From nobody Fri Sep 20 11:31:57 2024 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 25F98EEAA5D for ; Thu, 14 Sep 2023 18:41:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242125AbjINSlu (ORCPT ); Thu, 14 Sep 2023 14:41:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37752 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241993AbjINSj5 (ORCPT ); Thu, 14 Sep 2023 14:39:57 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D03EE2713; Thu, 14 Sep 2023 11:39:03 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716742; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Zy6q0L16Kf/KS6E7GOqWz6KYdIr63xhUHPEN74PlZEE=; b=O92aHgkVbGKPJl2oWelrZRGt1hi4ABLEooGQ4nQ9fCBmHNvENAraqDtpqPzxFMlxHv2SYg vs16YS6VAZvUSjTum3CqnCHtjaiEHzehqMRfoTA8QZ8++r/yGaNP6Xb4+h+8T9WDfggheH 10H0J/LPuz9H4l1GiMulPxSc+OfDZycHKF+O10GVr9ypv2MGkwGIMmPn0GdBRRoGNpqDrT MVKX86GnRPFOPvsNuCxNN0KyYuuBiy8f/fxQHcRsFMI3GCUp+faWu11v4RJJ8MibW5K9+s ypVwnSHBmyq5LmbgpSg/l/Ek0mCkFRnVTV9T3t2z/cB7BbWlvkf8//sARgINeA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716742; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Zy6q0L16Kf/KS6E7GOqWz6KYdIr63xhUHPEN74PlZEE=; b=xq0a3lU7Ye8KLD0iDn7GDbg27VseXJ6HbyT3vmZtU5JRykbFWRlis6URvJgMHHS34BCNDL YMeQ8ccCDr68/WDg== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, Lech Perczak , Hugo Villeneuve , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Andy Shevchenko , =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Isaac True Subject: [PATCH tty v1 55/74] serial: sc16is7xx: Use port lock wrappers Date: Thu, 14 Sep 2023 20:44:12 +0206 Message-Id: <20230914183831.587273-56-john.ogness@linutronix.de> In-Reply-To: <20230914183831.587273-1-john.ogness@linutronix.de> References: <20230914183831.587273-1-john.ogness@linutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Thomas Gleixner 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 --- drivers/tty/serial/sc16is7xx.c | 40 +++++++++++++++++----------------- 1 file changed, 20 insertions(+), 20 deletions(-) diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index f61d98e09dc3..9d8307f5fc36 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -667,9 +667,9 @@ static void sc16is7xx_handle_tx(struct uart_port *port) } =20 if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); sc16is7xx_stop_tx(port); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); return; } =20 @@ -695,13 +695,13 @@ static void sc16is7xx_handle_tx(struct uart_port *por= t) sc16is7xx_fifo_write(port, to_send); } =20 - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); =20 if (uart_circ_empty(xmit)) sc16is7xx_stop_tx(port); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } =20 static unsigned int sc16is7xx_get_hwmctrl(struct uart_port *port) @@ -733,7 +733,7 @@ static void sc16is7xx_update_mlines(struct sc16is7xx_on= e *one) =20 one->old_mctrl =3D status; =20 - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); if ((changed & TIOCM_RNG) && (status & TIOCM_RNG)) port->icount.rng++; if (changed & TIOCM_DSR) @@ -744,7 +744,7 @@ static void sc16is7xx_update_mlines(struct sc16is7xx_on= e *one) uart_handle_cts_change(port, status & TIOCM_CTS); =20 wake_up_interruptible(&port->state->port.delta_msr_wait); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } =20 static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno) @@ -823,9 +823,9 @@ static void sc16is7xx_tx_proc(struct kthread_work *ws) sc16is7xx_handle_tx(port); mutex_unlock(&s->efr_lock); =20 - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); sc16is7xx_ier_set(port, SC16IS7XX_IER_THRI_BIT); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } =20 static void sc16is7xx_reconf_rs485(struct uart_port *port) @@ -836,14 +836,14 @@ static void sc16is7xx_reconf_rs485(struct uart_port *= port) struct serial_rs485 *rs485 =3D &port->rs485; unsigned long irqflags; =20 - spin_lock_irqsave(&port->lock, irqflags); + uart_port_lock_irqsave(port, &irqflags); if (rs485->flags & SER_RS485_ENABLED) { efcr |=3D SC16IS7XX_EFCR_AUTO_RS485_BIT; =20 if (rs485->flags & SER_RS485_RTS_AFTER_SEND) efcr |=3D SC16IS7XX_EFCR_RTS_INVERT_BIT; } - spin_unlock_irqrestore(&port->lock, irqflags); + uart_port_unlock_irqrestore(port, irqflags); =20 sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, mask, efcr); } @@ -854,10 +854,10 @@ static void sc16is7xx_reg_proc(struct kthread_work *w= s) struct sc16is7xx_one_config config; unsigned long irqflags; =20 - spin_lock_irqsave(&one->port.lock, irqflags); + uart_port_lock_irqsave(&one->port, &irqflags); config =3D one->config; memset(&one->config, 0, sizeof(one->config)); - spin_unlock_irqrestore(&one->port.lock, irqflags); + uart_port_unlock_irqrestore(&one->port, irqflags); =20 if (config.flags & SC16IS7XX_RECONF_MD) { u8 mcr =3D 0; @@ -963,18 +963,18 @@ static void sc16is7xx_throttle(struct uart_port *port) * value set in MCR register. Stop reading data from RX FIFO so the * AutoRTS feature will de-activate RTS output. */ - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); sc16is7xx_ier_clear(port, SC16IS7XX_IER_RDI_BIT); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } =20 static void sc16is7xx_unthrottle(struct uart_port *port) { unsigned long flags; =20 - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); sc16is7xx_ier_set(port, SC16IS7XX_IER_RDI_BIT); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } =20 static unsigned int sc16is7xx_tx_empty(struct uart_port *port) @@ -1113,7 +1113,7 @@ static void sc16is7xx_set_termios(struct uart_port *p= ort, /* Setup baudrate generator */ baud =3D sc16is7xx_set_baud(port, baud); =20 - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); =20 /* Update timeout according to new baud rate */ uart_update_timeout(port, termios->c_cflag, baud); @@ -1121,7 +1121,7 @@ static void sc16is7xx_set_termios(struct uart_port *p= ort, if (UART_ENABLE_MS(port, termios->c_cflag)) sc16is7xx_enable_ms(port); =20 - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } =20 static int sc16is7xx_config_rs485(struct uart_port *port, struct ktermios = *termios, @@ -1208,9 +1208,9 @@ static int sc16is7xx_startup(struct uart_port *port) sc16is7xx_port_write(port, SC16IS7XX_IER_REG, val); =20 /* Enable modem status polling */ - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); sc16is7xx_enable_ms(port); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); =20 return 0; } --=20 2.39.2