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 <>
Cc: Andrew Morton <>
Cc: Andy Lutomirski <>
Cc: Arnd Bergmann <>
Cc: Borislav Petkov <>
Cc: Brian Gerst <>
Cc: Dave Hansen <>
Cc: Denys Vlasenko <>
Cc: H. Peter Anvin <>
Cc: Josh Poimboeuf <>
Cc: Linus Torvalds <>
Cc: Michal Hocko <>
Cc: Peter Zijlstra <>
Cc: Thomas Gleixner <>

Signed-off-by: default avatarIngo Molnar <>
parent ea3b5e60
......@@ -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);
} 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);
} 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;
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