On Thu, Oct 10, 2024 at 10:56 AM Yonghong Song <yonghong.song@xxxxxxxxx> wrote:
>
> Two helpers are extracted from bpf/x86 jit:
> - a helper to handle 'reg1 <op>= reg2' where <op> is add/sub/and/or/xor
> - a helper to handle 'reg *= imm'
>
> Both helpers will be used in the subsequent patch.
>
> Signed-off-by: Yonghong Song <yonghong.song@xxxxxxxxx>
> ---
> arch/x86/net/bpf_jit_comp.c | 51 ++++++++++++++++++++++++-------------
> 1 file changed, 34 insertions(+), 17 deletions(-)
>
> diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
> index a6ba85cec49a..297dd64f4b6a 100644
> --- a/arch/x86/net/bpf_jit_comp.c
> +++ b/arch/x86/net/bpf_jit_comp.c
> @@ -1475,6 +1475,37 @@ static void emit_alu_helper_1(u8 **pprog, u8 insn_code, u32 dst_reg, s32 imm32)
> *pprog = prog;
> }
>
> +/* emit ADD/SUB/AND/OR/XOR 'reg1 <op>= reg2' operations */
> +static void emit_alu_helper_2(u8 **pprog, u8 insn_code, u32 dst_reg, u32 src_reg)
> +{
> + u8 b2 = 0;
> + u8 *prog = *pprog;
> +
> + maybe_emit_mod(&prog, dst_reg, src_reg,
> + BPF_CLASS(insn_code) == BPF_ALU64);
> + b2 = simple_alu_opcodes[BPF_OP(insn_code)];
> + EMIT2(b2, add_2reg(0xC0, dst_reg, src_reg));
> +
> + *pprog = prog;
> +}
> +
> +/* emit 'reg *= imm' operations */
> +static void emit_alu_helper_3(u8 **pprog, u8 insn_code, u32 dst_reg, s32 imm32)
_1, _2, _3 ?!
There must be a better way to name the helpers. Like:
_1 -> emit_alu_imm
_2 -> emit_alu_reg
_3 -> emit_mul_imm
