| Date | Tue, 5 Dec 2017 19:33:21 +0100 | From | Borislav Petkov <> | Subject | Re: [patch 33/60] x86/mm/kpti: Allocate a separate user PGD |
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On Mon, Dec 04, 2017 at 03:07:39PM +0100, Thomas Gleixner wrote: > From: Dave Hansen <dave.hansen@linux.intel.com> > > Kernel page table isolation requires to have two PGDs. One for the kernel, > which contains the full kernel mapping plus the user space mapping and one > for user space which contains the user space mappings and the minimal set > of kernel mappings which are required by the architecture to be able to > transition from and to user space. > > Add the necessary preliminaries. > > [ tglx: Split out from the big kaiser dump ] > > Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > > --- > arch/x86/kernel/head_64.S | 30 +++++++++++++++++++++++++++--- > arch/x86/mm/pgtable.c | 16 ++++++++++++++-- > 2 files changed, 41 insertions(+), 5 deletions(-)
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> --- a/arch/x86/mm/pgtable.c > +++ b/arch/x86/mm/pgtable.c > @@ -355,14 +355,26 @@ static inline void _pgd_free(pgd_t *pgd) > kmem_cache_free(pgd_cache, pgd); > } > #else > + > +#ifdef CONFIG_KERNEL_PAGE_TABLE_ISOLATION > +/* > + * Instead of one pgd, we aquire two pgds. Being order-1, it is
"acquire"
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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