nfp: bpf: add map deletes from the datapath

Support calling map_delete_elem() FW helper from the datapath
programs.  For JIT checks and code are basically equivalent
to map lookups.  Similarly to other map helper key must be on
the stack.  Different pointer types are left for future extension.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

drivers/net/ethernet/netronome/nfp/bpf/jit.c

@@ -2329,6 +2329,7 @@ static int call(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
 		return adjust_head(nfp_prog, meta);
 	case BPF_FUNC_map_lookup_elem:
 	case BPF_FUNC_map_update_elem:
+	case BPF_FUNC_map_delete_elem:
 		return map_call_stack_common(nfp_prog, meta);
 	default:
 		WARN_ONCE(1, "verifier allowed unsupported function\n");
@@ -3216,6 +3217,9 @@ void *nfp_bpf_relo_for_vnic(struct nfp_prog *nfp_prog, struct nfp_bpf_vnic *bv)
 			case BPF_FUNC_map_update_elem:
 				val = nfp_prog->bpf->helpers.map_update;
 				break;
+			case BPF_FUNC_map_delete_elem:
+				val = nfp_prog->bpf->helpers.map_delete;
+				break;
 			default:
 				pr_err("relocation of unknown helper %d\n",
 				       val);

drivers/net/ethernet/netronome/nfp/bpf/main.c

@@ -287,6 +287,9 @@ nfp_bpf_parse_cap_func(struct nfp_app_bpf *bpf, void __iomem *value, u32 length)
 	case BPF_FUNC_map_update_elem:
 		bpf->helpers.map_update = readl(&cap->func_addr);
 		break;
+	case BPF_FUNC_map_delete_elem:
+		bpf->helpers.map_delete = readl(&cap->func_addr);
+		break;
 	}
 
 	return 0;

drivers/net/ethernet/netronome/nfp/bpf/main.h

@@ -129,6 +129,7 @@ enum pkt_vec {
  * @helpers:		helper addressess for various calls
  * @helpers.map_lookup:		map lookup helper address
  * @helpers.map_update:		map update helper address
+ * @helpers.map_delete:		map delete helper address
  */
 struct nfp_app_bpf {
 	struct nfp_app *app;
@@ -164,6 +165,7 @@ struct nfp_app_bpf {
 	struct {
 		u32 map_lookup;
 		u32 map_update;
+		u32 map_delete;
 	} helpers;
 };
 

drivers/net/ethernet/netronome/nfp/bpf/verifier.c

@@ -201,6 +201,14 @@ nfp_bpf_check_call(struct nfp_prog *nfp_prog, struct bpf_verifier_env *env,
 		    !nfp_bpf_stack_arg_ok("map_update", env, reg3, NULL))
 			return -EOPNOTSUPP;
 		break;
+
+	case BPF_FUNC_map_delete_elem:
+		if (!nfp_bpf_map_call_ok("map_delete", env, meta,
+					 bpf->helpers.map_delete, reg1) ||
+		    !nfp_bpf_stack_arg_ok("map_delete", env, reg2,
+					  meta->func_id ? &meta->arg2 : NULL))
+			return -EOPNOTSUPP;
+		break;
 	default:
 		pr_vlog(env, "unsupported function id: %d\n", func_id);
 		return -EOPNOTSUPP;