netdev - [PATCH bpf-next 0/2] arm64/bpf: remove 128MB limit for BPF JIT programs

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Date:   Wed,  3 Nov 2021 09:49:27 +0000
From:   Alan Maguire <alan.maguire@...cle.com>
To:     ardb@...nel.org, catalin.marinas@....com, will@...nel.org,
        daniel@...earbox.net, ast@...nel.org
Cc:     zlim.lnx@...il.com, andrii@...nel.org, kafai@...com,
        songliubraving@...com, yhs@...com, john.fastabend@...il.com,
        kpsingh@...nel.org, andreyknvl@...il.com,
        vincenzo.frascino@....com, mark.rutland@....com,
        samitolvanen@...gle.com, joey.gouly@....com, maz@...nel.org,
        daizhiyuan@...tium.com.cn, jthierry@...hat.com,
        tiantao6@...ilicon.com, pcc@...gle.com, akpm@...ux-foundation.org,
        rppt@...nel.org, Jisheng.Zhang@...aptics.com,
        liu.hailong6@....com.cn, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        bpf@...r.kernel.org, Alan Maguire <alan.maguire@...cle.com>
Subject: [PATCH bpf-next 0/2] arm64/bpf: remove 128MB limit for BPF JIT programs

There is a 128MB limit on BPF JIT program allocations; this is
to ensure BPF programs are in branching range of each other.
Patch 1 in this series removes this restriction, but because
BPF exception handling used the contiguous nature of the JIT
region in fixing up exceptions, changes are needed in exception
handling.  To verify exception handling still works, a test
case to validate exception handling in BPF programs is added in
patch 2.

There was previous discussion around this topic [1], in particular
would be good to get feedback from Daniel if this approach makes
sense.

[1] https://lore.kernel.org/all/20181121131733.14910-1-ard.biesheuvel@linaro.org/

Alan Maguire (1):
  selftests/bpf: add exception handling selftests for tp_bpf program

Russell King (1):
  arm64/bpf: remove 128MB limit for BPF JIT programs

 arch/arm64/include/asm/extable.h                   |  9 -----
 arch/arm64/include/asm/memory.h                    |  5 +--
 arch/arm64/kernel/traps.c                          |  2 +-
 arch/arm64/mm/extable.c                            | 13 +++++--
 arch/arm64/mm/ptdump.c                             |  2 -
 arch/arm64/net/bpf_jit_comp.c                      | 10 +++--
 tools/testing/selftests/bpf/prog_tests/exhandler.c | 45 ++++++++++++++++++++++
 tools/testing/selftests/bpf/progs/exhandler_kern.c | 35 +++++++++++++++++
 8 files changed, 97 insertions(+), 24 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/exhandler.c
 create mode 100644 tools/testing/selftests/bpf/progs/exhandler_kern.c

-- 
1.8.3.1