From 1d5503331b12a76266049289747dfd94f1643fde Mon Sep 17 00:00:00 2001
From: Colin Ian King <colin.king@canonical.com>
Date: Tue, 18 Aug 2020 13:09:14 +0100
Subject: [PATCH] drm/amd/display: fix potential integer overflow when shifting 32 bit variable bl_pwm
Git-commit: 1d5503331b12a76266049289747dfd94f1643fde
Patch-mainline: v5.10-rc1
References: git-fixes
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 <colin.king@canonical.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpu/drm/amd/display/dc/dce/dce_panel_cntl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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 a6d73d30837c..df7f826eebd8 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
@@ -76,7 +76,7 @@ static unsigned int dce_get_16_bit_backlight_from_pwm(struct panel_cntl *panel_c
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;
--
2.26.2