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Commit b50858ce authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Ingo Molnar
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x86/mm/vmalloc: Add 5-level paging support 



Modify vmalloc_fault() to handle additional page table level.

With 4-level paging, copying happens on p4d level, as we have pgd_none()
always false if p4d_t is folded.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170313143309.16020-6-kirill.shutemov@linux.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent ea3b5e60

arch/x86/mm/fault.c

+24 −3
Original line number Diff line number Diff line
@@ -435,6 +435,7 @@ void vmalloc_sync_all(void) 
static noinline int vmalloc_fault(unsigned long address)

{

	pgd_t *pgd, *pgd_ref;

	p4d_t *p4d, *p4d_ref;

	pud_t *pud, *pud_ref;

	pmd_t *pmd, *pmd_ref;

	pte_t *pte, *pte_ref;
@@ -458,17 +459,37 @@ static noinline int vmalloc_fault(unsigned long address) 
	if (pgd_none(*pgd)) {

		set_pgd(pgd, *pgd_ref);

		arch_flush_lazy_mmu_mode();

	} else {

	} else if (CONFIG_PGTABLE_LEVELS > 4) {

		/*

		 * With folded p4d, pgd_none() is always false, so the pgd may

		 * point to an empty page table entry and pgd_page_vaddr()

		 * will return garbage.

		 *

		 * We will do the correct sanity check on the p4d level.

		 */

		BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));

	}



	/* With 4-level paging, copying happens on the p4d level. */

	p4d = p4d_offset(pgd, address);

	p4d_ref = p4d_offset(pgd_ref, address);

	if (p4d_none(*p4d_ref))

		return -1;



	if (p4d_none(*p4d)) {

		set_p4d(p4d, *p4d_ref);

		arch_flush_lazy_mmu_mode();

	} else {

		BUG_ON(p4d_pfn(*p4d) != p4d_pfn(*p4d_ref));

	}



	/*

	 * Below here mismatches are bugs because these lower tables

	 * are shared:

	 */



	pud = pud_offset(pgd, address);

	pud_ref = pud_offset(pgd_ref, address);

	pud = pud_offset(p4d, address);

	pud_ref = pud_offset(p4d_ref, address);

	if (pud_none(*pud_ref))

		return -1;