Re: [PATCH v6 10/11] mm: add a user_virt_to_phys symbol

From: Christoph Hellwig
Date: Mon Sep 11 2017 - 03:36:33 EST

On Fri, Sep 08, 2017 at 08:44:22AM -0700, Kees Cook wrote:
> On Fri, Sep 8, 2017 at 12:55 AM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> > On Thu, Sep 07, 2017 at 11:36:08AM -0600, Tycho Andersen wrote:
> >> We need someting like this for testing XPFO. Since it's architecture
> >> specific, putting it in the test code is slightly awkward, so let's make it
> >> an arch-specific symbol and export it for use in LKDTM.
> >
> > We really should not add an export for this.
> >
> > I think you'll want to just open code it in your test module.
> Isn't that going to be fragile? Why not an export?

It is a little fragile, but it is functionality not needed at all by
the kernel, so we should not add it to the kernel image and/or export