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

From: Dmitry Safonov
Date: Mon Aug 29 2016 - 05:53:54 EST

On 08/28/2016 11:14 PM, Cyrill Gorcunov wrote:
On Thu, Aug 25, 2016 at 06:21:08PM +0300, Dmitry Safonov 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.

Signed-off-by: Dmitry Safonov <dsafonov@xxxxxxxxxxxxx>

Hi Cyrill,

Dmitry, could you clarify please, why "old way" remains in the code?
Even if RFC is not the new approach is supposing to completely remove
old one? Or I miss something obvious?

Well, I left it for RFC, I think on post-RFC we can leave it as
cmd-param (alike vdso{64,32}_enabled) so it could be easily disabled if
it brokes something in userspace. I guess, that's preferred way to
introduce something like that.