nfp: bpf: support optimizing dead branches (a32014b3) · Commits · 戴 / test

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

+14 −0

Original line number	Diff line number	Diff line
		@@ -412,6 +412,17 @@ static inline bool is_mbpf_div(const struct nfp_insn_meta *meta)
		return is_mbpf_alu(meta) && mbpf_op(meta) == BPF_DIV;
		}

		static inline bool is_mbpf_cond_jump(const struct nfp_insn_meta *meta)
		{
		u8 op;

		if (BPF_CLASS(meta->insn.code) != BPF_JMP)
		return false;

		op = BPF_OP(meta->insn.code);
		return op != BPF_JA && op != BPF_EXIT && op != BPF_CALL;
		}

		static inline bool is_mbpf_helper_call(const struct nfp_insn_meta *meta)
		{
		struct bpf_insn insn = meta->insn;
		@@ -520,6 +531,9 @@ int nfp_verify_insn(struct bpf_verifier_env *env, int insn_idx,
		int prev_insn_idx);
		int nfp_bpf_finalize(struct bpf_verifier_env *env);

		int nfp_bpf_opt_replace_insn(struct bpf_verifier_env *env, u32 off,
		struct bpf_insn *insn);

		extern const struct bpf_prog_offload_ops nfp_bpf_dev_ops;

		struct netdev_bpf;

+1 −0

Original line number	Diff line number	Diff line
		@@ -592,6 +592,7 @@ int nfp_net_bpf_offload(struct nfp_net nn, struct bpf_prog prog,
		const struct bpf_prog_offload_ops nfp_bpf_dev_ops = {
		.insn_hook = nfp_verify_insn,
		.finalize = nfp_bpf_finalize,
		.replace_insn = nfp_bpf_opt_replace_insn,
		.prepare = nfp_bpf_verifier_prep,
		.translate = nfp_bpf_translate,
		.destroy = nfp_bpf_destroy,

+34 −0

Original line number	Diff line number	Diff line
		@@ -786,3 +786,37 @@ int nfp_bpf_finalize(struct bpf_verifier_env *env)

		return 0;
		}

		int nfp_bpf_opt_replace_insn(struct bpf_verifier_env *env, u32 off,
		struct bpf_insn *insn)
		{
		struct nfp_prog *nfp_prog = env->prog->aux->offload->dev_priv;
		struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
		struct nfp_insn_meta *meta = nfp_prog->verifier_meta;

		meta = nfp_bpf_goto_meta(nfp_prog, meta, aux_data[off].orig_idx);
		nfp_prog->verifier_meta = meta;

		/* conditional jump to jump conversion */
		if (is_mbpf_cond_jump(meta) &&
		insn->code == (BPF_JMP \| BPF_JA \| BPF_K)) {
		unsigned int tgt_off;

		tgt_off = off + insn->off + 1;

		if (!insn->off) {
		meta->jmp_dst = list_next_entry(meta, l);
		meta->jump_neg_op = false;
		} else if (meta->jmp_dst->n != aux_data[tgt_off].orig_idx) {
		pr_vlog(env, "branch hard wire at %d changes target %d -> %d\n",
		off, meta->jmp_dst->n,
		aux_data[tgt_off].orig_idx);
		return -EINVAL;
		}
		return 0;
		}

		pr_vlog(env, "unsupported instruction replacement %hhx -> %hhx\n",
		meta->insn.code, insn->code);
		return -EINVAL;
		}