[PATCH 1/2] powerpc: bpf: Use correct mask while accessing the VLAN tag

[PATCH 1/2] powerpc: bpf: Use correct mask while accessing the VLAN tag

[Denis Kirjanov]

Use the proper mask which is 0xefff
---
 arch/powerpc/net/bpf_jit_comp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index 6dcdade..af0ed4d 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -393,7 +393,7 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 			PPC_LHZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
 							  vlan_tci));
 			if (code == (BPF_ANC | SKF_AD_VLAN_TAG))
-				PPC_ANDI(r_A, r_A, VLAN_VID_MASK);
+				PPC_ANDI(r_A, r_A, ~VLAN_TAG_PRESENT);
 			else
 				PPC_ANDI(r_A, r_A, VLAN_TAG_PRESENT);
 			break;
-- 
2.0.0

[PATCH 2/2] powerpc: bpf: Fix the broken LD_VLAN_TAG_PRESENT test

[Denis Kirjanov]

We have to return the boolean here if the tag presents
or not, not jusr ORing the TCI with the mask which results to:

[  709.412097] test_bpf: #18 LD_VLAN_TAG_PRESENT
[  709.412245] ret 4096 != 1
[  709.412332] ret 4096 != 1
[  709.412333] FAIL (2 times)
---
 arch/powerpc/net/bpf_jit_comp.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index af0ed4d..a3d8f58 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -394,8 +394,10 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 							  vlan_tci));
 			if (code == (BPF_ANC | SKF_AD_VLAN_TAG))
 				PPC_ANDI(r_A, r_A, ~VLAN_TAG_PRESENT);
-			else
+			else {
 				PPC_ANDI(r_A, r_A, VLAN_TAG_PRESENT);
+				PPC_SRWI(r_A, r_A, 12);
+			}
 			break;
 		case BPF_ANC | SKF_AD_QUEUE:
 			BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
-- 
2.0.0

Re: [PATCH 2/2] powerpc: bpf: Fix the broken LD_VLAN_TAG_PRESENT test

[Sergei Shtylyov]

Hello.

On 06/24/2014 01:59 PM, Denis Kirjanov wrote:

> We have to return the boolean here if the tag presents
> or not, not jusr ORing the TCI with the mask which results to:

> [  709.412097] test_bpf: #18 LD_VLAN_TAG_PRESENT
> [  709.412245] ret 4096 != 1
> [  709.412332] ret 4096 != 1
> [  709.412333] FAIL (2 times)

    You need to sign off on the patch, else it won't be applied.

> ---
>   arch/powerpc/net/bpf_jit_comp.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)

> diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
> index af0ed4d..a3d8f58 100644
> --- a/arch/powerpc/net/bpf_jit_comp.c
> +++ b/arch/powerpc/net/bpf_jit_comp.c
> @@ -394,8 +394,10 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
>   							  vlan_tci));
>   			if (code == (BPF_ANC | SKF_AD_VLAN_TAG))
>   				PPC_ANDI(r_A, r_A, ~VLAN_TAG_PRESENT);
> -			else
> +			else {

    All arms of the *if* statement should have {} if one branch has {}.

>   				PPC_ANDI(r_A, r_A, VLAN_TAG_PRESENT);
> +				PPC_SRWI(r_A, r_A, 12);
> +			}
>   			break;
>   		case BPF_ANC | SKF_AD_QUEUE:
>   			BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,

WBR, Sergei

Re: [PATCH 2/2] powerpc: bpf: Fix the broken LD_VLAN_TAG_PRESENT test

[Denis Kirjanov]

On 6/24/14, Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> wrote:
> Hello.
>
> On 06/24/2014 01:59 PM, Denis Kirjanov wrote:
>
>> We have to return the boolean here if the tag presents
>> or not, not jusr ORing the TCI with the mask which results to:
>
>> [  709.412097] test_bpf: #18 LD_VLAN_TAG_PRESENT
>> [  709.412245] ret 4096 != 1
>> [  709.412332] ret 4096 != 1
>> [  709.412333] FAIL (2 times)
>
>     You need to sign off on the patch, else it won't be applied.

Oh, right. Moreover I've made a mistake in the description (we're ANDing)

Thanks!

>> ---
>>   arch/powerpc/net/bpf_jit_comp.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>
>> diff --git a/arch/powerpc/net/bpf_jit_comp.c
>> b/arch/powerpc/net/bpf_jit_comp.c
>> index af0ed4d..a3d8f58 100644
>> --- a/arch/powerpc/net/bpf_jit_comp.c
>> +++ b/arch/powerpc/net/bpf_jit_comp.c
>> @@ -394,8 +394,10 @@ static int bpf_jit_build_body(struct sk_filter *fp,
>> u32 *image,
>>   							  vlan_tci));
>>   			if (code == (BPF_ANC | SKF_AD_VLAN_TAG))
>>   				PPC_ANDI(r_A, r_A, ~VLAN_TAG_PRESENT);
>> -			else
>> +			else {
>
>     All arms of the *if* statement should have {} if one branch has {}.
>
>>   				PPC_ANDI(r_A, r_A, VLAN_TAG_PRESENT);
>> +				PPC_SRWI(r_A, r_A, 12);
>> +			}
>>   			break;
>>   		case BPF_ANC | SKF_AD_QUEUE:
>>   			BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
>
> WBR, Sergei
>
>

Re: [PATCH 1/2] powerpc: bpf: Use correct mask while accessing the VLAN tag

[Alexei Starovoitov]

On Tue, Jun 24, 2014 at 2:59 AM, Denis Kirjanov <kda@linux-powerpc.org> wrote:
> Use the proper mask which is 0xefff

sob is missing.

also please expand the commit message a bit, otherwise it's too cryptic for
folks who don't know bpf details.

> ---
>  arch/powerpc/net/bpf_jit_comp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
> index 6dcdade..af0ed4d 100644
> --- a/arch/powerpc/net/bpf_jit_comp.c
> +++ b/arch/powerpc/net/bpf_jit_comp.c
> @@ -393,7 +393,7 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
>                         PPC_LHZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
>                                                           vlan_tci));
>                         if (code == (BPF_ANC | SKF_AD_VLAN_TAG))
> -                               PPC_ANDI(r_A, r_A, VLAN_VID_MASK);
> +                               PPC_ANDI(r_A, r_A, ~VLAN_TAG_PRESENT);
>                         else
>                                 PPC_ANDI(r_A, r_A, VLAN_TAG_PRESENT);
>                         break;
> --
> 2.0.0
>
> --
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