From patchwork Fri Mar 1 21:45:23 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 777620 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 913D759141 for ; Fri, 1 Mar 2024 21:52:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709329977; cv=none; b=Y9z42Zp30QpTZxrIy75fHmpaMYNoutPNEuGaW4r4+Lg+x1pjOD5kPUp8U2yYyxzPcUu4s5Y6uKZqvQtRYqfXprqTQRAnobwajO6f7KxuS5k9Ni0TZv4t823YUmXVYL/JMpP1GlrsynSYmHtZbb45e6F0g60kZueOskTdsf2OHwY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709329977; c=relaxed/simple; bh=uymOQEaGyz5PP5tvxdnNv2kYIFvbiI3h6jTV0u0UjkY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=IxbEl0epiIlgQtTgsAY66lV4VDPW98AiJz5R+wOf9uFE4WljGtmrhaSSx3vKCV5Hu23wWEKqI4cxvCAiV1aI8Vpsn766P777ACIwcxav19xmM/zKEcQI7Fz/OHAyMzgH1QE0wQDWsUL/fBnfeYPej08tynIurvX5T8da5ZfodTM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=32PpjUGO; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=SsMk5Jrp; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="32PpjUGO"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="SsMk5Jrp" From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1709329972; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9WNSSuDhcj1L0hdKTmzZHOjjPZHLEmPBI6eyJikJAxs=; b=32PpjUGOijguemtgK5OGL/uEcf+Ed5E32JT6lbtR3GdeCV/eo5rXQWWEWRbAFi8twtwK+Z DpCoTwloeyPP3686UB83pPO1uTmvR/F89B3IpF7mms7xnOvECB6bQuCtL94tOj84OMiFZ+ zzdm3c4XGpuplfAOzcvELdBKzvPp2nWjC/dxcOGVNJno8zju2BTyiz2fcCRBpRpAF8yY9z da3gu/2i764YDfyrXFaXdfx176v+rJ+rBI0h+vHTNQRHJwyX7sxc+viQLOTIZ4CN0wbHWs aHTHl9HXan2ME0xdmsyxgcwR9DhvF/kj6ox19EMx1oecaTh1wVMO/mKJGoc3Hw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1709329972; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9WNSSuDhcj1L0hdKTmzZHOjjPZHLEmPBI6eyJikJAxs=; b=SsMk5Jrp930Xb5w5e046HrQjoh1Hx9Ojuzkx+xUxFIuhu7kwcDYIMuFG26sXao5zaumeRr pvOTdEiB48/6juBg== To: linux-serial@vger.kernel.org Cc: Greg Kroah-Hartman , Jiri Slaby , Thomas Gleixner , Sebastian Andrzej Siewior , =?utf-8?q?Andreas_F?= =?utf-8?q?=C3=A4rber?= , Manivannan Sadhasivam , linux-arm-kernel@lists.infradead.org, linux-actions@lists.infradead.org Subject: [PATCH 10/18] serial: owl: Use uart_prepare_sysrq_char() to handle sysrq. Date: Fri, 1 Mar 2024 22:45:23 +0100 Message-ID: <20240301215246.891055-11-bigeasy@linutronix.de> In-Reply-To: <20240301215246.891055-1-bigeasy@linutronix.de> References: <20240301215246.891055-1-bigeasy@linutronix.de> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT. The driver splits the locking function into two parts: local_irq_save() and uart_port_lock() and this breaks PREEMPT_RT. Handle sysrq requests sysrq once the port lock is dropped. Remove the special case in the console write routine an always use the complete locking function. Cc: "Andreas Färber" Cc: Manivannan Sadhasivam Cc: linux-arm-kernel@lists.infradead.org Cc: linux-actions@lists.infradead.org Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/owl-uart.c | 30 ++++++++++++------------------ 1 file changed, 12 insertions(+), 18 deletions(-) diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c index d9fe85397741d..8b60ac0ad7cd3 100644 --- a/drivers/tty/serial/owl-uart.c +++ b/drivers/tty/serial/owl-uart.c @@ -199,6 +199,7 @@ static void owl_uart_receive_chars(struct uart_port *port) stat = owl_uart_read(port, OWL_UART_STAT); while (!(stat & OWL_UART_STAT_RFEM)) { char flag = TTY_NORMAL; + bool sysrq; if (stat & OWL_UART_STAT_RXER) port->icount.overrun++; @@ -217,7 +218,9 @@ static void owl_uart_receive_chars(struct uart_port *port) val = owl_uart_read(port, OWL_UART_RXDAT); val &= 0xff; - if ((stat & port->ignore_status_mask) == 0) + sysrq = uart_prepare_sysrq_char(port, val); + + if (!sysrq && (stat & port->ignore_status_mask) == 0) tty_insert_flip_char(&port->state->port, val, flag); stat = owl_uart_read(port, OWL_UART_STAT); @@ -229,10 +232,9 @@ static void owl_uart_receive_chars(struct uart_port *port) static irqreturn_t owl_uart_irq(int irq, void *dev_id) { struct uart_port *port = dev_id; - unsigned long flags; u32 stat; - uart_port_lock_irqsave(port, &flags); + uart_port_lock(port); stat = owl_uart_read(port, OWL_UART_STAT); @@ -246,7 +248,7 @@ static irqreturn_t owl_uart_irq(int irq, void *dev_id) stat |= OWL_UART_STAT_RIP | OWL_UART_STAT_TIP; owl_uart_write(port, stat, OWL_UART_STAT); - uart_port_unlock_irqrestore(port, flags); + uart_unlock_and_check_sysrq(port); return IRQ_HANDLED; } @@ -508,18 +510,12 @@ static void owl_uart_port_write(struct uart_port *port, const char *s, { u32 old_ctl, val; unsigned long flags; - int locked; + int locked = 1; - local_irq_save(flags); - - if (port->sysrq) - locked = 0; - else if (oops_in_progress) - locked = uart_port_trylock(port); - else { - uart_port_lock(port); - locked = 1; - } + if (oops_in_progress) + locked = uart_port_trylock_irqsave(port, &flags); + else + uart_port_lock_irqsave(port, &flags); old_ctl = owl_uart_read(port, OWL_UART_CTL); val = old_ctl | OWL_UART_CTL_TRFS_TX; @@ -541,9 +537,7 @@ static void owl_uart_port_write(struct uart_port *port, const char *s, owl_uart_write(port, old_ctl, OWL_UART_CTL); if (locked) - uart_port_unlock(port); - - local_irq_restore(flags); + uart_port_unlock_irqrestore(port, flags); } static void owl_uart_console_write(struct console *co, const char *s,