drm/amd/pp: Fix potential NULL pointer dereference in atomctrl_initia…

…lize_mc_reg_table

The function atomctrl_initialize_mc_reg_table() and
atomctrl_initialize_mc_reg_table_v2_2() does not check the return
value of smu_atom_get_data_table(). If smu_atom_get_data_table()
fails to retrieve vram_info, it returns NULL which is later
dereferenced.

Fixes: b3892e2 ("drm/amd/pp: Use atombios api directly in powerplay (v2)")
Fixes: 5f92b48 ("drm/amd/pm: add mc register table initialization")
Signed-off-by: Charles Han <hanchunchao@inspur.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/powerplay/hwmgr/ppatomctrl.c

@@ -143,6 +143,10 @@ int atomctrl_initialize_mc_reg_table(
 	vram_info = (ATOM_VRAM_INFO_HEADER_V2_1 *)
 		smu_atom_get_data_table(hwmgr->adev,
 				GetIndexIntoMasterTable(DATA, VRAM_Info), &size, &frev, &crev);
+	if (!vram_info) {
+		pr_err("Could not retrieve the VramInfo table!");
+		return -EINVAL;
+	}
 
 	if (module_index >= vram_info->ucNumOfVRAMModule) {
 		pr_err("Invalid VramInfo table.");
@@ -180,6 +184,10 @@ int atomctrl_initialize_mc_reg_table_v2_2(
 	vram_info = (ATOM_VRAM_INFO_HEADER_V2_2 *)
 		smu_atom_get_data_table(hwmgr->adev,
 				GetIndexIntoMasterTable(DATA, VRAM_Info), &size, &frev, &crev);
+	if (!vram_info) {
+		pr_err("Could not retrieve the VramInfo table!");
+		return -EINVAL;
+	}
 
 	if (module_index >= vram_info->ucNumOfVRAMModule) {
 		pr_err("Invalid VramInfo table.");