[PATCH] bpf, powerpc: fix jit for seccomp_data access

[Naveen N. Rao]

Mark Lord wrote:
> On 18-02-21 07:52 AM, Mark Lord wrote:
>> On 18-02-21 03:35 AM, Naveen N. Rao wrote:
> ..
>>> Looks good to me, but I am not able to apply this patch. There seems to be whitespace damage.
>> 
>> Here (attached) is a clean copy.
> 
> Again, this time with the commit message included!

Thanks. However...
I am able to apply this using 'patch', but not with 'git am' since the 
headers are missing. FWIW, the usual workflow is to make the changes and 
commit it into your repository using 'git commit' and then use 'git 
format-patch' to generate a patch file that you can then post.

I'll defer to Michael on whether he is ok to process this as it is.

> 
> I am using SECCOMP to filter syscalls on a ppc32 platform,
> and noticed that the JIT compiler was failing on the BPF
> even though the interpreter was working fine.
> 
> The issue was that the compiler was missing one of the instructions
> used by SECCOMP, so here is a patch to enable JIT for that instruction.
> 
> Signed-Off-By:  Mark Lord <mlord at pobox.com>

Minot nit: The correct (TM) tag to use is:
Signed-off-by:
(note the case)

> 
> --- old/arch/powerpc/net/bpf_jit_comp.c 2018-02-16 14:07:01.000000000 -0500
> +++ linux/arch/powerpc/net/bpf_jit_comp.c       2018-02-20 14:41:20.805227494 -0500
> @@ -329,6 +329,9 @@ static int bpf_jit_build_body(struct bpf
>                         BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
>                         PPC_LWZ_OFFS(r_A, r_skb, offsetof(struct sk_buff, len));
>                         break;
> +               case BPF_LDX | BPF_W | BPF_ABS: /* A = *((u32 *)(seccomp_data + K)); */
> +                       PPC_LWZ_OFFS(r_A, r_skb, K);
> +                       break;
>                 case BPF_LDX | BPF_W | BPF_LEN: /* X = skb->len; */
>                         PPC_LWZ_OFFS(r_X, r_skb, offsetof(struct sk_buff, len));
>                         break;

Apart from those aspects, for this patch:
Acked-by: Naveen N. Rao <naveen.n.rao at linux.vnet.ibm.com>


- Naveen