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Martin Stein 71d30297ff hw: clean up scheduling-readiness syscalls 
This cleans up the syscalls that are mainly used to control the
scheduling readiness of a thread. The different use cases and
requirements were somehow mixed together in the previous interface. The
new syscall set is:

1) pause_thread and resume_thread

They don't affect the state of the thread (IPC, signalling, etc.) but
merely decide wether the thread is allowed for scheduling or not, the
so-called pause state. The pause state is orthogonal to the thread state
and masks it when it comes to scheduling. In contrast to the stopped
state, which is described in "stop_thread and restart_thread", the
thread state and the UTCB content of a thread may change while in the
paused state. However, the register state of a thread doesn't change
while paused. The "pause" and "resume" syscalls are both core-restricted
and may target any thread. They are used as back end for the CPU session
calls "pause" and "resume". The "pause/resume" feature is made for
applications like the GDB monitor that transparently want to stop and
continue the execution of a thread no matter what state the thread is
in.

2) stop_thread and restart_thread

The stop syscall can only be used on a thread in the non-blocking
("active") thread state. The thread then switches to the "stopped"
thread state in wich it explicitely waits for a restart. The restart
syscall can only be used on a thread in the "stopped" or the "active"
thread state. The thread then switches back to the "active" thread state
and the syscall returns whether the thread was stopped. Both syscalls
are not core-restricted. "Stop" always targets the calling thread while
"restart" may target any thread in the same PD as the caller. Thread
state and UTCB content of a thread don't change while in the stopped
state. The "stop/restart" feature is used when an active thread wants to
wait for an event that is not known to the kernel. Actually the syscalls
are used when waiting for locks and on thread exit.

3) cancel_thread_blocking

Does cleanly cancel a cancelable blocking thread state (IPC, signalling,
stopped). The thread whose blocking was cancelled goes back to the
"active" thread state. It may receive a syscall return value that
reflects the cancellation. This syscall doesn't affect the pause state
of the thread which means that it may still not get scheduled. The
syscall is core-restricted and may target any thread.

4) yield_thread

Does its best that a thread is scheduled as few as possible in the
current scheduling super-period without touching the thread or pause
state. In the next superperiod, however, the thread is scheduled
"normal" again. The syscall is not core-restricted and always targets
the caller.

Fixes #2104
2016-12-14 11:22:27 +01:00
..
base Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
base-fiasco Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
base-foc Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
base-hw hw: clean up scheduling-readiness syscalls 2016-12-14 11:22:27 +01:00
base-linux Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
base-nova Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
base-okl4 Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
base-pistachio Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
base-sel4 Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
dde_bsd Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
dde_ipxe Use default component stack size where appropriate 2016-11-30 13:38:06 +01:00
dde_linux Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
dde_rump Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
demo Make label prefixing more strict 2016-11-30 13:37:07 +01:00
gems Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
hello_tutorial Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
libports base: rename 'Volatile_object' to 'Reconstructible' 2016-12-01 17:46:50 +01:00
os Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
ports Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
ports-foc Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
README

README 

                      ===============================
                      Genode source-code repositories
                      ===============================


This directory contains the source-code repositories of the Genode OS
Framework. Each sub directory has the same principle layout as described in the
build-system manual:

:Build-system manual:

  [https://genode.org/documentation/developer-resources/build_system]

The build system uses a configurable selection of those reposities to obtain
the source codes for the build process. The repositories are not independent
but build upon of each other:

:'base':

  This directory contains the source-code repository of the fundamental
  frameworks and interfaces of Genode. Furthermore, it contains the generic
  parts of core.

:'base-<platform>':
  These directories contain platform-specific source-code repositories
  complementing the 'base' repository. The following platforms are supported:

  :'linux':
    Linux kernel (both x86_32 and x86_64)

  :'nova':
    NOVA hypervisor developed at University of Technology Dresden
    See [https://genode.org/documentation/platforms/nova]

  :'foc':
    Fiasco.OC is a modernized version of the Fiasco microkernel with a
    completely revised kernel interface fostering capability-based
    security. It is not compatible with L4/Fiasco.
    See [https://genode.org/documentation/platforms/foc]

  :'hw':
    The hw platform allows the execution of Genode on bare ARM and x86 hardware
    without the need for a separate kernel. The kernel functionality is
    included in core except in the special case of the Muen separation
    kernel.
    See [https://genode.org/documentation/platforms/hw] and
    [https://genode.org/documentation/platforms/muen]

  :'okl4':
    OKL4 kernel (x86_32 and ARM) developed at Open-Kernel-Labs.
    See [https://genode.org/documentation/platforms/okl4]

  :'pistachio':
    L4ka::Pistachio kernel developed at University of Karlsruhe.
    See [https://genode.org/documentation/platforms/pistachio]

  :'fiasco':
    L4/Fiasco kernel developed at University of Technology Dresden.
    See [https://genode.org/documentation/platforms/fiasco]

  :'sel4':
    seL4 microkernel developed at NICTA/General Dynamics
    See[https://sel4.systems/]

:'os':

  This directory contains the non-base OS components such as the init process,
  device drivers, and basic system services.

:'demo':

  This directory contains the source-code repository of various services and
  applications that we use for demonstration purposes. For example, a graphical
  application launcher called Launchpad and the Scout tutorial browser.

:'hello_tutorial':

  Tutorial for creating a simple client-server scenario with Genode. This
  repository includes documentation and the complete source code.

:'libports':

  This source-code repository contains ports of popular open-source libraries
  to Genode, most importantly the C library. The repository contains no
  upstream source code but means to download the code and adapt it to Genode.
  For instructions about how to use this mechanism, please consult the README
  file at the top level of the repository. Among the 3rd-party libraries
  are Qt5, libSDL, freetype, Python, ncurses, Mesa, and libav.

:'dde_linux':

  This source-code repository contains the device driver environment for
  executing Linux device drivers natively on Genode. Currently, this
  repository hosts the USB stack.

:'dde_ipxe':

  This source-code repository contains the device-driver environment for
  executing drivers of the iPXE project.

:'dde_bsd':

  This source-code repository contains the device-driver environment for
  drivers of the OpenBSD operating system.

:'dde_rump':

  This source-code repository contains the port of rump kernels, which are
  used to execute subsystems of the NetBSD kernel as user level processes.
  The repository contains a server that uses a rump kernel to provide
  various NetBSD file systems to Genode.

:'ports':

  This source-code repository hosts ports of 3rd-party applications to
  Genode. The repository does not contain upstream source code but provides
  a mechanism for downloading the official source distributions and adapt
  them to the Genode environment. The used mechanism is roughly the same
  as used for the 'libports' repository. Please consult 'libports/README'
  for further information.

:'ports-<platform>':

  These platform-specific source-code repositories contain software that
  capitalizes special features of the respective kernel platform.
  For the Fiasco.OC platform, 'ports-foc' hosts a port of the L4Linux
  kernel. For further information, please refer to the README file at the
  top level of the respective repository.

:'gems':

  This source-code repository contains Genode applications that use
  both native Genode interfaces as well as features of other high-level
  repositories, in particular shared libraries provided by 'libports'.