powerpc/mm/hash64: use _PAGE_PTE when checking for pte_present

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This makes the pte_present check stricter by checking for additional _PAGE_PTE
bit. A level 1 pte pointer (THP pte) can be switched to a pointer to level 0 pte
page table page by following two operations.

1) THP split.
2) madvise(MADV_DONTNEED) in parallel to page fault.

A lockless page table walk need to make sure we can handle such changes
gracefully.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200505071729.54912-4-aneesh.kumar@linux.ibm.com

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Aneesh Kumar K.V 2020-05-05 12:47:10 +05:30 • committed by Michael Ellerman

parent c46241a370

commit ec4abf1e70

2 changed files with 19 additions and 7 deletions

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15

arch/powerpc/include/asm/book3s/64/pgtable.h

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11

arch/powerpc/mm/book3s64/hash_utils.c

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