From mboxrd@z Thu Jan 1 00:00:00 1970 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 EB948C46CA1 for ; Mon, 18 Sep 2023 06:24:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230157AbjIRGXq (ORCPT ); Mon, 18 Sep 2023 02:23:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42176 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239784AbjIRGXl (ORCPT ); Mon, 18 Sep 2023 02:23:41 -0400 X-Greylist: delayed 577 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Sun, 17 Sep 2023 23:23:33 PDT Received: from mail.tkos.co.il (guitar.tkos.co.il [84.110.109.230]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93FC7E6; Sun, 17 Sep 2023 23:23:33 -0700 (PDT) Received: from tarshish (unknown [10.0.8.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.tkos.co.il (Postfix) with ESMTPS id AD2884403F6; Mon, 18 Sep 2023 09:13:45 +0300 (IDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=tkos.co.il; s=default; t=1695017625; bh=Jkjkzg9+FWNM+WB3mmUntEF1fe6JQVYGAp+gupXTDJY=; h=References:From:To:Cc:Subject:Date:In-reply-to:From; b=Y3oGG3qHY8fQsIe5PHgjs3LNVmtf7Ri83TiHiCRWIUnD55zq3AVrYr6RtXoz5c2Xy B5JDQNHaZV4oV3+87w8djkFun8KovoESmz74DTYTT+aFyiCY/taf0q59kox7iLR5NC BLuYrPTPp+AzIzWJF6NE0ZQJX4CSz98/GNZg6KSOtstfXqhxFGlhypRp6QWyc1NB9g rAzPGE3e7/JVOIOoTNKPlfyYnT3ZhLnZ7/v3DDYl2nP9DfOEAArsIXedIkknnvnfRk ltEzYLDpgtf0a2+nnWIXhWDdccrGh7W23J4pmljZHdipS0Yz5aLlhWJGhEvDHDoVBl O+jajhadsu9Xg== References: <20230914183831.587273-1-john.ogness@linutronix.de> <20230914183831.587273-25-john.ogness@linutronix.de> User-agent: mu4e 1.9.21; emacs 29.1 From: Baruch Siach To: John Ogness Cc: Greg Kroah-Hartman , Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, Tobias Klauser , Richard GENOUD , Ilpo =?utf-8?Q?J=C3=A4rvinen?= , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH tty v1 24/74] serial: digicolor: Use port lock wrappers Date: Mon, 18 Sep 2023 09:13:03 +0300 In-reply-to: <20230914183831.587273-25-john.ogness@linutronix.de> Message-ID: <87il88m2jk.fsf@tarshish> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Hi John, On Thu, Sep 14 2023, John Ogness wrote: > 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: Baruch Siach Thanks, baruch > --- > drivers/tty/serial/digicolor-usart.c | 18 +++++++++--------- > 1 file changed, 9 insertions(+), 9 deletions(-) > > diff --git a/drivers/tty/serial/digicolor-usart.c b/drivers/tty/serial/digicolor-usart.c > index 128b5479e813..5004125f3045 100644 > --- a/drivers/tty/serial/digicolor-usart.c > +++ b/drivers/tty/serial/digicolor-usart.c > @@ -133,7 +133,7 @@ static void digicolor_uart_rx(struct uart_port *port) > { > unsigned long flags; > > - spin_lock_irqsave(&port->lock, flags); > + uart_port_lock_irqsave(port, &flags); > > while (1) { > u8 status, ch, ch_flag; > @@ -172,7 +172,7 @@ static void digicolor_uart_rx(struct uart_port *port) > ch_flag); > } > > - spin_unlock_irqrestore(&port->lock, flags); > + uart_port_unlock_irqrestore(port, flags); > > tty_flip_buffer_push(&port->state->port); > } > @@ -185,7 +185,7 @@ static void digicolor_uart_tx(struct uart_port *port) > if (digicolor_uart_tx_full(port)) > return; > > - spin_lock_irqsave(&port->lock, flags); > + uart_port_lock_irqsave(port, &flags); > > if (port->x_char) { > writeb_relaxed(port->x_char, port->membase + UA_EMI_REC); > @@ -211,7 +211,7 @@ static void digicolor_uart_tx(struct uart_port *port) > uart_write_wakeup(port); > > out: > - spin_unlock_irqrestore(&port->lock, flags); > + uart_port_unlock_irqrestore(port, flags); > } > > static irqreturn_t digicolor_uart_int(int irq, void *dev_id) > @@ -333,7 +333,7 @@ static void digicolor_uart_set_termios(struct uart_port *port, > port->ignore_status_mask |= UA_STATUS_OVERRUN_ERR > | UA_STATUS_PARITY_ERR | UA_STATUS_FRAME_ERR; > > - spin_lock_irqsave(&port->lock, flags); > + uart_port_lock_irqsave(port, &flags); > > uart_update_timeout(port, termios->c_cflag, baud); > > @@ -341,7 +341,7 @@ static void digicolor_uart_set_termios(struct uart_port *port, > writeb_relaxed(divisor & 0xff, port->membase + UA_HBAUD_LO); > writeb_relaxed(divisor >> 8, port->membase + UA_HBAUD_HI); > > - spin_unlock_irqrestore(&port->lock, flags); > + uart_port_unlock_irqrestore(port, flags); > } > > static const char *digicolor_uart_type(struct uart_port *port) > @@ -398,14 +398,14 @@ static void digicolor_uart_console_write(struct console *co, const char *c, > int locked = 1; > > if (oops_in_progress) > - locked = spin_trylock_irqsave(&port->lock, flags); > + locked = uart_port_trylock_irqsave(port, &flags); > else > - spin_lock_irqsave(&port->lock, flags); > + uart_port_lock_irqsave(port, &flags); > > uart_console_write(port, c, n, digicolor_uart_console_putchar); > > if (locked) > - spin_unlock_irqrestore(&port->lock, flags); > + uart_port_unlock_irqrestore(port, flags); > > /* Wait for transmitter to become empty */ > do { -- ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch@tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -