@@ -824,6 +824,29 @@ nfp_prog_prepare(struct nfp_prog *nfp_prog, const struct bpf_insn *prog,
}
/* --- Optimizations --- */
+static void nfp_bpf_opt_reg_init(struct nfp_prog *nfp_prog)
+{
+ struct nfp_insn_meta *meta;
+
+ list_for_each_entry(meta, &nfp_prog->insns, l) {
+ struct bpf_insn insn = meta->insn;
+
+ /* Programs converted from cBPF start with register xoring */
+ if (insn.code == (BPF_ALU64 | BPF_XOR | BPF_X) &&
+ insn.src_reg == insn.dst_reg)
+ continue;
+
+ /* Programs start with R6 = R1 but we ignore the skb pointer */
+ if (insn.code == (BPF_ALU64 | BPF_MOV | BPF_X) &&
+ insn.src_reg == 1 && insn.dst_reg == 6)
+ meta->skip = true;
+
+ /* Return as soon as something doesn't match */
+ if (!meta->skip)
+ return;
+ }
+}
+
/* Remove masking after load since our load guarantees this is not needed */
static void nfp_bpf_opt_ld_mask(struct nfp_prog *nfp_prog)
{
@@ -900,6 +923,7 @@ static void nfp_bpf_opt_ld_shift(struct nfp_prog *nfp_prog)
static void nfp_bpf_optimize(struct nfp_prog *nfp_prog)
{
+ nfp_bpf_opt_reg_init(nfp_prog);
nfp_bpf_opt_ld_mask(nfp_prog);
nfp_bpf_opt_ld_shift(nfp_prog);
}