[09/70] drm/radeon/kms: add bounds checking to avivo pll algo

[Greg KH]

2.6.37-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Alex Deucher <alexdeucher@xxxxxxxxx>

commit a4b40d5d97f5c9ad0b7f4bf2818291ca184bb433 upstream.

Prevent divider overflow.
Fixes:
https://bugzilla.kernel.org/show_bug.cgi?id=28932

Signed-off-by: Alex Deucher <alexdeucher@xxxxxxxxx>
Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/gpu/drm/radeon/radeon_display.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -461,6 +461,11 @@ static void avivo_get_fb_div(struct rade
 	tmp *= target_clock;
 	*fb_div = tmp / pll->reference_freq;
 	*frac_fb_div = tmp % pll->reference_freq;
+
+        if (*fb_div > pll->max_feedback_div)
+		*fb_div = pll->max_feedback_div;
+        else if (*fb_div < pll->min_feedback_div)
+                *fb_div = pll->min_feedback_div;
 }
 
 static u32 avivo_get_post_div(struct radeon_pll *pll,
@@ -494,6 +499,11 @@ static u32 avivo_get_post_div(struct rad
 			post_div--;
 	}
 
+	if (post_div > pll->max_post_div)
+		post_div = pll->max_post_div;
+	else if (post_div < pll->min_post_div)
+		post_div = pll->min_post_div;
+
 	return post_div;
 }
 


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