Commit-ID: e3238faf20fb1b51a814497751398ab525a2c884 Gitweb: https://git.kernel.org/tip/e3238faf20fb1b51a814497751398ab525a2c884 Author: Joerg Roedel <jroe...@suse.de> AuthorDate: Wed, 18 Jul 2018 11:40:54 +0200 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Fri, 20 Jul 2018 01:11:41 +0200
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 <jroe...@suse.de> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Tested-by: Pavel Machek <pa...@ucw.cz> Cc: "H . Peter Anvin" <h...@zytor.com> Cc: linux...@kvack.org Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Andy Lutomirski <l...@kernel.org> Cc: Dave Hansen <dave.han...@intel.com> Cc: Josh Poimboeuf <jpoim...@redhat.com> Cc: Juergen Gross <jgr...@suse.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Borislav Petkov <b...@alien8.de> Cc: Jiri Kosina <jkos...@suse.cz> Cc: Boris Ostrovsky <boris.ostrov...@oracle.com> Cc: Brian Gerst <brge...@gmail.com> Cc: David Laight <david.lai...@aculab.com> Cc: Denys Vlasenko <dvlas...@redhat.com> Cc: Eduardo Valentin <edu...@amazon.com> Cc: Greg KH <gre...@linuxfoundation.org> Cc: Will Deacon <will.dea...@arm.com> Cc: aligu...@amazon.com Cc: daniel.gr...@iaik.tugraz.at Cc: hu...@google.com Cc: keesc...@google.com Cc: Andrea Arcangeli <aarca...@redhat.com> Cc: Waiman Long <ll...@redhat.com> Cc: "David H . Gutteridge" <dhgutteri...@sympatico.ca> Cc: j...@8bytes.org Link: https://lkml.kernel.org/r/1531906876-13451-18-git-send-email-j...@8bytes.org --- arch/x86/kernel/head_32.S | 20 +++++++++++++++----- arch/x86/mm/pgtable.c | 5 +++-- 2 files changed, 18 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index abe6df15a8fb..30f9cb2c0b55 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -512,11 +512,18 @@ ENTRY(initial_code) ENTRY(setup_once_ref) .long setup_once +#ifdef CONFIG_PAGE_TABLE_ISOLATION +#define PGD_ALIGN (2 * PAGE_SIZE) +#define PTI_USER_PGD_FILL 1024 +#else +#define PGD_ALIGN (PAGE_SIZE) +#define PTI_USER_PGD_FILL 0 +#endif /* * BSS section */ __PAGE_ALIGNED_BSS - .align PAGE_SIZE + .align PGD_ALIGN #ifdef CONFIG_X86_PAE .globl initial_pg_pmd initial_pg_pmd: @@ -526,14 +533,17 @@ initial_pg_pmd: initial_page_table: .fill 1024,4,0 #endif + .align PGD_ALIGN initial_pg_fixmap: .fill 1024,4,0 -.globl empty_zero_page -empty_zero_page: - .fill 4096,1,0 .globl swapper_pg_dir + .align PGD_ALIGN swapper_pg_dir: .fill 1024,4,0 + .fill PTI_USER_PGD_FILL,4,0 +.globl empty_zero_page +empty_zero_page: + .fill 4096,1,0 EXPORT_SYMBOL(empty_zero_page) /* @@ -542,7 +552,7 @@ EXPORT_SYMBOL(empty_zero_page) #ifdef CONFIG_X86_PAE __PAGE_ALIGNED_DATA /* Page-aligned for the benefit of paravirt? */ - .align PAGE_SIZE + .align PGD_ALIGN ENTRY(initial_page_table) .long pa(initial_pg_pmd+PGD_IDENT_ATTR),0 /* low identity map */ # if KPMDS == 3 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); }
