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 6/9] powerpc/bpf: Fix BPF_SUB when imm == 0x80000000
Date: Fri, 1 Oct 2021 15:01:07 -0700 [thread overview]
Message-ID: <CAPhsuW5NraEPybLVcKWzHva4ksTa05msv-2PBdFXPt_J+=xTyw@mail.gmail.com> (raw)
In-Reply-To: <1912a409447071f46ac6cc957ce8edea0e5232b7.1633104510.git.naveen.n.rao@linux.vnet.ibm.com>
On Fri, Oct 1, 2021 at 2:17 PM Naveen N. Rao
<naveen.n.rao@linux.vnet.ibm.com> wrote:
>
> We aren't handling subtraction involving an immediate value of
> 0x80000000 properly. Fix the same.
>
> 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 | 16 ++++++++--------
> 1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
> index ffb7a2877a8469..4641a50e82d50d 100644
> --- a/arch/powerpc/net/bpf_jit_comp64.c
> +++ b/arch/powerpc/net/bpf_jit_comp64.c
> @@ -333,15 +333,15 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
> case BPF_ALU | BPF_SUB | BPF_K: /* (u32) dst -= (u32) imm */
> case BPF_ALU64 | BPF_ADD | BPF_K: /* dst += imm */
> case BPF_ALU64 | BPF_SUB | BPF_K: /* dst -= imm */
> - if (BPF_OP(code) == BPF_SUB)
> - imm = -imm;
> - if (imm) {
> - if (imm >= -32768 && imm < 32768)
> - EMIT(PPC_RAW_ADDI(dst_reg, dst_reg, IMM_L(imm)));
> - else {
> - PPC_LI32(b2p[TMP_REG_1], imm);
> + if (imm > -32768 && imm < 32768) {
> + EMIT(PPC_RAW_ADDI(dst_reg, dst_reg,
> + BPF_OP(code) == BPF_SUB ? IMM_L(-imm) : IMM_L(imm)));
> + } else {
> + PPC_LI32(b2p[TMP_REG_1], imm);
> + if (BPF_OP(code) == BPF_SUB)
> + EMIT(PPC_RAW_SUB(dst_reg, dst_reg, b2p[TMP_REG_1]));
> + else
> EMIT(PPC_RAW_ADD(dst_reg, dst_reg, b2p[TMP_REG_1]));
> - }
> }
> goto bpf_alu32_trunc;
> case BPF_ALU | BPF_MUL | BPF_X: /* (u32) dst *= (u32) src */
> --
> 2.33.0
>
next prev parent reply other threads:[~2021-10-01 22:02 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
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 [this message]
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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