diff options
Diffstat (limited to 'debian/patches-rt/0048-serial-pxa-Use-port-lock-wrappers.patch')
| -rw-r--r-- | debian/patches-rt/0048-serial-pxa-Use-port-lock-wrappers.patch | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/debian/patches-rt/0048-serial-pxa-Use-port-lock-wrappers.patch b/debian/patches-rt/0048-serial-pxa-Use-port-lock-wrappers.patch new file mode 100644 index 000000000..b0df211b6 --- /dev/null +++ b/debian/patches-rt/0048-serial-pxa-Use-port-lock-wrappers.patch @@ -0,0 +1,150 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:44:05 +0206 +Subject: [PATCH 048/134] serial: pxa: 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/20230914183831.587273-49-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/pxa.c | 30 +++++++++++++++--------------- + 1 file changed, 15 insertions(+), 15 deletions(-) + +--- a/drivers/tty/serial/pxa.c ++++ b/drivers/tty/serial/pxa.c +@@ -225,14 +225,14 @@ static inline irqreturn_t serial_pxa_irq + iir = serial_in(up, UART_IIR); + if (iir & UART_IIR_NO_INT) + return IRQ_NONE; +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + lsr = serial_in(up, UART_LSR); + if (lsr & UART_LSR_DR) + receive_chars(up, &lsr); + check_modem_status(up); + if (lsr & UART_LSR_THRE) + transmit_chars(up); +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + return IRQ_HANDLED; + } + +@@ -242,9 +242,9 @@ static unsigned int serial_pxa_tx_empty( + unsigned long flags; + unsigned int ret; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0; +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + return ret; + } +@@ -295,13 +295,13 @@ static void serial_pxa_break_ctl(struct + struct uart_pxa_port *up = (struct uart_pxa_port *)port; + unsigned long flags; + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + if (break_state == -1) + up->lcr |= UART_LCR_SBC; + else + up->lcr &= ~UART_LCR_SBC; + serial_out(up, UART_LCR, up->lcr); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static int serial_pxa_startup(struct uart_port *port) +@@ -346,10 +346,10 @@ static int serial_pxa_startup(struct uar + */ + serial_out(up, UART_LCR, UART_LCR_WLEN8); + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + up->port.mctrl |= TIOCM_OUT2; + serial_pxa_set_mctrl(&up->port, up->port.mctrl); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + /* + * Finally, enable interrupts. Note: Modem status interrupts +@@ -383,10 +383,10 @@ static void serial_pxa_shutdown(struct u + up->ier = 0; + serial_out(up, UART_IER, 0); + +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + up->port.mctrl &= ~TIOCM_OUT2; + serial_pxa_set_mctrl(&up->port, up->port.mctrl); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + + /* + * Disable break condition and FIFOs +@@ -434,7 +434,7 @@ serial_pxa_set_termios(struct uart_port + * Ok, we're now changing the port state. Do it with + * interrupts disabled. + */ +- spin_lock_irqsave(&up->port.lock, flags); ++ uart_port_lock_irqsave(&up->port, &flags); + + /* + * Ensure the port will be enabled. +@@ -504,7 +504,7 @@ serial_pxa_set_termios(struct uart_port + up->lcr = cval; /* Save LCR */ + serial_pxa_set_mctrl(&up->port, up->port.mctrl); + serial_out(up, UART_FCR, fcr); +- spin_unlock_irqrestore(&up->port.lock, flags); ++ uart_port_unlock_irqrestore(&up->port, flags); + } + + static void +@@ -608,9 +608,9 @@ serial_pxa_console_write(struct console + if (up->port.sysrq) + locked = 0; + else if (oops_in_progress) +- locked = spin_trylock(&up->port.lock); ++ locked = uart_port_trylock(&up->port); + else +- spin_lock(&up->port.lock); ++ uart_port_lock(&up->port); + + /* + * First save the IER then disable the interrupts +@@ -628,7 +628,7 @@ serial_pxa_console_write(struct console + serial_out(up, UART_IER, ier); + + if (locked) +- spin_unlock(&up->port.lock); ++ uart_port_unlock(&up->port); + local_irq_restore(flags); + clk_disable(up->clk); + |