netdev - Re: [PATCH v4 1/2] bpf: add __weak hook for allocating executable memory

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Message-ID: <a16dc0bb806d6a0685978bb94c2e3f19588c063f.camel@intel.com>
Date:   Mon, 26 Nov 2018 17:02:35 +0000
From:   "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "ard.biesheuvel@...aro.org" <ard.biesheuvel@...aro.org>
CC:     "daniel@...earbox.net" <daniel@...earbox.net>,
        "keescook@...omium.org" <keescook@...omium.org>,
        "jeyu@...nel.org" <jeyu@...nel.org>,
        "jannh@...gle.com" <jannh@...gle.com>,
        "ast@...nel.org" <ast@...nel.org>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "catalin.marinas@....com" <catalin.marinas@....com>,
        "will.deacon@....com" <will.deacon@....com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "eric.dumazet@...il.com" <eric.dumazet@...il.com>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "arnd@...db.de" <arnd@...db.de>
Subject: Re: [PATCH v4 1/2] bpf: add __weak hook for allocating executable
 memory

On Fri, 2018-11-23 at 23:18 +0100, Ard Biesheuvel wrote:
> By default, BPF uses module_alloc() to allocate executable memory,
> but this is not necessary on all arches and potentially undesirable
> on some of them.
> 
> So break out the module_alloc() and module_memfree() calls into __weak
> functions to allow them to be overridden in arch code.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
> ---

It looks like some of the architectures call module_alloc directly in their
bpf_jit_compile implementations as well.

Rick