110 lines
4.2 KiB
Diff
110 lines
4.2 KiB
Diff
From: Thomas Gleixner <tglx@linutronix.de>
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Date: Thu, 14 Sep 2023 20:43:49 +0206
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Subject: [PATCH 032/134] serial: liteuart: 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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Acked-by: Gabriel Somlo <gsomlo@gmail.com>
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Signed-off-by: John Ogness <john.ogness@linutronix.de>
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Link: https://lore.kernel.org/r/20230914183831.587273-33-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/liteuart.c | 20 ++++++++++----------
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1 file changed, 10 insertions(+), 10 deletions(-)
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--- a/drivers/tty/serial/liteuart.c
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+++ b/drivers/tty/serial/liteuart.c
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@@ -139,13 +139,13 @@ static irqreturn_t liteuart_interrupt(in
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* if polling, the context would be "in_serving_softirq", so use
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* irq[save|restore] spin_lock variants to cover all possibilities
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*/
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- spin_lock_irqsave(&port->lock, flags);
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+ uart_port_lock_irqsave(port, &flags);
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isr = litex_read8(port->membase + OFF_EV_PENDING) & uart->irq_reg;
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if (isr & EV_RX)
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liteuart_rx_chars(port);
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if (isr & EV_TX)
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liteuart_tx_chars(port);
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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_RETVAL(isr);
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}
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@@ -195,10 +195,10 @@ static int liteuart_startup(struct uart_
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}
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}
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- spin_lock_irqsave(&port->lock, flags);
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+ uart_port_lock_irqsave(port, &flags);
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/* only enabling rx irqs during startup */
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liteuart_update_irq_reg(port, true, EV_RX);
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- spin_unlock_irqrestore(&port->lock, flags);
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+ uart_port_unlock_irqrestore(port, flags);
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if (!port->irq) {
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timer_setup(&uart->timer, liteuart_timer, 0);
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@@ -213,9 +213,9 @@ static void liteuart_shutdown(struct uar
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struct liteuart_port *uart = to_liteuart_port(port);
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unsigned long flags;
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- spin_lock_irqsave(&port->lock, flags);
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+ uart_port_lock_irqsave(port, &flags);
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liteuart_update_irq_reg(port, false, EV_RX | EV_TX);
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- spin_unlock_irqrestore(&port->lock, flags);
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+ uart_port_unlock_irqrestore(port, flags);
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if (port->irq)
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free_irq(port->irq, port);
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@@ -229,13 +229,13 @@ static void liteuart_set_termios(struct
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unsigned int baud;
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unsigned long flags;
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- spin_lock_irqsave(&port->lock, flags);
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+ uart_port_lock_irqsave(port, &flags);
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/* update baudrate */
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baud = uart_get_baud_rate(port, new, old, 0, 460800);
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uart_update_timeout(port, new->c_cflag, baud);
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- spin_unlock_irqrestore(&port->lock, flags);
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+ uart_port_unlock_irqrestore(port, flags);
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}
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static const char *liteuart_type(struct uart_port *port)
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@@ -382,9 +382,9 @@ static void liteuart_console_write(struc
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uart = (struct liteuart_port *)xa_load(&liteuart_array, co->index);
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port = &uart->port;
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- spin_lock_irqsave(&port->lock, flags);
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+ uart_port_lock_irqsave(port, &flags);
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uart_console_write(port, s, count, liteuart_putchar);
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- spin_unlock_irqrestore(&port->lock, flags);
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+ uart_port_unlock_irqrestore(port, flags);
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}
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static int liteuart_console_setup(struct console *co, char *options)
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