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From: Thomas Gleixner <tglx@linutronix.de>
To: Andi Kleen <andi@firstfloor.org>
Cc: Andi Kleen <ak@suse.de>, mingo@elte.hu, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] [1/5] CPA: Split static_protections into required_static_prot and advised_static_prot
Date: Sat, 9 Feb 2008 18:09:23 +0100 (CET)	[thread overview]
Message-ID: <alpine.LFD.1.00.0802091806220.3145@apollo.tec.linutronix.de> (raw)
In-Reply-To: <20080209163904.GA24548@one.firstfloor.org>

On Sat, 9 Feb 2008, Andi Kleen wrote:
> > > Note the behaviour for pageattr and thus DEBUG_RODATA / debugging
> > > sitations where you don't care about your TLB this
> > > does not change, this makes only a difference for the initial init_32
> > > direct mapping setup.
> > 
> > Your patches do change the behaviour. The range checking breaks the
> > enforcement of some restrictions for the sake of keeping the large
> > page intact.
> 
> You mean in try_preserve_large_page()?
> 
> No actually they were not completely enforced previously at all, because
> it did only check the restrictions of the first page.

Right, you poked my nose to it. I did not think about it when I coded
it. It is wrong and needs to be fixed, but not by the range check you
introduced.
 
> On the end of my patch series the enforcement is actually stricter
> than it was before, although not 100%.

As far as I can tell it is more relaxed, as it will make overlapping
regions of rodata and rwdata completely rw instead of splitting it up.

Thanks,
	tglx

  reply	other threads:[~2008-02-09 17:09 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-08 16:36 [PATCH] [0/5] pageattr protection patchkit v2 for the latest kernel Andi Kleen
2008-02-08 16:36 ` [PATCH] [1/5] CPA: Split static_protections into required_static_prot and advised_static_prot Andi Kleen
2008-02-09 14:56   ` Thomas Gleixner
2008-02-09 15:13     ` Andi Kleen
2008-02-09 15:50       ` Thomas Gleixner
2008-02-09 16:39         ` Andi Kleen
2008-02-09 17:09           ` Thomas Gleixner [this message]
2008-02-10  9:39             ` Andi Kleen
2008-02-08 16:36 ` [PATCH] [2/5] Support range checking for required/advisory protections Andi Kleen
2008-02-08 16:36 ` [PATCH] [3/5] CPA: Make advised protection check truly advisory Andi Kleen
2008-02-09 15:38   ` Thomas Gleixner
2008-02-09 16:56     ` Andi Kleen
2008-02-09 17:38       ` Thomas Gleixner
2008-02-10  9:19         ` Andi Kleen
2008-02-10 16:50           ` Thomas Gleixner
2008-02-08 16:36 ` [PATCH] [4/5] Don't use inline for the protection checks Andi Kleen
2008-02-08 16:36 ` [PATCH] [5/5] Switch i386 early boot page table initialization over to use required_static_prot() Andi Kleen
  -- strict thread matches above, loose matches on Subject: below --
2008-02-08 13:27 [PATCH] [1/5] CPA: Split static_protections into required_static_prot and advised_static_prot Andi Kleen

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