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    SubjectRe: [PATCH 02/23] x86, kaiser: do not set _PAGE_USER for init_mm page tables
    On Thu, 2 Nov 2017, Andy Lutomirski wrote:
    > On Wed, Nov 1, 2017 at 2:28 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
    > > On Wed, 1 Nov 2017, Andy Lutomirski wrote:
    > >
    > >> On Wed, Nov 1, 2017 at 2:11 PM, Thomas Gleixner <tglx@linutronix.de> 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.
    > >
    > > Groan, forgot about that abomination, but still there is no point in having
    > > it marked PAGE_USER in the init_mm at all, kaiser or not.
    > >
    >
    > How can it be PAGE_USER in user mms but not init_mm? It's the same page table.

    Right you are. Brain was already shutdown it seems.

    Thanks,

    tglx

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