From patchwork Thu Sep 14 18:38:29 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 722999 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 5B9DAEEAA63 for ; Thu, 14 Sep 2023 18:44:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240622AbjINSo3 (ORCPT ); Thu, 14 Sep 2023 14:44:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60836 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241770AbjINSm3 (ORCPT ); Thu, 14 Sep 2023 14:42:29 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B8CF30F0; Thu, 14 Sep 2023 11:39:11 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716749; 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=h4vNSSSfbKzMTl5dIaX+nKFLqtsf/7qFsjWyC6l0EH0=; b=Btvxqnk4X2os6S5PrOaEvdQj5QO8ypBR/vcabWe3Gj5lhywtI34HkX9oqmk/uN8pbMIMfW I36GzlO0wMYRThI7KH1lMM/7nxcrYd1F9UhOwQDEjh8Ro10ODzExtzippTDQ7xkrpGTQ8R /afpljVJSX4wsuCyOws5j7Ay2eYLJtPePh3JpHOCtohYDUa24cIVB6b+2rSG/THHGoxEo1 2yJvl9M2jPGFBw6rEt9JljlPfa80dVAzz7Tk3ynReIsFt0hbRYD3tY6LfhhqbzzK8gEI+b 2P2Z7R5JL0rdoozdGeXCuCLpQ6NHXbmemuyVTCAScZ9i7ZcbmJfp99qRUiG8Jw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716749; 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=h4vNSSSfbKzMTl5dIaX+nKFLqtsf/7qFsjWyC6l0EH0=; b=skOOWWSloirPh2qLF10hQ5qRfe3vdZMKCUw5YKRzGtn51G9SzuSd9vTdeNuK3ueDbstJiR QFsCirT45QgYgiBA== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, Timur Tabi , linuxppc-dev@lists.ozlabs.org Subject: [PATCH tty v1 72/74] serial: ucc_uart: Use port lock wrappers Date: Thu, 14 Sep 2023 20:44:29 +0206 Message-Id: <20230914183831.587273-73-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: Timur Tabi --- drivers/tty/serial/ucc_uart.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/ucc_uart.c b/drivers/tty/serial/ucc_uart.c index b06661b80f41..ed7a6bb5596a 100644 --- a/drivers/tty/serial/ucc_uart.c +++ b/drivers/tty/serial/ucc_uart.c @@ -931,7 +931,7 @@ static void qe_uart_set_termios(struct uart_port *port, baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16); /* Do we really need a spinlock here? */ - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* Update the per-port timeout. */ uart_update_timeout(port, termios->c_cflag, baud); @@ -949,7 +949,7 @@ static void qe_uart_set_termios(struct uart_port *port, qe_setbrg(qe_port->us_info.tx_clock, baud, 16); } - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } /*