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serial: pxa: Use uart_prepare_sysrq_char().

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The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.

Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-8-bigeasy@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sebastian Andrzej Siewior 2024-03-01 22:45:20 +01:00 committed by Greg Kroah-Hartman
parent 63bd93ac61
commit 51f7ed071c
1 changed files with 6 additions and 11 deletions
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17
drivers/tty/serial/pxa.c
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@ -151,7 +151,7 @@ static inline void receive_chars(struct uart_pxa_port *up, int *status)
flag = TTY_FRAME;
}
if (uart_handle_sysrq_char(&up->port, ch))
if (uart_prepare_sysrq_char(&up->port, ch))
goto ignore_char;
uart_insert_char(&up->port, *status, UART_LSR_OE, ch, flag);
@ -232,7 +232,7 @@ static inline irqreturn_t serial_pxa_irq(int irq, void *dev_id)
check_modem_status(up);
if (lsr & UART_LSR_THRE)
transmit_chars(up);
uart_port_unlock(&up->port);
uart_unlock_and_check_sysrq(&up->port);
return IRQ_HANDLED;
}
@ -604,13 +604,10 @@ serial_pxa_console_write(struct console *co, const char *s, unsigned int count)
int locked = 1;
clk_enable(up->clk);
local_irq_save(flags);
if (up->port.sysrq)
locked = 0;
else if (oops_in_progress)
locked = uart_port_trylock(&up->port);
if (oops_in_progress)
locked = uart_port_trylock_irqsave(&up->port, &flags);
else
uart_port_lock(&up->port);
uart_port_lock_irqsave(&up->port, &flags);
/*
* First save the IER then disable the interrupts
@ -628,10 +625,8 @@ serial_pxa_console_write(struct console *co, const char *s, unsigned int count)
serial_out(up, UART_IER, ier);
if (locked)
uart_port_unlock(&up->port);
local_irq_restore(flags);
uart_port_unlock_irqrestore(&up->port, flags);
clk_disable(up->clk);
}
#ifdef CONFIG_CONSOLE_POLL