Messages in this thread | | | From | Ard Biesheuvel <> | Subject | [PATCH 0/4] bpf: permit JIT allocations to be served outside the module region | Date | Sat, 17 Nov 2018 10:57:11 -0800 |
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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@iogearbox.net> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Rick Edgecombe <rick.p.edgecombe@intel.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <keescook@chromium.org>
Cc: Jessica Yu <jeyu@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> Cc: James Hogan <jhogan@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "David S. Miller" <davem@davemloft.net> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linuxppc-dev@lists.ozlabs.org Cc: sparclinux@vger.kernel.org Cc: netdev@vger.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
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