[PATCH v4 0/11] x86/mm: Handle large PAT bit in pud/pmd interfaces

From: Toshi Kani
Date: Tue Aug 25 2015 - 18:00:08 EST

The PAT bit gets relocated to bit 12 when PUD/PMD mappings are used. This
bit 12, however, is not covered by PTE_FLAGS_MASK, which is corrently used
for masking pfn and flags for all levels. This patch-set updates pud/pmd
interfaces and multiple functions to handle the large PAT bit properly.

Patch 1/11-2/11 make changes necessary for patch 3/11 to use P?D_PAGE_MASK.

Patch 3/11-4/11 fix pud/pmd interfaces to handle the PAT bit properly.

Patch 5/11 adds p?d_pgprot() interfaces for PUD/PMD.

Patch 6/11 fixes /sys/kernel/debug/kernel_page_tables to show the PAT bit

Patch 7/11-10/11 fix multiple functions to handle the large PAT bit properly.

Patch 11/11 fixes the no-change case in try_preserve_large_page() by
leveraging the changes made in patch 9/11.

Note, the PAT bit is first enabled in 4.2-rc1 with WT mapping. The functions
fixed by patch 7/11-10/11 are not used with WT mapping yet. These fixes will
protect them from future use of the PAT bit set.

The patchset is based on -tip branch.

- Add descriptions of the issue fixed by patch 01/11 (Thomas Gleixner).
- Split patch 03 into two patches, mask and pud/pmd interfaces.
(Thomas Gleixner).

- Add patch 4/11 and 6/11-9/11 for multiple interfaces to handle the large
PAT bit.
- Add patch 11/11 to fix the same pgprot handling in

- Change p?n_pfn() to handle the PAT bit. (Juergen Gross)
- Mask pfn and flags with P?D_PAGE_MASK. (Juergen Gross)
- Change p?d_page_vaddr() and p?d_page() to handle the PAT bit.

Toshi Kani (11):
1/11 x86/vdso32: Define PGTABLE_LEVELS to 32bit VDSO
2/11 x86/asm: Move PUD_PAGE macros to page_types.h
3/11 x86/asm: Add pud/pmd mask interfaces to handle large PAT bit
4/11 x86/asm: Fix pud/pmd interfaces to handle large PAT bit
5/11 x86/asm: Add pud_pgprot() and pmd_pgprot()
6/11 x86/mm: Fix page table dump to show PAT bit
7/11 x86/mm: Fix slow_virt_to_phys() to handle large PAT bit
8/11 x86/mm: Fix gup_huge_p?d() to handle large PAT bit
9/11 x86/mm: Fix try_preserve_large_page() to handle large PAT bit
10/11 x86/mm: Fix __split_large_page() to handle large PAT bit
11/11 x86/mm: Fix no-change case in try_preserve_large_page()

arch/x86/entry/vdso/vdso32/vclock_gettime.c | 2 +
arch/x86/include/asm/page_64_types.h | 3 --
arch/x86/include/asm/page_types.h | 3 ++
arch/x86/include/asm/pgtable.h | 18 ++++---
arch/x86/include/asm/pgtable_types.h | 40 +++++++++++++--
arch/x86/mm/dump_pagetables.c | 39 +++++++-------
arch/x86/mm/gup.c | 18 +++----
arch/x86/mm/pageattr.c | 79 ++++++++++++++++++-----------
8 files changed, 131 insertions(+), 71 deletions(-)

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