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authorLinus Torvalds <torvalds@linux-foundation.org>2017-03-10 17:59:07 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2017-03-10 17:59:07 +0100
commitbaeedc7158da5b0f489d04125ba6adfba532a6f7 (patch)
tree1f42b5cd4a961ed10673578a28602dd13d09ab99 /mm/huge_memory.c
parentMerge branch 'akpm' (patches from Andrew) (diff)
parentmm: introduce __p4d_alloc() (diff)
downloadlinux-baeedc7158da5b0f489d04125ba6adfba532a6f7.tar.xz
linux-baeedc7158da5b0f489d04125ba6adfba532a6f7.zip
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
Diffstat (limited to 'mm/huge_memory.c')
-rw-r--r--mm/huge_memory.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 8f037e256c54..1ebc93e179f3 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2048,6 +2048,7 @@ void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address,
bool freeze, struct page *page)
{
pgd_t *pgd;
+ p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
@@ -2055,7 +2056,11 @@ void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address,
if (!pgd_present(*pgd))
return;
- pud = pud_offset(pgd, address);
+ p4d = p4d_offset(pgd, address);
+ if (!p4d_present(*p4d))
+ return;
+
+ pud = pud_offset(p4d, address);
if (!pud_present(*pud))
return;