Re: [PATCH 01/11] x86/mm: factor out pageattr _PAGE_GLOBAL setting

[Linus Torvalds]

On Mon, Apr 2, 2018 at 10:27 AM, Dave Hansen
<dave.hansen@xxxxxxxxxxxxxxx> wrote:
>
> Aside: _PAGE_GLOBAL is ignored when CR4.PGE=1, so why do we
> even go to the trouble of filtering it anywhere?

I'm assuming this is a typo, and you mean "when CR4.PGE=0".

The question you raise may be valid, but within the particular context
of *this* patch it is not.

In the context of this particular patch, the issue is that we use
_PAGE_GLOBAL as _PAGE_BIT_PROTNONE when the present bit isn't set.

       Linus