Commit 5edc8c68 authored by Ahmad Fatoum's avatar Ahmad Fatoum Committed by Wim Van Sebroeck
Browse files

watchdog: f71808e_wdt: do stricter parameter validation 



We check the f71862fg_pin module parameter every time a watchdog device
for the f71862fg is opened, but the parameter can't change at runtime.

If we move the check to the start of init:

  - We catch userspace passing invalid, but unused, values
  - We check the condition only once
  - We simplify the code

Do so.

Signed-off-by: default avatarAhmad Fatoum <a.fatoum@pengutronix.de>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200611191750.28096-6-a.fatoum@pengutronix.de


Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarWim Van Sebroeck <wim@linux-watchdog.org>
parent 4f39d575

drivers/watchdog/f71808e_wdt.c

+12 −25
Original line number Diff line number Diff line
@@ -306,27 +306,6 @@ static int watchdog_keepalive(void) 
	return err;

}



static int f71862fg_pin_configure(unsigned short ioaddr)

{

	/* When ioaddr is non-zero the calling function has to take care of

	   mutex handling and superio preparation! */



	if (f71862fg_pin == 63) {

		if (ioaddr) {

			/* SPI must be disabled first to use this pin! */

			superio_clear_bit(ioaddr, SIO_REG_ROM_ADDR_SEL, 6);

			superio_set_bit(ioaddr, SIO_REG_MFUNCT3, 4);

		}

	} else if (f71862fg_pin == 56) {

		if (ioaddr)

			superio_set_bit(ioaddr, SIO_REG_MFUNCT1, 1);

	} else {

		pr_err("Invalid argument f71862fg_pin=%d\n", f71862fg_pin);

		return -EINVAL;

	}

	return 0;

}



static int watchdog_start(void)

{

	int err;
@@ -352,9 +331,13 @@ static int watchdog_start(void) 
		break;



	case f71862fg:

		err = f71862fg_pin_configure(watchdog.sioaddr);

		if (err)

			goto exit_superio;

		if (f71862fg_pin == 63) {

			/* SPI must be disabled first to use this pin! */

			superio_clear_bit(watchdog.sioaddr, SIO_REG_ROM_ADDR_SEL, 6);

			superio_set_bit(watchdog.sioaddr, SIO_REG_MFUNCT3, 4);

		} else if (f71862fg_pin == 56) {

			superio_set_bit(watchdog.sioaddr, SIO_REG_MFUNCT1, 1);

		}

		break;



	case f71868:
@@ -810,7 +793,6 @@ static int __init f71808e_find(int sioaddr) 
		break;

	case SIO_F71862_ID:

		watchdog.type = f71862fg;

		err = f71862fg_pin_configure(0); /* validate module parameter */

		break;

	case SIO_F71868_ID:

		watchdog.type = f71868;
@@ -859,6 +841,11 @@ static int __init f71808e_init(void) 
	int err = -ENODEV;

	int i;



	if (f71862fg_pin != 63 && f71862fg_pin != 56) {

		pr_err("Invalid argument f71862fg_pin=%d\n", f71862fg_pin);

		return -EINVAL;

	}



	for (i = 0; i < ARRAY_SIZE(addrs); i++) {

		err = f71808e_find(addrs[i]);

		if (err == 0)