From 9c62e33c81f5ebc11109025dac639666c5b9a01a Mon Sep 17 00:00:00 2001 From: Thomas Gleixner <tglx@linutronix.de> Date: Thu, 14 Sep 2023 20:43:42 +0206 Subject: [PATCH 051/204] serial: dz: Use port lock wrappers 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/20230914183831.587273-26-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/dz.c | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) Index: linux-6.6.58-rt45/drivers/tty/serial/dz.c =================================================================== @ linux-6.6.58-rt45/drivers/tty/serial/dz.c:271 @ static inline void dz_transmit_chars(str } /* If nothing to do or stopped or hardware stopped. */ if (uart_circ_empty(xmit) || uart_tx_stopped(&dport->port)) { - spin_lock(&dport->port.lock); + uart_port_lock(&dport->port); dz_stop_tx(&dport->port); - spin_unlock(&dport->port.lock); + uart_port_unlock(&dport->port); return; } @ linux-6.6.58-rt45/drivers/tty/serial/dz.c:290 @ static inline void dz_transmit_chars(str /* Are we are done. */ if (uart_circ_empty(xmit)) { - spin_lock(&dport->port.lock); + uart_port_lock(&dport->port); dz_stop_tx(&dport->port); - spin_unlock(&dport->port.lock); + uart_port_unlock(&dport->port); } } @ linux-6.6.58-rt45/drivers/tty/serial/dz.c:418 @ static int dz_startup(struct uart_port * return ret; } - spin_lock_irqsave(&dport->port.lock, flags); + uart_port_lock_irqsave(&dport->port, &flags); /* Enable interrupts. */ tmp = dz_in(dport, DZ_CSR); tmp |= DZ_RIE | DZ_TIE; dz_out(dport, DZ_CSR, tmp); - spin_unlock_irqrestore(&dport->port.lock, flags); + uart_port_unlock_irqrestore(&dport->port, flags); return 0; } @ linux-6.6.58-rt45/drivers/tty/serial/dz.c:446 @ static void dz_shutdown(struct uart_port int irq_guard; u16 tmp; - spin_lock_irqsave(&dport->port.lock, flags); + uart_port_lock_irqsave(&dport->port, &flags); dz_stop_tx(&dport->port); - spin_unlock_irqrestore(&dport->port.lock, flags); + uart_port_unlock_irqrestore(&dport->port, flags); irq_guard = atomic_add_return(-1, &mux->irq_guard); if (!irq_guard) { @ linux-6.6.58-rt45/drivers/tty/serial/dz.c:494 @ static void dz_break_ctl(struct uart_por unsigned long flags; unsigned short tmp, mask = 1 << dport->port.line; - spin_lock_irqsave(&uport->lock, flags); + uart_port_lock_irqsave(uport, &flags); tmp = dz_in(dport, DZ_TCR); if (break_state) tmp |= mask; else tmp &= ~mask; dz_out(dport, DZ_TCR, tmp); - spin_unlock_irqrestore(&uport->lock, flags); + uart_port_unlock_irqrestore(uport, flags); } static int dz_encode_baud_rate(unsigned int baud) @ linux-6.6.58-rt45/drivers/tty/serial/dz.c:611 @ static void dz_set_termios(struct uart_p if (termios->c_cflag & CREAD) cflag |= DZ_RXENAB; - spin_lock_irqsave(&dport->port.lock, flags); + uart_port_lock_irqsave(&dport->port, &flags); uart_update_timeout(uport, termios->c_cflag, baud); @ linux-6.6.58-rt45/drivers/tty/serial/dz.c:634 @ static void dz_set_termios(struct uart_p if (termios->c_iflag & IGNBRK) dport->port.ignore_status_mask |= DZ_BREAK; - spin_unlock_irqrestore(&dport->port.lock, flags); + uart_port_unlock_irqrestore(&dport->port, flags); } /* @ linux-6.6.58-rt45/drivers/tty/serial/dz.c:648 @ static void dz_pm(struct uart_port *upor struct dz_port *dport = to_dport(uport); unsigned long flags; - spin_lock_irqsave(&dport->port.lock, flags); + uart_port_lock_irqsave(&dport->port, &flags); if (state < 3) dz_start_tx(&dport->port); else dz_stop_tx(&dport->port); - spin_unlock_irqrestore(&dport->port.lock, flags); + uart_port_unlock_irqrestore(&dport->port, flags); } @ linux-6.6.58-rt45/drivers/tty/serial/dz.c:814 @ static void dz_console_putchar(struct ua unsigned short csr, tcr, trdy, mask; int loops = 10000; - spin_lock_irqsave(&dport->port.lock, flags); + uart_port_lock_irqsave(&dport->port, &flags); csr = dz_in(dport, DZ_CSR); dz_out(dport, DZ_CSR, csr & ~DZ_TIE); tcr = dz_in(dport, DZ_TCR); @ linux-6.6.58-rt45/drivers/tty/serial/dz.c:822 @ static void dz_console_putchar(struct ua mask = tcr; dz_out(dport, DZ_TCR, mask); iob(); - spin_unlock_irqrestore(&dport->port.lock, flags); + uart_port_unlock_irqrestore(&dport->port, flags); do { trdy = dz_in(dport, DZ_CSR);