diff options
Diffstat (limited to 'debian/patches-rt/0016-serial-amba-pl010-Use-port-lock-wrappers.patch')
| -rw-r--r-- | debian/patches-rt/0016-serial-amba-pl010-Use-port-lock-wrappers.patch | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/debian/patches-rt/0016-serial-amba-pl010-Use-port-lock-wrappers.patch b/debian/patches-rt/0016-serial-amba-pl010-Use-port-lock-wrappers.patch new file mode 100644 index 0000000000..f3ba735bfc --- /dev/null +++ b/debian/patches-rt/0016-serial-amba-pl010-Use-port-lock-wrappers.patch @@ -0,0 +1,112 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 14 Sep 2023 20:43:33 +0206 +Subject: [PATCH 016/134] serial: amba-pl010: 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/20230914183831.587273-17-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/amba-pl010.c | 20 ++++++++++---------- + 1 file changed, 10 insertions(+), 10 deletions(-) + +--- a/drivers/tty/serial/amba-pl010.c ++++ b/drivers/tty/serial/amba-pl010.c +@@ -207,7 +207,7 @@ static irqreturn_t pl010_int(int irq, vo + unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT; + int handled = 0; + +- spin_lock(&port->lock); ++ uart_port_lock(port); + + status = readb(port->membase + UART010_IIR); + if (status) { +@@ -228,7 +228,7 @@ static irqreturn_t pl010_int(int irq, vo + handled = 1; + } + +- spin_unlock(&port->lock); ++ uart_port_unlock(port); + + return IRQ_RETVAL(handled); + } +@@ -270,14 +270,14 @@ static void pl010_break_ctl(struct uart_ + unsigned long flags; + unsigned int lcr_h; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + lcr_h = readb(port->membase + UART010_LCRH); + if (break_state == -1) + lcr_h |= UART01x_LCRH_BRK; + else + lcr_h &= ~UART01x_LCRH_BRK; + writel(lcr_h, port->membase + UART010_LCRH); +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static int pl010_startup(struct uart_port *port) +@@ -385,7 +385,7 @@ pl010_set_termios(struct uart_port *port + if (port->fifosize > 1) + lcr_h |= UART01x_LCRH_FEN; + +- spin_lock_irqsave(&port->lock, flags); ++ uart_port_lock_irqsave(port, &flags); + + /* + * Update the per-port timeout. +@@ -438,22 +438,22 @@ pl010_set_termios(struct uart_port *port + writel(lcr_h, port->membase + UART010_LCRH); + writel(old_cr, port->membase + UART010_CR); + +- spin_unlock_irqrestore(&port->lock, flags); ++ uart_port_unlock_irqrestore(port, flags); + } + + static void pl010_set_ldisc(struct uart_port *port, struct ktermios *termios) + { + if (termios->c_line == N_PPS) { + port->flags |= UPF_HARDPPS_CD; +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + pl010_enable_ms(port); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + } else { + port->flags &= ~UPF_HARDPPS_CD; + if (!UART_ENABLE_MS(port, termios->c_cflag)) { +- spin_lock_irq(&port->lock); ++ uart_port_lock_irq(port); + pl010_disable_ms(port); +- spin_unlock_irq(&port->lock); ++ uart_port_unlock_irq(port); + } + } + } |