Merge branch 'prep-for-5level'

Merge 5-level page table prep from Kirill Shutemov:
 "Here's relatively low-risk part of 5-level paging patchset. Merging it
  now will make x86 5-level paging enabling in v4.12 easier.

  The first patch is actually x86-specific: detect 5-level paging
  support. It boils down to single define.

  The rest of patchset converts Linux MMU abstraction from 4- to 5-level
  paging.

  Enabling of new abstraction in most cases requires adding single line
  of code in arch-specific code. The rest is taken care by asm-generic/.

  Changes to mm/ code are mostly mechanical: add support for new page
  table level -- p4d_t -- where we deal with pud_t now.

  v2:
   - fix build on microblaze (Michal);
   - comment for __ARCH_HAS_5LEVEL_HACK in kasan_populate_zero_shadow();
   - acks from Michal"

* emailed patches from Kirill A Shutemov <kirill.shutemov@linux.intel.com>:
  mm: introduce __p4d_alloc()
  mm: convert generic code to 5-level paging
  asm-generic: introduce <asm-generic/pgtable-nop4d.h>
  arch, mm: convert all architectures to use 5level-fixup.h
  asm-generic: introduce __ARCH_USE_5LEVEL_HACK
  asm-generic: introduce 5level-fixup.h
  x86/cpufeature: Add 5-level paging detection

1 files changed, 23 insertions, 3 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 521ef9b6064f..178130880b90 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1517,7 +1517,7 @@ static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud,
 	return 0;
 }
 
-static inline int unuse_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
+static inline int unuse_pud_range(struct vm_area_struct *vma, p4d_t *p4d,
 				unsigned long addr, unsigned long end,
 				swp_entry_t entry, struct page *page)
 {
@@ -1525,7 +1525,7 @@ static inline int unuse_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
 	unsigned long next;
 	int ret;
 
-	pud = pud_offset(pgd, addr);
+	pud = pud_offset(p4d, addr);
 	do {
 		next = pud_addr_end(addr, end);
 		if (pud_none_or_clear_bad(pud))
@@ -1537,6 +1537,26 @@ static inline int unuse_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
 	return 0;
 }
 
+static inline int unuse_p4d_range(struct vm_area_struct *vma, pgd_t *pgd,
+				unsigned long addr, unsigned long end,
+				swp_entry_t entry, struct page *page)
+{
+	p4d_t *p4d;
+	unsigned long next;
+	int ret;
+
+	p4d = p4d_offset(pgd, addr);
+	do {
+		next = p4d_addr_end(addr, end);
+		if (p4d_none_or_clear_bad(p4d))
+			continue;
+		ret = unuse_pud_range(vma, p4d, addr, next, entry, page);
+		if (ret)
+			return ret;
+	} while (p4d++, addr = next, addr != end);
+	return 0;
+}
+
 static int unuse_vma(struct vm_area_struct *vma,
 				swp_entry_t entry, struct page *page)
 {
@@ -1560,7 +1580,7 @@ static int unuse_vma(struct vm_area_struct *vma,
 		next = pgd_addr_end(addr, end);
 		if (pgd_none_or_clear_bad(pgd))
 			continue;
-		ret = unuse_pud_range(vma, pgd, addr, next, entry, page);
+		ret = unuse_p4d_range(vma, pgd, addr, next, entry, page);
 		if (ret)
 			return ret;
 	} while (pgd++, addr = next, addr != end);