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From: Kees Cook <keescook@chromium.org>
Date: Thu, 16 Jun 2016 10:08:03 -0700
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Subject: Re: [PATCH v2] ARM: mm: fix location of _etext
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Russell King <linux@armlinux.org.uk>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Matt Fleming <matt@codeblueprint.co.uk>,
        Pratyush Anand <panand@redhat.com>,
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        Vladimir Murzin <vladimir.murzin@arm.com>,
        Toshi Kani <toshi.kani@hpe.com>, Stephen Boyd <sboyd@codeaurora.org>,
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On Thu, Jun 16, 2016 at 5:04 AM, Ard Biesheuvel
<ard.biesheuvel@linaro.org> wrote:
> On 15 June 2016 at 22:24, Kees Cook <keescook@chromium.org> wrote:
>> The _etext position is defined to be the end of the kernel text code,
>> and should not include any part of the data segments. This interferes
>> with things that might check memory ranges and expect executable code
>> up to _etext. Just to be conservative, leave the kernel resource as
>> it was, using __init_begin instead of _etext as the end mark.
>>
>> Signed-off-by: Kees Cook <keescook@chromium.org>
>> ---
>> v2:
>> - Switched resource tracker to using __init_begin, rmk
>
> Actually, Linus removed the x86 /proc/iomem resources for kernel segments in
>
> c4004b02f8e5 ("x86: remove the kernel code/data/bss resources from /proc/iomem")
>
> so I wonder if we should not just do the same for ARM and arm64?

Nope, that got reverted. Removing it breaks things.

4046d6e81f33b7ef50d6668b78076d54c5e066b6

-Kees

-- 
Kees Cook
Chrome OS & Brillo Security