From patchwork Thu Sep 14 18:37:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 723022 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 79699EEAA69 for ; Thu, 14 Sep 2023 18:39:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241853AbjINSjF (ORCPT ); Thu, 14 Sep 2023 14:39:05 -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 S241716AbjINSi5 (ORCPT ); Thu, 14 Sep 2023 14:38:57 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 87C912118; Thu, 14 Sep 2023 11:38:49 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716728; 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=YJInWHcVqt4j3eK/rdEfaKxcD8K2U9aP/8B1IuSlnT4=; b=WJ4kvtW/Klk/02gMpc/36dTKSEBiKrsPeyQpTm47TyugrlRa3xSvyphTVBdLWkj9HyCEXy Qe6cvcJeo0g78iUJIHJ59KvdU2Tzmku8IDNIqcDv98mhoyIy4h4P7uN8ZayAi7WW0zbV3S QLxLZhkPt7PiZqd3EdZYLSDFyPr+PkYSQDb4G7uhGDD3CMBUYreQygN79bpiL40W4Rs9Y6 ocWTdUS6+trFldWScC3epmB+dXCmQ4s+Q3VTeSUyjKard3ZefZVNEQbNoq/YVy7oXenGlw 1Yelc3nlPF6ymmmW123ooVQ6AUTo5qZjHXN+fLKHHED4EBKaYfKDxSp09jt9ww== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716728; 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=YJInWHcVqt4j3eK/rdEfaKxcD8K2U9aP/8B1IuSlnT4=; b=qzZ73KVlbH94C0/unIwHIzsufL+EDGFyJaBMYq/cOVMeReYLKBF1RMmw+o04bW9Lq3Rw26 oUJdipfVYni+ihDg== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, Christophe Leroy , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , =?utf-8?q?U?= =?utf-8?q?we_Kleine-K=C3=B6nig?= Subject: [PATCH tty v1 23/74] serial: cpm_uart: Use port lock wrappers Date: Thu, 14 Sep 2023 20:43:40 +0206 Message-Id: <20230914183831.587273-24-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/cpm_uart.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/cpm_uart.c b/drivers/tty/serial/cpm_uart.c index 626423022d62..be4af6eda4c2 100644 --- a/drivers/tty/serial/cpm_uart.c +++ b/drivers/tty/serial/cpm_uart.c @@ -569,7 +569,7 @@ static void cpm_uart_set_termios(struct uart_port *port, if ((termios->c_cflag & CREAD) == 0) port->read_status_mask &= ~BD_SC_EMPTY; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); if (IS_SMC(pinfo)) { unsigned int bits = tty_get_frame_size(termios->c_cflag); @@ -609,7 +609,7 @@ static void cpm_uart_set_termios(struct uart_port *port, clk_set_rate(pinfo->clk, baud); else cpm_setbrg(pinfo->brg - 1, baud); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static const char *cpm_uart_type(struct uart_port *port) @@ -1386,9 +1386,9 @@ static void cpm_uart_console_write(struct console *co, const char *s, cpm_uart_early_write(pinfo, s, count, true); local_irq_restore(flags); } else { - spin_lock_irqsave(&pinfo->port.lock, flags); + uart_port_lock_irqsave(&pinfo->port, &flags); cpm_uart_early_write(pinfo, s, count, true); - spin_unlock_irqrestore(&pinfo->port.lock, flags); + uart_port_unlock_irqrestore(&pinfo->port, flags); } }