu, 14 Sep 2023 20:43:48 +0206 Subject: [PATCH 031/134] serial: jsm: Use port lock wrappers Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz 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 Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/jsm/jsm_neo.c | 4 ++-- drivers/tty/serial/jsm/jsm_tty.c | 16 ++++++++-------- 2 files changed, 10 insertions(+), 10 deletions(-) --- a/drivers/tty/serial/jsm/jsm_neo.c +++ b/drivers/tty/serial/jsm/jsm_neo.c @@ -816,9 +816,9 @@ static void neo_parse_isr(struct jsm_boa /* Parse any modem signal changes */ jsm_dbg(INTR, &ch->ch_bd->pci_dev, "MOD_STAT: sending to parse_modem_sigs\n"); - spin_lock_irqsave(&ch->uart_port.lock, lock_flags); + uart_port_lock_irqsave(&ch->uart_port, &lock_flags); neo_parse_modem(ch, readb(&ch->ch_neo_uart->msr)); - spin_unlock_irqrestore(&ch->uart_port.lock, lock_flags); + uart_port_unlock_irqrestore(&ch->uart_port, lock_flags); } } --- 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 ua 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_po 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 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 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 u 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 u 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)