As synchronization of signal contexts is now the users business instead of
cores and the signal framework ensures that every context of a receiver gets
synchronously destructed before the destruction of the receiver itself
synchronization and thus blocking at the destruction of a kernel
receiver-object isn't necessary anymore.
ref #989
Kernel::signal_context_kill can be used by any program to halt the processing
of a signal context synchronously to prevent broken refs when core destructs
the according kernel object. In turn, Kernel::bin_signal_context doesn't block
anymore and destructs a signal context no matter if there are unacknowledged
signals. This way, cores entrypoint doesn't depend on signal acks of a
untrustworthy client anymore.
ref #989
In the future bin_* means the direct destruction of a kernel object
without any blocking. kill_* in contrast is used for bringing a
kernel object such as signal contexts synchronized into a sleeping
state from where they can be destructed without the risk of getting
broken refs in userland.
ref #989
Struct Msg was introduced due to the handling of pagefaults
and interrupts via synchronous IPC. Its only purpose was to provide
the message type in front of the typed message. Now pagefaults and
interrupts are handled via signals and struct Msg is not necessary
anymore.
ref #958
Every thread receives a startup message from its creator through the initial
state of its userland thread-context. The thread-startup code remembers the
kernel name of the new thread by reading this message before the userland
thread-context gets polluted. This way, Kernel::current_thread_id becomes
unnecessary.
fix#953
Don't set priority and label in platform thread and then communicate this
core object via Kernel::new_thread but communicate priority and label directly.
This way kernel doesn't need to know anymore what a platform thread is.
ref #953
Instead of writing initial thread context to the platform-thread members
and then communicating this core object to kernel, core calls
Kernel::access_thread_regs first to initialize thread context and then
Kernel::start_thread without a platform-thread pointer. This way
the frontend as well as the backend of Kernel::start_thread loose
complexity and it is a first step to remove platform thread from the
vocabulary of the kernel.
ref #953
