From 1be2266392196de82d1cfcc8a68e770cf8f48c60 Mon Sep 17 00:00:00 2001 From: Takatoshi Akiyama Date: Thu, 2 Nov 2017 11:14:55 +0100 Subject: serial: sh-sci: Fix unlocked access to SCSCR register The SCSCR register access in sci_break_ctl() is not locked. sci_start_tx() and sci_set_termios() changes the SCSCR register, but does not lock sci_port. Therefore, this patch adds lock during register access. Also, remove the log output that leads to a double lock. Some analysis of where locks are not taken is as follows. It appears that the lock is not taken in: - sci_start_tx(), sci_stop_tx() as this is installed as a callback. And all callers of the callback take the lock. - start_rx as callers take the lock. - stop_rx. this is both installed as a callback and called directly. In both cases the caller takes the lock. Signed-off-by: Takatoshi Akiyama Signed-off-by: Takeshi Kihara Signed-off-by: Simon Horman Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/sh-sci.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index d5714de..d5e07dd 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1226,8 +1226,11 @@ static void sci_rx_dma_release(struct sci_port *s, bool enable_pio) dma_free_coherent(chan->device->dev, s->buf_len_rx * 2, s->rx_buf[0], sg_dma_address(&s->sg_rx[0])); dma_release_channel(chan); - if (enable_pio) + if (enable_pio) { + spin_lock_irqsave(&port->lock, flags); sci_start_rx(port); + spin_unlock_irqrestore(&port->lock, flags); + } } static void sci_dma_rx_complete(void *arg) @@ -1294,8 +1297,11 @@ static void sci_tx_dma_release(struct sci_port *s, bool enable_pio) dma_unmap_single(chan->device->dev, s->tx_dma_addr, UART_XMIT_SIZE, DMA_TO_DEVICE); dma_release_channel(chan); - if (enable_pio) + if (enable_pio) { + spin_lock_irqsave(&port->lock, flags); sci_start_tx(port); + spin_unlock_irqrestore(&port->lock, flags); + } } static void sci_submit_rx(struct sci_port *s) @@ -2004,6 +2010,7 @@ static void sci_enable_ms(struct uart_port *port) static void sci_break_ctl(struct uart_port *port, int break_state) { unsigned short scscr, scsptr; + unsigned long flags; /* check wheter the port has SCSPTR */ if (!sci_getreg(port, SCSPTR)->size) { @@ -2014,6 +2021,7 @@ static void sci_break_ctl(struct uart_port *port, int break_state) return; } + spin_lock_irqsave(&port->lock, flags); scsptr = serial_port_in(port, SCSPTR); scscr = serial_port_in(port, SCSCR); @@ -2027,6 +2035,7 @@ static void sci_break_ctl(struct uart_port *port, int break_state) serial_port_out(port, SCSPTR, scsptr); serial_port_out(port, SCSCR, scscr); + spin_unlock_irqrestore(&port->lock, flags); } static int sci_startup(struct uart_port *port) @@ -2255,6 +2264,7 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios, int min_err = INT_MAX, err; unsigned long max_freq = 0; int best_clk = -1; + unsigned long flags; if ((termios->c_cflag & CSIZE) == CS7) smr_val |= SCSMR_CHR; @@ -2364,6 +2374,8 @@ done: serial_port_out(port, SCCKS, sccks); } + spin_lock_irqsave(&port->lock, flags); + sci_reset(port); uart_update_timeout(port, termios->c_cflag, baud); @@ -2381,9 +2393,6 @@ done: case 27: smr_val |= SCSMR_SRC_27; break; } smr_val |= cks; - dev_dbg(port->dev, - "SCR 0x%x SMR 0x%x BRR %u CKS 0x%x DL %u SRR %u\n", - scr_val, smr_val, brr, sccks, dl, srr); serial_port_out(port, SCSCR, scr_val | s->hscif_tot); serial_port_out(port, SCSMR, smr_val); serial_port_out(port, SCBRR, brr); @@ -2397,7 +2406,6 @@ done: scr_val = s->cfg->scscr & (SCSCR_CKE1 | SCSCR_CKE0); smr_val |= serial_port_in(port, SCSMR) & (SCSMR_CKEDG | SCSMR_SRC_MASK | SCSMR_CKS); - dev_dbg(port->dev, "SCR 0x%x SMR 0x%x\n", scr_val, smr_val); serial_port_out(port, SCSCR, scr_val | s->hscif_tot); serial_port_out(port, SCSMR, smr_val); } @@ -2434,7 +2442,6 @@ done: scr_val |= SCSCR_RE | SCSCR_TE | (s->cfg->scscr & ~(SCSCR_CKE1 | SCSCR_CKE0)); - dev_dbg(port->dev, "SCSCR 0x%x\n", scr_val); serial_port_out(port, SCSCR, scr_val | s->hscif_tot); if ((srr + 1 == 5) && (port->type == PORT_SCIFA || port->type == PORT_SCIFB)) { @@ -2481,8 +2488,6 @@ done: s->rx_frame = (100 * bits * HZ) / (baud / 10); #ifdef CONFIG_SERIAL_SH_SCI_DMA s->rx_timeout = DIV_ROUND_UP(s->buf_len_rx * 2 * s->rx_frame, 1000); - dev_dbg(port->dev, "DMA Rx t-out %ums, tty t-out %u jiffies\n", - s->rx_timeout * 1000 / HZ, port->timeout); if (s->rx_timeout < msecs_to_jiffies(20)) s->rx_timeout = msecs_to_jiffies(20); #endif @@ -2490,6 +2495,8 @@ done: if ((termios->c_cflag & CREAD) != 0) sci_start_rx(port); + spin_unlock_irqrestore(&port->lock, flags); + sci_port_disable(s); if (UART_ENABLE_MS(port, termios->c_cflag)) -- cgit v1.1