From fe89def79c48e2149abdd1e816523e69a9067191 Mon Sep 17 00:00:00 2001 From: Darren Hart Date: Tue, 19 Jun 2012 14:00:18 -0700 Subject: pch_uart: Add eg20t_port lock field, avoid recursive spinlocks pch_uart_interrupt() takes priv->port.lock which leads to two recursive spinlock calls if low_latency==1 or CONFIG_PREEMPT_RT_FULL=y (one otherwise): pch_uart_interrupt spin_lock_irqsave(priv->port.lock, flags) case PCH_UART_IID_RDR_TO (data ready) handle_rx_to push_rx tty_port_tty_get spin_lock_irqsave(&port->lock, flags) <--- already hold this lock ... tty_flip_buffer_push ... flush_to_ldisc spin_lock_irqsave(&tty->buf.lock) spin_lock_irqsave(&tty->buf.lock) disc->ops->receive_buf(tty, char_buf) n_tty_receive_buf tty->ops->flush_chars() uart_flush_chars uart_start spin_lock_irqsave(&port->lock) <--- already hold this lock Avoid this by using a dedicated lock to protect the eg20t_port structure and IO access to its membase. This is more consistent with the 8250 driver. Ensure priv->lock is always take prior to priv->port.lock when taken at the same time. V2: Remove inadvertent whitespace change. V3: Account for oops_in_progress for the private lock in pch_console_write(). Note: Like the 8250 driver, if a printk is introduced anywhere inside the pch_console_write() critical section, the kernel will hang on a recursive spinlock on the private lock. The oops case is handled by using a trylock in the oops_in_progress case. Signed-off-by: Darren Hart CC: Tomoya MORINAGA CC: Feng Tang CC: Alexander Stein Acked-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/pch_uart.c | 38 ++++++++++++++++++++++++++------------ 1 file changed, 26 insertions(+), 12 deletions(-) (limited to 'drivers/tty/serial/pch_uart.c') diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c index 4fdec6a6b758..d291518a58a4 100644 --- a/drivers/tty/serial/pch_uart.c +++ b/drivers/tty/serial/pch_uart.c @@ -253,6 +253,9 @@ struct eg20t_port { dma_addr_t rx_buf_dma; struct dentry *debugfs; + + /* protect the eg20t_port private structure and io access to membase */ + spinlock_t lock; }; /** @@ -1058,7 +1061,7 @@ static irqreturn_t pch_uart_interrupt(int irq, void *dev_id) int next = 1; u8 msr; - spin_lock_irqsave(&priv->port.lock, flags); + spin_lock_irqsave(&priv->lock, flags); handled = 0; while (next) { iid = pch_uart_hal_get_iid(priv); @@ -1116,7 +1119,7 @@ static irqreturn_t pch_uart_interrupt(int irq, void *dev_id) handled |= (unsigned int)ret; } - spin_unlock_irqrestore(&priv->port.lock, flags); + spin_unlock_irqrestore(&priv->lock, flags); return IRQ_RETVAL(handled); } @@ -1226,9 +1229,9 @@ static void pch_uart_break_ctl(struct uart_port *port, int ctl) unsigned long flags; priv = container_of(port, struct eg20t_port, port); - spin_lock_irqsave(&port->lock, flags); + spin_lock_irqsave(&priv->lock, flags); pch_uart_hal_set_break(priv, ctl); - spin_unlock_irqrestore(&port->lock, flags); + spin_unlock_irqrestore(&priv->lock, flags); } /* Grab any interrupt resources and initialise any low level driver state. */ @@ -1376,7 +1379,8 @@ static void pch_uart_set_termios(struct uart_port *port, baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16); - spin_lock_irqsave(&port->lock, flags); + spin_lock_irqsave(&priv->lock, flags); + spin_lock(&port->lock); uart_update_timeout(port, termios->c_cflag, baud); rtn = pch_uart_hal_set_line(priv, baud, parity, bits, stb); @@ -1389,7 +1393,8 @@ static void pch_uart_set_termios(struct uart_port *port, tty_termios_encode_baud_rate(termios, baud, baud); out: - spin_unlock_irqrestore(&port->lock, flags); + spin_unlock(&port->lock); + spin_unlock_irqrestore(&priv->lock, flags); } static const char *pch_uart_type(struct uart_port *port) @@ -1538,8 +1543,9 @@ pch_console_write(struct console *co, const char *s, unsigned int count) { struct eg20t_port *priv; unsigned long flags; + int priv_locked = 1; + int port_locked = 1; u8 ier; - int locked = 1; priv = pch_uart_ports[co->index]; @@ -1547,12 +1553,16 @@ pch_console_write(struct console *co, const char *s, unsigned int count) local_irq_save(flags); if (priv->port.sysrq) { - /* serial8250_handle_port() already took the lock */ - locked = 0; + spin_lock(&priv->lock); + /* serial8250_handle_port() already took the port lock */ + port_locked = 0; } else if (oops_in_progress) { - locked = spin_trylock(&priv->port.lock); - } else + priv_locked = spin_trylock(&priv->lock); + port_locked = spin_trylock(&priv->port.lock); + } else { + spin_lock(&priv->lock); spin_lock(&priv->port.lock); + } /* * First save the IER then disable the interrupts @@ -1570,8 +1580,10 @@ pch_console_write(struct console *co, const char *s, unsigned int count) wait_for_xmitr(priv, BOTH_EMPTY); iowrite8(ier, priv->membase + UART_IER); - if (locked) + if (port_locked) spin_unlock(&priv->port.lock); + if (priv_locked) + spin_unlock(&priv->lock); local_irq_restore(flags); } @@ -1669,6 +1681,8 @@ static struct eg20t_port *pch_uart_init_port(struct pci_dev *pdev, pci_enable_msi(pdev); pci_set_master(pdev); + spin_lock_init(&priv->lock); + iobase = pci_resource_start(pdev, 0); mapbase = pci_resource_start(pdev, 1); priv->mapbase = mapbase; -- cgit v1.2.3 From 669bd45f117cc8c7309acd6b6bb054fe4d9e46c0 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Mon, 2 Jul 2012 18:51:38 +0100 Subject: pch_uart: Fix missing break for 16 byte fifo Otherwise we fall back to the wrong value. Reported-by: Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=44091 Signed-off-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/pch_uart.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/tty/serial/pch_uart.c') diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c index d291518a58a4..c5bc23d6ade9 100644 --- a/drivers/tty/serial/pch_uart.c +++ b/drivers/tty/serial/pch_uart.c @@ -1266,6 +1266,7 @@ static int pch_uart_startup(struct uart_port *port) break; case 16: fifo_size = PCH_UART_HAL_FIFO16; + break; case 1: default: fifo_size = PCH_UART_HAL_FIFO_DIS; -- cgit v1.2.3 From ae213f30358e5bf68a05badf059bb4d9115755f5 Mon Sep 17 00:00:00 2001 From: Tomoya MORINAGA Date: Fri, 6 Jul 2012 17:19:42 +0900 Subject: pch_uart: Fix rx error interrupt setting issue Rx Error interrupt(E.G. parity error) is not enabled. So, when parity error occurs, error interrupt is not occurred. As a result, the received data is not dropped. This patch adds enable/disable rx error interrupt code. Signed-off-by: Tomoya MORINAGA Acked-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/pch_uart.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) (limited to 'drivers/tty/serial/pch_uart.c') diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c index c5bc23d6ade9..2cc9b4694625 100644 --- a/drivers/tty/serial/pch_uart.c +++ b/drivers/tty/serial/pch_uart.c @@ -757,7 +757,8 @@ static void pch_dma_rx_complete(void *arg) tty_flip_buffer_push(tty); tty_kref_put(tty); async_tx_ack(priv->desc_rx); - pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_RX_INT); + pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_RX_INT | + PCH_UART_HAL_RX_ERR_INT); } static void pch_dma_tx_complete(void *arg) @@ -812,7 +813,8 @@ static int handle_rx_to(struct eg20t_port *priv) int rx_size; int ret; if (!priv->start_rx) { - pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_RX_INT); + pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_RX_INT | + PCH_UART_HAL_RX_ERR_INT); return 0; } buf = &priv->rxbuf; @@ -1081,11 +1083,13 @@ static irqreturn_t pch_uart_interrupt(int irq, void *dev_id) case PCH_UART_IID_RDR: /* Received Data Ready */ if (priv->use_dma) { pch_uart_hal_disable_interrupt(priv, - PCH_UART_HAL_RX_INT); + PCH_UART_HAL_RX_INT | + PCH_UART_HAL_RX_ERR_INT); ret = dma_handle_rx(priv); if (!ret) pch_uart_hal_enable_interrupt(priv, - PCH_UART_HAL_RX_INT); + PCH_UART_HAL_RX_INT | + PCH_UART_HAL_RX_ERR_INT); } else { ret = handle_rx(priv); } @@ -1211,7 +1215,8 @@ static void pch_uart_stop_rx(struct uart_port *port) struct eg20t_port *priv; priv = container_of(port, struct eg20t_port, port); priv->start_rx = 0; - pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_RX_INT); + pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_RX_INT | + PCH_UART_HAL_RX_ERR_INT); } /* Enable the modem status interrupts. */ @@ -1304,7 +1309,8 @@ static int pch_uart_startup(struct uart_port *port) pch_request_dma(port); priv->start_rx = 1; - pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_RX_INT); + pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_RX_INT | + PCH_UART_HAL_RX_ERR_INT); uart_update_timeout(port, CS8, default_baud); return 0; -- cgit v1.2.3 From 2fc39aebf682bed97a78d278f6adf6c395700d19 Mon Sep 17 00:00:00 2001 From: Tomoya MORINAGA Date: Fri, 6 Jul 2012 17:19:43 +0900 Subject: pch_uart: Fix parity setting issue Parity Setting value is reverse. E.G. In case of setting ODD parity, EVEN value is set. This patch inverts "if" condition. Signed-off-by: Tomoya MORINAGA Acked-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/pch_uart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/tty/serial/pch_uart.c') diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c index 2cc9b4694625..558ce8509a9a 100644 --- a/drivers/tty/serial/pch_uart.c +++ b/drivers/tty/serial/pch_uart.c @@ -1368,7 +1368,7 @@ static void pch_uart_set_termios(struct uart_port *port, stb = PCH_UART_HAL_STB1; if (termios->c_cflag & PARENB) { - if (!(termios->c_cflag & PARODD)) + if (termios->c_cflag & PARODD) parity = PCH_UART_HAL_PARITY_ODD; else parity = PCH_UART_HAL_PARITY_EVEN; -- cgit v1.2.3 From a92098a1cb7ec08c86d1b97d1831d8edaf26b1a2 Mon Sep 17 00:00:00 2001 From: Fengguang Wu Date: Sat, 28 Jul 2012 20:43:57 +0800 Subject: pch_uart: check kzalloc result in dma_handle_tx() Reported by coccinelle: drivers/tty/serial/pch_uart.c:979:1-14: alloc with no test, possible model on line 994 Signed-off-by: Fengguang Wu Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/pch_uart.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'drivers/tty/serial/pch_uart.c') diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c index 558ce8509a9a..4cd6c2381528 100644 --- a/drivers/tty/serial/pch_uart.c +++ b/drivers/tty/serial/pch_uart.c @@ -979,6 +979,10 @@ static unsigned int dma_handle_tx(struct eg20t_port *priv) priv->tx_dma_use = 1; priv->sg_tx_p = kzalloc(sizeof(struct scatterlist)*num, GFP_ATOMIC); + if (!priv->sg_tx_p) { + dev_err(priv->port.dev, "%s:kzalloc Failed\n", __func__); + return 0; + } sg_init_table(priv->sg_tx_p, num); /* Initialize SG table */ sg = priv->sg_tx_p; -- cgit v1.2.3