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authorGeert Uytterhoeven <geert+renesas@glider.be>2021-07-14 11:48:06 +0200
committerSam Ravnborg <sam@ravnborg.org>2021-07-25 14:15:18 +0200
commit47956bc86ee4e8530cac386a04f62a6095f7afbe (patch)
tree1c3f48e19ecfd084870e7515f4deba2a8f9ed397
parentdt-bindings: display: simple: add some Logic Technologies and Multi-Inno panels (diff)
downloadlinux-dev-47956bc86ee4e8530cac386a04f62a6095f7afbe.tar.xz
linux-dev-47956bc86ee4e8530cac386a04f62a6095f7afbe.zip
drm/bridge: nwl-dsi: Avoid potential multiplication overflow on 32-bit
As nwl_dsi.lanes is u32, and NSEC_PER_SEC is 1000000000L, the second multiplication in dsi->lanes * 8 * NSEC_PER_SEC will overflow on a 32-bit platform. Fix this by making the constant unsigned long long, forcing 64-bit arithmetic. As iMX8 is arm64, this driver is currently used on 64-bit platforms only, where long is 64-bit, so this cannot happen. But the issue will start to happen when the driver is reused for a 32-bit SoC (e.g. i.MX7ULP), or when code is copied for a new driver. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Fabio Estevam <festevam@gmail.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/ebb82941a86b4e35c4fcfb1ef5a5cfad7c1fceab.1626255956.git.geert+renesas@glider.be
-rw-r--r--drivers/gpu/drm/bridge/nwl-dsi.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c
index d7986067eefe..ed8ac5059cd2 100644
--- a/drivers/gpu/drm/bridge/nwl-dsi.c
+++ b/drivers/gpu/drm/bridge/nwl-dsi.c
@@ -190,7 +190,7 @@ static u32 ps2bc(struct nwl_dsi *dsi, unsigned long long ps)
u32 bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
return DIV64_U64_ROUND_UP(ps * dsi->mode.clock * bpp,
- dsi->lanes * 8 * NSEC_PER_SEC);
+ dsi->lanes * 8ULL * NSEC_PER_SEC);
}
/*