From nobody Fri Sep 20 11:28:58 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 ABDD8EEAA64 for ; Thu, 14 Sep 2023 18:39:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241963AbjINSjk (ORCPT ); Thu, 14 Sep 2023 14:39:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37386 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241675AbjINSix (ORCPT ); Thu, 14 Sep 2023 14:38:53 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C03E72115; Thu, 14 Sep 2023 11:38:48 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716727; 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=k7D9LsjqZuZo5dBqqfv/ExL4revQqVd4yA1Xdog29cQ=; b=eDObBDkcYp97Vikc2x/bBgVaipIN82wI+Nuxdvnn0VQ5FmGbVViHzrJviSZS3c25s+4h+o 642QV53qKfKLNBrjn6a+eNzVD1LPnjU0sW39bfdFCMwBwgBG9fdOCZLCzKcUriqCWjqwbh BeAHFIXIldQIEPNy4vHBC7/h1V5LisXKjDGO7I7VdtzhYYL0/AP/0QLTq+Qj2bsqtwFyLJ suFwkXQ1A9qFxfCbgIf48XqyuByw4g2nBe3DgYMzSq/d1c2xLHltB1I4pvoIqhnS8q4uRL bl3KL8ZDICk/1vUnGDd5JyRcfmjFCl+COv8nMyQDWl1p0/6ty60eHiJGbo99Vw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716727; 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=k7D9LsjqZuZo5dBqqfv/ExL4revQqVd4yA1Xdog29cQ=; b=wahnM7I+mOzIehgyY6oKhLre/DDgS5f9aweqXQAddREo15iBbFTZTQIhhZSzWLdmRNpBEN ZOE1ovRXuOSTwVCQ== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, Richard Genoud , Nicolas Ferre , Alexandre Belloni , Claudiu Beznea , linux-arm-kernel@lists.infradead.org Subject: [PATCH tty v1 21/74] serial: atmel: Use port lock wrappers Date: Thu, 14 Sep 2023 20:43:38 +0206 Message-Id: <20230914183831.587273-22-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/atmel_serial.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_s= erial.c index 88cdafa5ac54..1946fafc3f3e 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -861,7 +861,7 @@ static void atmel_complete_tx_dma(void *arg) struct dma_chan *chan =3D atmel_port->chan_tx; unsigned long flags; =20 - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); =20 if (chan) dmaengine_terminate_all(chan); @@ -893,7 +893,7 @@ static void atmel_complete_tx_dma(void *arg) atmel_port->tx_done_mask); } =20 - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } =20 static void atmel_release_tx_dma(struct uart_port *port) @@ -1711,9 +1711,9 @@ static void atmel_tasklet_rx_func(struct tasklet_stru= ct *t) struct uart_port *port =3D &atmel_port->uart; =20 /* The interrupt handler does not take the lock */ - spin_lock(&port->lock); + uart_port_lock(port); atmel_port->schedule_rx(port); - spin_unlock(&port->lock); + uart_port_unlock(port); } =20 static void atmel_tasklet_tx_func(struct tasklet_struct *t) @@ -1723,9 +1723,9 @@ static void atmel_tasklet_tx_func(struct tasklet_stru= ct *t) struct uart_port *port =3D &atmel_port->uart; =20 /* The interrupt handler does not take the lock */ - spin_lock(&port->lock); + uart_port_lock(port); atmel_port->schedule_tx(port); - spin_unlock(&port->lock); + uart_port_unlock(port); } =20 static void atmel_init_property(struct atmel_uart_port *atmel_port, @@ -2175,7 +2175,7 @@ static void atmel_set_termios(struct uart_port *port, } else mode |=3D ATMEL_US_PAR_NONE; =20 - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); =20 port->read_status_mask =3D ATMEL_US_OVRE; if (termios->c_iflag & INPCK) @@ -2377,22 +2377,22 @@ static void atmel_set_termios(struct uart_port *por= t, else atmel_disable_ms(port); =20 - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } =20 static void atmel_set_ldisc(struct uart_port *port, struct ktermios *termi= os) { if (termios->c_line =3D=3D N_PPS) { port->flags |=3D UPF_HARDPPS_CD; - spin_lock_irq(&port->lock); + uart_port_lock_irq(port); atmel_enable_ms(port); - spin_unlock_irq(&port->lock); + uart_port_unlock_irq(port); } else { port->flags &=3D ~UPF_HARDPPS_CD; if (!UART_ENABLE_MS(port, termios->c_cflag)) { - spin_lock_irq(&port->lock); + uart_port_lock_irq(port); atmel_disable_ms(port); - spin_unlock_irq(&port->lock); + uart_port_unlock_irq(port); } } } --=20 2.39.2