From patchwork Fri Mar 1 21:45:18 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 13579167 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 2A3AA57873; Fri, 1 Mar 2024 21:52:54 +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=fkky0ttq57w3oJDRlganBj2UrtzlIzd1eS3dJWeh4aRD8kPfKjTP6ZvAM4hTL0m9LWIacZf0EVEEypwVBRBfJrAiOXLfcVimqwUBOINhHE5rdph+c5TJLIcDaOOvsKTVLWL8pDHZBCn7l2LJeMutDjI7qUXJzKNt8IfWhn4vSV4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709329977; c=relaxed/simple; bh=ZSHo7yW56q/OlHOuR8ZSf19ghp6NekGXo4YcajF/HdA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fqMsUW3/K5+3re97vCiS/ETufMD3bq2cMpqqKg2wAc1pbnwS+/pOrjQApdNLNxxpUj5Sp9KYVeFv7pdo7gnR3nmME15ZDs0zE4aYD6pDa3ZNYw8Ayh09tPT3lfhgxWooTbdTl6T8JUF0qqjU73OXsn3TfUNhd1sPfQSzR2U/vdY= 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=hPVorvr4; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=/KYP3h6W; 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="hPVorvr4"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="/KYP3h6W" From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1709329971; 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=XmPH4B4axTpKo5FxjSK3NcariRNbGHfCM6HFELDE+lQ=; b=hPVorvr4HEx95TVYMIAgH+mUMaPHgAkQKpg/1R+JW9QNsO6/wzm/AaCImUQAhvuv1GSowQ x4qCesKySc7anz3pLghuyOr5uePiwGPQOS4HuMO0+XrVDsUHnWBWHIvBzMehjHTvVut95B 4JeGs5GZWq1BDTjx57BgEetqBGJIpJvmLpeyPUHC1uLa+JvmodKSVl5QyUgvm+bzgOsy/8 TaAryy8aCFxeiiG3jcRJ+DJXGuuFDn47XXW466vBH3zj7E/GTO9psU3VehjYE7f0hbZ6f/ E0266TCHeosRsZUPRsunaI0Nw6DXVpDKnXIQustsXLyZSZ8ZOArEfxiQ/IdlBg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1709329971; 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=XmPH4B4axTpKo5FxjSK3NcariRNbGHfCM6HFELDE+lQ=; b=/KYP3h6W869OPAT3O4R56gPNrKlXFktxAb3iKcn1GjGPj1waQH6kBcx/CIFWeKlTQWB06/ X9pH9Nj4rJbfmNBw== To: linux-serial@vger.kernel.org Cc: Greg Kroah-Hartman , Jiri Slaby , Thomas Gleixner , Sebastian Andrzej Siewior , Bjorn Andersson , Konrad Dybcio , linux-arm-msm@vger.kernel.org Subject: [PATCH 05/18] serial: msm: Use uart_prepare_sysrq_char(). Date: Fri, 1 Mar 2024 22:45:18 +0100 Message-ID: <20240301215246.891055-6-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-arm-msm@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. Delay handling sysrq until port lock is dropped. Remove the special case in the console write routine an always use the complete locking function. Cc: Bjorn Andersson Cc: Konrad Dybcio Cc: linux-arm-msm@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/msm_serial.c | 33 ++++++++++----------------------- 1 file changed, 10 insertions(+), 23 deletions(-) diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c index e24204ad35def..d27c4c8c84e13 100644 --- a/drivers/tty/serial/msm_serial.c +++ b/drivers/tty/serial/msm_serial.c @@ -588,16 +588,14 @@ static void msm_complete_rx_dma(void *args) if (!(port->read_status_mask & MSM_UART_SR_RX_BREAK)) flag = TTY_NORMAL; - uart_port_unlock_irqrestore(port, flags); - sysrq = uart_handle_sysrq_char(port, dma->virt[i]); - uart_port_lock_irqsave(port, &flags); + sysrq = uart_prepare_sysrq_char(port, dma->virt[i]); if (!sysrq) tty_insert_flip_char(tport, dma->virt[i], flag); } msm_start_rx_dma(msm_port); done: - uart_port_unlock_irqrestore(port, flags); + uart_unlock_and_check_sysrq_irqrestore(port, flags); if (count) tty_flip_buffer_push(tport); @@ -763,9 +761,7 @@ static void msm_handle_rx_dm(struct uart_port *port, unsigned int misr) if (!(port->read_status_mask & MSM_UART_SR_RX_BREAK)) flag = TTY_NORMAL; - uart_port_unlock(port); - sysrq = uart_handle_sysrq_char(port, buf[i]); - uart_port_lock(port); + sysrq = uart_prepare_sysrq_char(port, buf[i]); if (!sysrq) tty_insert_flip_char(tport, buf[i], flag); } @@ -825,9 +821,7 @@ static void msm_handle_rx(struct uart_port *port) else if (sr & MSM_UART_SR_PAR_FRAME_ERR) flag = TTY_FRAME; - uart_port_unlock(port); - sysrq = uart_handle_sysrq_char(port, c); - uart_port_lock(port); + sysrq = uart_prepare_sysrq_char(port, c); if (!sysrq) tty_insert_flip_char(tport, c, flag); } @@ -948,11 +942,10 @@ static irqreturn_t msm_uart_irq(int irq, void *dev_id) struct uart_port *port = dev_id; struct msm_port *msm_port = to_msm_port(port); struct msm_dma *dma = &msm_port->rx_dma; - unsigned long flags; unsigned int misr; u32 val; - uart_port_lock_irqsave(port, &flags); + uart_port_lock(port); misr = msm_read(port, MSM_UART_MISR); msm_write(port, 0, MSM_UART_IMR); /* disable interrupt */ @@ -984,7 +977,7 @@ static irqreturn_t msm_uart_irq(int irq, void *dev_id) msm_handle_delta_cts(port); msm_write(port, msm_port->imr, MSM_UART_IMR); /* restore interrupt */ - uart_port_unlock_irqrestore(port, flags); + uart_unlock_and_check_sysrq(port); return IRQ_HANDLED; } @@ -1621,14 +1614,10 @@ static void __msm_console_write(struct uart_port *port, const char *s, num_newlines++; count += num_newlines; - local_irq_save(flags); - - if (port->sysrq) - locked = 0; - else if (oops_in_progress) - locked = uart_port_trylock(port); + if (oops_in_progress) + locked = uart_port_trylock_irqsave(port, &flags); else - uart_port_lock(port); + uart_port_lock_irqsave(port, &flags); if (is_uartdm) msm_reset_dm_count(port, count); @@ -1667,9 +1656,7 @@ static void __msm_console_write(struct uart_port *port, const char *s, } if (locked) - uart_port_unlock(port); - - local_irq_restore(flags); + uart_port_unlock_irqrestore(port, flags); } static void msm_console_write(struct console *co, const char *s,