• Christophe Leroy's avatar
    powerpc/8xx: Implement support of hugepages · 4b914286
    Christophe Leroy authored
    8xx uses a two level page table with two different linux page size
    support (4k and 16k). 8xx also support two different hugepage sizes
    512k and 8M. In order to support them on linux we define two different
    page table layout.
    
    The size of pages is in the PGD entry, using PS field (bits 28-29):
    00 : Small pages (4k or 16k)
    01 : 512k pages
    10 : reserved
    11 : 8M pages
    
    For 512K hugepage size a pgd entry have the below format
    [<hugepte address >0101] . The hugepte table allocated will contain 8
    entries pointing to 512K huge pte in 4k pages mode and 64 entries in
    16k pages mode.
    
    For 8M in 16k mode, a pgd entry have the below format
    [<hugepte address >1101] . The hugepte table allocated will contain 8
    entries pointing to 8M huge pte.
    
    For 8M in 4k mode, multiple pgd entries point to the same hugepte
    address and pgd entry will have the below format
    [<hugepte address>1101]. The hugepte table allocated will only have one
    entry.
    
    For the time being, we do not support CPU15 ERRATA when HUGETLB is
    selected
    Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
    Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> (v3, for the generic bits)
    Signed-off-by: default avatarScott Wood <oss@buserror.net>
    4b914286
mmu-8xx.h 8.37 KB