On Fri, Mar 10, 2017 at 02:14:05PM -0800, David Daney wrote:
> This let's us pass some additional "modprobe test-bpf" tests.
>
> Reuse the code for SKF_AD_IFINDEX, but substitute the offset and size
> of the "type" field.
>
> Signed-off-by: David Daney <david.daney@xxxxxxxxxx>
I think the BPF maintainers should probably be Cc'd on this patch.
Cc'ing now.
> ---
> arch/mips/net/bpf_jit.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c
> index 49a2e22..f613708 100644
> --- a/arch/mips/net/bpf_jit.c
> +++ b/arch/mips/net/bpf_jit.c
> @@ -1111,6 +1111,7 @@ static int build_body(struct jit_ctx *ctx)
> emit_load(r_A, 28, off, ctx);
> break;
> case BPF_ANC | SKF_AD_IFINDEX:
> + case BPF_ANC | SKF_AD_HATYPE:
> /* A = skb->dev->ifindex */
this comment should probably be updated.
> ctx->flags |= SEEN_SKB | SEEN_A;
> off = offsetof(struct sk_buff, dev);
> @@ -1120,10 +1121,15 @@ static int build_body(struct jit_ctx *ctx)
> emit_bcond(MIPS_COND_EQ, r_s0, r_zero,
> b_imm(prog->len, ctx), ctx);
> emit_reg_move(r_ret, r_zero, ctx);
> - BUILD_BUG_ON(FIELD_SIZEOF(struct net_device,
> - ifindex) != 4);
> - off = offsetof(struct net_device, ifindex);
> - emit_load(r_A, r_s0, off, ctx);
> + if (code == (BPF_ANC | SKF_AD_IFINDEX)) {
> + BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
> + off = offsetof(struct net_device, ifindex);
> + emit_load(r_A, r_s0, off, ctx);
> + } else { /* (code == (BPF_ANC | SKF_AD_HATYPE) */
> + BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
> + off = offsetof(struct net_device, type);
> + emit_half_load(r_A, r_s0, off, ctx);
Technically net_device::type is unsigned, and emit_half_load uses LH
which sign extends. Does that matter in practice.
Cheers
James
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