linux-kernel - Re: [PATCH v2] ARM: mm: fix location of

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Message-ID: <CAGXu5jKuwkiaVCtTSbcY-UAE4_5rJDX0t0e22O1+A+NYDUZ9oA@mail.gmail.com>
Date:	Thu, 16 Jun 2016 10:08:03 -0700
From:	Kees Cook <keescook@...omium.org>
To:	Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc:	Russell King <linux@...linux.org.uk>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Matt Fleming <matt@...eblueprint.co.uk>,
	Pratyush Anand <panand@...hat.com>,
	Nicolas Pitre <nicolas.pitre@...aro.org>,
	Vladimir Murzin <vladimir.murzin@....com>,
	Toshi Kani <toshi.kani@....com>,
	Stephen Boyd <sboyd@...eaurora.org>,
	Chris Brandt <chris.brandt@...esas.com>,
	Alexander Potapenko <glider@...gle.com>,
	Marc Zyngier <marc.zyngier@....com>,
	Arnd Bergmann <arnd@...db.de>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v2] ARM: mm: fix location of _etext

On Thu, Jun 16, 2016 at 5:04 AM, Ard Biesheuvel
<ard.biesheuvel@...aro.org> wrote:
> On 15 June 2016 at 22:24, Kees Cook <keescook@...omium.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@...omium.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