On Wed, Sep 22, 2021 at 09:52:07PM +0200, Borislav Petkov wrote:
> On Wed, Sep 22, 2021 at 05:30:15PM +0300, Kirill A. Shutemov wrote:
> > Not fine, but waiting to blowup with random build environment change.
>
> Why is it not fine?
>
> Are you suspecting that the compiler might generate something else and
> not a rip-relative access?
Yes. We had it before for __supported_pte_mask and other users of
fixup_pointer().
See for instance 4a09f0210c8b ("x86/boot/64/clang: Use fixup_pointer() to
access '__supported_pte_mask'")
Unless we find other way to guarantee RIP-relative access, we must use
fixup_pointer() to access any global variables.
--
Kirill A. Shutemov
