meta-amd-bsp/recipes-kernel/linux/linux-yocto-4.19.8/2834-drm-amd-powerplay-Zero-initialize-current_rpm-in-veg.patch


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44

From d4067512364a0c2c4e58531b5ee200a8cff9df80 Mon Sep 17 00:00:00 2001
From: Nathan Chancellor <natechancellor@gmail.com>
Date: Wed, 3 Jul 2019 22:52:18 -0700
Subject: [PATCH 2834/2940] drm/amd/powerplay: Zero initialize current_rpm in
 vega20_get_fan_speed_percent

clang warns (trimmed for brevity):

drivers/gpu/drm/amd/amdgpu/../powerplay/vega20_ppt.c:3023:8: warning:
variable 'current_rpm' is used uninitialized whenever '?:' condition is
false [-Wsometimes-uninitialized]
        ret = smu_get_current_rpm(smu, &current_rpm);
              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

smu_get_current_rpm expands to a ternary operator conditional on
smu->funcs->get_current_rpm being not NULL. When this is false,
current_rpm will be uninitialized. Zero initialize current_rpm to
avoid using random stack values if that ever happens.

Fixes: ee0db82027ee ("drm/amd/powerplay: move PPTable_t uses into asic level")
Link: https://github.com/ClangBuiltLinux/linux/issues/588
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---
 drivers/gpu/drm/amd/powerplay/vega20_ppt.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/powerplay/vega20_ppt.c b/drivers/gpu/drm/amd/powerplay/vega20_ppt.c
index 9a535f79a545..b779d2b511cf 100644
--- a/drivers/gpu/drm/amd/powerplay/vega20_ppt.c
+++ b/drivers/gpu/drm/amd/powerplay/vega20_ppt.c
@@ -3016,8 +3016,7 @@ static int vega20_get_fan_speed_percent(struct smu_context *smu,
 					uint32_t *speed)
 {
 	int ret = 0;
-	uint32_t percent = 0;
-	uint32_t current_rpm;
+	uint32_t current_rpm = 0, percent = 0;
 	PPTable_t *pptable = smu->smu_table.driver_pptable;
 
 	ret = smu_get_current_rpm(smu, &current_rpm);
-- 
2.17.1