linux-kernel - [PATCH 4.14 086/228] drm/arm: fix unintentional integer overflow on left shift

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Message-Id: <20200820091611.914793815@linuxfoundation.org>
Date:   Thu, 20 Aug 2020 11:21:01 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Colin Ian King <colin.king@...onical.com>,
        Liviu Dudau <liviu.dudau@....com>,
        Liviu Dudau <Liviu.Dudau@....com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.14 086/228] drm/arm: fix unintentional integer overflow on left shift

From: Colin Ian King <colin.king@...onical.com>

[ Upstream commit 5f368ddea6fec519bdb93b5368f6a844b6ea27a6 ]

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@...onical.com>
Acked-by: Liviu Dudau <liviu.dudau@....com>
Signed-off-by: Liviu Dudau <Liviu.Dudau@....com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200618100400.11464-1-colin.king@canonical.com
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/arm/malidp_planes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/arm/malidp_planes.c b/drivers/gpu/drm/arm/malidp_planes.c
index 16b8b310ae5c7..7072d738b072b 100644
--- a/drivers/gpu/drm/arm/malidp_planes.c
+++ b/drivers/gpu/drm/arm/malidp_planes.c
@@ -369,7 +369,7 @@ int malidp_de_planes_init(struct drm_device *drm)
 	const struct malidp_hw_regmap *map = &malidp->dev->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;
 	u32 *formats;
-- 
2.25.1