Re: [patch 05/16] mm: Allow special mappings with user access cleared

[Andy Lutomirski]

On Tue, Dec 12, 2017 at 9:32 AM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> From: Peter Zijstra <peterz@xxxxxxxxxxxxx>
>
> In order to create VMAs that are not accessible to userspace create a new
> VM_NOUSER flag. This can be used in conjunction with
> install_special_mapping() to inject 'kernel' data into the userspace map.
>
> Similar to how arch_vm_get_page_prot() allows adding _PAGE_flags to
> pgprot_t, introduce arch_vm_get_page_prot_excl() which masks
> _PAGE_flags from pgprot_t and use this to implement VM_NOUSER for x86.

How does this interact with get_user_pages(), etc?