64 lines
2.5 KiB
Diff
64 lines
2.5 KiB
Diff
From 6c67e782fccb3ff27f786fe76a440707709ab23b 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 20:44:15 +0206
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Subject: [PATCH 084/198] serial: mctrl_gpio: 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/20230914183831.587273-59-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/serial_mctrl_gpio.c | 4 ++--
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1 file changed, 2 insertions(+), 2 deletions(-)
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diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c
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index 7d5aaa8d422b..e51ca593ab86 100644
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--- a/drivers/tty/serial/serial_mctrl_gpio.c
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+++ b/drivers/tty/serial/serial_mctrl_gpio.c
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@@ -184,7 +184,7 @@ static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
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mctrl_gpio_get(gpios, &mctrl);
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- spin_lock_irqsave(&port->lock, flags);
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+ uart_port_lock_irqsave(port, &flags);
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mctrl_diff = mctrl ^ gpios->mctrl_prev;
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gpios->mctrl_prev = mctrl;
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@@ -205,7 +205,7 @@ static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
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wake_up_interruptible(&port->state->port.delta_msr_wait);
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}
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- spin_unlock_irqrestore(&port->lock, flags);
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+ uart_port_unlock_irqrestore(port, flags);
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return IRQ_HANDLED;
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}
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--
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2.44.0
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