On Wed, Oct 6, 2021 at 12:43 PM Jie Meng <jmeng@xxxxxx> wrote:
>
> Introduce a single reg version of maybe_emit_mod() and factor out
> common code in more cases.
>
> Signed-off-by: Jie Meng <jmeng@xxxxxx>
Acked-by: Song Liu <songliubraving@xxxxxx>
> ---
> arch/x86/net/bpf_jit_comp.c | 67 +++++++++++++++++--------------------
> 1 file changed, 31 insertions(+), 36 deletions(-)
>
> diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
> index 5a0edea3cc2e..e474718d152b 100644
> --- a/arch/x86/net/bpf_jit_comp.c
> +++ b/arch/x86/net/bpf_jit_comp.c
> @@ -721,6 +721,20 @@ static void maybe_emit_mod(u8 **pprog, u32 dst_reg, u32 src_reg, bool is64)
> *pprog = prog;
> }
>
> +/*
> + * Similar version of maybe_emit_mod() for a single register
> + */
> +static void maybe_emit_1mod(u8 **pprog, u32 reg, bool is64)
> +{
> + u8 *prog = *pprog;
> +
> + if (is64)
> + EMIT1(add_1mod(0x48, reg));
> + else if (is_ereg(reg))
> + EMIT1(add_1mod(0x40, reg));
> + *pprog = prog;
> +}
> +
> /* LDX: dst_reg = *(u8*)(src_reg + off) */
> static void emit_ldx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off)
> {
> @@ -951,10 +965,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
> /* neg dst */
> case BPF_ALU | BPF_NEG:
> case BPF_ALU64 | BPF_NEG:
> - if (BPF_CLASS(insn->code) == BPF_ALU64)
> - EMIT1(add_1mod(0x48, dst_reg));
> - else if (is_ereg(dst_reg))
> - EMIT1(add_1mod(0x40, dst_reg));
> + maybe_emit_1mod(&prog, dst_reg,
> + BPF_CLASS(insn->code) == BPF_ALU64);
> EMIT2(0xF7, add_1reg(0xD8, dst_reg));
> break;
>
> @@ -968,10 +980,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
> case BPF_ALU64 | BPF_AND | BPF_K:
> case BPF_ALU64 | BPF_OR | BPF_K:
> case BPF_ALU64 | BPF_XOR | BPF_K:
> - if (BPF_CLASS(insn->code) == BPF_ALU64)
> - EMIT1(add_1mod(0x48, dst_reg));
> - else if (is_ereg(dst_reg))
> - EMIT1(add_1mod(0x40, dst_reg));
> + maybe_emit_1mod(&prog, dst_reg,
> + BPF_CLASS(insn->code) == BPF_ALU64);
>
> /*
> * b3 holds 'normal' opcode, b2 short form only valid
> @@ -1059,11 +1069,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
> */
> EMIT2(0x31, 0xd2);
>
> - if (is64)
> - EMIT1(add_1mod(0x48, src_reg));
> - else if (is_ereg(src_reg))
> - EMIT1(add_1mod(0x40, src_reg));
> /* div src_reg */
> + maybe_emit_1mod(&prog, src_reg, is64);
> EMIT2(0xF7, add_1reg(0xF0, src_reg));
>
> if (BPF_OP(insn->code) == BPF_MOD &&
> @@ -1084,10 +1091,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
>
> case BPF_ALU | BPF_MUL | BPF_K:
> case BPF_ALU64 | BPF_MUL | BPF_K:
> - if (BPF_CLASS(insn->code) == BPF_ALU64)
> - EMIT1(add_2mod(0x48, dst_reg, dst_reg));
> - else if (is_ereg(dst_reg))
> - EMIT1(add_2mod(0x40, dst_reg, dst_reg));
> + maybe_emit_mod(&prog, dst_reg, dst_reg,
> + BPF_CLASS(insn->code) == BPF_ALU64);
>
> if (is_imm8(imm32))
> /* imul dst_reg, dst_reg, imm8 */
> @@ -1102,10 +1107,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
>
> case BPF_ALU | BPF_MUL | BPF_X:
> case BPF_ALU64 | BPF_MUL | BPF_X:
> - if (BPF_CLASS(insn->code) == BPF_ALU64)
> - EMIT1(add_2mod(0x48, src_reg, dst_reg));
> - else if (is_ereg(dst_reg) || is_ereg(src_reg))
> - EMIT1(add_2mod(0x40, src_reg, dst_reg));
> + maybe_emit_mod(&prog, src_reg, dst_reg,
> + BPF_CLASS(insn->code) == BPF_ALU64);
>
> /* imul dst_reg, src_reg */
> EMIT3(0x0F, 0xAF, add_2reg(0xC0, src_reg, dst_reg));
> @@ -1118,10 +1121,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
> case BPF_ALU64 | BPF_LSH | BPF_K:
> case BPF_ALU64 | BPF_RSH | BPF_K:
> case BPF_ALU64 | BPF_ARSH | BPF_K:
> - if (BPF_CLASS(insn->code) == BPF_ALU64)
> - EMIT1(add_1mod(0x48, dst_reg));
> - else if (is_ereg(dst_reg))
> - EMIT1(add_1mod(0x40, dst_reg));
> + maybe_emit_1mod(&prog, dst_reg,
> + BPF_CLASS(insn->code) == BPF_ALU64);
>
> b3 = simple_alu_opcodes[BPF_OP(insn->code)];
> if (imm32 == 1)
> @@ -1152,10 +1153,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
> }
>
> /* shl %rax, %cl | shr %rax, %cl | sar %rax, %cl */
> - if (BPF_CLASS(insn->code) == BPF_ALU64)
> - EMIT1(add_1mod(0x48, dst_reg));
> - else if (is_ereg(dst_reg))
> - EMIT1(add_1mod(0x40, dst_reg));
> + maybe_emit_1mod(&prog, dst_reg,
> + BPF_CLASS(insn->code) == BPF_ALU64);
>
> b3 = simple_alu_opcodes[BPF_OP(insn->code)];
> EMIT2(0xD3, add_1reg(b3, dst_reg));
> @@ -1465,10 +1464,8 @@ st: if (is_imm8(insn->off))
> case BPF_JMP | BPF_JSET | BPF_K:
> case BPF_JMP32 | BPF_JSET | BPF_K:
> /* test dst_reg, imm32 */
> - if (BPF_CLASS(insn->code) == BPF_JMP)
> - EMIT1(add_1mod(0x48, dst_reg));
> - else if (is_ereg(dst_reg))
> - EMIT1(add_1mod(0x40, dst_reg));
> + maybe_emit_1mod(&prog, dst_reg,
> + BPF_CLASS(insn->code) == BPF_JMP);
> EMIT2_off32(0xF7, add_1reg(0xC0, dst_reg), imm32);
> goto emit_cond_jmp;
>
> @@ -1501,10 +1498,8 @@ st: if (is_imm8(insn->off))
> }
>
> /* cmp dst_reg, imm8/32 */
> - if (BPF_CLASS(insn->code) == BPF_JMP)
> - EMIT1(add_1mod(0x48, dst_reg));
> - else if (is_ereg(dst_reg))
> - EMIT1(add_1mod(0x40, dst_reg));
> + maybe_emit_1mod(&prog, dst_reg,
> + BPF_CLASS(insn->code) == BPF_JMP);
>
> if (is_imm8(imm32))
> EMIT3(0x83, add_1reg(0xF8, dst_reg), imm32);
> --
> 2.30.2
>
