Turn Genode user-level spinlock into a user-level "helpinglock". This requires
support by the kernel introduced with kernel branch r5.
The commit avoids live-locks when multiple threads with SCs on different
priority levels compete for the same user-level Genode "spinlock".
Issue #986
The commit switches the kernel branch to r5 and updates the syscall bindings
in base-nova accordingly. Beside some cleanups, r5 extents the ec_ctrl syscall
to support following features:
* An EC may yield its current timeslice. The timeslice gets enqueued at the end
of the run queue without refreshing the left budget of the quantum.
* An EC helps with the current SC another EC. Used in Genode to implement
helping over a user-level lock to avoid live-lock situation. (Think of
a limited priority-inheritance mechanism.)
* An EC requests a new scheduler decision. Used in Genode to transfer back the
potentially helping SC to the helper EC.
Issue #986
Set cpu_session default affinity space already during
construction of the thread, so that main thread is placed in the cpu affinity
space as defined by the parent. Otherwise the main thread is placed potentially
outside the affinity space, typically on the first/boot CPU.
Fixes#1107
Otherwise affinity space is set to 1x1 and in cpu_session_component.cc the cpu
session local affinity space defined by parent is not taken because
"Location::valid()" returns true.
Issue #1107
Kernel::resume_thread was restricted to core when the targeted thread was in
another domain. Now there are two kernel calls, resume_local_thread and
resume_thread, where the former is never restricted and is provided via
public kernel/interface.h and the latter is always restricted to core and
is provided via core-local kernel/core_interface.h.
ref #1101
Kernel::pause_current_thread can be implemented much simpler and is not
restricted to core threads, in contrast to Kernel::pause_thread which
also benefits from the split and can be moved to core_interface.h.
ref #1101
