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From: Song Liu <song@kernel.org>
To: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>,
	Johan Almbladh <johan.almbladh@anyfinetworks.com>,
	Nicholas Piggin <npiggin@gmail.com>, bpf <bpf@vger.kernel.org>,
	linuxppc-dev@lists.ozlabs.org,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>
Subject: Re: [PATCH 5/9] powerpc/bpf: Fix BPF_MOD when imm == 1
Date: Fri, 1 Oct 2021 14:55:09 -0700	[thread overview]
Message-ID: <CAPhsuW6uHz=c_devNF3Rpub8bt6EPT-98Y1mifJUhW0U3gZLcg@mail.gmail.com> (raw)
In-Reply-To: <8cb6a1725cf3c38ca90ed7f195f78a5b5a83bb25.1633104510.git.naveen.n.rao@linux.vnet.ibm.com>

On Fri, Oct 1, 2021 at 2:16 PM Naveen N. Rao
<naveen.n.rao@linux.vnet.ibm.com> wrote:
>
> Only ignore the operation if dividing by 1.
>
> Fixes: 156d0e290e969c ("powerpc/ebpf/jit: Implement JIT compiler for extended BPF")
> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>

Acked-by: Song Liu <songliubraving@fb.com>

> ---
>  arch/powerpc/net/bpf_jit_comp64.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
> index 3351a866ef6207..ffb7a2877a8469 100644
> --- a/arch/powerpc/net/bpf_jit_comp64.c
> +++ b/arch/powerpc/net/bpf_jit_comp64.c
> @@ -391,8 +391,14 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
>                 case BPF_ALU64 | BPF_DIV | BPF_K: /* dst /= imm */
>                         if (imm == 0)
>                                 return -EINVAL;
> -                       else if (imm == 1)
> -                               goto bpf_alu32_trunc;
> +                       if (imm == 1) {
> +                               if (BPF_OP(code) == BPF_DIV) {
> +                                       goto bpf_alu32_trunc;
> +                               } else {
> +                                       EMIT(PPC_RAW_LI(dst_reg, 0));
> +                                       break;
> +                               }
> +                       }
>
>                         PPC_LI32(b2p[TMP_REG_1], imm);
>                         switch (BPF_CLASS(code)) {
> --
> 2.33.0
>

  reply	other threads:[~2021-10-01 21:56 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-01 21:14 [PATCH 0/9] powerpc/bpf: Various fixes Naveen N. Rao
2021-10-01 21:14 ` [PATCH 1/9] powerpc/lib: Add helper to check if offset is within conditional branch range Naveen N. Rao
2021-10-01 21:37   ` Song Liu
2021-10-04 18:02     ` Naveen N. Rao
2021-10-03  7:50   ` Christophe Leroy
2021-10-04 18:03     ` Naveen N. Rao
2021-10-01 21:14 ` [PATCH 2/9] powerpc/bpf: Validate branch ranges Naveen N. Rao
2021-10-01 21:45   ` Song Liu
2021-10-02 17:29   ` Johan Almbladh
2021-10-03  7:54   ` Christophe Leroy
2021-10-04 18:11     ` Naveen N. Rao
2021-10-01 21:14 ` [PATCH 3/9] powerpc/bpf: Remove unused SEEN_STACK Naveen N. Rao
2021-10-01 21:47   ` Song Liu
2021-10-02 17:30   ` Johan Almbladh
2021-10-03  7:55   ` Christophe Leroy
2021-10-04 18:11     ` Naveen N. Rao
2021-10-05  5:50       ` Christophe Leroy
2021-10-05 20:22         ` Naveen N. Rao
2021-10-01 21:14 ` [PATCH 4/9] powerpc/bpf: Handle large branch ranges with BPF_EXIT Naveen N. Rao
2021-10-01 21:53   ` Song Liu
2021-10-02 17:31   ` Johan Almbladh
2021-10-03  7:59   ` Christophe Leroy
2021-10-04 18:24     ` Naveen N. Rao
2021-10-05  5:46       ` Christophe Leroy
2022-01-07 11:46         ` Naveen N. Rao
2021-10-01 21:14 ` [PATCH 5/9] powerpc/bpf: Fix BPF_MOD when imm == 1 Naveen N. Rao
2021-10-01 21:55   ` Song Liu [this message]
2021-10-02 17:32   ` Johan Almbladh
2021-10-01 21:14 ` [PATCH 6/9] powerpc/bpf: Fix BPF_SUB when imm == 0x80000000 Naveen N. Rao
2021-10-01 22:01   ` Song Liu
2021-10-02 17:33   ` Johan Almbladh
2021-10-03  8:07   ` Christophe Leroy
2021-10-04 18:18     ` Naveen N. Rao
2021-10-05  5:40       ` Christophe Leroy
2021-10-01 21:14 ` [PATCH 7/9] powerpc/bpf: Limit 'ldbrx' to processors compliant with ISA v2.06 Naveen N. Rao
2021-10-02 17:35   ` Johan Almbladh
2021-10-01 21:14 ` [PATCH 8/9] powerpc/security: Add a helper to query stf_barrier type Naveen N. Rao
2021-10-01 21:14 ` [PATCH 9/9] powerpc/bpf: Emit stf barrier instruction sequences for BPF_NOSPEC Naveen N. Rao
2021-10-02 17:41 ` [PATCH 0/9] powerpc/bpf: Various fixes Johan Almbladh
2021-10-04 18:19   ` Naveen N. Rao

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