drm/amd/pm: parse pp_handle under appropriate conditions

amdgpu_dpm_is_overdrive_supported is a common API across all
asics, so we should cast pp_handle into correct structure
under different power frameworks.

v2: using return directly to simplify code
v3: SI asic does not carry od_enabled member in pp_handle, and update Fixes tag

Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2541
Fixes: eb4900a ("drm/amdgpu: Fix kernel NULL pointer dereference in dpm functions")
Suggested-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Guchun Chen <guchun.chen@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

Author: Guchun Chen

drivers/gpu/drm/amd/pm/amdgpu_dpm.c

@@ -1460,15 +1460,21 @@ int amdgpu_dpm_get_smu_prv_buf_details(struct amdgpu_device *adev,
 
 int amdgpu_dpm_is_overdrive_supported(struct amdgpu_device *adev)
 {
-	struct pp_hwmgr *hwmgr = adev->powerplay.pp_handle;
-	struct smu_context *smu = adev->powerplay.pp_handle;
+	if (is_support_sw_smu(adev)) {
+		struct smu_context *smu = adev->powerplay.pp_handle;
+
+		return (smu->od_enabled || smu->is_apu);
+	} else {
+		struct pp_hwmgr *hwmgr;
 
-	if ((is_support_sw_smu(adev) && smu->od_enabled) ||
-	    (is_support_sw_smu(adev) && smu->is_apu) ||
-		(!is_support_sw_smu(adev) && hwmgr->od_enabled))
-		return true;
+		/* SI asic does not carry od_enabled */
+		if (adev->family == AMDGPU_FAMILY_SI)
+			return false;
 
-	return false;
+		hwmgr = (struct pp_hwmgr *)adev->powerplay.pp_handle;
+
+		return hwmgr->od_enabled;
+	}
 }
 
 int amdgpu_dpm_set_pp_table(struct amdgpu_device *adev,