netdev - [PATCH v2 0/4] Fix up bpf_jit

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Message-Id: <20211012135935.37054-1-lmb@cloudflare.com>
Date:   Tue, 12 Oct 2021 14:59:31 +0100
From:   Lorenz Bauer <lmb@...udflare.com>
To:     nicolas.dichtel@...nd.com, luke.r.nels@...il.com,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>
Cc:     kernel-team@...udflare.com, Lorenz Bauer <lmb@...udflare.com>,
        linux-riscv@...ts.infradead.org, netdev@...r.kernel.org,
        bpf@...r.kernel.org
Subject: [PATCH v2 0/4] Fix up bpf_jit_limit some more

Some more cleanups around bpf_jit_limit to make it readable via sysctl.

Jakub raised the point that a sysctl toggle is UAPI and therefore
can't be easily changed later on. I tried to find another place to stick
the info, but couldn't find a good one. All the current BPF knobs are in
sysctl.

There are examples of read only sysctls:
$ sudo find /proc/sys -perm 0444 | wc -l
90

There are no examples of sysctls with mode 0400 however:
$ sudo find /proc/sys -perm 0400 | wc -l
0

Thoughts?

Changes in v2:
* riscv not sparcv (Luke)
* Expose bpf_jit_current in bytes, not pages (Nicholas)

Lorenz Bauer (4):
  bpf: define bpf_jit_alloc_exec_limit for riscv JIT
  bpf: define bpf_jit_alloc_exec_limit for arm64 JIT
  bpf: prevent increasing bpf_jit_limit above max
  bpf: export bpf_jit_current

 Documentation/admin-guide/sysctl/net.rst |  6 ++++++
 arch/arm64/net/bpf_jit_comp.c            |  5 +++++
 arch/riscv/net/bpf_jit_core.c            |  5 +++++
 include/linux/filter.h                   |  2 ++
 kernel/bpf/core.c                        |  7 ++++---
 net/core/sysctl_net_core.c               | 26 +++++++++++++++++++++++-
 6 files changed, 47 insertions(+), 4 deletions(-)

-- 
2.30.2