58 lines
2.3 KiB
Diff
58 lines
2.3 KiB
Diff
From 74a615bca2e2128d4ae9b52795a2e60dcaf9c712 Mon Sep 17 00:00:00 2001
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Thu, 14 Sep 2023 20:43:26 +0206
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Subject: [PATCH 035/196] serial: 8250_exar: Use port lock wrappers
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When a serial port is used for kernel console output, then all
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modifications to the UART registers which are done from other contexts,
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e.g. getty, termios, are interference points for the kernel console.
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So far this has been ignored and the printk output is based on the
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principle of hope. The rework of the console infrastructure which aims to
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support threaded and atomic consoles, requires to mark sections which
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modify the UART registers as unsafe. This allows the atomic write function
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to make informed decisions and eventually to restore operational state. It
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also allows to prevent the regular UART code from modifying UART registers
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while printk output is in progress.
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All modifications of UART registers are guarded by the UART port lock,
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which provides an obvious synchronization point with the console
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infrastructure.
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To avoid adding this functionality to all UART drivers, wrap the
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spin_[un]lock*() invocations for uart_port::lock into helper functions
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which just contain the spin_[un]lock*() invocations for now. In a
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subsequent step these helpers will gain the console synchronization
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mechanisms.
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Converted with coccinelle. No functional change.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: John Ogness <john.ogness@linutronix.de>
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Link: https://lore.kernel.org/r/20230914183831.587273-10-john.ogness@linutronix.de
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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drivers/tty/serial/8250/8250_exar.c | 4 ++--
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1 file changed, 2 insertions(+), 2 deletions(-)
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diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c
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index 8385be846840..91cf690b7c71 100644
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--- a/drivers/tty/serial/8250/8250_exar.c
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+++ b/drivers/tty/serial/8250/8250_exar.c
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@@ -201,9 +201,9 @@ static int xr17v35x_startup(struct uart_port *port)
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*
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* Synchronize UART_IER access against the console.
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*/
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- spin_lock_irq(&port->lock);
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+ uart_port_lock_irq(port);
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serial_port_out(port, UART_IER, 0);
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- spin_unlock_irq(&port->lock);
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+ uart_port_unlock_irq(port);
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return serial8250_do_startup(port);
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}
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--
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2.43.2
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