From: Colin Ian King Date: Tue, 18 Aug 2020 12:09:14 +0000 (+0100) Subject: drm/amd/display: fix potential integer overflow when shifting 32 bit variable bl_pwm X-Git-Tag: v5.8.17~462 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8135d168d84cf6f9d244b001e59db0149c1b9d94;p=thirdparty%2Fkernel%2Fstable.git drm/amd/display: fix potential integer overflow when shifting 32 bit variable bl_pwm [ Upstream commit 1d5503331b12a76266049289747dfd94f1643fde ] The 32 bit unsigned integer bl_pwm is being shifted using 32 bit arithmetic and then being assigned to a 64 bit unsigned integer. There is a potential for a 32 bit overflow so cast bl_pwm to enforce a 64 bit shift operation to avoid this. Addresses-Coverity: ("unintentional integer overflow") Fixes: 3ba01817365c ("drm/amd/display: Move panel_cntl specific register from abm to panel_cntl.") Signed-off-by: Colin Ian King Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_panel_cntl.c b/drivers/gpu/drm/amd/display/dc/dce/dce_panel_cntl.c index ebff9b1e312e5..124c081a0f2ca 100644 --- a/drivers/gpu/drm/amd/display/dc/dce/dce_panel_cntl.c +++ b/drivers/gpu/drm/amd/display/dc/dce/dce_panel_cntl.c @@ -75,7 +75,7 @@ static unsigned int calculate_16_bit_backlight_from_pwm(struct dce_panel_cntl *d else bl_pwm &= 0xFFFF; - current_backlight = bl_pwm << (1 + bl_int_count); + current_backlight = (uint64_t)bl_pwm << (1 + bl_int_count); if (bl_period == 0) bl_period = 0xFFFF;