pipeline: add check against loops

Detect when a jump instruction, either conditional or unconditional,
is jumping to itself, thus creating a loop, which is not allowed in
data plane code.

Signed-off-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>
Signed-off-by: Harshad Narayane <harshad.suresh.narayane@intel.com>

diff --git a/lib/pipeline/rte_swx_pipeline.c b/lib/pipeline/rte_swx_pipeline.c
index c332d44bd13b1e2a337e9da189b6f54349d5ad28..1a50c4bb7248a33d3f28eb29bca49e5ea2dacb6f 100644 (file)
--- a/lib/pipeline/rte_swx_pipeline.c
+++ b/lib/pipeline/rte_swx_pipeline.c
@@ -6000,6 +6000,19 @@ instr_label_check(struct instruction_data *instruction_data,
                        CHECK(strcmp(label, instruction_data[j].label), EINVAL);
        }
 
+       /* Check that no jump instruction (either conditional or not) can jump to itself (loop). */
+       for (i = 0; i < n_instructions; i++) {
+               struct instruction_data *data = &instruction_data[i];
+               char *label = data->label;
+               char *jmp_label = data->jmp_label;
+
+               /* Continue if this instruction does not have a label or it is not a jump. */
+               if (!label[0] || !jmp_label[0])
+                       continue;
+
+               CHECK(strcmp(label, jmp_label), EINVAL);
+       }
+
        /* Get users for each instruction label. */
        for (i = 0; i < n_instructions; i++) {
                struct instruction_data *data = &instruction_data[i];