From patchwork Thu Sep 14 18:37:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 723030 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 4479CEEAA69 for ; Thu, 14 Sep 2023 18:38:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241693AbjINSi4 (ORCPT ); Thu, 14 Sep 2023 14:38:56 -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 S241609AbjINSix (ORCPT ); Thu, 14 Sep 2023 14:38:53 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 871682101; Thu, 14 Sep 2023 11:38:45 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716724; 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=LC6ee95LLgICXwmE0USSEBuHjBCWJtZsDUgyx/Ctu9I=; b=R1TuVbNostHa0wM4yepEE7v6WHYuLqdxHUqaYn+qB5pl6tCd4QoP0ouCPBj/gYuUjWU2Hl qZSxgx+XXc/VQiIbUuVilNn3nM35W92GRgdyC6GzHPzgXIzngraczIF+lQGD9zNMwJBoVE orO2MdWxWEsso3g+/W+4DPjj1PAxTEk4Ngx2Oi+rIWTZF+orsNP2nKu4Q3yVlYIW1gI/to QdnLyyvD3oIXml7AgZqrVHTRaq5qTQuWRRt2xEKRNBtXo5LM/raiC8Fp2QnzPPv8+4HCmj PiYmbhKFmSLs+5ksgnA4L6VU/drWEG5TNzjchepMiTwFo+4Ae8GZ2/3YVbPhzw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716724; 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=LC6ee95LLgICXwmE0USSEBuHjBCWJtZsDUgyx/Ctu9I=; b=CZYVJekgCab/O5x5km8To1UaDf+NZCMKRy3KHKXP+YTu0UQJ7PUVdCpMdSS2HphSeJTuVJ /2B0cSEgLlc3bHDA== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, Kumaravel Thiagarajan , Tharun Kumar P Subject: [PATCH tty v1 13/74] serial: 8250_pci1xxxx: Use port lock wrappers Date: Thu, 14 Sep 2023 20:43:30 +0206 Message-Id: <20230914183831.587273-14-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/8250/8250_pci1xxxx.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/8250/8250_pci1xxxx.c b/drivers/tty/serial/8250/8250_pci1xxxx.c index a3b25779d921..53e238c8cc89 100644 --- a/drivers/tty/serial/8250/8250_pci1xxxx.c +++ b/drivers/tty/serial/8250/8250_pci1xxxx.c @@ -225,10 +225,10 @@ static bool pci1xxxx_port_suspend(int line) if (port->suspended == 0 && port->dev) { wakeup_mask = readb(up->port.membase + UART_WAKE_MASK_REG); - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); port->mctrl &= ~TIOCM_OUT2; port->ops->set_mctrl(port, port->mctrl); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); ret = (wakeup_mask & UART_WAKE_SRCS) != UART_WAKE_SRCS; } @@ -251,10 +251,10 @@ static void pci1xxxx_port_resume(int line) writeb(UART_WAKE_SRCS, port->membase + UART_WAKE_REG); if (port->suspended == 0) { - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); port->mctrl |= TIOCM_OUT2; port->ops->set_mctrl(port, port->mctrl); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } mutex_unlock(&tport->mutex); }