With 4-level paging copying happens on p4d level, as we have pgd_none()
always false when p4d_t folded.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
arch/x86/mm/fault.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 1bbdbb0594a3..820e8c284796 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -434,6 +434,7 @@ 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;
@@ -461,13 +462,26 @@ static noinline int vmalloc_fault(unsigned long address)
BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
}
+ /* With 4-level paging copying happens on 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;
--
2.10.2
--
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