Pu Lehui <pulehui@xxxxxxxxxxxxxxx> writes:
> From: Pu Lehui <pulehui@xxxxxxxxxx>
>
> Add 8-bit and 16-bit sign-extention wraper with Zbb support to optimize
> sign-extension mov instructions.
>
> Signed-off-by: Pu Lehui <pulehui@xxxxxxxxxx>
> ---
> arch/riscv/net/bpf_jit.h | 20 ++++++++++++++++++++
> arch/riscv/net/bpf_jit_comp64.c | 5 +++--
> 2 files changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/arch/riscv/net/bpf_jit.h b/arch/riscv/net/bpf_jit.h
> index 4e24fb2bd..944bdd6e4 100644
> --- a/arch/riscv/net/bpf_jit.h
> +++ b/arch/riscv/net/bpf_jit.h
> @@ -1110,6 +1110,26 @@ static inline void emit_subw(u8 rd, u8 rs1, u8 rs2, struct rv_jit_context *ctx)
> emit(rv_subw(rd, rs1, rs2), ctx);
> }
>
> +static inline void emit_sextb(u8 rd, u8 rs, struct rv_jit_context *ctx)
> +{
> + if (rvzbb_enabled()) {
> + emit(rvzbb_sextb(rd, rs), ctx);
> + } else {
> + emit_slli(rd, rs, 56, ctx);
> + emit_srai(rd, rd, 56, ctx);
> + }
> +}
> +
> +static inline void emit_sexth(u8 rd, u8 rs, struct rv_jit_context *ctx)
> +{
> + if (rvzbb_enabled()) {
> + emit(rvzbb_sexth(rd, rs), ctx);
> + } else {
> + emit_slli(rd, rs, 48, ctx);
> + emit_srai(rd, rd, 48, ctx);
> + }
> +}
Nit/personal style: I really find it easier to read early-exit code,
than nested if-else.
| if (cond) {
| foo();
| return;
| }
|
| bar();
> +
> static inline void emit_sextw(u8 rd, u8 rs, struct rv_jit_context *ctx)
> {
> emit_addiw(rd, rs, 0, ctx);
> diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
> index 0c6ffe11a..f4ca6b787 100644
> --- a/arch/riscv/net/bpf_jit_comp64.c
> +++ b/arch/riscv/net/bpf_jit_comp64.c
> @@ -1027,9 +1027,10 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
> emit_mv(rd, rs, ctx);
> break;
> case 8:
> + emit_sextb(rd, rs, ctx);
> + break;
> case 16:
> - emit_slli(RV_REG_T1, rs, 64 - insn->off, ctx);
> - emit_srai(rd, RV_REG_T1, 64 - insn->off, ctx);
> + emit_sexth(rd, rs, ctx);
Acked-by: Björn Töpel <bjorn@xxxxxxxxxx>
