From: Yonghong Song <yhs@fb.com>
To: Brendan Jackman <jackmanb@google.com>, <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
KP Singh <kpsingh@chromium.org>,
Florent Revest <revest@chromium.org>,
<linux-kernel@vger.kernel.org>, Jann Horn <jannh@google.com>
Subject: Re: [PATCH v2 bpf-next 05/13] bpf: Rename BPF_XADD and prepare to encode other atomics in .imm
Date: Fri, 27 Nov 2020 19:43:46 -0800 [thread overview]
Message-ID: <bdc90ccd-e017-b7b1-7ba8-f5e261ad7296@fb.com> (raw)
In-Reply-To: <20201127175738.1085417-6-jackmanb@google.com>
On 11/27/20 9:57 AM, Brendan Jackman wrote:
> A subsequent patch will add additional atomic operations. These new
> operations will use the same opcode field as the existing XADD, with
> the immediate discriminating different operations.
>
> In preparation, rename the instruction mode BPF_ATOMIC and start
> calling the zero immediate BPF_ADD.
>
> This is possible (doesn't break existing valid BPF progs) because the
> immediate field is currently reserved MBZ and BPF_ADD is zero.
>
> All uses are removed from the tree but the BPF_XADD definition is
> kept around to avoid breaking builds for people including kernel
> headers.
>
> Signed-off-by: Brendan Jackman <jackmanb@google.com>
> ---
> Documentation/networking/filter.rst | 30 +++++++-----
> arch/arm/net/bpf_jit_32.c | 7 ++-
> arch/arm64/net/bpf_jit_comp.c | 16 +++++--
> arch/mips/net/ebpf_jit.c | 11 +++--
> arch/powerpc/net/bpf_jit_comp64.c | 25 ++++++++--
> arch/riscv/net/bpf_jit_comp32.c | 20 ++++++--
> arch/riscv/net/bpf_jit_comp64.c | 16 +++++--
> arch/s390/net/bpf_jit_comp.c | 27 ++++++-----
> arch/sparc/net/bpf_jit_comp_64.c | 17 +++++--
> arch/x86/net/bpf_jit_comp.c | 46 ++++++++++++++-----
> arch/x86/net/bpf_jit_comp32.c | 6 +--
> drivers/net/ethernet/netronome/nfp/bpf/jit.c | 14 ++++--
> drivers/net/ethernet/netronome/nfp/bpf/main.h | 4 +-
> .../net/ethernet/netronome/nfp/bpf/verifier.c | 15 ++++--
> include/linux/filter.h | 8 ++--
> include/uapi/linux/bpf.h | 3 +-
> kernel/bpf/core.c | 31 +++++++++----
> kernel/bpf/disasm.c | 6 ++-
> kernel/bpf/verifier.c | 24 ++++++----
> lib/test_bpf.c | 2 +-
> samples/bpf/bpf_insn.h | 4 +-
> samples/bpf/sock_example.c | 2 +-
> samples/bpf/test_cgrp2_attach.c | 4 +-
> tools/include/linux/filter.h | 7 +--
> tools/include/uapi/linux/bpf.h | 3 +-
> .../bpf/prog_tests/cgroup_attach_multi.c | 4 +-
> tools/testing/selftests/bpf/verifier/ctx.c | 7 ++-
> .../testing/selftests/bpf/verifier/leak_ptr.c | 4 +-
> tools/testing/selftests/bpf/verifier/unpriv.c | 3 +-
> tools/testing/selftests/bpf/verifier/xadd.c | 2 +-
> 30 files changed, 248 insertions(+), 120 deletions(-)
>
> diff --git a/Documentation/networking/filter.rst b/Documentation/networking/filter.rst
[...]
> diff --git a/drivers/net/ethernet/netronome/nfp/bpf/jit.c b/drivers/net/ethernet/netronome/nfp/bpf/jit.c
> index 0a721f6e8676..1c9efc74edfc 100644
> --- a/drivers/net/ethernet/netronome/nfp/bpf/jit.c
> +++ b/drivers/net/ethernet/netronome/nfp/bpf/jit.c
> @@ -3109,13 +3109,19 @@ mem_xadd(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta, bool is64)
> return 0;
> }
>
> -static int mem_xadd4(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
> +static int mem_atomic4(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
> {
> + if (meta->insn.off != BPF_ADD)
> + return -EOPNOTSUPP;
You probably missed this change. it should be meta->insn.imm != BPF_ADD.
> +
> return mem_xadd(nfp_prog, meta, false);
> }
>
> -static int mem_xadd8(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
> +static int mem_atomic8(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
> {
> + if (meta->insn.off != BPF_ADD)
same as above.
> + return -EOPNOTSUPP;
> +
> return mem_xadd(nfp_prog, meta, true);
> }
>
> @@ -3475,8 +3481,8 @@ static const instr_cb_t instr_cb[256] = {
> [BPF_STX | BPF_MEM | BPF_H] = mem_stx2,
> [BPF_STX | BPF_MEM | BPF_W] = mem_stx4,
> [BPF_STX | BPF_MEM | BPF_DW] = mem_stx8,
> - [BPF_STX | BPF_XADD | BPF_W] = mem_xadd4,
> - [BPF_STX | BPF_XADD | BPF_DW] = mem_xadd8,
> + [BPF_STX | BPF_ATOMIC | BPF_W] = mem_atomic4,
> + [BPF_STX | BPF_ATOMIC | BPF_DW] = mem_atomic8,
> [BPF_ST | BPF_MEM | BPF_B] = mem_st1,
> [BPF_ST | BPF_MEM | BPF_H] = mem_st2,
> [BPF_ST | BPF_MEM | BPF_W] = mem_st4,
[...]
next prev parent reply other threads:[~2020-11-28 5:01 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-27 17:57 [PATCH v2 bpf-next 00/13] Atomics for eBPF Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 01/13] bpf: x86: Factor out emission of ModR/M for *(reg + off) Brendan Jackman
2020-11-29 1:15 ` Alexei Starovoitov
2020-12-01 12:14 ` Brendan Jackman
2020-12-02 5:50 ` Alexei Starovoitov
2020-12-02 10:52 ` Brendan Jackman
2020-12-02 17:35 ` Alexei Starovoitov
2020-11-27 17:57 ` [PATCH v2 bpf-next 02/13] bpf: x86: Factor out emission of REX byte Brendan Jackman
2020-11-29 1:14 ` Alexei Starovoitov
2020-12-01 12:12 ` Brendan Jackman
2020-12-02 5:48 ` Alexei Starovoitov
2020-12-02 10:54 ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 03/13] bpf: x86: Factor out function to emit NEG Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 04/13] bpf: x86: Factor out a lookup table for some ALU opcodes Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 05/13] bpf: Rename BPF_XADD and prepare to encode other atomics in .imm Brendan Jackman
2020-11-28 3:43 ` Yonghong Song [this message]
2020-12-01 12:17 ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 06/13] bpf: Move BPF_STX reserved field check into BPF_STX verifier code Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 07/13] bpf: Add BPF_FETCH field / create atomic_fetch_add instruction Brendan Jackman
2020-11-28 4:15 ` Yonghong Song
2020-12-01 12:22 ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 08/13] bpf: Add instructions for atomic_[cmp]xchg Brendan Jackman
2020-11-28 5:25 ` Yonghong Song
2020-12-01 12:27 ` Brendan Jackman
2020-11-29 1:27 ` Alexei Starovoitov
2020-12-01 12:32 ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 09/13] bpf: Pull out a macro for interpreting atomic ALU operations Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 10/13] bpf: Add instructions for atomic[64]_[fetch_]sub Brendan Jackman
2020-11-27 21:39 ` kernel test robot
2020-11-27 21:39 ` [RFC PATCH] bpf: bpf_atomic_alu_string[] can be static kernel test robot
2020-11-28 5:35 ` [PATCH v2 bpf-next 10/13] bpf: Add instructions for atomic[64]_[fetch_]sub Yonghong Song
2020-11-29 1:34 ` Alexei Starovoitov
2020-11-30 17:18 ` Yonghong Song
2020-12-01 12:38 ` Brendan Jackman
2020-12-02 5:55 ` Alexei Starovoitov
2020-12-02 11:19 ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 11/13] bpf: Add bitwise atomic instructions Brendan Jackman
2020-11-28 5:39 ` Yonghong Song
2020-11-29 1:36 ` Alexei Starovoitov
2020-11-30 17:20 ` Yonghong Song
2020-11-27 17:57 ` [PATCH v2 bpf-next 12/13] bpf: Add tests for new BPF atomic operations Brendan Jackman
2020-12-01 3:55 ` Yonghong Song
2020-12-01 12:56 ` Brendan Jackman
2020-12-01 17:24 ` Yonghong Song
2020-12-02 2:22 ` Andrii Nakryiko
2020-12-02 12:26 ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 13/13] bpf: Document new atomic instructions Brendan Jackman
2020-11-28 5:53 ` [PATCH v2 bpf-next 00/13] Atomics for eBPF Yonghong Song
2020-11-29 1:40 ` Alexei Starovoitov
2020-11-30 17:22 ` Yonghong Song
2020-12-01 3:48 ` Yonghong Song
2020-12-02 2:00 ` Andrii Nakryiko
2020-12-02 5:05 ` Yonghong Song
2020-12-02 5:53 ` John Fastabend
2020-12-02 5:59 ` Andrii Nakryiko
2020-12-02 6:27 ` John Fastabend
2020-12-02 8:03 ` Yonghong Song
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