From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
To: "linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"ard.biesheuvel@linaro.org" <ard.biesheuvel@linaro.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"daniel@iogearbox.net" <daniel@iogearbox.net>,
"keescook@chromium.org" <keescook@chromium.org>,
"jeyu@kernel.org" <jeyu@kernel.org>,
"jannh@google.com" <jannh@google.com>,
"ast@kernel.org" <ast@kernel.org>,
"mark.rutland@arm.com" <mark.rutland@arm.com>,
"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
"will.deacon@arm.com" <will.deacon@arm.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"eric.dumazet@gmail.com" <eric.dumazet@gmail.com>,
"davem@davemloft.net" <davem@davemloft.net>,
"arnd@arndb.de" <arnd@arndb.de>
Subject: Re: [PATCH v2 0/2] bpf: permit JIT allocations to be served outside the module region
Date: Wed, 21 Nov 2018 19:48:07 +0000 [thread overview]
Message-ID: <9d7f77959e1be0a9a3ff511a8fc45518068c85a6.camel@intel.com> (raw)
In-Reply-To: <20181121131733.14910-1-ard.biesheuvel@linaro.org>
On Wed, 2018-11-21 at 14:17 +0100, Ard Biesheuvel wrote:
> 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.
>
Hi Ard,
I am looking at adding optional BPF JIT in vmalloc functionality for x86 that
would use this refactor. In fact I have done the same thing with just different
names.
My implementation intends to use the module space until a usage limit is reached
and then overflow into vmalloc, so it would be an additional knob like
"bpf_jit_limit". Wondering if that should be a cross-arch concept that connects
to this. Does it fit in with what you are trying to do for arm64 here?
Thanks,
Rick
next prev parent reply other threads:[~2018-11-21 19:48 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-21 13:17 [PATCH v2 0/2] bpf: permit JIT allocations to be served outside the module region Ard Biesheuvel
2018-11-21 13:17 ` [PATCH v2 1/2] bpf: add __weak hook for allocating executable memory Ard Biesheuvel
2018-11-22 20:01 ` kbuild test robot
2018-11-22 21:08 ` Ard Biesheuvel
2018-11-21 13:17 ` [PATCH v2 2/2] arm64/bpf: don't allocate BPF JIT programs in module memory Ard Biesheuvel
2018-11-21 23:20 ` Daniel Borkmann
2018-11-22 8:02 ` Ard Biesheuvel
2018-11-22 22:49 ` Daniel Borkmann
2018-11-24 2:57 ` kbuild test robot
2018-11-21 19:48 ` Edgecombe, Rick P [this message]
2018-11-21 20:36 ` [PATCH v2 0/2] bpf: permit JIT allocations to be served outside the module region Ard Biesheuvel
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