1 files changed, 53 insertions, 5 deletions

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
index a6e9248669e1..db7e186dae56 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
@@ -108,6 +108,46 @@ exit_set_location:
 	nfp_prog->adjust_head_location = location;
 }
 
+static bool nfp_bpf_map_update_value_ok(struct bpf_verifier_env *env)
+{
+	const struct bpf_reg_state *reg1 = cur_regs(env) + BPF_REG_1;
+	const struct bpf_reg_state *reg3 = cur_regs(env) + BPF_REG_3;
+	struct bpf_offloaded_map *offmap;
+	struct bpf_func_state *state;
+	struct nfp_bpf_map *nfp_map;
+	int off, i;
+
+	state = env->cur_state->frame[reg3->frameno];
+
+	/* We need to record each time update happens with non-zero words,
+	 * in case such word is used in atomic operations.
+	 * Implicitly depend on nfp_bpf_stack_arg_ok(reg3) being run before.
+	 */
+
+	offmap = map_to_offmap(reg1->map_ptr);
+	nfp_map = offmap->dev_priv;
+	off = reg3->off + reg3->var_off.value;
+
+	for (i = 0; i < offmap->map.value_size; i++) {
+		struct bpf_stack_state *stack_entry;
+		unsigned int soff;
+
+		soff = -(off + i) - 1;
+		stack_entry = &state->stack[soff / BPF_REG_SIZE];
+		if (stack_entry->slot_type[soff % BPF_REG_SIZE] == STACK_ZERO)
+			continue;
+
+		if (nfp_map->use_map[i / 4].type == NFP_MAP_USE_ATOMIC_CNT) {
+			pr_vlog(env, "value at offset %d/%d may be non-zero, bpf_map_update_elem() is required to initialize atomic counters to zero to avoid offload endian issues\n",
+				i, soff);
+			return false;
+		}
+		nfp_map->use_map[i / 4].non_zero_update = 1;
+	}
+
+	return true;
+}
+
 static int
 nfp_bpf_stack_arg_ok(const char *fname, struct bpf_verifier_env *env,
 		     const struct bpf_reg_state *reg,
@@ -198,7 +238,8 @@ nfp_bpf_check_call(struct nfp_prog *nfp_prog, struct bpf_verifier_env *env,
 					 bpf->helpers.map_update, reg1) ||
 		    !nfp_bpf_stack_arg_ok("map_update", env, reg2,
 					  meta->func_id ? &meta->arg2 : NULL) ||
-		    !nfp_bpf_stack_arg_ok("map_update", env, reg3, NULL))
+		    !nfp_bpf_stack_arg_ok("map_update", env, reg3, NULL) ||
+		    !nfp_bpf_map_update_value_ok(env))
 			return -EOPNOTSUPP;
 		break;
 
@@ -376,15 +417,22 @@ nfp_bpf_map_mark_used_one(struct bpf_verifier_env *env,
 			  struct nfp_bpf_map *nfp_map,
 			  unsigned int off, enum nfp_bpf_map_use use)
 {
-	if (nfp_map->use_map[off / 4] != NFP_MAP_UNUSED &&
-	    nfp_map->use_map[off / 4] != use) {
+	if (nfp_map->use_map[off / 4].type != NFP_MAP_UNUSED &&
+	    nfp_map->use_map[off / 4].type != use) {
 		pr_vlog(env, "map value use type conflict %s vs %s off: %u\n",
-			nfp_bpf_map_use_name(nfp_map->use_map[off / 4]),
+			nfp_bpf_map_use_name(nfp_map->use_map[off / 4].type),
 			nfp_bpf_map_use_name(use), off);
 		return -EOPNOTSUPP;
 	}
 
-	nfp_map->use_map[off / 4] = use;
+	if (nfp_map->use_map[off / 4].non_zero_update &&
+	    use == NFP_MAP_USE_ATOMIC_CNT) {
+		pr_vlog(env, "atomic counter in map value may already be initialized to non-zero value off: %u\n",
+			off);
+		return -EOPNOTSUPP;
+	}
+
+	nfp_map->use_map[off / 4].type = use;
 
 	return 0;
 }