[PATCH v2 bpf-next 4/7] nfp: bpf: implement jitting of BPF_ALU | BPF_ARSH | BPF_*
From: Jiong Wang <hidden>
Date: 2018-12-05 18:53:22
Subsystem:
bpf jit for nfp nics, netronome ethernet drivers, networking drivers, the rest · Maintainers:
Jakub Kicinski, Andrew Lunn, "David S. Miller", Eric Dumazet, Paolo Abeni, Linus Torvalds
BPF_X support needs indirect shift mode, please see code comments for details. Reviewed-by: Jakub Kicinski <redacted> Signed-off-by: Jiong Wang <redacted> --- drivers/net/ethernet/netronome/nfp/bpf/jit.c | 45 ++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+)
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/jit.c b/drivers/net/ethernet/netronome/nfp/bpf/jit.c
index 97d33bb..662cbc2 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/jit.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/jit.c@@ -2382,6 +2382,49 @@ static int neg_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta) return 0; } +static int __ashr_imm(struct nfp_prog *nfp_prog, u8 dst, u8 shift_amt) +{ + /* Set signedness bit (MSB of result). */ + emit_alu(nfp_prog, reg_none(), reg_a(dst), ALU_OP_OR, reg_imm(0)); + emit_shf(nfp_prog, reg_both(dst), reg_none(), SHF_OP_ASHR, reg_b(dst), + SHF_SC_R_SHF, shift_amt); + wrp_immed(nfp_prog, reg_both(dst + 1), 0); + + return 0; +} + +static int ashr_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta) +{ + const struct bpf_insn *insn = &meta->insn; + u64 umin, umax; + u8 dst, src; + + dst = insn->dst_reg * 2; + umin = meta->umin_src; + umax = meta->umax_src; + if (umin == umax) + return __ashr_imm(nfp_prog, dst, umin); + + src = insn->src_reg * 2; + /* NOTE: the first insn will set both indirect shift amount (source A) + * and signedness bit (MSB of result). + */ + emit_alu(nfp_prog, reg_none(), reg_a(src), ALU_OP_OR, reg_b(dst)); + emit_shf_indir(nfp_prog, reg_both(dst), reg_none(), SHF_OP_ASHR, + reg_b(dst), SHF_SC_R_SHF); + wrp_immed(nfp_prog, reg_both(dst + 1), 0); + + return 0; +} + +static int ashr_imm(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta) +{ + const struct bpf_insn *insn = &meta->insn; + u8 dst = insn->dst_reg * 2; + + return __ashr_imm(nfp_prog, dst, insn->imm); +} + static int shl_imm(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta) { const struct bpf_insn *insn = &meta->insn;
@@ -3286,6 +3329,8 @@ static const instr_cb_t instr_cb[256] = { [BPF_ALU | BPF_DIV | BPF_K] = div_imm, [BPF_ALU | BPF_NEG] = neg_reg, [BPF_ALU | BPF_LSH | BPF_K] = shl_imm, + [BPF_ALU | BPF_ARSH | BPF_X] = ashr_reg, + [BPF_ALU | BPF_ARSH | BPF_K] = ashr_imm, [BPF_ALU | BPF_END | BPF_X] = end_reg32, [BPF_LD | BPF_IMM | BPF_DW] = imm_ld8, [BPF_LD | BPF_ABS | BPF_B] = data_ld1,
--
2.7.4