[PATCH] drm/amd/powerplay: fix null pointer dereference around dpm state relates

[Deucher, Alexander]

Reviewed-by: Alex Deucher <alexander.deucher at amd.com>
________________________________
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> on behalf of Evan Quan <evan.quan at amd.com>
Sent: Thursday, July 25, 2019 12:23 AM
To: amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>
Cc: Quan, Evan <Evan.Quan at amd.com>
Subject: [PATCH] drm/amd/powerplay: fix null pointer dereference around dpm state relates

DPM state relates are not supported on the new SW SMU ASICs. But still
it's not OK to trigger null pointer dereference on accessing them.

Change-Id: I368d108fbea438ed5d9e3b849d006ddd5308052b
Signed-off-by: Evan Quan <evan.quan at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c     | 18 +++++++++++++-----
 drivers/gpu/drm/amd/powerplay/amdgpu_smu.c |  3 ++-
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
index 304626b21a8c..61312b02b5c7 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
@@ -209,12 +209,16 @@ static ssize_t amdgpu_get_dpm_state(struct device *dev,
         struct amdgpu_device *adev = ddev->dev_private;
         enum amd_pm_state_type pm;

-       if (is_support_sw_smu(adev) && adev->smu.ppt_funcs->get_current_power_state)
-               pm = amdgpu_smu_get_current_power_state(adev);
-       else if (adev->powerplay.pp_funcs->get_current_power_state)
+       if (is_support_sw_smu(adev)) {
+               if (adev->smu.ppt_funcs->get_current_power_state)
+                       pm = amdgpu_smu_get_current_power_state(adev);
+               else
+                       pm = adev->pm.dpm.user_state;
+       } else if (adev->powerplay.pp_funcs->get_current_power_state) {
                 pm = amdgpu_dpm_get_current_power_state(adev);
-       else
+       } else {
                 pm = adev->pm.dpm.user_state;
+       }

         return snprintf(buf, PAGE_SIZE, "%s\n",
                         (pm == POWER_STATE_TYPE_BATTERY) ? "battery" :
@@ -241,7 +245,11 @@ static ssize_t amdgpu_set_dpm_state(struct device *dev,
                 goto fail;
         }

-       if (adev->powerplay.pp_funcs->dispatch_tasks) {
+       if (is_support_sw_smu(adev)) {
+               mutex_lock(&adev->pm.mutex);
+               adev->pm.dpm.user_state = state;
+               mutex_unlock(&adev->pm.mutex);
+       } else if (adev->powerplay.pp_funcs->dispatch_tasks) {
                 amdgpu_dpm_dispatch_task(adev, AMD_PP_TASK_ENABLE_USER_STATE, &state);
         } else {
                 mutex_lock(&adev->pm.mutex);
diff --git a/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c b/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c
index a5079b93caa3..3ecd67e6e65c 100644
--- a/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c
+++ b/drivers/gpu/drm/amd/powerplay/amdgpu_smu.c
@@ -304,7 +304,8 @@ int smu_get_power_num_states(struct smu_context *smu,

         /* not support power state */
         memset(state_info, 0, sizeof(struct pp_states_info));
-       state_info->nums = 0;
+       state_info->nums = 1;
+       state_info->states[0] = POWER_STATE_TYPE_DEFAULT;

         return 0;
 }
--
2.22.0

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