From: Thomas Gleixner Date: Thu, 14 Sep 2023 20:44:24 +0206 Subject: [PATCH 067/134] serial: sunsab: 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 Signed-off-by: John Ogness Link: https://lore.kernel.org/r/20230914183831.587273-68-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/sunsab.c | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-) --- a/drivers/tty/serial/sunsab.c +++ b/drivers/tty/serial/sunsab.c @@ -310,7 +310,7 @@ static irqreturn_t sunsab_interrupt(int unsigned long flags; unsigned char gis; - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); status.stat = 0; gis = readb(&up->regs->r.gis) >> up->gis_shift; @@ -331,7 +331,7 @@ static irqreturn_t sunsab_interrupt(int transmit_chars(up, &status); } - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); if (port) tty_flip_buffer_push(port); @@ -473,12 +473,12 @@ static void sunsab_send_xchar(struct uar if (ch == __DISABLED_CHAR) return; - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); sunsab_tec_wait(up); writeb(ch, &up->regs->w.tic); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } /* port->lock held by caller. */ @@ -499,7 +499,7 @@ static void sunsab_break_ctl(struct uart unsigned long flags; unsigned char val; - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); val = up->cached_dafo; if (break_state) @@ -512,7 +512,7 @@ static void sunsab_break_ctl(struct uart if (test_bit(SAB82532_XPR, &up->irqflags)) sunsab_tx_idle(up); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } /* port->lock is not held. */ @@ -527,7 +527,7 @@ static int sunsab_startup(struct uart_po if (err) return err; - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); /* * Wait for any commands or immediate characters @@ -582,7 +582,7 @@ static int sunsab_startup(struct uart_po set_bit(SAB82532_ALLS, &up->irqflags); set_bit(SAB82532_XPR, &up->irqflags); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); return 0; } @@ -594,7 +594,7 @@ static void sunsab_shutdown(struct uart_ container_of(port, struct uart_sunsab_port, port); unsigned long flags; - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); /* Disable Interrupts */ up->interrupt_mask0 = 0xff; @@ -628,7 +628,7 @@ static void sunsab_shutdown(struct uart_ writeb(tmp, &up->regs->rw.ccr0); #endif - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); free_irq(up->port.irq, up); } @@ -779,9 +779,9 @@ static void sunsab_set_termios(struct ua unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000); unsigned int quot = uart_get_divisor(port, baud); - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); sunsab_convert_to_sab(up, termios->c_cflag, termios->c_iflag, baud, quot); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } static const char *sunsab_type(struct uart_port *port) @@ -857,15 +857,15 @@ static void sunsab_console_write(struct int locked = 1; if (up->port.sysrq || oops_in_progress) - locked = spin_trylock_irqsave(&up->port.lock, flags); + locked = uart_port_trylock_irqsave(&up->port, &flags); else - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); uart_console_write(&up->port, s, n, sunsab_console_putchar); sunsab_tec_wait(up); if (locked) - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } static int sunsab_console_setup(struct console *con, char *options) @@ -914,7 +914,7 @@ static int sunsab_console_setup(struct c */ sunsab_startup(&up->port); - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); /* * Finally, enable interrupts @@ -932,7 +932,7 @@ static int sunsab_console_setup(struct c sunsab_convert_to_sab(up, con->cflag, 0, baud, quot); sunsab_set_mctrl(&up->port, TIOCM_DTR | TIOCM_RTS); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); return 0; }