bpf: Factor out atomic_ptr_type_ok()

Factor out atomic_ptr_type_ok() as a helper function to be used later.

Signed-off-by: Peilin Ye <yepeilin@google.com>
Link: https://lore.kernel.org/r/e5ef8b3116f3fffce78117a14060ddce05eba52a.1740978603.git.yepeilin@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index eb1624f6e743440ef8c65c73cf50dfa4df74f400..66b19fa4be48992c5052f7b2610608581b1a4af5 100644 (file)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -6195,6 +6195,26 @@ static bool is_arena_reg(struct bpf_verifier_env *env, int regno)
        return reg->type == PTR_TO_ARENA;
 }
 
+/* Return false if @regno contains a pointer whose type isn't supported for
+ * atomic instruction @insn.
+ */
+static bool atomic_ptr_type_ok(struct bpf_verifier_env *env, int regno,
+                              struct bpf_insn *insn)
+{
+       if (is_ctx_reg(env, regno))
+               return false;
+       if (is_pkt_reg(env, regno))
+               return false;
+       if (is_flow_key_reg(env, regno))
+               return false;
+       if (is_sk_reg(env, regno))
+               return false;
+       if (is_arena_reg(env, regno))
+               return bpf_jit_supports_insn(insn, true);
+
+       return true;
+}
+
 static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
 #ifdef CONFIG_NET
        [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
@@ -7652,11 +7672,7 @@ static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_i
                return -EACCES;
        }
 
-       if (is_ctx_reg(env, insn->dst_reg) ||
-           is_pkt_reg(env, insn->dst_reg) ||
-           is_flow_key_reg(env, insn->dst_reg) ||
-           is_sk_reg(env, insn->dst_reg) ||
-           (is_arena_reg(env, insn->dst_reg) && !bpf_jit_supports_insn(insn, true))) {
+       if (!atomic_ptr_type_ok(env, insn->dst_reg, insn)) {
                verbose(env, "BPF_ATOMIC stores into R%d %s is not allowed\n",
                        insn->dst_reg,
                        reg_type_str(env, reg_state(env, insn->dst_reg)->type));