linux-kernel - [PATCH 3/8] serial: 8250: save rs485

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 16 Nov 2011 17:24:40 +0100
From:	Wolfram Sang <w.sang@...gutronix.de>
To:	linux-serial@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, Alan Cox <alan@...ux.intel.com>,
	Claudio Scordino <claudio@...dence.eu.com>,
	Juergen Beisert <jbe@...gutronix.de>,
	Matthias Fuchs <mfuchs@...fu.de>,
	Wolfram Sang <w.sang@...gutronix.de>
Subject: [PATCH 3/8] serial: 8250: save rs485_flags per instance

This avoids mangling with registers when reading the RS485 status via IOCTL.
Also, features can check their configuration at runtime which will be needed
for a later patch.

Signed-off-by: Wolfram Sang <w.sang@...gutronix.de>
---
 drivers/tty/serial/8250.c |   16 +++++-----------
 1 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/drivers/tty/serial/8250.c b/drivers/tty/serial/8250.c
index 920b4df..b5d3248 100644
--- a/drivers/tty/serial/8250.c
+++ b/drivers/tty/serial/8250.c
@@ -154,6 +154,7 @@ struct uart_8250_port {
 	unsigned char		lsr_saved_flags;
 #define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA
 	unsigned char		msr_saved_flags;
+	__u32			rs485_flags;	/* copied from IOCTL */
 };
 
 struct irq_info {
@@ -2729,28 +2730,21 @@ static int serial8250_ioctl_port(struct uart_port *port,
 		serial_outp(up, UART_FCTR, fctr);
 		serial_outp(up, UART_LCR, lcr);
 		spin_unlock_irqrestore(&up->port.lock, flags);
+
+		up->rs485_flags = rs485ctrl.flags;
+
 		return 0;
 	}
 
 	case TIOCGRS485:
 	{
 		struct serial_rs485 rs485ctrl;
-		unsigned char lcr;
 
 		if (port->type != PORT_16850)
 			return -ENOTTY;
 
 		memset(&rs485ctrl, 0, sizeof(rs485ctrl));
-
-		spin_lock_irqsave(&up->port.lock, flags);
-		lcr = serial_inp(up, UART_LCR);
-		serial_outp(up, UART_LCR, UART_LCR_CONF_MODE_B);
-		if (serial_inp(up, UART_FCTR) & UART_FCTR_RS485)
-			rs485ctrl.flags = SER_RS485_ENABLED;
-		else
-			rs485ctrl.flags = 0;
-		serial_outp(up, UART_LCR, lcr);
-		spin_unlock_irqrestore(&up->port.lock, flags);
+		rs485ctrl.flags = up->rs485_flags;
 
 		if (copy_to_user((struct serial_rs485 *)arg, &rs485ctrl,
 				 sizeof(rs485ctrl)))
-- 
1.7.7.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/