• David S. Miller's avatar
    sparc64: Encode huge PMDs using PTE encoding. · a7b9403f
    David S. Miller authored
    Now that we have 64-bits for PMDs we can stop using special encodings
    for the huge PMD values, and just put real PTEs in there.
    
    We allocate a _PAGE_PMD_HUGE bit to distinguish between plain PMDs and
    huge ones.  It is the same for both 4U and 4V PTE layouts.
    
    We also use _PAGE_SPECIAL to indicate the splitting state, since a
    huge PMD cannot also be special.
    
    All of the PMD --> PTE translation code disappears, and most of the
    huge PMD bit modifications and tests just degenerate into the PTE
    operations.  In particular USER_PGTABLE_CHECK_PMD_HUGE becomes
    trivial.
    
    As a side effect, normal PMDs don't shift the physical address around.
    This also speeds up the page table walks in the TLB miss paths since
    they don't have to do the shifts any more.
    
    Another non-trivial aspect is that pte_modify() has to be changed
    to preserve the _PAGE_PMD_HUGE bits as well as the page size field
    of the pte.
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    a7b9403f
pgtable_64.h 27.7 KB