| Date | Wed, 6 Dec 2017 22:18:00 +0100 | From | Borislav Petkov <> | Subject | Re: [patch 39/60] x86/mm/kpti: Share cpu_entry_area PMDs |
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On Mon, Dec 04, 2017 at 03:07:45PM +0100, Thomas Gleixner wrote: > From: Andy Lutomirski <luto@kernel.org> > > Share the FIX_USR_SHARED PMDs so the user space and kernel space page > tables have the same PMD page. > > [ tglx: Made it use the FIX_USR_SHARED range so later additions > are covered automatically ] > > Signed-off-by: Andy Lutomirski <luto@kernel.org> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > --- > arch/x86/mm/kpti.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > --- a/arch/x86/mm/kpti.c > +++ b/arch/x86/mm/kpti.c > @@ -167,6 +167,23 @@ kpti_clone_pmds(unsigned long start, uns > } > > /* > + * Clone the populated PMDs of the user shared fixmaps into the user space > + * visible page table. > + */ > +static void __init kpti_clone_user_shared(void) > +{ > + unsigned long bot, top; > + > + bot = __fix_to_virt(FIX_USR_SHARED_BOTTOM); > + top = __fix_to_virt(FIX_USR_SHARED_TOP) + PAGE_SIZE; > + > + /* Top of the user shared block must be PMD-aligned. */ > + WARN_ON(top & ~PMD_MASK);
Or
WARN_ON(top & (PMD_SIZE - 1));
Otherwise:
Reviewed-by: Borislav Petkov <bp@suse.de>
-- Regards/Gruss, Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --
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