Genode OS Framework
Go to file
Piotr Tworek 80e8cf99e2 base: Make Genode::List clang friendly.
Clang is generally fine with Genode::List and compiles code using it
without emitting any warnings. There is however one exception. Clang
fails hard when building base-hw/src/core/kernel/object.cc.
This is due to a call to Genode::List::remove made from
Object_identity::invalidate function. The error message clang
produces is:

  list.h:96:33: error: 'Genode::List<Kernel::Object_identity_reference>::Element::_next'
  is not a member of class 'const Kernel::Object_identity'
                              _first = le->List::Element::_next;
                                           ~~~~~~~~~~~~~~~^

When we look at the declaration of the Kernel::Object class on which
the remove method is called. as expected it does inherit Genode::List:

using Object_identity_list
	= Genode::List<Kernel::Object_identity>;

class Kernel::Object : private Object_identity_list
{
...
}

Given the error message we see that List::Element should be resolved to
Genode::List<Kernel::Object_identity>::Element, and not
Genode::List<Kernel::Object_identity_reference>::Element. But how does
clang manage to figure out we're talking about Object_identity_refecence
list here? Well, I admit I don't know the exact steps it takes to arrive
at this conclusion, but it is not entirely wrong. If we take a look at
what Kernel::Object_identity is we'll see:

class Kernel::Object_identity
: public Object_identity_list::Element,
  public Kernel::Object_identity_reference_list
{
...
}

Where as one can guess Object_identity_reference_list is defined as:

using Object_identity_reference_list
	= Genode::List<Object_identity_reference>;

Long story short Kernel::Object has Genode::List of both Kernel::Object_identity
and Kernel::Object_identity_reference in its inheritance chain and clang
is not really sure to which of those the code refers to in
Genode::List::remove method by using List::Element::.

The fix for this is relatively simple, explicitly state the full type of
the base class the code intends to refer to. Replacing List::Element,
with List<LT>::Element makes the code buildable with both clang and GCC.

Fixes #3990
2021-01-25 13:58:10 +01:00
depot depot: update public key for cnuke 2020-02-27 14:46:57 +01:00
doc Road map for 2021 2021-01-25 13:58:09 +01:00
repos base: Make Genode::List clang friendly. 2021-01-25 13:58:10 +01:00
tool tool/run: search repos for run-tool plugins 2021-01-25 13:58:10 +01:00
.gitignore Tool for assembling API/source/binary archives 2017-05-31 13:15:56 +02:00
LICENSE Update URLs in LICENSE 2020-03-26 11:38:54 +01:00
README Update README 2017-08-30 10:01:35 +02:00
VERSION version: 20.11 2020-11-27 14:01:47 +01:00

                      =================================
                      Genode Operating System Framework
                      =================================


This is the source tree of the reference implementation of the Genode OS
architecture. For a general overview about the architecture, please refer to
the project's official website:

:Official project website for the Genode OS Framework:

  [https://genode.org/documentation/general-overview]

The current implementation can be compiled for 8 different kernels: Linux,
L4ka::Pistachio, L4/Fiasco, OKL4, NOVA, Fiasco.OC, seL4, and a custom
kernel for running Genode directly on ARM-based hardware. Whereas the Linux
version serves us as development vehicle and enables us to rapidly develop the
generic parts of the system, the actual target platforms of the framework are
microkernels. There is no "perfect" microkernel - and neither should there be
one. If a microkernel pretended to be fit for all use cases, it wouldn't be
"micro". Hence, all microkernels differ in terms of their respective features,
complexity, and supported hardware architectures.

Genode allows the use of each of the kernels listed above with a rich set of
device drivers, protocol stacks, libraries, and applications in a uniform way.
For developers, the framework provides an easy way to target multiple different
kernels instead of tying the development to a particular kernel technology. For
kernel developers, Genode contributes advanced workloads, stress-testing their
kernel, and enabling a variety of application use cases that would not be
possible otherwise. For users and system integrators, it enables the choice of
the kernel that fits best with the requirements at hand for the particular
usage scenario.


Documentation
#############

The primary documentation is the book "Genode Foundations", which is available
on the front page of Genode website:

:Download the book "Genode Foundations":

  [https://genode.org]

The book describes Genode in a holistic and comprehensive way. It equips you
with a thorough understanding of the architecture, assists developers with the
explanation of the development environment and system configuration, and
provides a look under the hood of the framework. Furthermore, it contains the
specification of the framework's programming interface.

The project has a quarterly release cycle. Each version is accompanied with
detailed release documentation, which is available at the documentation
section of the project website:

:Release documentation:

  [https://genode.org/documentation/release-notes/]


Directory overview
##################

The source tree is composed of the following subdirectories:

:'doc':

  This directory contains general documentation. Please consider the following
  document for a quick guide to get started with the framework:

  ! doc/getting_started.txt

  If you are curious about the ready-to-use components that come with the
  framework, please review the components overview:

  ! doc/components.txt

:'repos':

  This directory contains the so-called source-code repositories of Genode.
  Please refer to the README file in the 'repos' directory to learn more
  about the roles of the individual repositories.

:'tool':

  Source-code management tools and scripts. Please refer to the README file
  contained in the directory.

:'depot' and 'public':

  Local depot and public archive of Genode packages. Please refer to

  ! doc/depot.txt

  for more details.


Additional community-maintained components
##########################################

The components found within the main source tree are complemented by a growing
library of additional software, which can be seamlessly integrated into Genode
system scenarios.

:Genode-world repository:

  [https://github.com/genodelabs/genode-world]


Contact
#######

The best way to get in touch with Genode developers and users is the project's
mailing list. Please feel welcome to join in!

:Genode Mailing Lists:

  [https://genode.org/community/mailing-lists]


Commercial support
##################

The driving force behind the Genode OS Framework is the German company Genode
Labs. The company offers commercial licensing, trainings, support, and
contracted development work:

:Genode Labs website:

  [https://www.genode-labs.com]