From: David Daney <ddaney.cavm@gmail.com>
To: James Hogan <james.hogan@imgtec.com>,
David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org, ralf@linux-mips.org,
linux-kernel@vger.kernel.org,
"Steven J. Hill" <steven.hill@cavium.com>,
Alexei Starovoitov <ast@kernel.org>,
netdev@vger.kernel.org
Subject: Re: [PATCH] MIPS: BPF: Add support for SKF_AD_HATYPE
Date: Mon, 13 Mar 2017 09:45:26 -0700 [thread overview]
Message-ID: <9da6cebb-b991-e89f-bc88-a2ec530e32ec@gmail.com> (raw)
In-Reply-To: <20170313105659.GJ996@jhogan-linux.le.imgtec.org>
On 03/13/2017 03:56 AM, James Hogan wrote:
> 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@cavium.com>
>
> I think the BPF maintainers should probably be Cc'd on this patch.
> Cc'ing now.
>
Good point.
Since there are some corrections needed, I will send another version and
CC the proper people.
>> ---
>> 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.
Right.
>
>> 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.
The next version will use LHU.
>
> Cheers
> James
>
prev parent reply other threads:[~2017-03-13 16:45 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20170310221405.30648-1-david.daney@cavium.com>
2017-03-13 10:56 ` [PATCH] MIPS: BPF: Add support for SKF_AD_HATYPE James Hogan
2017-03-13 16:45 ` David Daney [this message]
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