intel/gen_decoder: return -1 for unknown command formats

Decoding with aubinator encountered a command of 0xffffffff. With the
previous code, it caused aubinator to jump 255 + 2 dwords to start
decoding again.

Instead we can attempt to detect the known instruction formats. If the
format is not recognized, then we can advance just 1 dword.

v2:
 * Update aubinator_error_decode
 * Actually convert the length variable returned into a *signed* integer
   in aubinator.c, intel_batchbuffer.c and aubinator_error_decode.c.

Signed-off-by: Jordan Justen <[email protected]>
Acked-by: Lionel Landwerlin <[email protected]>

1 files changed, 15 insertions, 7 deletions

diff --git a/src/intel/common/gen_decoder.c b/src/intel/common/gen_decoder.c
index 1244f4c4480..03c9c7f8d46 100644
--- a/src/intel/common/gen_decoder.c
+++ b/src/intel/common/gen_decoder.c
@@ -692,28 +692,36 @@ gen_group_get_length(struct gen_group *group, const uint32_t *p)
 
    case 3: /* Render */ {
       uint32_t subtype = field(h, 27, 28);
+      uint32_t opcode = field(h, 24, 26);
       switch (subtype) {
       case 0:
-         return field(h, 0, 7) + 2;
+         if (opcode < 2)
+            return field(h, 0, 7) + 2;
+         else
+            return -1;
       case 1:
-         return 1;
+         if (opcode < 2)
+            return 1;
+         else
+            return -1;
       case 2: {
-         uint32_t opcode = field(h, 24, 26);
-         assert(opcode < 3 /* 3 and above currently reserved */);
          if (opcode == 0)
             return field(h, 0, 7) + 2;
          else if (opcode < 3)
             return field(h, 0, 15) + 2;
          else
-            return 1; /* FIXME: if more opcodes are added */
+            return -1;
       }
       case 3:
-         return field(h, 0, 7) + 2;
+         if (opcode < 4)
+            return field(h, 0, 7) + 2;
+         else
+            return -1;
       }
    }
    }
 
-   unreachable("bad opcode");
+   return -1;
 }
 
 void