netdev - [PATCH 0/4] bpf: permit JIT allocations to be served outside the module region

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Message-Id: <20181117185715.25198-1-ard.biesheuvel@linaro.org>
Date:   Sat, 17 Nov 2018 10:57:11 -0800
From:   Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:     linux-kernel@...r.kernel.org
Cc:     Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Alexei Starovoitov <ast@...nel.org>,
        Rick Edgecombe <rick.p.edgecombe@...el.com>,
        Eric Dumazet <eric.dumazet@...il.com>,
        Jann Horn <jannh@...gle.com>,
        Kees Cook <keescook@...omium.org>,
        Jessica Yu <jeyu@...nel.org>, Arnd Bergmann <arnd@...db.de>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Mark Rutland <mark.rutland@....com>,
        Ralf Baechle <ralf@...ux-mips.org>,
        Paul Burton <paul.burton@...s.com>,
        James Hogan <jhogan@...nel.org>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        "David S. Miller" <davem@...emloft.net>,
        linux-arm-kernel@...ts.infradead.org, linux-mips@...ux-mips.org,
        linuxppc-dev@...ts.ozlabs.org, sparclinux@...r.kernel.org,
        netdev@...r.kernel.org
Subject: [PATCH 0/4] bpf: permit JIT allocations to be served outside the module region

On arm64, modules are allocated from a 128 MB window which is close to
the core kernel, so that relative direct branches are guaranteed to be
in range (except in some KASLR configurations). Also, module_alloc()
is in charge of allocating KASAN shadow memory when running with KASAN
enabled.

This means that the way BPF reuses module_alloc()/module_memfree() is
undesirable on arm64 (and potentially other architectures as well),
and so this series refactors BPF's use of those functions to permit
architectures to change this behavior.

Patch #1 fixes a bug introduced during the merge window, where the new
alloc/free tracking does not account for memory that is freed by some
arch code.

Patch #2 refactors the freeing path so that architectures can switch to
something other than module_memfree().

Patch #3 does the same for module_alloc().

Patch #4 implements the new alloc/free overrides for arm64

Cc: Daniel Borkmann <daniel@...earbox.net>
Cc: Alexei Starovoitov <ast@...nel.org>
Cc: Rick Edgecombe <rick.p.edgecombe@...el.com>
Cc: Eric Dumazet <eric.dumazet@...il.com>
Cc: Jann Horn <jannh@...gle.com>
Cc: Kees Cook <keescook@...omium.org>

Cc: Jessica Yu <jeyu@...nel.org>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will.deacon@....com>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Ralf Baechle <ralf@...ux-mips.org>
Cc: Paul Burton <paul.burton@...s.com>
Cc: James Hogan <jhogan@...nel.org>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: "David S. Miller" <davem@...emloft.net>
Cc: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org
Cc: linux-mips@...ux-mips.org
Cc: linuxppc-dev@...ts.ozlabs.org
Cc: sparclinux@...r.kernel.org
Cc: netdev@...r.kernel.org

Ard Biesheuvel (4):
  bpf: account for freed JIT allocations in arch code
  net/bpf: refactor freeing of executable allocations
  bpf: add __weak hook for allocating executable memory
  arm64/bpf: don't allocate BPF JIT programs in module memory

 arch/arm64/net/bpf_jit_comp.c     | 11 ++++++++++
 arch/mips/net/bpf_jit.c           |  7 ++-----
 arch/powerpc/net/bpf_jit_comp.c   |  7 ++-----
 arch/powerpc/net/bpf_jit_comp64.c | 12 +++--------
 arch/sparc/net/bpf_jit_comp_32.c  |  7 ++-----
 kernel/bpf/core.c                 | 22 ++++++++++----------
 6 files changed, 31 insertions(+), 35 deletions(-)

-- 
2.17.1