Re: [PATCH] [4/7] Don't use large pages to map the first 2/4MB ofmemory

From: Thomas Gleixner
Date: Fri Mar 21 2008 - 14:03:48 EST


On Fri, 21 Mar 2008, Andi Kleen wrote:
> > Also we split the first GB mapping anyway due to the various regions
> > (NX, RO, UC) in there.
>
> I didn't think so unless you have DEBUG_RODATA enabled?

NX is independent of DEBUG_RODATA and the RODATA protection should be
made unconditional on anyway.

> Also there
> should be no UC region there as known by the kernel. There might
> be a WC region there from the frame buffer code, but that is an MTRR,
> not a pageattr.

The first ioremap of the PCI space splits the GB page as well.

Thanks,

tglx
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