• Jan Kiszka's avatar
    ipipe: Introduce infrastructure for userspace return notifier · a3654dd9
    Jan Kiszka authored and Philippe Gerum's avatar Philippe Gerum committed
    A little bit inspired by the kernel's user return notifier, this
    introduces an I-pipe hook before the kernel jumps back to a userspace
    context from the root domain. The hook is design to allow a switch back
    to the head domain, thus will not run through signal/preemption checks
    when returning from the callback over head. It is guaranteed to fire on
    return from interrupts and exceptions but may also fire on certain
    syscall-return paths.
    The first use case for the hook is resumption of ptraced tasks over
    head if they were stopped in that domain.
    This provides just the generic infrastructure, the invocation of
    __ipipe_notify_user_intreturn as well as the definition of
    TIP_USERINTRET are architecture-specific.
    Signed-off-by: Jan Kiszka's avatarJan Kiszka <jan.kiszka@siemens.com>