From e3238faf20fb1b51a814497751398ab525a2c884 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Wed, 18 Jul 2018 11:40:54 +0200 Subject: x86/pgtable/32: Allocate 8k page-tables when PTI is enabled Allocate a kernel and a user page-table root when PTI is enabled. Also allocate a full page per root for PAE because otherwise the bit to flip in CR3 to switch between them would be non-constant, which creates a lot of hassle. Keep that for a later optimization. Signed-off-by: Joerg Roedel Signed-off-by: Thomas Gleixner Tested-by: Pavel Machek Cc: "H . Peter Anvin" Cc: linux-mm@kvack.org Cc: Linus Torvalds Cc: Andy Lutomirski Cc: Dave Hansen Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Peter Zijlstra Cc: Borislav Petkov Cc: Jiri Kosina Cc: Boris Ostrovsky Cc: Brian Gerst Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: Will Deacon Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Cc: Andrea Arcangeli Cc: Waiman Long Cc: "David H . Gutteridge" Cc: joro@8bytes.org Link: https://lkml.kernel.org/r/1531906876-13451-18-git-send-email-joro@8bytes.org --- arch/x86/mm/pgtable.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'arch/x86/mm/pgtable.c') diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index 47b5951e592b..db6fb7740bf7 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -343,7 +343,8 @@ static inline pgd_t *_pgd_alloc(void) * We allocate one page for pgd. */ if (!SHARED_KERNEL_PMD) - return (pgd_t *)__get_free_page(PGALLOC_GFP); + return (pgd_t *)__get_free_pages(PGALLOC_GFP, + PGD_ALLOCATION_ORDER); /* * Now PAE kernel is not running as a Xen domain. We can allocate @@ -355,7 +356,7 @@ static inline pgd_t *_pgd_alloc(void) static inline void _pgd_free(pgd_t *pgd) { if (!SHARED_KERNEL_PMD) - free_page((unsigned long)pgd); + free_pages((unsigned long)pgd, PGD_ALLOCATION_ORDER); else kmem_cache_free(pgd_cache, pgd); } -- cgit v1.2.3