From: Takatoshi Akiyama <takatoshi.akiyama.kj@xxxxxxxxxxxxxxxxxxxxxxxx>
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.
Signed-off-by: Takatoshi Akiyama <takatoshi.akiyama.kj@xxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Takeshi Kihara <takeshi.kihara.df@xxxxxxxxxxx>
Signed-off-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>
---
This is a patch from the Gen3 3.3.2 BSP.
Geert, please consider it for mainline.
It appears that the lock is not taken in start_tx() as this is installed
as a callback. And all callers of the callback take the lock.
---
drivers/tty/serial/sh-sci.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 91e7dddbf72c..f4d705399d25 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1243,8 +1243,11 @@ 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)
@@ -1934,6 +1937,7 @@ 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) {
@@ -1944,6 +1948,7 @@ 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);
@@ -1957,6 +1962,7 @@ 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)
@@ -2168,6 +2174,7 @@ 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;
@@ -2277,6 +2284,8 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
serial_port_out(port, SCCKS, sccks);
}
+ spin_lock_irqsave(&port->lock, flags);
+
sci_reset(port);
uart_update_timeout(port, termios->c_cflag, baud);
@@ -2294,9 +2303,6 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
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);
serial_port_out(port, SCSMR, smr_val);
serial_port_out(port, SCBRR, brr);
@@ -2310,7 +2316,6 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
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);
serial_port_out(port, SCSMR, smr_val);
}
@@ -2342,7 +2347,6 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
}
scr_val |= s->cfg->scscr & ~(SCSCR_CKE1 | SCSCR_CKE0);
- dev_dbg(port->dev, "SCSCR 0x%x\n", scr_val);
serial_port_out(port, SCSCR, scr_val);
if ((srr + 1 == 5) &&
(port->type == PORT_SCIFA || port->type == PORT_SCIFB)) {
@@ -2391,8 +2395,6 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
bits++;
s->rx_timeout = DIV_ROUND_UP((s->buf_len_rx * 2 * bits * HZ) /
(baud / 10), 10);
- 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);
}
@@ -2401,6 +2403,8 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
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))
--
2.7.0.rc3.207.g0ac5344
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