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serial: jsm: Use port lock wrappers

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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 <tglx@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/r/20230914183831.587273-32-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Thomas Gleixner 2023-09-14 20:43:48 +02:06 committed by Greg Kroah-Hartman
parent 893d225197
commit e0e6d8b474
2 changed files with 10 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/tty/serial/jsm/jsm_neo.c
View File

@ -816,9 +816,9 @@ static void neo_parse_isr(struct jsm_board *brd, u32 port)
/* Parse any modem signal changes */ /* Parse any modem signal changes */
jsm_dbg(INTR, &ch->ch_bd->pci_dev, jsm_dbg(INTR, &ch->ch_bd->pci_dev,
"MOD_STAT: sending to parse_modem_sigs\n"); "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)); 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);
} }
} }

16
drivers/tty/serial/jsm/jsm_tty.c
View File

@ -152,14 +152,14 @@ static void jsm_tty_send_xchar(struct uart_port *port, char ch)
container_of(port, struct jsm_channel, uart_port); container_of(port, struct jsm_channel, uart_port);
struct ktermios *termios; struct ktermios *termios;
spin_lock_irqsave(&port->lock, lock_flags); uart_port_lock_irqsave(port, &lock_flags);
termios = &port->state->port.tty->termios; termios = &port->state->port.tty->termios;
if (ch == termios->c_cc[VSTART]) if (ch == termios->c_cc[VSTART])
channel->ch_bd->bd_ops->send_start_character(channel); channel->ch_bd->bd_ops->send_start_character(channel);
if (ch == termios->c_cc[VSTOP]) if (ch == termios->c_cc[VSTOP])
channel->ch_bd->bd_ops->send_stop_character(channel); 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) 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 = struct jsm_channel *channel =
container_of(port, struct jsm_channel, uart_port); 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) if (break_state == -1)
channel->ch_bd->bd_ops->send_break(channel); channel->ch_bd->bd_ops->send_break(channel);
else else
channel->ch_bd->bd_ops->clear_break(channel); 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) 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_cached_lsr = 0;
channel->ch_stops_sent = 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; termios = &port->state->port.tty->termios;
channel->ch_c_cflag = termios->c_cflag; channel->ch_c_cflag = termios->c_cflag;
channel->ch_c_iflag = termios->c_iflag; channel->ch_c_iflag = termios->c_iflag;
@ -261,7 +261,7 @@ static int jsm_tty_open(struct uart_port *port)
jsm_carrier(channel); jsm_carrier(channel);
channel->ch_open_count++; 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"); jsm_dbg(OPEN, &channel->ch_bd->pci_dev, "finish\n");
return 0; return 0;
@ -307,7 +307,7 @@ static void jsm_tty_set_termios(struct uart_port *port,
struct jsm_channel *channel = struct jsm_channel *channel =
container_of(port, struct jsm_channel, uart_port); 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_cflag = termios->c_cflag;
channel->ch_c_iflag = termios->c_iflag; channel->ch_c_iflag = termios->c_iflag;
channel->ch_c_oflag = termios->c_oflag; 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); channel->ch_bd->bd_ops->param(channel);
jsm_carrier(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) static const char *jsm_tty_type(struct uart_port *port)