pan/mdg: Add 16 bytes of padding to the end of shaders

Fixes INSTR_INVALID_PC faults when a shader ends on a 16MB boundary.

Cc: mesa-stable
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11551>

src/panfrost/midgard/midgard_compile.c

@@ -3238,6 +3238,12 @@ midgard_compile_shader_nir(nir_shader *nir,
                 fflush(stdout);
         }
 
+        /* A shader ending on a 16MB boundary causes INSTR_INVALID_PC faults,
+         * workaround by adding some padding to the end of the shader. (The
+         * kernel makes sure shader BOs can't cross 16MB boundaries.) */
+        if (binary->size)
+                memset(util_dynarray_grow(binary, uint8_t, 16), 0, 16);
+
         if ((midgard_debug & MIDGARD_DBG_SHADERDB || inputs->shaderdb) &&
             !nir->info.internal) {
                 unsigned nr_bundles = 0, nr_ins = 0;