Re: [PATCH 02/23] x86, kaiser: do not set _PAGE_USER for init_mm page tables

[Andy Lutomirski]

On Wed, Nov 1, 2017 at 2:11 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> On Tue, 31 Oct 2017, Dave Hansen wrote:
>
>>
>> init_mm is for kernel-exclusive use.  If someone is allocating page
>> tables in it, do not set _PAGE_USER on them.  This ensures that
>> we do *not* set NX on these page tables in the KAISER code.
>
> This changelog is confusing at best.
>
> Why is this a kaiser issue? Nothing should ever create _PAGE_USER entries
> in init_mm, right?

The vsyscall page is _PAGE_USER and lives in init_mm via the fixmap.

--Andy