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From: Andy Lutomirski <luto@kernel.org>
Date: Tue, 12 Dec 2017 10:00:08 -0800
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Subject: Re: [patch 05/16] mm: Allow special mappings with user access cleared
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
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On Tue, Dec 12, 2017 at 9:32 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
> From: Peter Zijstra <peterz@infradead.org>
>
> 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?