From: Peter Hurley <peter@hurleysoftware.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>,
linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
Peter Hurley <peter@hurleysoftware.com>
Subject: [PATCH 7/7] serial: 8250: Prevent concurrent updates to shadow registers
Date: Thu, 22 Jan 2015 12:24:31 -0500 [thread overview]
Message-ID: <1421947471-6396-8-git-send-email-peter@hurleysoftware.com> (raw)
In-Reply-To: <1421947471-6396-1-git-send-email-peter@hurleysoftware.com>
The port shadow registers, ->fcr and ->mcr, must be protected from
concurrent updates. Relocate the shadow register updates in
serial8250_do_set_termios() to the port lock critical section.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
---
drivers/tty/serial/8250/8250_core.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 8fd4b57..ed15341 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -2526,6 +2526,15 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
port->uartclk / 16);
quot = serial8250_get_divisor(up, baud, &frac);
+ /*
+ * Ok, we're now changing the port state. Do it with
+ * interrupts disabled.
+ */
+ serial8250_rpm_get(up);
+ spin_lock_irqsave(&port->lock, flags);
+
+ up->lcr = cval; /* Save computed LCR */
+
if (up->capabilities & UART_CAP_FIFO && port->fifosize > 1) {
/* NOTE: If fifo_bug is not set, a user can set RX_trigger. */
if ((baud < 2400 && !up->dma) || up->fifo_bug) {
@@ -2549,15 +2558,6 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
}
/*
- * Ok, we're now changing the port state. Do it with
- * interrupts disabled.
- */
- serial8250_rpm_get(up);
- spin_lock_irqsave(&port->lock, flags);
-
- up->lcr = cval; /* Save computed LCR */
-
- /*
* Update the per-port timeout.
*/
uart_update_timeout(port, termios->c_cflag, baud);
--
2.2.2
prev parent reply other threads:[~2015-01-22 17:24 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-22 17:24 [PATCH 0/7] serial: 8250: restart console after suspend Peter Hurley
2015-01-22 17:24 ` [PATCH 1/7] serial: core: Simplify console suspend logic in uart_suspend_port() Peter Hurley
2015-01-22 17:24 ` [PATCH 2/7] serial: 8250: Move UART_BUG_QUOT workaround Peter Hurley
2015-01-22 17:24 ` [PATCH 3/7] serial: 8250: Refactor LCR computation Peter Hurley
2015-01-22 17:24 ` [PATCH 4/7] serial: 8250: Refactor divisor programming Peter Hurley
2015-01-22 17:24 ` [PATCH 5/7] serial: 8250: Refactor XR17V35X divisor calculation Peter Hurley
2015-01-22 17:46 ` Peter Hurley
2015-01-22 17:24 ` [PATCH 6/7] serial: 8250: Use canary to restart console after suspend Peter Hurley
2015-01-22 17:24 ` Peter Hurley [this message]
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