From nobody Fri Sep 20 11:37:12 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 A54AFEEAA62 for ; Thu, 14 Sep 2023 18:40:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242023AbjINSkN (ORCPT ); Thu, 14 Sep 2023 14:40:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37608 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241789AbjINSi7 (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 D780D2109; 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=1694716732; 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=B/YEVP6mWwFo6/xhfhUTWYtdghju7JIkgzq7NY/TOjo=; b=0HDJH4mxjCm5HX8gWyLjpF6KeeBvYaaN9tDWvnW/Td7Yvq3ytL5x42DJcRx0Y3de7ueaod 87Eeu/kJ8jzEzJRQ8D3fpXGIz1xPrQr15ZVGFZxSgw/G/abw68XswubNUM/aSoimMwisDQ HbCWUM9OSAFllmMopxC5SzBqN0E6R57WC0fmxKib3z76SMx1H/xp2r8P/HgmrI3aSsXyxe Z1HCcW9uGLSaTMjd2ByXAb927zjGJDJFf4wrxXH6bTJ1l0+pJzrgKMw2aGVMqCJOOMqrfs Y/oUqNG7RbkeE+tnFDQkunt8PJjYDAXBmGZTgEa+WKxrTnYRF84EmJLDGU26PA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716732; 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=B/YEVP6mWwFo6/xhfhUTWYtdghju7JIkgzq7NY/TOjo=; b=THdCdqmkDOMQ6RV/8UcNabNFfW7AqzyKAXtxCI78QFQRSlvdfobIL3mXavhPEkaw7SKFQQ Q0MfUPqE9lVT2wCg== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, Jacky Huang , Shan-Chun Hung , linux-arm-kernel@lists.infradead.org Subject: [PATCH tty v1 34/74] serial: ma35d1: Use port lock wrappers Date: Thu, 14 Sep 2023 20:43:51 +0206 Message-Id: <20230914183831.587273-35-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/ma35d1_serial.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/drivers/tty/serial/ma35d1_serial.c b/drivers/tty/serial/ma35d1= _serial.c index 465b1def9e11..6fac924f7c12 100644 --- a/drivers/tty/serial/ma35d1_serial.c +++ b/drivers/tty/serial/ma35d1_serial.c @@ -269,16 +269,16 @@ static void receive_chars(struct uart_ma35d1_port *up) if (uart_handle_sysrq_char(&up->port, ch)) continue; =20 - spin_lock(&up->port.lock); + uart_port_lock(&up->port); uart_insert_char(&up->port, fsr, MA35_FSR_RX_OVER_IF, ch, flag); - spin_unlock(&up->port.lock); + uart_port_unlock(&up->port); =20 fsr =3D serial_in(up, MA35_FSR_REG); } while (!(fsr & MA35_FSR_RX_EMPTY) && (max_count-- > 0)); =20 - spin_lock(&up->port.lock); + uart_port_lock(&up->port); tty_flip_buffer_push(&up->port.state->port); - spin_unlock(&up->port.lock); + uart_port_unlock(&up->port); } =20 static irqreturn_t ma35d1serial_interrupt(int irq, void *dev_id) @@ -364,14 +364,14 @@ static void ma35d1serial_break_ctl(struct uart_port *= port, int break_state) unsigned long flags; u32 lcr; =20 - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); lcr =3D serial_in(up, MA35_LCR_REG); if (break_state !=3D 0) lcr |=3D MA35_LCR_BREAK; else lcr &=3D ~MA35_LCR_BREAK; serial_out(up, MA35_LCR_REG, lcr); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } =20 static int ma35d1serial_startup(struct uart_port *port) @@ -441,7 +441,7 @@ static void ma35d1serial_set_termios(struct uart_port *= port, * Ok, we're now changing the port state. Do it with * interrupts disabled. */ - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); =20 up->port.read_status_mask =3D MA35_FSR_RX_OVER_IF; if (termios->c_iflag & INPCK) @@ -475,7 +475,7 @@ static void ma35d1serial_set_termios(struct uart_port *= port, =20 serial_out(up, MA35_LCR_REG, lcr); =20 - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } =20 static const char *ma35d1serial_type(struct uart_port *port) @@ -560,9 +560,9 @@ static void ma35d1serial_console_write(struct console *= co, const char *s, u32 co if (up->port.sysrq) locked =3D 0; else if (oops_in_progress) - locked =3D spin_trylock_irqsave(&up->port.lock, flags); + locked =3D uart_port_trylock_irqsave(&up->port, &flags); else - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); =20 /* * First save the IER then disable the interrupts @@ -576,7 +576,7 @@ static void ma35d1serial_console_write(struct console *= co, const char *s, u32 co serial_out(up, MA35_IER_REG, ier); =20 if (locked) - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } =20 static int __init ma35d1serial_console_setup(struct console *co, char *opt= ions) --=20 2.39.2