linux-kernel - Re: [PATCH v1 0/2] Introduce the initify gcc plugin

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Message-ID: <1467150555.24287.77.camel@perches.com>
Date:	Tue, 28 Jun 2016 14:49:15 -0700
From:	Joe Perches <joe@...ches.com>
To:	Emese Revfy <re.emese@...il.com>,
	kernel-hardening@...ts.openwall.com,
	Matt Davis <mattdavis9@...il.com>
Cc:	pageexec@...email.hu, spender@...ecurity.net, mmarek@...e.com,
	keescook@...omium.org, linux-kernel@...r.kernel.org,
	yamada.masahiro@...ionext.com, linux-kbuild@...r.kernel.org,
	minipli@...linux.so, linux@...linux.org.uk,
	catalin.marinas@....com, linux@...musvillemoes.dk,
	david.brown@...aro.org, benh@...nel.crashing.org,
	tglx@...utronix.de, akpm@...ux-foundation.org,
	jlayton@...chiereds.net, arnd@...db.de
Subject: Re: [PATCH v1 0/2] Introduce the initify gcc plugin

On Tue, 2016-06-28 at 13:34 +0200, Emese Revfy wrote:
> I would like to introduce the initify gcc plugin. The kernel already has
> a mechanism to free up code and data memory that is only used during kernel
> or module initialization.
> This plugin will teach the compiler to find more such code and data that
> can be freed after initialization. It reduces memory usage.
> The initify gcc plugin can be useful for embedded systems.

Another potentially useful plugin, especially for embedded systems,
would be to compress any string literal marked with

	 __attribute__((format(printf, string-index,)))

and decompress the compressed format on the stack in lib/vsprintf.c
vsnprintf just before use.

I've started to experiment with that.