[PATCH] arm: bpf_jit: support MOD operation
Vladimir Murzin
murzin.v at gmail.com
Mon Sep 2 13:49:32 EDT 2013
Ping
On Wed, Aug 28, 2013 at 02:52:32AM +0400, Vladimir Murzin wrote:
> commit b6069a9570 (filter: add MOD operation) added generic
> support for modulus operation in BPF.
>
> This patch brings JIT support for ARM.
>
> Signed-off-by: Vladimir Murzin <murzin.v at gmail.com>
> ---
> arch/arm/net/bpf_jit_32.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
> index f50d223..0bfff55 100644
> --- a/arch/arm/net/bpf_jit_32.c
> +++ b/arch/arm/net/bpf_jit_32.c
> @@ -636,6 +636,24 @@ load_ind:
> update_on_xread(ctx);
> emit(ARM_MUL(r_A, r_A, r_X), ctx);
> break;
> + case BPF_S_ALU_MOD_X: /* A %= X; */
> + update_on_xread(ctx);
> + emit(ARM_CMP_I(r_X, 0), ctx);
> + emit_err_ret(ARM_COND_EQ, ctx);
> + emit_udiv(r_scratch, r_A, r_X, ctx);
> + emit(ARM_MUL(r_scratch, r_X, r_scratch), ctx);
> + emit(ARM_SUB_R(r_A, r_A, r_scratch), ctx);
> + break;
> + case BPF_S_ALU_MOD_K: /* A %= K; */
> + /*
> + * reuse ARM_R1 as the temp register - it should be safe
> + * as soon as udiv may touch it too.
> + */
> + emit_mov_i(ARM_R1, k, ctx);
> + emit_udiv(r_scratch, r_A, ARM_R1, ctx);
> + emit(ARM_MUL(r_scratch, ARM_R1, r_scratch), ctx);
> + emit(ARM_SUB_R(r_A, r_A, r_scratch), ctx);
> + break;
> case BPF_S_ALU_DIV_K:
> /* current k == reciprocal_value(userspace k) */
> emit_mov_i(r_scratch, k, ctx);
> --
> 1.8.1.5
>
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