[PATCH][next] drm/amd/powerplay: fix various dereferences of a pointer before it is null checked

From: Colin King
Date: Thu Dec 12 2019 - 13:17:09 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

There are several occurrances of the pointer hwmgr being dereferenced
before it is null checked. Fix these by performing the dereference
of hwmgr after it has been null checked.

Addresses-Coverity: ("Dereference before null check")
Fixes: 8497d2bcdee1 ("drm/amd/powerplay: enable pp one vf mode for vega10")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
drivers/gpu/drm/amd/powerplay/amd_powerplay.c | 6 +++---
drivers/gpu/drm/amd/powerplay/hwmgr/hwmgr.c | 15 +++------------
2 files changed, 6 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/amd/powerplay/amd_powerplay.c b/drivers/gpu/drm/amd/powerplay/amd_powerplay.c
index 5087d6bdba60..322c2015d3a0 100644
--- a/drivers/gpu/drm/amd/powerplay/amd_powerplay.c
+++ b/drivers/gpu/drm/amd/powerplay/amd_powerplay.c
@@ -275,12 +275,12 @@ static int pp_dpm_load_fw(void *handle)
{
struct pp_hwmgr *hwmgr = handle;

- if (!hwmgr->not_vf)
- return 0;
-
if (!hwmgr || !hwmgr->smumgr_funcs || !hwmgr->smumgr_funcs->start_smu)
return -EINVAL;

+ if (!hwmgr->not_vf)
+ return 0;
+
if (hwmgr->smumgr_funcs->start_smu(hwmgr)) {
pr_err("fw load failed\n");
return -EINVAL;
diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/hwmgr.c
index e2b82c902948..f48fdc7f0382 100644
--- a/drivers/gpu/drm/amd/powerplay/hwmgr/hwmgr.c
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/hwmgr.c
@@ -282,10 +282,7 @@ int hwmgr_hw_init(struct pp_hwmgr *hwmgr)

int hwmgr_hw_fini(struct pp_hwmgr *hwmgr)
{
- if (!hwmgr->not_vf)
- return 0;
-
- if (!hwmgr || !hwmgr->pm_en)
+ if (!hwmgr || !hwmgr->pm_en || !hwmgr->not_vf)
return 0;

phm_stop_thermal_controller(hwmgr);
@@ -305,10 +302,7 @@ int hwmgr_suspend(struct pp_hwmgr *hwmgr)
{
int ret = 0;

- if (!hwmgr->not_vf)
- return 0;
-
- if (!hwmgr || !hwmgr->pm_en)
+ if (!hwmgr || !hwmgr->pm_en || !hwmgr->not_vf)
return 0;

phm_disable_smc_firmware_ctf(hwmgr);
@@ -327,13 +321,10 @@ int hwmgr_resume(struct pp_hwmgr *hwmgr)
{
int ret = 0;

- if (!hwmgr->not_vf)
- return 0;
-
if (!hwmgr)
return -EINVAL;

- if (!hwmgr->pm_en)
+ if (!hwmgr->not_vf || !hwmgr->pm_en)
return 0;

ret = phm_setup_asic(hwmgr);
--
2.24.0