From nobody Sun Nov 10 11:11:29 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 1CB99EEAA5D for ; Thu, 14 Sep 2023 18:41:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241975AbjINSlm (ORCPT ); Thu, 14 Sep 2023 14:41:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241971AbjINSjm (ORCPT ); Thu, 14 Sep 2023 14:39:42 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 235D52705; Thu, 14 Sep 2023 11:39:02 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716740; 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=4go78jqQjBoLjBGzmCHOv9NrC20UwwVa764/6PmFVf4=; b=KycCGl+Z0tSDZryL3lQvmTDKcENvZ0bElfbOFWqhLIP3byAP8mJeI8s7trSAyJ04mQsP2N 1/M3CFlEDWRY4Z5SF8LpTdGxlleEfdxtDAci9kbM93yX+OoCLRndlWnDkjX9SKjrnzp/5r lorsjYHtyFt5l2tvoeCNi95kjntjmBRR2DCVB41fw2zUWbr1VVIhrzZ9cEfdmvwIGCQfMN /tQ3hy7AwDUhqDzBhBfrALwSGfKsBc6a3fEJAD01Miv3D8x8TQnVNgKkBI7QOpEW0GQGtN DLVoatFnfmYeO9QruW6684ou7F878JmG8Kr9OaSmLDT6TYpvas/aNOo7t/Q32w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716740; 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=4go78jqQjBoLjBGzmCHOv9NrC20UwwVa764/6PmFVf4=; b=0CSYNn68lqfVz1Tm7+KGTJLruBkCCmjvrxg4X3MZa6H8cRhjyOQ8S2f5ycLq3ZJtfVSNjo aLXikOoIdOkjNHCA== 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=20J=C3=A4rvinen?= , Thierry Reding , Tobias Klauser Subject: [PATCH tty v1 52/74] serial: sa1100: Use port lock wrappers Date: Thu, 14 Sep 2023 20:44:09 +0206 Message-Id: <20230914183831.587273-53-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/sa1100.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/drivers/tty/serial/sa1100.c b/drivers/tty/serial/sa1100.c index ad011f1e2f4d..be7bcd75d9f4 100644 --- a/drivers/tty/serial/sa1100.c +++ b/drivers/tty/serial/sa1100.c @@ -115,9 +115,9 @@ static void sa1100_timeout(struct timer_list *t) unsigned long flags; =20 if (sport->port.state) { - spin_lock_irqsave(&sport->port.lock, flags); + uart_port_lock_irqsave(&sport->port, &flags); sa1100_mctrl_check(sport); - spin_unlock_irqrestore(&sport->port.lock, flags); + uart_port_unlock_irqrestore(&sport->port, flags); =20 mod_timer(&sport->timer, jiffies + MCTRL_TIMEOUT); } @@ -247,7 +247,7 @@ static irqreturn_t sa1100_int(int irq, void *dev_id) struct sa1100_port *sport =3D dev_id; unsigned int status, pass_counter =3D 0; =20 - spin_lock(&sport->port.lock); + uart_port_lock(&sport->port); status =3D UART_GET_UTSR0(sport); status &=3D SM_TO_UTSR0(sport->port.read_status_mask) | ~UTSR0_TFS; do { @@ -276,7 +276,7 @@ static irqreturn_t sa1100_int(int irq, void *dev_id) status &=3D SM_TO_UTSR0(sport->port.read_status_mask) | ~UTSR0_TFS; } while (status & (UTSR0_TFS | UTSR0_RFS | UTSR0_RID)); - spin_unlock(&sport->port.lock); + uart_port_unlock(&sport->port); =20 return IRQ_HANDLED; } @@ -321,14 +321,14 @@ static void sa1100_break_ctl(struct uart_port *port, = int break_state) unsigned long flags; unsigned int utcr3; =20 - spin_lock_irqsave(&sport->port.lock, flags); + uart_port_lock_irqsave(&sport->port, &flags); utcr3 =3D UART_GET_UTCR3(sport); if (break_state =3D=3D -1) utcr3 |=3D UTCR3_BRK; else utcr3 &=3D ~UTCR3_BRK; UART_PUT_UTCR3(sport, utcr3); - spin_unlock_irqrestore(&sport->port.lock, flags); + uart_port_unlock_irqrestore(&sport->port, flags); } =20 static int sa1100_startup(struct uart_port *port) @@ -354,9 +354,9 @@ static int sa1100_startup(struct uart_port *port) /* * Enable modem status interrupts */ - spin_lock_irq(&sport->port.lock); + uart_port_lock_irq(&sport->port); sa1100_enable_ms(&sport->port); - spin_unlock_irq(&sport->port.lock); + uart_port_unlock_irq(&sport->port); =20 return 0; } @@ -423,7 +423,7 @@ sa1100_set_termios(struct uart_port *port, struct kterm= ios *termios, =20 del_timer_sync(&sport->timer); =20 - spin_lock_irqsave(&sport->port.lock, flags); + uart_port_lock_irqsave(&sport->port, &flags); =20 sport->port.read_status_mask &=3D UTSR0_TO_SM(UTSR0_TFS); sport->port.read_status_mask |=3D UTSR1_TO_SM(UTSR1_ROR); @@ -485,7 +485,7 @@ sa1100_set_termios(struct uart_port *port, struct kterm= ios *termios, if (UART_ENABLE_MS(&sport->port, termios->c_cflag)) sa1100_enable_ms(&sport->port); =20 - spin_unlock_irqrestore(&sport->port.lock, flags); + uart_port_unlock_irqrestore(&sport->port, flags); } =20 static const char *sa1100_type(struct uart_port *port) --=20 2.39.2