From: Clemens Ladisch <clemens@ladisch.de>
Date: Sun, 30 Oct 2005 23:03:29 +0000 (-0800)
Subject: [PATCH] hpet: disallow zero interrupt frequency
X-Git-Tag: v3.12-rc1~40274^2~72^2~28
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=9090e6db87e3bdb2a2c187ebc0f9175a9f9e5c6f;p=kernel%2Fkernel-generic.git

[PATCH] hpet: disallow zero interrupt frequency

Disallow setting an interrupt frequency of zero (which would result in a
division by zero), and disallow enabling the interrupt when the frequency
hasn't yet been set (which would use an interrupt period of zero).

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index c055bb6..b619ca5 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -364,6 +364,9 @@ static int hpet_ioctl_ieon(struct hpet_dev *devp)
 	hpet = devp->hd_hpet;
 	hpetp = devp->hd_hpets;
 
+	if (!devp->hd_ireqfreq)
+		return -EIO;
+
 	v = readq(&timer->hpet_config);
 	spin_lock_irq(&hpet_lock);
 
@@ -516,7 +519,7 @@ hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
 			break;
 		}
 
-		if (arg & (arg - 1)) {
+		if (!arg || (arg & (arg - 1))) {
 			err = -EINVAL;
 			break;
 		}