From patchwork Fri Mar 1 21:45:24 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: 777622 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 912FE58ADB 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=aum0c3dbwOBJ1mAQnOFdRhj9/Y28pBRUDuTRpZnqnKFsiHzCyb84PZPrmrZdZ435rywHp84UIYEay2MidYzOfTwcIftciJP99MIHAq3O2by++lTafC0hXKM+byyvxtTtTRRvmbe2yAEKBsdRy+Q20ISbKip0XEBJj8y9i0HWdHM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709329977; c=relaxed/simple; bh=VMH61/tHRAbj2Ekc0mQyrj2xuDBqI7ViaojJrJByZW8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Y9Q+ZNCas9x8plw6OedHJOnZAQfaRF4qznYkXESohucvqxaq7ejrTGiqo+LEI7uPaxEdowc8JA40CLXjNYFEERmY5nIm8qIf07zAMxdlWwlIjHUbIWv/GqhMTuMCcFYY26evmylYa8Zrbo9lY8/kdBrhgZJICeLwMyLwH8VoXoM= 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=DYeW/M1O; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=VXU5xXqD; 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="DYeW/M1O"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="VXU5xXqD" 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tledTIFDDr1sldln/W0Iqtq8p3bbY99HUvZ3jjp5lks=; b=DYeW/M1ORa4YklCaqL330/U85u/jJ+vZdIf5XzcCr1ZY8J/qa4tkUvBtBUyrosws1Hp3ox fGCNR3vwyXJH7mvvWemhuptLbwbDMIpZNfXelPUl85mEdRWx1JZ6P/9Wws6Fk/Hfg0cbMw gfHmTsKbtOCui97hgqP+kSTDOdz40MB+Ygiql02qRl61ZregVOlBI3Uo5/Rl0d98bjlV9S i2AiEKCIeGaop0mWb1xOTnHdNeCXSPavl4SdFCES7EmT++cWQjoA8JyNAGaFt1p+GHwIXk FNCI8PqstTDTWvZEdrC4uIG6lrukcv50FKN4Ygl8Tez7tdf3V3VTZ5qT0bUZXQ== 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tledTIFDDr1sldln/W0Iqtq8p3bbY99HUvZ3jjp5lks=; b=VXU5xXqD7rHLIprKYFCb/dOHvMV74MKNJXd1UQwUXThVIFJHiP3eKZA1Gmxa9738uXpO2Y 8jYRQNUskQ+VH8CA== To: linux-serial@vger.kernel.org Cc: Greg Kroah-Hartman , Jiri Slaby , Thomas Gleixner , Sebastian Andrzej Siewior , Manivannan Sadhasivam , linux-arm-kernel@lists.infradead.org, linux-unisoc@lists.infradead.org Subject: [PATCH 11/18] serial: rda: Use uart_prepare_sysrq_char() to handle sysrq. Date: Fri, 1 Mar 2024 22:45:24 +0100 Message-ID: <20240301215246.891055-12-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: Manivannan Sadhasivam Cc: linux-arm-kernel@lists.infradead.org Cc: linux-unisoc@lists.infradead.org Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/rda-uart.c | 28 ++++++++++------------------ 1 file changed, 10 insertions(+), 18 deletions(-) diff --git a/drivers/tty/serial/rda-uart.c b/drivers/tty/serial/rda-uart.c index 13deb355cf1bc..82def9b8632a5 100644 --- a/drivers/tty/serial/rda-uart.c +++ b/drivers/tty/serial/rda-uart.c @@ -394,7 +394,8 @@ static void rda_uart_receive_chars(struct uart_port *port) val &= 0xff; port->icount.rx++; - tty_insert_flip_char(&port->state->port, val, flag); + if (!uart_prepare_sysrq_char(port, val)) + tty_insert_flip_char(&port->state->port, val, flag); status = rda_uart_read(port, RDA_UART_STATUS); } @@ -405,10 +406,9 @@ static void rda_uart_receive_chars(struct uart_port *port) static irqreturn_t rda_interrupt(int irq, void *dev_id) { struct uart_port *port = dev_id; - unsigned long flags; u32 val, irq_mask; - uart_port_lock_irqsave(port, &flags); + uart_port_lock(port); /* Clear IRQ cause */ val = rda_uart_read(port, RDA_UART_IRQ_CAUSE); @@ -425,7 +425,7 @@ static irqreturn_t rda_interrupt(int irq, void *dev_id) rda_uart_send_chars(port); } - uart_port_unlock_irqrestore(port, flags); + uart_unlock_and_check_sysrq(port); return IRQ_HANDLED; } @@ -590,18 +590,12 @@ static void rda_uart_port_write(struct uart_port *port, const char *s, { u32 old_irq_mask; 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_irq_mask = rda_uart_read(port, RDA_UART_IRQ_MASK); rda_uart_write(port, 0, RDA_UART_IRQ_MASK); @@ -615,9 +609,7 @@ static void rda_uart_port_write(struct uart_port *port, const char *s, rda_uart_write(port, old_irq_mask, RDA_UART_IRQ_MASK); if (locked) - uart_port_unlock(port); - - local_irq_restore(flags); + uart_port_unlock_irqrestore(port, flags); } static void rda_uart_console_write(struct console *co, const char *s,