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, 17 insertions, 10 deletions

diff --git a/drivers/gpu/nvgpu/gv11b/gr_gv11b.c b/drivers/gpu/nvgpu/gv11b/gr_gv11b.c
index 8b3253a1..296d8e90 100644
--- a/drivers/gpu/nvgpu/gv11b/gr_gv11b.c
+++ b/drivers/gpu/nvgpu/gv11b/gr_gv11b.c
@@ -1121,7 +1121,7 @@ int gr_gv11b_load_stencil_default_tbl(struct gk20a *g,
                  struct gr_gk20a *gr)
 {
         struct zbc_entry zbc_val;
-        u32 err;
+        int err;
 
         /* load default stencil table */
         zbc_val.type = GV11B_ZBC_TYPE_STENCIL;
@@ -1129,23 +1129,30 @@ int gr_gv11b_load_stencil_default_tbl(struct gk20a *g,
         zbc_val.depth = 0x0;
         zbc_val.format = ZBC_STENCIL_CLEAR_FMT_U8;
         err = gr_gk20a_add_zbc(g, gr, &zbc_val);
-
+        if (err != 0) {
+                goto fail;
+        }
         zbc_val.depth = 0x1;
         zbc_val.format = ZBC_STENCIL_CLEAR_FMT_U8;
-        err |= gr_gk20a_add_zbc(g, gr, &zbc_val);
+        err = gr_gk20a_add_zbc(g, gr, &zbc_val);
+        if (err != 0) {
+                goto fail;
+        }
 
         zbc_val.depth = 0xff;
         zbc_val.format = ZBC_STENCIL_CLEAR_FMT_U8;
-        err |= gr_gk20a_add_zbc(g, gr, &zbc_val);
-
-        if (!err) {
-                gr->max_default_s_index = 3;
-        } else {
-                nvgpu_err(g, "fail to load default zbc stencil table");
-                return err;
+        err = gr_gk20a_add_zbc(g, gr, &zbc_val);
+        if (err != 0) {
+                goto fail;
         }
 
+        gr->max_default_s_index = 3;
+
         return 0;
+
+fail:
+        nvgpu_err(g, "fail to load default zbc stencil table");
+        return err;
 }
 
 int gr_gv11b_load_stencil_tbl(struct gk20a *g, struct gr_gk20a *gr)