nfp: bpf: prepare for call support

Add skeleton of verifier checks and translation handler
for call instructions.  Make sure jump target resolution
will not treat them as jumps.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/jit.c b/drivers/net/ethernet/netronome/nfp/bpf/jit.c
index 3419ad4..7afdc6d 100644 (file)
--- a/drivers/net/ethernet/netronome/nfp/bpf/jit.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/jit.c
@@ -1930,6 +1930,15 @@ static int jne_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
        return wrp_test_reg(nfp_prog, meta, ALU_OP_XOR, BR_BNE);
 }
 
+static int call(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
+{
+       switch (meta->insn.imm) {
+       default:
+               WARN_ONCE(1, "verifier allowed unsupported function\n");
+               return -EOPNOTSUPP;
+       }
+}
+
 static int goto_out(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
 {
        wrp_br_special(nfp_prog, BR_UNC, OP_BR_GO_OUT);
@@ -2002,6 +2011,7 @@ static const instr_cb_t instr_cb[256] = {
        [BPF_JMP | BPF_JLE | BPF_X] =   jle_reg,
        [BPF_JMP | BPF_JSET | BPF_X] =  jset_reg,
        [BPF_JMP | BPF_JNE | BPF_X] =   jne_reg,
+       [BPF_JMP | BPF_CALL] =          call,
        [BPF_JMP | BPF_EXIT] =          goto_out,
 };
 
@@ -2026,6 +2036,8 @@ static int nfp_fixup_branches(struct nfp_prog *nfp_prog)
        list_for_each_entry(meta, &nfp_prog->insns, l) {
                if (meta->skip)
                        continue;
+               if (meta->insn.code == (BPF_JMP | BPF_CALL))
+                       continue;
                if (BPF_CLASS(meta->insn.code) != BPF_JMP)
                        continue;
 

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
index d2bf29c..3b940b6 100644 (file)
--- a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
@@ -69,6 +69,20 @@ nfp_bpf_goto_meta(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
 }
 
 static int
+nfp_bpf_check_call(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
+{
+       u32 func_id = meta->insn.imm;
+
+       switch (func_id) {
+       default:
+               pr_warn("unsupported function id: %d\n", func_id);
+               return -EOPNOTSUPP;
+       }
+
+       return 0;
+}
+
+static int
 nfp_bpf_check_exit(struct nfp_prog *nfp_prog,
                   struct bpf_verifier_env *env)
 {
@@ -177,6 +191,8 @@ nfp_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn_idx)
                return -EINVAL;
        }
 
+       if (meta->insn.code == (BPF_JMP | BPF_CALL))
+               return nfp_bpf_check_call(nfp_prog, meta);
        if (meta->insn.code == (BPF_JMP | BPF_EXIT))
                return nfp_bpf_check_exit(nfp_prog, env);