linux-kernel - Re: [PATCH] ARM: move body of head-common.S back to text section

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Message-ID: <20130703100044.GG24642@n2100.arm.linux.org.uk>
Date:	Wed, 3 Jul 2013 11:00:44 +0100
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Paul Gortmaker <paul.gortmaker@...driver.com>
Cc:	Stephen Warren <swarren@...dotorg.org>,
	Stephen Boyd <sboyd@...eaurora.org>,
	Will Deacon <will.deacon@....com>,
	linux-kernel@...r.kernel.org, Joseph Lo <josephl@...dia.com>,
	linux-tegra@...r.kernel.org, Stephen Warren <swarren@...dia.com>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] ARM: move body of head-common.S back to text section

On Wed, Jul 03, 2013 at 01:19:07AM -0400, Paul Gortmaker wrote:
> As an aside, I'm now thinking any __INIT that implicitly rely on EOF for
> closure are nasty traps waiting to happen and it might be worthwhile to
> audit and explicitly __FINIT them before someone appends to the file...

That hides a different kind of bug though - I hate __FINIT for exactly
that reason.  Consider this:

	.text
	blah blah blah
	__INIT
	lots of init stuff
	__FINIT
	more .text stuff

Now, someone comes along and modifies this to be:

	.text
	blah blah blah
	.data
	something else
	__INIT
	lots of init stuff
	__FINIT
	more .text stuff

Now, what is the effect of that __FINIT now?  You get the following .text
emitted into the .data section instead.  This is basically the same problem
you've just encounted.

Maybe:

	__FINIT
	.text

is the safest solution - and __FINIT becomes just a no-op marker to avoid
anyone relying on its properties.
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