From patchwork Thu Sep 14 18:37:41 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 13385820 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DAA4CEEAA63 for ; Thu, 14 Sep 2023 18:39:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=IHGpTMkkE98o6u5bdpP6zV39MAXR6M5was98sGbhiwg=; b=I4IKog3Wvb+v0f Tk326h6/UvkumVBaPY/CNoaYckDn9GNn6UwrcUZIfxIle1CZ7cMiFQJVMbDwPoraJFHv0qP5oMnzu h0v+5yO9Q+rAUEd6qK7cHgS9seHznDe/RuNIeW8l2COE0r7XFQp0ZPBrhlQpWSZIUbGTMyLxboI4d aHVet8XExWI1Tj6zsXGKEhk00XZ0neXINzne1Zvif1vVMxRnqwCb+tyfdutyFrj5J6NDyaYAaicTM Cu/6BMR9OWCH0aGluO4efjP0rsKUcBxYS9FdEWDbMPDIo/PkdgIsirBHHZUlXeOtE7gfeNjKxd26J 0ba51VD1qIRYT4NiIiMA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qgrF8-0094xA-0W; Thu, 14 Sep 2023 18:39:10 +0000 Received: from galois.linutronix.de ([2a0a:51c0:0:12e:550::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qgrEv-0094oC-2Y for linux-arm-kernel@lists.infradead.org; Thu, 14 Sep 2023 18:39:00 +0000 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=lSEvjVL+BxuTqhoV6y++5iFzUZwHV0OnCUueADVyxEA=; b=IVquxk0Z+ro6LFHKJw51lwIPigfWCMfmclUU2+JcehI3LOaX5BkNwJRLblrY0cbagILQic RqiElXu91Wnj1AhvgvDxpBl8H4wZs16fjHk6JDxf7RHlZytj1RGhivPhRjLqRbQGhMxpEy vg/kQ1k3mVm1xZnPUIn7+mrqPqddMnw5g3lnvkbYeAfM5GK9kjiAKhJJO1cRKYHo3CMe2D bbcknb4FzDKQZjdNHh8XHtx01Lip0J/J3MtvXpgDJScQb8lF5ZDAXULO+IUJr1FN+XgeG5 WasYgGIMC0IPIVLI1Q5P/xd2hLixAvMXU+m/Fa8R6mu0GRkyln7ivVnmHKqBqA== 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=lSEvjVL+BxuTqhoV6y++5iFzUZwHV0OnCUueADVyxEA=; b=r6+fh09oHfENkWCN4lF8MffdwEGUKNIjvSkxoPrQxnv1rhnu/nekiAEHappQ9NFpa+bmJT nA9poxy/eDhflsDg== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, Baruch Siach , Tobias Klauser , Richard GENOUD , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , linux-arm-kernel@lists.infradead.org Subject: [PATCH tty v1 24/74] serial: digicolor: Use port lock wrappers Date: Thu, 14 Sep 2023 20:43:41 +0206 Message-Id: <20230914183831.587273-25-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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230914_113858_128743_E0DF8465 X-CRM114-Status: GOOD ( 14.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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 Acked-by: Baruch Siach --- 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 {