diff options
| author | Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2020-05-05 12:47:10 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-05-05 21:20:14 +1000 |
| commit | ec4abf1e70cf6a3fe6e571d640260005c997c6e1 (patch) | |
| tree | 462eec65473b6412610769f1c37e4efbf0f21b7d /arch/powerpc/include/asm/book3s/64/pgtable.h | |
| parent | c46241a370a61f0f264791abb9fc869016e749ce (diff) | |
powerpc/mm/hash64: use _PAGE_PTE when checking for pte_present
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
Diffstat (limited to 'arch/powerpc/include/asm/book3s/64/pgtable.h')
| -rw-r--r-- | arch/powerpc/include/asm/book3s/64/pgtable.h | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index 368b136517e0..03521a8b0292 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -553,6 +553,12 @@ static inline pte_t pte_clear_savedwrite(pte_t pte) } #endif /* CONFIG_NUMA_BALANCING */ +static inline bool pte_hw_valid(pte_t pte) +{ + return (pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT | _PAGE_PTE)) == + cpu_to_be64(_PAGE_PRESENT | _PAGE_PTE); +} + static inline int pte_present(pte_t pte) { /* @@ -561,12 +567,11 @@ static inline int pte_present(pte_t pte) * invalid during ptep_set_access_flags. Hence we look for _PAGE_INVALID * if we find _PAGE_PRESENT cleared. */ - return !!(pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT | _PAGE_INVALID)); -} -static inline bool pte_hw_valid(pte_t pte) -{ - return !!(pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT)); + if (pte_hw_valid(pte)) + return true; + return (pte_raw(pte) & cpu_to_be64(_PAGE_INVALID | _PAGE_PTE)) == + cpu_to_be64(_PAGE_INVALID | _PAGE_PTE); } #ifdef CONFIG_PPC_MEM_KEYS |