mirror of
https://github.com/genodelabs/genode.git
synced 2024-12-24 07:46:42 +00:00
9e6f3be806
This patch updates seL4 from the experimental branch of one year ago to the master branch of version 2.1. The transition has the following implications. In contrast to the experimental branch, the master branch has no way to manually define the allocation of kernel objects within untyped memory ranges. Instead, the kernel maintains a built-in allocation policy. This policy rules out the deallocation of once-used parts of untyped memory. The only way to reuse memory is to revoke the entire untyped memory range. Consequently, we cannot share a large untyped memory range for kernel objects of different protection domains. In order to reuse memory at a reasonably fine granularity, we need to split the initial untyped memory ranges into small chunks that can be individually revoked. Those chunks are called "untyped pages". An untyped page is a 4 KiB untyped memory region. The bootstrapping of core has to employ a two-stage allocation approach now. For creating the initial kernel objects for core, which remain static during the entire lifetime of the system, kernel objects are created directly out of the initial untyped memory regions as reported by the kernel. The so-called "initial untyped pool" keeps track of the consumption of those untyped memory ranges by mimicking the kernel's internal allocation policy. Kernel objects created this way can be of any size. For example the phys CNode, which is used to store page-frame capabilities is 16 MiB in size. Also, core's CSpace uses a relatively large CNode. After the initial setup phase, all remaining untyped memory is turned into untyped pages. From this point on, new created kernel objects cannot exceed 4 KiB in size because one kernel object cannot span multiple untyped memory regions. The capability selectors for untyped pages are organized similarly to those of page-frame capabilities. There is a new 2nd-level CNode (UNTYPED_CORE_CNODE) that is dimensioned according to the maximum amount of physical memory (1M entries, each entry representing 4 KiB). The CNode is organized such that an index into the CNode directly corresponds to the physical frame number of the underlying memory. This way, we can easily determine a untyped page selector for any physical addresses, i.e., for revoking the kernel objects allocated at a specific physical page. The downside is the need for another 16 MiB chunk of meta data. Also, we need to keep in mind that this approach won't scale to 64-bit systems. We will eventually need to replace the PHYS_CORE_CNODE and UNTYPED_CORE_CNODE by CNode hierarchies to model a sparsely populated CNode. The size constrain of kernel objects has the immediate implication that the VM CSpaces of protection domains must be organized via several levels of CNodes. I.e., as the top-level CNode of core has a size of 2^12, the remaining 20 PD-specific CSpace address bits are organized as a 2nd-level 2^4 padding CNode, a 3rd-level 2^8 CNode, and several 4th-level 2^8 leaf CNodes. The latter contain the actual selectors for the page tables and page-table entries of the respective PD. As another slight difference from the experimental branch, the master branch requires the explicit assignment of page directories to an ASID pool. Besides the adjustment to the new seL4 version, the patch introduces a dedicated type for capability selectors. Previously, we just used to represent them as unsigned integer values, which became increasingly confusing. The new type 'Cap_sel' is a PD-local capability selector. The type 'Cnode_index' is an index into a CNode (which is not generally not the entire CSpace of the PD). Fixes #1887 |
||
|---|---|---|
| .. | ||
| base | ||
| base-fiasco | ||
| base-foc | ||
| base-hw | ||
| base-linux | ||
| base-nova | ||
| base-okl4 | ||
| base-pistachio | ||
| base-sel4 | ||
| dde_bsd | ||
| dde_ipxe | ||
| dde_linux | ||
| dde_rump | ||
| demo | ||
| gems | ||
| hello_tutorial | ||
| libports | ||
| os | ||
| ports | ||
| ports-foc | ||
| 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:
[http://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 [http://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 [http://genode.org/documentation/platforms/foc]
:'hw':
The hw platform allows the execution of Genode on bare ARM hardware
without the need for a separate kernel. The kernel functionality is
included in core.
See [http://genode.org/documentation/platforms/hw]
:'okl4':
OKL4 kernel (x86_32 and ARM) developed at Open-Kernel-Labs.
See [http://genode.org/documentation/platforms/okl4]
:'pistachio':
L4ka::Pistachio kernel developed at University of Karlsruhe.
See [http://genode.org/documentation/platforms/pistachio]
:'fiasco':
L4/Fiasco kernel developed at University of Technology Dresden.
See [http://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'.