From patchwork Thu Sep 14 18:37:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 723017 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 B84C1EEAA64 for ; Thu, 14 Sep 2023 18:39:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241956AbjINSjh (ORCPT ); Thu, 14 Sep 2023 14:39:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37680 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241740AbjINSjA (ORCPT ); Thu, 14 Sep 2023 14:39:00 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 997702683; Thu, 14 Sep 2023 11:38:54 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716733; 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=xu+MA3nvAGpQibJHqwBXfavhwazXxpOBvYT7SUXxurg=; b=VNedMCHdngMxNzKkI4Tk3e/Scyd10wBR9UsJz4Nv9l3mO40AvsIaYB5UO8o6dA/4/jwD5J iOCuPIyDf16h72BERJcVXy0VZ8a6A3zmwzjMPFpuLjj9OyfkzzeRQXOKaPMUpDV2fULhy8 cGnJl0BWhMxtQC9bl5QNvRo0WWzmM/QKhUAxbsaRPX/uxVCjwzMn6eCyLOAR9nnTZBLmGF VQD1UySg+AtbVJpq2cc+vjZB4BINNtIEFjbBtzLV5e4b7IH+k1u/ONNntwWMv8CEHhCQ7w s+awbpMjvgek91Sh+gVYrmY3I8Bui727eu0LEcRwRdJMrrXD97PtfYhQv0hLOQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716733; 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=xu+MA3nvAGpQibJHqwBXfavhwazXxpOBvYT7SUXxurg=; b=BDeS7WcDlvoxrWV5nRJyybaIh6Ix6LKXdIjVcLazyjC0Pcx+K4Imt04CGw4/ALxm62UPmZ PGHFzBpNpEyz6ECQ== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, =?utf-8?q?Ilpo_J=C3=A4rvinen?= Subject: [PATCH tty v1 36/74] serial: men_z135_uart: Use port lock wrappers Date: Thu, 14 Sep 2023 20:43:53 +0206 Message-Id: <20230914183831.587273-37-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 --- drivers/tty/serial/men_z135_uart.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/men_z135_uart.c b/drivers/tty/serial/men_z135_uart.c index d2502aaa3e8c..8048fa542fc4 100644 --- a/drivers/tty/serial/men_z135_uart.c +++ b/drivers/tty/serial/men_z135_uart.c @@ -392,7 +392,7 @@ static irqreturn_t men_z135_intr(int irq, void *data) if (!irq_id) goto out; - spin_lock(&port->lock); + uart_port_lock(port); /* It's save to write to IIR[7:6] RXC[9:8] */ iowrite8(irq_id, port->membase + MEN_Z135_STAT_REG); @@ -418,7 +418,7 @@ static irqreturn_t men_z135_intr(int irq, void *data) handled = true; } - spin_unlock(&port->lock); + uart_port_unlock(port); out: return IRQ_RETVAL(handled); } @@ -708,7 +708,7 @@ static void men_z135_set_termios(struct uart_port *port, baud = uart_get_baud_rate(port, termios, old, 0, uart_freq / 16); - spin_lock_irq(&port->lock); + uart_port_lock_irq(port); if (tty_termios_baud_rate(termios)) tty_termios_encode_baud_rate(termios, baud, baud); @@ -716,7 +716,7 @@ static void men_z135_set_termios(struct uart_port *port, iowrite32(bd_reg, port->membase + MEN_Z135_BAUD_REG); uart_update_timeout(port, termios->c_cflag, baud); - spin_unlock_irq(&port->lock); + uart_port_unlock_irq(port); } static const char *men_z135_type(struct uart_port *port)