From patchwork Thu Sep 14 18:37:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 723019 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 02FCDEEAA65 for ; Thu, 14 Sep 2023 18:39:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241877AbjINSjJ (ORCPT ); Thu, 14 Sep 2023 14:39:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37348 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241778AbjINSi7 (ORCPT ); Thu, 14 Sep 2023 14:38:59 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 148E8213A; Thu, 14 Sep 2023 11:38:53 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716731; 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=UlpF/H9lKMDrxmXTuNUKsAvkYnpqtMAZIidKoYfk2m8=; b=OvnQvp6FrSEUwDayVfCSyaTaDBzuc0qDHdbES+H9OAPO6Ha87bRKvDnKy+aUS4pdZFLLmB jDxwD/L3qDChRCkKs0q+jzzmJmJZiwqpSy8A1vQM9uRhSkNw2idhoRuvvgsJxrK+wZx4QG XqxrNYbAK6u7sE1Tzcyz/LRQvnyD2tzuxG6rvJL6EQObHJpanuV55slsCsY84hl6Zyio/3 pQD3+PfXQ3qkNC9MvbiF4uH2PApwczoZNDT9+YaqQDJfAN6RMTd8Q0wfobK08utaA6SImc QzGgZlJy1nebH8t5hloy88cBPuR+IEjxhUWo45LfVr3WtSj7eG3UDcwTb/G12w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716731; 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=UlpF/H9lKMDrxmXTuNUKsAvkYnpqtMAZIidKoYfk2m8=; b=NkoS64+YSQlVmh/kcYnHAvKRouOJW5bYLm3LDjq5+uZbRS0+LZRledqxXPhj4J2guP/ZOw dmliYWM9jDfA5hBA== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, Karol Gugala , Mateusz Holenko , Gabriel Somlo , Joel Stanley Subject: [PATCH tty v1 32/74] serial: liteuart: Use port lock wrappers Date: Thu, 14 Sep 2023 20:43:49 +0206 Message-Id: <20230914183831.587273-33-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 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org 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 Acked-by: Gabriel Somlo --- drivers/tty/serial/liteuart.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c index d881cdd2a58f..a25ab1efe38f 100644 --- a/drivers/tty/serial/liteuart.c +++ b/drivers/tty/serial/liteuart.c @@ -139,13 +139,13 @@ static irqreturn_t liteuart_interrupt(int irq, void *data) * if polling, the context would be "in_serving_softirq", so use * irq[save|restore] spin_lock variants to cover all possibilities */ - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); isr = litex_read8(port->membase + OFF_EV_PENDING) & uart->irq_reg; if (isr & EV_RX) liteuart_rx_chars(port); if (isr & EV_TX) liteuart_tx_chars(port); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); return IRQ_RETVAL(isr); } @@ -195,10 +195,10 @@ static int liteuart_startup(struct uart_port *port) } } - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* only enabling rx irqs during startup */ liteuart_update_irq_reg(port, true, EV_RX); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); if (!port->irq) { timer_setup(&uart->timer, liteuart_timer, 0); @@ -213,9 +213,9 @@ static void liteuart_shutdown(struct uart_port *port) struct liteuart_port *uart = to_liteuart_port(port); unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); liteuart_update_irq_reg(port, false, EV_RX | EV_TX); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); if (port->irq) free_irq(port->irq, port); @@ -229,13 +229,13 @@ static void liteuart_set_termios(struct uart_port *port, struct ktermios *new, unsigned int baud; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* update baudrate */ baud = uart_get_baud_rate(port, new, old, 0, 460800); uart_update_timeout(port, new->c_cflag, baud); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static const char *liteuart_type(struct uart_port *port) @@ -382,9 +382,9 @@ static void liteuart_console_write(struct console *co, const char *s, uart = (struct liteuart_port *)xa_load(&liteuart_array, co->index); port = &uart->port; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); uart_console_write(port, s, count, liteuart_putchar); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static int liteuart_console_setup(struct console *co, char *options)