CHROMIUM: drm: rockchip/dw_hdmi-rockchip: Protect against > 2GHz pixel clocks

Add a check just to make sure that someone doesn't try to give us a
pixel clock that is > 2GHz.  If they did that, some of our math might
overflow, so it's good to make sure we don't do it.

Change-Id: I451602f0d771bb16b399b43e376e1054b7ee060f
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Yakir Yang <ykk@rock-chips.com>
Reviewed-on: https://chromium-review.googlesource.com/284642
Reviewed-by: Alexandru Stan <amstan@chromium.org>

diff --git a/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c b/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
index 23a610e4b31ecf2d4a5498e1128d153e65c15b58..1e500e76e60836dc4df473f820bae25fc313f077 100644 (file)
--- a/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
@@ -243,6 +243,14 @@ dw_hdmi_rockchip_mode_valid(struct drm_connector *connector,
        int num_rates = ARRAY_SIZE(dw_hdmi_rates);
        int i;
 
+       /*
+        * Pixel clocks we support are always < 2GHz and so fit in an
+        * int.  We should make sure source rate does too so we don't get
+        * overflow when we multiply by 1000.
+        */
+       if (mode->clock > INT_MAX / 1000)
+               return MODE_BAD;
+
        for (i = 0; i < num_rates; i++) {
                int slop = CLK_SLOP(pclk);