[PATCH net-next 2/2] nfp: bpf: support [BPF_ALU | BPF_ALU64] | BPF_NEG

[Jakub Kicinski]

From: Jiong Wang <jiong.w...@netronome.com>

This patch supports BPF_NEG under both BPF_ALU64 and BPF_ALU. LLVM recently
starts to generate it.

NOTE: BPF_NEG takes single operand which is an register and serve as both
input and output.

Signed-off-by: Jiong Wang <jiong.w...@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicin...@netronome.com>
---
 drivers/net/ethernet/netronome/nfp/bpf/jit.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/jit.c 
b/drivers/net/ethernet/netronome/nfp/bpf/jit.c
index 369173100fcf..2609a2487100 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/jit.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/jit.c
@@ -1218,6 +1218,18 @@ static int sub_imm64(struct nfp_prog *nfp_prog, struct 
nfp_insn_meta *meta)
        return 0;
 }
 
+static int neg_reg64(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
+{
+       const struct bpf_insn *insn = &meta->insn;
+
+       emit_alu(nfp_prog, reg_both(insn->dst_reg * 2), reg_imm(0),
+                ALU_OP_SUB, reg_b(insn->dst_reg * 2));
+       emit_alu(nfp_prog, reg_both(insn->dst_reg * 2 + 1), reg_imm(0),
+                ALU_OP_SUB_C, reg_b(insn->dst_reg * 2 + 1));
+
+       return 0;
+}
+
 static int shl_imm64(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
 {
        const struct bpf_insn *insn = &meta->insn;
@@ -1338,6 +1350,16 @@ static int sub_imm(struct nfp_prog *nfp_prog, struct 
nfp_insn_meta *meta)
        return wrp_alu32_imm(nfp_prog, meta, ALU_OP_SUB, !meta->insn.imm);
 }
 
+static int neg_reg(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
+{
+       u8 dst = meta->insn.dst_reg * 2;
+
+       emit_alu(nfp_prog, reg_both(dst), reg_imm(0), ALU_OP_SUB, reg_b(dst));
+       wrp_immed(nfp_prog, reg_both(meta->insn.dst_reg * 2 + 1), 0);
+
+       return 0;
+}
+
 static int shl_imm(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
 {
        const struct bpf_insn *insn = &meta->insn;
@@ -1847,6 +1869,7 @@ static const instr_cb_t instr_cb[256] = {
        [BPF_ALU64 | BPF_ADD | BPF_K] = add_imm64,
        [BPF_ALU64 | BPF_SUB | BPF_X] = sub_reg64,
        [BPF_ALU64 | BPF_SUB | BPF_K] = sub_imm64,
+       [BPF_ALU64 | BPF_NEG] =         neg_reg64,
        [BPF_ALU64 | BPF_LSH | BPF_K] = shl_imm64,
        [BPF_ALU64 | BPF_RSH | BPF_K] = shr_imm64,
        [BPF_ALU | BPF_MOV | BPF_X] =   mov_reg,
@@ -1861,6 +1884,7 @@ static const instr_cb_t instr_cb[256] = {
        [BPF_ALU | BPF_ADD | BPF_K] =   add_imm,
        [BPF_ALU | BPF_SUB | BPF_X] =   sub_reg,
        [BPF_ALU | BPF_SUB | BPF_K] =   sub_imm,
+       [BPF_ALU | BPF_NEG] =           neg_reg,
        [BPF_ALU | BPF_LSH | BPF_K] =   shl_imm,
        [BPF_ALU | BPF_END | BPF_X] =   end_reg32,
        [BPF_LD | BPF_IMM | BPF_DW] =   imm_ld8,
-- 
2.14.1