Re: [RFC PATCH 6/6] ppc: ebpf/jit: Implement JIT compiler for extended BPF

From	Alexei Starovoitov <ast@fb.com>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH 6/6] ppc: ebpf/jit: Implement JIT compiler for extended BPF
Date	2016-04-01 20:20 +0200
Message-ID	<rjbPP-8gR-9@gated-at.bofh.it> (permalink)
References	<rj4bE-2M5-3@gated-at.bofh.it> <rj4bE-2M5-9@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 4/1/16 2:58 AM, Naveen N. Rao wrote:
> PPC64 eBPF JIT compiler. Works for both ABIv1 and ABIv2.
>
> Enable with:
> echo 1 > /proc/sys/net/core/bpf_jit_enable
> or
> echo 2 > /proc/sys/net/core/bpf_jit_enable
>
> ... to see the generated JIT code. This can further be processed with
> tools/net/bpf_jit_disasm.
>
> With CONFIG_TEST_BPF=m and 'modprobe test_bpf':
> test_bpf: Summary: 291 PASSED, 0 FAILED, [234/283 JIT'ed]
>
> ... on both ppc64 BE and LE.
>
> The details of the approach are documented through various comments in
> the code, as are the TODOs. Some of the prominent TODOs include
> implementing BPF tail calls and skb loads.
>
> Cc: Matt Evans <matt@ozlabs.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Alexei Starovoitov <ast@fb.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> ---
>   arch/powerpc/include/asm/ppc-opcode.h |  19 +-
>   arch/powerpc/net/Makefile             |   4 +
>   arch/powerpc/net/bpf_jit.h            |  66 ++-
>   arch/powerpc/net/bpf_jit64.h          |  58 +++
>   arch/powerpc/net/bpf_jit_comp64.c     | 828 ++++++++++++++++++++++++++++++++++
>   5 files changed, 973 insertions(+), 2 deletions(-)
>   create mode 100644 arch/powerpc/net/bpf_jit64.h
>   create mode 100644 arch/powerpc/net/bpf_jit_comp64.c
...
> -#ifdef CONFIG_PPC64
> +#if defined(CONFIG_PPC64) && (!defined(_CALL_ELF) || _CALL_ELF != 2)

impressive stuff!
Everything nicely documented. Could you add few words for the above
condition as well ?
Or may be a new macro, since it occurs many times?
What are these _CALL_ELF == 2 and != 2 conditions mean? ppc ABIs ?
Will there ever be v3 ?

So far most of the bpf jits were going via net-next tree, but if
in this case no changes to the core is necessary then I guess it's fine
to do it via powerpc tree. What's your plan?

Thread

[RFC PATCH 0/6] eBPF JIT for PPC64 "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-04-01 12:10 +0200
  [RFC PATCH 5/6] ppc: bpf/jit: Isolate classic BPF JIT specifics into a separate header "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-04-01 12:10 +0200
  [RFC PATCH 6/6] ppc: ebpf/jit: Implement JIT compiler for extended BPF "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-04-01 12:10 +0200
    Re: [RFC PATCH 6/6] ppc: ebpf/jit: Implement JIT compiler for  extended BPF Alexei Starovoitov <ast@fb.com> - 2016-04-01 20:20 +0200
      Re: [RFC PATCH 6/6] ppc: ebpf/jit: Implement JIT compiler for extended  BPF Daniel Borkmann <daniel@iogearbox.net> - 2016-04-01 20:40 +0200
        Re: [RFC PATCH 6/6] ppc: ebpf/jit: Implement JIT compiler for  extended BPF "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-04-04 19:20 +0200
  [RFC PATCH 3/6] ppc: bpf/jit: Introduce rotate immediate instructions "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-04-01 12:10 +0200
  [RFC PATCH 4/6] ppc: bpf/jit: A few cleanups "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-04-01 12:10 +0200
  [RFC PATCH 1/6] ppc: bpf/jit: Fix/enhance 32-bit Load Immediate implementation "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-04-01 12:10 +0200
  [RFC PATCH 2/6] ppc: bpf/jit: Optimize 64-bit Immediate loads "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-04-01 12:10 +0200
  Re: [RFC PATCH 0/6] eBPF JIT for PPC64 "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-04-01 12:30 +0200

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