From ab256143267a775d224c59cc3c2b24d2e620adf0 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner <tglx@linutronix.de> Date: Thu, 14 Sep 2023 20:44:22 +0206 Subject: [PATCH 091/204] serial: sunhv: 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/20230914183831.587273-66-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/sunhv.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) Index: linux-6.6.58-rt45/drivers/tty/serial/sunhv.c =================================================================== @ linux-6.6.58-rt45/drivers/tty/serial/sunhv.c:220 @ static irqreturn_t sunhv_interrupt(int i struct tty_port *tport; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); tport = receive_chars(port); transmit_chars(port); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); if (tport) tty_flip_buffer_push(tport); @ linux-6.6.58-rt45/drivers/tty/serial/sunhv.c:274 @ static void sunhv_send_xchar(struct uart if (ch == __DISABLED_CHAR) return; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); while (limit-- > 0) { long status = sun4v_con_putchar(ch); @ linux-6.6.58-rt45/drivers/tty/serial/sunhv.c:283 @ static void sunhv_send_xchar(struct uart udelay(1); } - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } /* port->lock held by caller. */ @ linux-6.6.58-rt45/drivers/tty/serial/sunhv.c:298 @ static void sunhv_break_ctl(struct uart_ unsigned long flags; int limit = 10000; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); while (limit-- > 0) { long status = sun4v_con_putchar(CON_BREAK); @ linux-6.6.58-rt45/drivers/tty/serial/sunhv.c:307 @ static void sunhv_break_ctl(struct uart_ udelay(1); } - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } } @ linux-6.6.58-rt45/drivers/tty/serial/sunhv.c:331 @ static void sunhv_set_termios(struct uar unsigned int iflag, cflag; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); iflag = termios->c_iflag; cflag = termios->c_cflag; @ linux-6.6.58-rt45/drivers/tty/serial/sunhv.c:346 @ static void sunhv_set_termios(struct uar uart_update_timeout(port, cflag, (port->uartclk / (16 * quot))); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static const char *sunhv_type(struct uart_port *port) @ linux-6.6.58-rt45/drivers/tty/serial/sunhv.c:440 @ static void sunhv_console_write_paged(st int locked = 1; if (port->sysrq || 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); while (n > 0) { unsigned long ra = __pa(con_write_page); @ linux-6.6.58-rt45/drivers/tty/serial/sunhv.c:473 @ static void sunhv_console_write_paged(st } if (locked) - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static inline void sunhv_console_putchar(struct uart_port *port, char c) @ linux-6.6.58-rt45/drivers/tty/serial/sunhv.c:495 @ static void sunhv_console_write_bychar(s int i, locked = 1; if (port->sysrq || 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); for (i = 0; i < n; i++) { if (*s == '\n') @ linux-6.6.58-rt45/drivers/tty/serial/sunhv.c:506 @ static void sunhv_console_write_bychar(s } if (locked) - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static struct console sunhv_console = {