From: Rusty Russell <rusty@rustcorp.com.au>
To: Arjan van de Ven <arjan@infradead.org>
Subject: Re: [PATCH v5] RO/NX protection for loadable kernel modules
Date: Sun, 12 Jul 2009 19:28:27 +0930
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Cc: Ingo Molnar <mingo@elte.hu>, Siarhei Liakh <sliakh.lkml@gmail.com>,
       linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org,
       James Morris <jmorris@namei.org>,
       Andrew Morton <akpm@linux-foundation.org>, Andi Kleen <ak@muc.de>,
       Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
       linux-cris-kernel@axis.com
References: <817ecb6f0907081610p6d60341cudbee42685eac1347@mail.gmail.com> <200907121410.39874.rusty@rustcorp.com.au> <20090712004524.2f0c4e57@infradead.org>
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On Sun, 12 Jul 2009 05:15:24 pm Arjan van de Ven wrote:
> Rusty Russell <rusty@rustcorp.com.au> wrote:
> > (I like the idea of trying kmalloc and falling back, simply because
> > it reduces TLB pressure, but that's probably best done after
> > unification).
>
> or using a non-power-of-two get_free_pages() thing...
>
> some architectures will need to know that memory needs to be executable
> at allocation time so that it can be put in an executable address range
> etc...

Yes, maybe that's better than kmalloc.  On my laptop I have 105 modules 
loaded, with 3778464 total length: I'm wasting 206944 bytes on unused tails of 
pages.  But that's only 0.06% of my memory.

Thanks,
Rusty.
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