gpu: nvgpu: Use perf table only if VBIOS supports it

We retrieve perf table from VBIOS only if respective HAL op is
implemented. Later in code we unconditionally dereference a pointer
which can lead to NULL pointer access.

Fix two new cases by early aborting creation of devinit tables if the
perf VBIOS getter is missing.

Bug 200192125

Change-Id: I30f20f1829305ecc1117c6301e26ff1b869967eb
Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/1280347
GVS: Gerrit_Virtual_Submit

1 files changed, 12 insertions, 9 deletions

diff --git a/drivers/gpu/nvgpu/perf/vfe_var.c b/drivers/gpu/nvgpu/perf/vfe_var.c
index f43e68e2..65ede64a 100644
--- a/drivers/gpu/nvgpu/perf/vfe_var.c
+++ b/drivers/gpu/nvgpu/perf/vfe_var.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2016-2017, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -868,14 +868,17 @@ static u32 devinit_get_vfe_var_table(struct gk20a *g,
 
         gk20a_dbg_info("");
 
-        if (g->ops.bios.get_perf_table_ptrs) {
-                vfevars_tbl_ptr = (u8 *)g->ops.bios.get_perf_table_ptrs(g,
-                                g->bios.perf_token,
-                                CONTINUOUS_VIRTUAL_BINNING_TABLE);
-                if (vfevars_tbl_ptr == NULL) {
-                        status = -EINVAL;
-                        goto done;
-                }
+        if (!g->ops.bios.get_perf_table_ptrs) {
+                status = -EINVAL;
+                goto done;
+        }
+
+        vfevars_tbl_ptr = (u8 *)g->ops.bios.get_perf_table_ptrs(g,
+                        g->bios.perf_token,
+                        CONTINUOUS_VIRTUAL_BINNING_TABLE);
+        if (vfevars_tbl_ptr == NULL) {
+                status = -EINVAL;
+                goto done;
         }
 
         memcpy(&vfevars_tbl_header, vfevars_tbl_ptr,