On Thu, Sep 12, 2013 at 02:18:37AM +0100, Matt Evans wrote:
> Hi Ben, Vladimir,
>
>
> *dusts off very thick PPC cobwebs* Sorry for the delay as I'm travelling,
> didn't get to this until now.
>
> On 02/09/2013, at 9:45 PM, Benjamin Herrenschmidt wrote:
>
> > On Mon, 2013-09-02 at 19:48 +0200, Vladimir Murzin wrote:
> >> Ping
> >>
> >> On Wed, Aug 28, 2013 at 02:49:52AM +0400, Vladimir Murzin wrote:
> >>> commit b6069a9570 (filter: add MOD operation) added generic
> >>> support for modulus operation in BPF.
> >>>
> > Sorry, nobody got a chance to review that yet. Unfortunately Matt
> > doesn't work for us anymore and none of us has experience with the
> > BPF code, so somebody (possibly me) will need to spend a bit of time
> > figuring it out before verifying that is correct.
> >
> > Do you have a test case/suite by any chance ?
> >
> > Ben.
> >
> >>> This patch brings JIT support for PPC64
> >>>
> >>> Signed-off-by: Vladimir Murzin <murzi...@gmail.com>
> >>> ---
> >>> arch/powerpc/net/bpf_jit_comp.c | 22 ++++++++++++++++++++++
> >>> 1 file changed, 22 insertions(+)
> >>>
> >>> diff --git a/arch/powerpc/net/bpf_jit_comp.c
> >>> b/arch/powerpc/net/bpf_jit_comp.c
> >>> index bf56e33..96f24dc 100644
> >>> --- a/arch/powerpc/net/bpf_jit_comp.c
> >>> +++ b/arch/powerpc/net/bpf_jit_comp.c
> >>> @@ -193,6 +193,28 @@ static int bpf_jit_build_body(struct sk_filter *fp,
> >>> u32 *image,
> >>> PPC_MUL(r_A, r_A, r_scratch1);
> >>> }
> >>> break;
> >>> + case BPF_S_ALU_MOD_X: /* A %= X; */
> >>> + ctx->seen |= SEEN_XREG;
> >>> + PPC_CMPWI(r_X, 0);
> >>> + if (ctx->pc_ret0 != -1) {
> >>> + PPC_BCC(COND_EQ, addrs[ctx->pc_ret0]);
> >>> + } else {
> >>> + PPC_BCC_SHORT(COND_NE, (ctx->idx*4)+12);
> >>> + PPC_LI(r_ret, 0);
> >>> + PPC_JMP(exit_addr);
> >>> + }
> >>> + PPC_DIVWU(r_scratch1, r_A, r_X);
> >>> + PPC_MUL(r_scratch1, r_X, r_scratch1);
> >>> + PPC_SUB(r_A, r_A, r_scratch1);
> >>> + break;
>
> Without having compiled & tested this, it looks fine to me (especially with
> the corrected DIVWU opcode in the other patch, oops...).
>
> >>> + case BPF_S_ALU_MOD_K: /* A %= K; */
> >>> +#define r_scratch2 (r_scratch1 + 1)
> >>> + PPC_LI32(r_scratch2, K);
> >>> + PPC_DIVWU(r_scratch1, r_A, r_scratch2);
> >>> + PPC_MUL(r_scratch1, r_scratch2, r_scratch1);
> >>> + PPC_SUB(r_A, r_A, r_scratch1);
> >>> +#undef r_scratch2
> >>> + break;
>
> If you need another scratch register, it should really be defined in
> bpf_jit.h instead.
>
> Once you define r_scratch2 in there,
>
> Acked-by: Matt Evans <m...@ozlabs.org>
>
>
> Thanks!
>
>
> Matt
>
Thanks!
Vladimir
>
>
>
> >>> case BPF_S_ALU_DIV_X: /* A /= X; */
> >>> ctx->seen |= SEEN_XREG;
> >>> PPC_CMPWI(r_X, 0);
> >>> --
> >>> 1.8.1.5
> >>>
> >
>
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