Re: [RFC 1/3] x86/vdso: create vdso file, use it for mapping

[Dmitry Safonov <dsafonov@virtuozzo.com>]

On 08/29/2016 12:28 PM, Andy Lutomirski wrote:
> On Thu, Aug 25, 2016 at 8:21 AM, Dmitry Safonov <dsafonov@virtuozzo.com> wrote:
>> I added here a new in-kernel fs with ramfs-like options.
>> Created vdso file in this fs (yet for testing, only 64-bit vdso).
>> Mapped this file to process's mm on setup_additional_pages.
>> Just for testing purpose it's done only for specific UID.
>
> I'm wondering whether all this code could be easily moved into the
> core special mapping helpers so that all special mappings get the same
> benefit.  We could embed a struct file * (or struct inode or whatever)
> in special_mapping if needed.

Hmm, yes, I guess. The only thing -- we'll still need per-arch changes
to initialize those files on booting. But that looks like the proper
generic place to move this code.

> Also, could this be simplified to use anon_inode?
>
> (I'm not a VFS expert at all, so I could be way off base.)

Well, I'll try to do the second version with anon_inode.

Thanks,
              Dmitry