• Martin Schwidefsky's avatar
    [S390] refactor page table functions for better pgste support · b2fa47e6
    Martin Schwidefsky authored
    Rework the architecture page table functions to access the bits in the
    page table extension array (pgste). There are a number of changes:
    1) Fix missing pgste update if the attach_count for the mm is <= 1.
    2) For every operation that affects the invalid bit in the pte or the
       rcp byte in the pgste the pcl lock needs to be acquired. The function
       pgste_get_lock gets the pcl lock and returns the current pgste value
       for a pte pointer. The function pgste_set_unlock stores the pgste
       and releases the lock. Between these two calls the bits in the pgste
       can be shuffled.
    3) Define two software bits in the pte _PAGE_SWR and _PAGE_SWC to avoid
       calling SetPageDirty and SetPageReferenced from pgtable.h. If the
       host reference backup bit or the host change backup bit has been
       set the dirty/referenced state is transfered to the pte. The common
       code will pick up the state from the pte.
    4) Add ptep_modify_prot_start and ptep_modify_prot_commit for mprotect.
    5) Remove pgd_populate_kernel, pud_populate_kernel, pmd_populate_kernel
       pgd_clear_kernel, pud_clear_kernel, pmd_clear_kernel and ptep_invalidate.
    6) Rename kvm_s390_test_and_clear_page_dirty to
       ptep_test_and_clear_user_dirty and add ptep_test_and_clear_user_young.
    7) Define mm_exclusive() and mm_has_pgste() helper to improve readability.
    Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
    b2fa47e6
init.c 5.93 KB