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serial: ar933x: 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/20240301215246.891055-3-bigeasy@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sebastian Andrzej Siewior 2024-03-01 22:45:15 +01:00 committed by Greg Kroah-Hartman
parent 2432f71c22
commit 244a758b3d
1 changed files with 6 additions and 12 deletions
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18
drivers/tty/serial/ar933x_uart.c
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@ -378,7 +378,7 @@ static void ar933x_uart_rx_chars(struct ar933x_uart_port *up)
up->port.icount.rx++;
ch = rdata & AR933X_UART_DATA_TX_RX_MASK;
if (uart_handle_sysrq_char(&up->port, ch))
if (uart_prepare_sysrq_char(&up->port, ch))
continue;
if ((up->port.ignore_status_mask & AR933X_DUMMY_STATUS_RD) == 0)
@ -468,7 +468,7 @@ static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id)
ar933x_uart_tx_chars(up);
}
uart_port_unlock(&up->port);
uart_unlock_and_check_sysrq(&up->port);
return IRQ_HANDLED;
}
@ -627,14 +627,10 @@ static void ar933x_uart_console_write(struct console *co, const char *s,
unsigned int int_en;
int locked = 1;
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
@ -654,9 +650,7 @@ static void ar933x_uart_console_write(struct console *co, const char *s,
ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS);
if (locked)
uart_port_unlock(&up->port);
local_irq_restore(flags);
uart_port_unlock_irqrestore(&up->port, flags);
}
static int ar933x_uart_console_setup(struct console *co, char *options)