diff options
| -rw-r--r-- | drivers/net/ethernet/netronome/nfp/bpf/jit.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/jit.c b/drivers/net/ethernet/netronome/nfp/bpf/jit.c index 9cc638718272..a5590988fc69 100644 --- a/drivers/net/ethernet/netronome/nfp/bpf/jit.c +++ b/drivers/net/ethernet/netronome/nfp/bpf/jit.c @@ -2777,6 +2777,40 @@ static void nfp_bpf_opt_reg_init(struct nfp_prog *nfp_prog) } } +/* abs(insn.imm) will fit better into unrestricted reg immediate - + * convert add/sub of a negative number into a sub/add of a positive one. + */ +static void nfp_bpf_opt_neg_add_sub(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; + + if (meta->skip) + continue; + + if (BPF_CLASS(insn.code) != BPF_ALU && + BPF_CLASS(insn.code) != BPF_ALU64) + continue; + if (BPF_SRC(insn.code) != BPF_K) + continue; + if (insn.imm >= 0) + continue; + + if (BPF_OP(insn.code) == BPF_ADD) + insn.code = BPF_CLASS(insn.code) | BPF_SUB; + else if (BPF_OP(insn.code) == BPF_SUB) + insn.code = BPF_CLASS(insn.code) | BPF_ADD; + else + continue; + + meta->insn.code = insn.code | BPF_K; + + meta->insn.imm = -insn.imm; + } +} + /* Remove masking after load since our load guarantees this is not needed */ static void nfp_bpf_opt_ld_mask(struct nfp_prog *nfp_prog) { @@ -3212,6 +3246,7 @@ static int nfp_bpf_optimize(struct nfp_prog *nfp_prog) { nfp_bpf_opt_reg_init(nfp_prog); + nfp_bpf_opt_neg_add_sub(nfp_prog); nfp_bpf_opt_ld_mask(nfp_prog); nfp_bpf_opt_ld_shift(nfp_prog); nfp_bpf_opt_ldst_gather(nfp_prog); |