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serial: sunhv: 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 <tglx@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/r/20230914183831.587273-66-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/318/merge
Thomas Gleixner 2023-09-14 20:44:22 +02:06 committed by Greg Kroah-Hartman
parent c5d0666255
commit 71007c5e78
1 changed files with 14 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
drivers/tty/serial/sunhv.c
View File

@ -217,10 +217,10 @@ static irqreturn_t sunhv_interrupt(int irq, void *dev_id)
struct tty_port *tport;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
uart_port_lock_irqsave(port, &flags);
tport = receive_chars(port);
transmit_chars(port);
spin_unlock_irqrestore(&port->lock, flags);
uart_port_unlock_irqrestore(port, flags);
if (tport)
tty_flip_buffer_push(tport);
@ -271,7 +271,7 @@ static void sunhv_send_xchar(struct uart_port *port, char ch)
if (ch == __DISABLED_CHAR)
return;
spin_lock_irqsave(&port->lock, flags);
uart_port_lock_irqsave(port, &flags);
while (limit-- > 0) {
long status = sun4v_con_putchar(ch);
@ -280,7 +280,7 @@ static void sunhv_send_xchar(struct uart_port *port, char ch)
udelay(1);
}
spin_unlock_irqrestore(&port->lock, flags);
uart_port_unlock_irqrestore(port, flags);
}
/* port->lock held by caller. */
@ -295,7 +295,7 @@ static void sunhv_break_ctl(struct uart_port *port, int break_state)
unsigned long flags;
int limit = 10000;
spin_lock_irqsave(&port->lock, flags);
uart_port_lock_irqsave(port, &flags);
while (limit-- > 0) {
long status = sun4v_con_putchar(CON_BREAK);
@ -304,7 +304,7 @@ static void sunhv_break_ctl(struct uart_port *port, int break_state)
udelay(1);
}
spin_unlock_irqrestore(&port->lock, flags);
uart_port_unlock_irqrestore(port, flags);
}
}
@ -328,7 +328,7 @@ static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios,
unsigned int iflag, cflag;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
uart_port_lock_irqsave(port, &flags);
iflag = termios->c_iflag;
cflag = termios->c_cflag;
@ -343,7 +343,7 @@ static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios,
uart_update_timeout(port, cflag,
(port->uartclk / (16 * quot)));
spin_unlock_irqrestore(&port->lock, flags);
uart_port_unlock_irqrestore(port, flags);
}
static const char *sunhv_type(struct uart_port *port)
@ -437,9 +437,9 @@ static void sunhv_console_write_paged(struct console *con, const char *s, unsign
int locked = 1;
if (port->sysrq || oops_in_progress)
locked = spin_trylock_irqsave(&port->lock, flags);
locked = uart_port_trylock_irqsave(port, &flags);
else
spin_lock_irqsave(&port->lock, flags);
uart_port_lock_irqsave(port, &flags);
while (n > 0) {
unsigned long ra = __pa(con_write_page);
@ -470,7 +470,7 @@ static void sunhv_console_write_paged(struct console *con, const char *s, unsign
}
if (locked)
spin_unlock_irqrestore(&port->lock, flags);
uart_port_unlock_irqrestore(port, flags);
}
static inline void sunhv_console_putchar(struct uart_port *port, char c)
@ -492,9 +492,9 @@ static void sunhv_console_write_bychar(struct console *con, const char *s, unsig
int i, locked = 1;
if (port->sysrq || oops_in_progress)
locked = spin_trylock_irqsave(&port->lock, flags);
locked = uart_port_trylock_irqsave(port, &flags);
else
spin_lock_irqsave(&port->lock, flags);
uart_port_lock_irqsave(port, &flags);
for (i = 0; i < n; i++) {
if (*s == '\n')
@ -503,7 +503,7 @@ static void sunhv_console_write_bychar(struct console *con, const char *s, unsig
}
if (locked)
spin_unlock_irqrestore(&port->lock, flags);
uart_port_unlock_irqrestore(port, flags);
}
static struct console sunhv_console = {