• Russell King's avatar
    ARM: vfp: use __copy_from_user() when restoring VFP state · 42019fc5
    Russell King authored
    __get_user_error() is used as a fast accessor to make copying structure
    members in the signal handling path as efficient as possible.  However,
    with software PAN and the recent Spectre variant 1, the efficiency is
    reduced as these are no longer fast accessors.
    In the case of software PAN, it has to switch the domain register around
    each access, and with Spectre variant 1, it would have to repeat the
    access_ok() check for each access.
    Use __copy_from_user() rather than __get_user_err() for individual
    members when restoring VFP state.
    Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
    Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>