gpu: nvgpu: fix zbc MISRA 10.1 violations

The gr_gk20a_add_zbc() routine returns a signed error
(errno) status value.

Current callers of this function use a bitwise OR to collect
the returned error status values to generate a single value
to return.

Bitwise OR on signed status values is flagged as a
violation of MISRA Rule 10.1 (not to mention that in this
case it potentially results in a garbage return value).

To eliminate such violations this change modifies the
following routines to fail immediately on the first error
from a call to gr_gk20a_add_zbc():

 * gr_gk20a_load_zbc_default_table()
 * gr_gv11b_load_stencil_default_tbl()

JIRA NVGPU-650

Change-Id: If733c1bb0e05943ff5d0355de729133c89233583
Signed-off-by: Scott Long <scottl@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1805501
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 31 insertions, 19 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gr_gk20a.c b/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
index d4c461af..dbf9ff05 100644
--- a/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
@@ -3985,7 +3985,8 @@ static int gr_gk20a_load_zbc_table(struct gk20a *g, struct gr_gk20a *gr)
 int gr_gk20a_load_zbc_default_table(struct gk20a *g, struct gr_gk20a *gr)
 {
         struct zbc_entry zbc_val;
-        u32 i, err;
+        u32 i;
+        int err;
 
         nvgpu_mutex_init(&gr->zbc_lock);
 
@@ -4001,6 +4002,9 @@ int gr_gk20a_load_zbc_default_table(struct gk20a *g, struct gr_gk20a *gr)
         zbc_val.color_l2[0] = 0xff000000;
         zbc_val.color_ds[3] = 0x3f800000;
         err = gr_gk20a_add_zbc(g, gr, &zbc_val);
+        if (err != 0) {
+                goto color_fail;
+        }
 
         /* Transparent black = (fmt 1 = zero) */
         zbc_val.format = gr_ds_zbc_color_fmt_val_zero_v();
@@ -4008,7 +4012,10 @@ int gr_gk20a_load_zbc_default_table(struct gk20a *g, struct gr_gk20a *gr)
                 zbc_val.color_ds[i] = 0;
                 zbc_val.color_l2[i] = 0;
         }
-        err |= gr_gk20a_add_zbc(g, gr, &zbc_val);
+        err = gr_gk20a_add_zbc(g, gr, &zbc_val);
+        if (err != 0) {
+                goto color_fail;
+        }
 
         /* Opaque white (i.e. solid white) = (fmt 2 = uniform 1) */
         zbc_val.format = gr_ds_zbc_color_fmt_val_unorm_one_v();
@@ -4016,42 +4023,47 @@ int gr_gk20a_load_zbc_default_table(struct gk20a *g, struct gr_gk20a *gr)
                 zbc_val.color_ds[i] = 0x3f800000;
                 zbc_val.color_l2[i] = 0xffffffff;
         }
-        err |= gr_gk20a_add_zbc(g, gr, &zbc_val);
-
-        if (!err)
-                gr->max_default_color_index = 3;
-        else {
-                nvgpu_err(g,
-                           "fail to load default zbc color table");
-                return err;
+        err = gr_gk20a_add_zbc(g, gr, &zbc_val);
+        if (err != 0) {
+                goto color_fail;
         }
 
+        gr->max_default_color_index = 3;
+
         /* load default depth table */
         zbc_val.type = GK20A_ZBC_TYPE_DEPTH;
 
         zbc_val.format = gr_ds_zbc_z_fmt_val_fp32_v();
         zbc_val.depth = 0x3f800000;
         err = gr_gk20a_add_zbc(g, gr, &zbc_val);
+        if (err != 0) {
+                goto depth_fail;
+        }
 
         zbc_val.format = gr_ds_zbc_z_fmt_val_fp32_v();
         zbc_val.depth = 0;
-        err |= gr_gk20a_add_zbc(g, gr, &zbc_val);
-
-        if (!err)
-                gr->max_default_depth_index = 2;
-        else {
-                nvgpu_err(g,
-                           "fail to load default zbc depth table");
-                return err;
+        err = gr_gk20a_add_zbc(g, gr, &zbc_val);
+        if (err != 0) {
+                goto depth_fail;
         }
 
+        gr->max_default_depth_index = 2;
+
         if (g->ops.gr.load_zbc_s_default_tbl) {
                 err = g->ops.gr.load_zbc_s_default_tbl(g, gr);
-                if (err)
+                if (err != 0) {
                         return err;
+                }
         }
 
         return 0;
+
+color_fail:
+        nvgpu_err(g, "fail to load default zbc color table");
+        return err;
+depth_fail:
+        nvgpu_err(g, "fail to load default zbc depth table");
+        return err;
 }
 
 int _gk20a_gr_zbc_set_table(struct gk20a *g, struct gr_gk20a *gr,