drm/arm: fix unintentional integer overflow on left shift

Shifting the integer value 1 is evaluated using 32-bit arithmetic
and then used in an expression that expects a long value leads to
a potential integer overflow. Fix this by using the BIT macro to
perform the shift to avoid the overflow.

Addresses-Coverity: ("Unintentional integer overflow")
Fixes: ad49f8602fe8 ("drm/arm: Add support for Mali Display Processors")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200618100400.11464-1-colin.king@canonical.com

diff --git a/drivers/gpu/drm/arm/malidp_planes.c b/drivers/gpu/drm/arm/malidp_planes.c
index 37715cc..ab45ac4 100644 (file)
--- a/drivers/gpu/drm/arm/malidp_planes.c
+++ b/drivers/gpu/drm/arm/malidp_planes.c
@@ -928,7 +928,7 @@ int malidp_de_planes_init(struct drm_device *drm)
        const struct malidp_hw_regmap *map = &malidp->dev->hw->map;
        struct malidp_plane *plane = NULL;
        enum drm_plane_type plane_type;
-       unsigned long crtcs = 1 << drm->mode_config.num_crtc;
+       unsigned long crtcs = BIT(drm->mode_config.num_crtc);
        unsigned long flags = DRM_MODE_ROTATE_0 | DRM_MODE_ROTATE_90 | DRM_MODE_ROTATE_180 |
                              DRM_MODE_ROTATE_270 | DRM_MODE_REFLECT_X | DRM_MODE_REFLECT_Y;
        unsigned int blend_caps = BIT(DRM_MODE_BLEND_PIXEL_NONE) |