This commit simplifies the creation of additional threads and VCPUs in L4linux.
By now, some Genode::Thread_base methods where overridden to use a Fiasco.OC
specific Cpu_session when creating threads.
Recent commit: 297538678e moved the actual creation
of the platform thread into the constructor of the generic Thread_base class.
Thereby the Vcpu class, which extended the Thread_base class, now unnecessarily
created two platform threads for each thread created via Vcpu. Nowadays, the
cpu_session capability is available via the Genode::env() environment. So we can
use the Thread_base parent class for the setup of the platform thread, and
afterwards create a Fiasco.OC specific cpu session client with the same cpu
session capability, Thread_base used for creation, to make use of the L4Linux
specific features of this interface (VCPU enabling, irq object creation etc.).
Open VCPU interrupts while the VCPU is in an IPC operation can badly influence
its state. That's why this commit fixes a whole bunch of places, where IRQs
weren't masked by now.
This commit comprises the following changes to enable L4Linux to use several
CPUs:
* change default configuration for x86 and ARM
* add atomic cmpxchg operation to l4re library
* implement l4_sleep (per thread)
* enable setting affinity for VCPUs and IRQs
* move "per CPU" section within linker-script (x86 only)
* introduce SMP run-script for pandaboard
* deactivate direct scheduler (Fiasco.OC syscall) access by L4Linux
This bug was introduced by commit c9c21ad39c, where Fiasco_capability
was removed, and enums defined in that class scope went to the namespace
Fiasco. In L4Linux some references to Fiasco_capability remained.
