From bea0437fa2260e6d4cfc41052b39dfc6ee5f9fc7 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner <tglx@linutronix.de> Date: Thu, 14 Sep 2023 20:44:04 +0206 Subject: [PATCH 073/204] serial: pmac_zilog: 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/20230914183831.587273-48-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/pmac_zilog.c | 52 ++++++++++++++++++++-------------------- 1 file changed, 26 insertions(+), 26 deletions(-) Index: linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c =================================================================== @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:248 @ static bool pmz_receive_chars(struct uar #endif /* USE_CTRL_O_SYSRQ */ if (uap->port.sysrq) { int swallow; - spin_unlock(&uap->port.lock); + uart_port_unlock(&uap->port); swallow = uart_handle_sysrq_char(&uap->port, ch); - spin_lock(&uap->port.lock); + uart_port_lock(&uap->port); if (swallow) goto next_char; } @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:424 @ static irqreturn_t pmz_interrupt(int irq uap_a = pmz_get_port_A(uap); uap_b = uap_a->mate; - spin_lock(&uap_a->port.lock); + uart_port_lock(&uap_a->port); r3 = read_zsreg(uap_a, R3); /* Channel A */ @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:445 @ static irqreturn_t pmz_interrupt(int irq rc = IRQ_HANDLED; } skip_a: - spin_unlock(&uap_a->port.lock); + uart_port_unlock(&uap_a->port); if (push) tty_flip_buffer_push(&uap->port.state->port); if (!uap_b) goto out; - spin_lock(&uap_b->port.lock); + uart_port_lock(&uap_b->port); push = false; if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) { if (!ZS_IS_OPEN(uap_b)) { @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:470 @ static irqreturn_t pmz_interrupt(int irq rc = IRQ_HANDLED; } skip_b: - spin_unlock(&uap_b->port.lock); + uart_port_unlock(&uap_b->port); if (push) tty_flip_buffer_push(&uap->port.state->port); @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:486 @ static inline u8 pmz_peek_status(struct unsigned long flags; u8 status; - spin_lock_irqsave(&uap->port.lock, flags); + uart_port_lock_irqsave(&uap->port, &flags); status = read_zsreg(uap, R0); - spin_unlock_irqrestore(&uap->port.lock, flags); + uart_port_unlock_irqrestore(&uap->port, flags); return status; } @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:674 @ static void pmz_break_ctl(struct uart_po else clear_bits |= SND_BRK; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); new_reg = (uap->curregs[R5] | set_bits) & ~clear_bits; if (new_reg != uap->curregs[R5]) { @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:682 @ static void pmz_break_ctl(struct uart_po write_zsreg(uap, R5, uap->curregs[R5]); } - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } #ifdef CONFIG_PPC_PMAC @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:854 @ static void pmz_irda_reset(struct uart_p { unsigned long flags; - spin_lock_irqsave(&uap->port.lock, flags); + uart_port_lock_irqsave(&uap->port, &flags); uap->curregs[R5] |= DTR; write_zsreg(uap, R5, uap->curregs[R5]); zssync(uap); - spin_unlock_irqrestore(&uap->port.lock, flags); + uart_port_unlock_irqrestore(&uap->port, flags); msleep(110); - spin_lock_irqsave(&uap->port.lock, flags); + uart_port_lock_irqsave(&uap->port, &flags); uap->curregs[R5] &= ~DTR; write_zsreg(uap, R5, uap->curregs[R5]); zssync(uap); - spin_unlock_irqrestore(&uap->port.lock, flags); + uart_port_unlock_irqrestore(&uap->port, flags); msleep(10); } @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:885 @ static int pmz_startup(struct uart_port * initialize the chip */ if (!ZS_IS_CONS(uap)) { - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); pwr_delay = __pmz_startup(uap); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } sprintf(uap->irq_name, PMACZILOG_NAME"%d", uap->port.line); if (request_irq(uap->port.irq, pmz_interrupt, IRQF_SHARED, @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:910 @ static int pmz_startup(struct uart_port pmz_irda_reset(uap); /* Enable interrupt requests for the channel */ - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); pmz_interrupt_control(uap, 1); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); return 0; } @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:922 @ static void pmz_shutdown(struct uart_por struct uart_pmac_port *uap = to_pmz(port); unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* Disable interrupt requests for the channel */ pmz_interrupt_control(uap, 0); @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:937 @ static void pmz_shutdown(struct uart_por pmz_maybe_update_regs(uap); } - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); /* Release interrupt handler */ free_irq(uap->port.irq, uap); - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); uap->flags &= ~PMACZILOG_FLAG_IS_OPEN; if (!ZS_IS_CONS(uap)) pmz_set_scc_power(uap, 0); /* Shut the chip down */ - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } /* Shared by TTY driver and serial console setup. The port lock is held @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:1236 @ static void pmz_set_termios(struct uart_ struct uart_pmac_port *uap = to_pmz(port); unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* Disable IRQs on the port */ pmz_interrupt_control(uap, 0); @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:1248 @ static void pmz_set_termios(struct uart_ if (ZS_IS_OPEN(uap)) pmz_interrupt_control(uap, 1); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static const char *pmz_type(struct uart_port *port) @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:1885 @ static void pmz_console_write(struct con struct uart_pmac_port *uap = &pmz_ports[con->index]; unsigned long flags; - spin_lock_irqsave(&uap->port.lock, flags); + uart_port_lock_irqsave(&uap->port, &flags); /* Turn of interrupts and enable the transmitter. */ write_zsreg(uap, R1, uap->curregs[1] & ~TxINT_ENAB); @ linux-6.6.58-rt45/drivers/tty/serial/pmac_zilog.c:1897 @ static void pmz_console_write(struct con write_zsreg(uap, R1, uap->curregs[1]); /* Don't disable the transmitter. */ - spin_unlock_irqrestore(&uap->port.lock, flags); + uart_port_unlock_irqrestore(&uap->port, flags); } /*