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Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0063-serial-st-asc-Use-port-lock-wrappers.patch | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/debian/patches-rt/0063-serial-st-asc-Use-port-lock-wrappers.patch b/debian/patches-rt/0063-serial-st-asc-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..99f4358e6 --- /dev/null +++ b/debian/patches-rt/0063-serial-st-asc-Use-port-lock-wrappers.patch @@ -0,0 +1,110 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:44:20 +0206 +Subject: [PATCH 063/134] serial: st-asc: Use port lock wrappers +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +When a serial port is used for kernel console output, then all +modifications to the UART registers which are done from other contexts, +e.g. getty, termios, are interference points for the kernel console. + +So far this has been ignored and the printk output is based on the +principle of hope. The rework of the console infrastructure which aims to +support threaded and atomic consoles, requires to mark sections which +modify the UART registers as unsafe. This allows the atomic write function +to make informed decisions and eventually to restore operational state. It +also allows to prevent the regular UART code from modifying UART registers +while printk output is in progress. + +All modifications of UART registers are guarded by the UART port lock, +which provides an obvious synchronization point with the console +infrastructure. + +To avoid adding this functionality to all UART drivers, wrap the +spin_[un]lock*() invocations for uart_port::lock into helper functions +which just contain the spin_[un]lock*() invocations for now. In a +subsequent step these helpers will gain the console synchronization +mechanisms. + +Converted with coccinelle. No functional change. + +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Signed-off-by: John Ogness <john.ogness@linutronix.de> +Link: https://lore.kernel.org/r/20230914183831.587273-64-john.ogness@linutronix.de +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/tty/serial/st-asc.c | 18 +++++++++--------- + 1 file changed, 9 insertions(+), 9 deletions(-) + +--- a/drivers/tty/serial/st-asc.c ++++ b/drivers/tty/serial/st-asc.c +@@ -319,7 +319,7 @@ static irqreturn_t asc_interrupt(int irq + struct uart_port *port = ptr; + u32 status; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + status = asc_in(port, ASC_STA); + +@@ -334,7 +334,7 @@ static irqreturn_t asc_interrupt(int irq + asc_transmit_chars(port); + } + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_HANDLED; + } +@@ -452,10 +452,10 @@ static void asc_pm(struct uart_port *por + * we can come to turning it off. Note this is not called with + * the port spinlock held. + */ +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + ctl = asc_in(port, ASC_CTL) & ~ASC_CTL_RUN; + asc_out(port, ASC_CTL, ctl); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + clk_disable_unprepare(ascport->clk); + break; + } +@@ -480,7 +480,7 @@ static void asc_set_termios(struct uart_ + baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16); + cflag = termios->c_cflag; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* read control register */ + ctrl_val = asc_in(port, ASC_CTL); +@@ -594,7 +594,7 @@ static void asc_set_termios(struct uart_ + /* write final value and enable port */ + asc_out(port, ASC_CTL, (ctrl_val | ASC_CTL_RUN)); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static const char *asc_type(struct uart_port *port) +@@ -849,9 +849,9 @@ static void asc_console_write(struct con + if (port->sysrq) + locked = 0; /* asc_interrupt has already claimed the lock */ + else if (oops_in_progress) +- locked = spin_trylock_irqsave(&port->lock, flags); ++ locked = uart_port_trylock_irqsave(port, &flags); + else +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* + * Disable interrupts so we don't get the IRQ line bouncing +@@ -869,7 +869,7 @@ static void asc_console_write(struct con + asc_out(port, ASC_INTEN, intenable); + + if (locked) +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int asc_console_setup(struct console *co, char *options) |