71 lines
2.9 KiB
Diff
71 lines
2.9 KiB
Diff
From: Thomas Gleixner <tglx@linutronix.de>
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Date: Thu, 14 Sep 2023 20:44:06 +0206
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Subject: [PATCH 049/134] serial: qcom-geni: Use port lock wrappers
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz
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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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Reviewed-by: Bjorn Andersson <quic_bjorande@quicinc.com>
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Signed-off-by: John Ogness <john.ogness@linutronix.de>
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Link: https://lore.kernel.org/r/20230914183831.587273-50-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/qcom_geni_serial.c | 8 ++++----
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1 file changed, 4 insertions(+), 4 deletions(-)
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--- a/drivers/tty/serial/qcom_geni_serial.c
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+++ b/drivers/tty/serial/qcom_geni_serial.c
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@@ -482,9 +482,9 @@ static void qcom_geni_serial_console_wri
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uport = &port->uport;
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if (oops_in_progress)
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- locked = spin_trylock_irqsave(&uport->lock, flags);
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+ locked = uart_port_trylock_irqsave(uport, &flags);
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else
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- spin_lock_irqsave(&uport->lock, flags);
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+ uart_port_lock_irqsave(uport, &flags);
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geni_status = readl(uport->membase + SE_GENI_STATUS);
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@@ -520,7 +520,7 @@ static void qcom_geni_serial_console_wri
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qcom_geni_serial_setup_tx(uport, port->tx_remaining);
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if (locked)
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- spin_unlock_irqrestore(&uport->lock, flags);
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+ uart_port_unlock_irqrestore(uport, flags);
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}
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static void handle_rx_console(struct uart_port *uport, u32 bytes, bool drop)
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@@ -970,7 +970,7 @@ static irqreturn_t qcom_geni_serial_isr(
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if (uport->suspended)
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return IRQ_NONE;
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- spin_lock(&uport->lock);
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+ uart_port_lock(uport);
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m_irq_status = readl(uport->membase + SE_GENI_M_IRQ_STATUS);
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s_irq_status = readl(uport->membase + SE_GENI_S_IRQ_STATUS);
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