• Will Deacon's avatar
    ARM: mm: introduce present, faulting entries for PAGE_NONE · 26ffd0d4
    Will Deacon authored
    PROT_NONE mappings apply the page protection attributes defined by _P000
    which translate to PAGE_NONE for ARM. These attributes specify an XN,
    RDONLY pte that is inaccessible to userspace. However, on kernels
    configured without support for domains, such a pte *is* accessible to
    the kernel and can be read via get_user, allowing tasks to read
    PROT_NONE pages via syscalls such as read/write over a pipe.
    This patch introduces a new software pte flag, L_PTE_NONE, that is set
    to identify faulting, present entries.
    Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
pgtable.h 10.4 KB