• Will Deacon's avatar
    arm64: mm: introduce present, faulting entries for PAGE_NONE · a6fadf7e
    Will Deacon authored
    This is mostly a port of dbf62d50 ("ARM: mm: introduce L_PTE_VALID
    for page table entries") and 26ffd0d4 ("ARM: mm: introduce present,
    faulting entries for PAGE_NONE") from ARM, which makes use of present,
    faulting page table entries for page table entries mapped as PROT_NONE.
    
    The main difference with this implementation is that we can make use of
    the two pte type bits in order to avoid allocating a software bit for
    identifying PROT_NONE pages, instead reserving the 10b suffix for these
    types of mappings.
    
    This is required to prevent users from accessing such pages via syscalls
    such as read/write over a pipe.
    Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
    Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
    a6fadf7e
pgtable.h 10.7 KB