From patchwork Thu Sep 14 18:37:47 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 723021 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 CEE47EEAA66 for ; Thu, 14 Sep 2023 18:39:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241856AbjINSjG (ORCPT ); Thu, 14 Sep 2023 14:39:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241763AbjINSi7 (ORCPT ); Thu, 14 Sep 2023 14:38:59 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F209212E; Thu, 14 Sep 2023 11:38:52 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716731; 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=7MhPKCrB1dOunNZkyVt5zeAFdISPvOBlSvfyFnl5/7k=; b=YLqoO2CmXARRUlFLHeB2M6ukd+zU/nFFgFSlVGTgtOrax7oXV7pPL8cSmw/pZDAElhtrfi tg+qdkkRjdfFcje2e6txYb3BMdaIg9i7e0Mh+YxmElDly4kDa3NAjK/0UG6MgVfELywhT2 V8orxiw3OetQDrZZDTQXxy5+hqdFeJ1HEll+tEKleM5gcgTzDHcNQToDDydnseVBtkUdYG gytRSgchp+eOFJON+5pvNC6JQu0C+5Da8EUAAMJ6Xa4aUQIiDLgBOmaNvJOGFL+X0eB7l+ ajIq4J62gfzDnlJBiRb8IMfsMmRoi6quQ96kG6szLXiQ26KdUa+1MgJWGskI1w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716731; 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=7MhPKCrB1dOunNZkyVt5zeAFdISPvOBlSvfyFnl5/7k=; b=3ww4vlg4w6dOUA/vLaMXWEJhpTPQP9RtHU84xi6hn3BhuNTqmvAXu3TlTrY1SAXMKgY3m8 pzcqy8Uf8lJvCrBg== 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?= , Thierry Reding , Tobias Klauser Subject: [PATCH tty v1 30/74] serial: ip22zilog: Use port lock wrappers Date: Thu, 14 Sep 2023 20:43:47 +0206 Message-Id: <20230914183831.587273-31-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/ip22zilog.c | 36 +++++++++++++++++----------------- 1 file changed, 18 insertions(+), 18 deletions(-) diff --git a/drivers/tty/serial/ip22zilog.c b/drivers/tty/serial/ip22zilog.c index 845ff706bc59..320b29cd4683 100644 --- a/drivers/tty/serial/ip22zilog.c +++ b/drivers/tty/serial/ip22zilog.c @@ -432,7 +432,7 @@ static irqreturn_t ip22zilog_interrupt(int irq, void *dev_id) unsigned char r3; bool push = false; - spin_lock(&up->port.lock); + uart_port_lock(&up->port); r3 = read_zsreg(channel, R3); /* Channel A */ @@ -448,7 +448,7 @@ static irqreturn_t ip22zilog_interrupt(int irq, void *dev_id) if (r3 & CHATxIP) ip22zilog_transmit_chars(up, channel); } - spin_unlock(&up->port.lock); + uart_port_unlock(&up->port); if (push) tty_flip_buffer_push(&up->port.state->port); @@ -458,7 +458,7 @@ static irqreturn_t ip22zilog_interrupt(int irq, void *dev_id) channel = ZILOG_CHANNEL_FROM_PORT(&up->port); push = false; - spin_lock(&up->port.lock); + uart_port_lock(&up->port); if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) { writeb(RES_H_IUS, &channel->control); ZSDELAY(); @@ -471,7 +471,7 @@ static irqreturn_t ip22zilog_interrupt(int irq, void *dev_id) if (r3 & CHBTxIP) ip22zilog_transmit_chars(up, channel); } - spin_unlock(&up->port.lock); + uart_port_unlock(&up->port); if (push) tty_flip_buffer_push(&up->port.state->port); @@ -504,11 +504,11 @@ static unsigned int ip22zilog_tx_empty(struct uart_port *port) unsigned char status; unsigned int ret; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); status = ip22zilog_read_channel_status(port); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); if (status & Tx_BUF_EMP) ret = TIOCSER_TEMT; @@ -664,7 +664,7 @@ static void ip22zilog_break_ctl(struct uart_port *port, int break_state) else clear_bits |= SND_BRK; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); new_reg = (up->curregs[R5] | set_bits) & ~clear_bits; if (new_reg != up->curregs[R5]) { @@ -674,7 +674,7 @@ static void ip22zilog_break_ctl(struct uart_port *port, int break_state) write_zsreg(channel, R5, up->curregs[R5]); } - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static void __ip22zilog_reset(struct uart_ip22zilog_port *up) @@ -735,9 +735,9 @@ static int ip22zilog_startup(struct uart_port *port) if (ZS_IS_CONS(up)) return 0; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); __ip22zilog_startup(up); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); return 0; } @@ -775,7 +775,7 @@ static void ip22zilog_shutdown(struct uart_port *port) if (ZS_IS_CONS(up)) return; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); channel = ZILOG_CHANNEL_FROM_PORT(port); @@ -788,7 +788,7 @@ static void ip22zilog_shutdown(struct uart_port *port) up->curregs[R5] &= ~SND_BRK; ip22zilog_maybe_update_regs(up, channel); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } /* Shared by TTY driver and serial console setup. The port lock is held @@ -880,7 +880,7 @@ ip22zilog_set_termios(struct uart_port *port, struct ktermios *termios, baud = uart_get_baud_rate(port, termios, old, 1200, 76800); - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR); @@ -894,7 +894,7 @@ ip22zilog_set_termios(struct uart_port *port, struct ktermios *termios, ip22zilog_maybe_update_regs(up, ZILOG_CHANNEL_FROM_PORT(port)); uart_update_timeout(port, termios->c_cflag, baud); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } static const char *ip22zilog_type(struct uart_port *port) @@ -1016,10 +1016,10 @@ ip22zilog_console_write(struct console *con, const char *s, unsigned int count) struct uart_ip22zilog_port *up = &ip22zilog_port_table[con->index]; unsigned long flags; - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); uart_console_write(&up->port, s, count, ip22zilog_put_char); udelay(2); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } static int __init ip22zilog_console_setup(struct console *con, char *options) @@ -1034,13 +1034,13 @@ static int __init ip22zilog_console_setup(struct console *con, char *options) printk(KERN_INFO "Console: ttyS%d (IP22-Zilog)\n", con->index); - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); up->curregs[R15] |= BRKIE; __ip22zilog_startup(up); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); if (options) uart_parse_options(options, &baud, &parity, &bits, &flow);