L4Re - L4 Runtime Environment
|
Moe is the default root-task implementation for L4Re-based systems.
Moe is the first task which is usually started in L4Re-based systems. The micro kernel starts Moe as the Root-Task.
Moe provides a default implementation for the basic L4Re abstractions, such as data spaces (L4Re::Dataspace), region maps (L4Re::Rm), memory allocators (L4Re::Mem_alloc, L4::Factory), name spaces (L4Re::Namespace) and so on (see L4Re Interface).
Moe consists of the following subsystems:
The generic factory in Moe is responsible for all kinds of dynamic object allocation. The interface is a combination of L4::Factory and, for traditional reasons, L4Re::Mem_alloc.
The generic factory interface allows allocation of the following objects:
The memory allocator in Moe is the alternative interface for allocating memory (RAM) in terms of L4Re::Dataspace-s (see also L4Re::Mem_alloc).
Dataspaces can be allocated with an arbitrary size. The granularity for memory allocation however is the machine page size (L4_PAGESIZE). A dataspace user must be aware that, as a result of this page-size granularity, there may be padding memory at the end of a dataspace which is accessible to each client. Moe currently allows most dataspace operations on this padding area. Nonetheless, the client must not make any assumptions about the size or content of the padding area, as this behaviour might change in the future.
The provided data spaces can have different characteristics:
Moe provides a name spaces conforming to the L4Re::Namespace interface (see Name-space API). Per default Moe creates a single name space for the Boot FS. That is available as rom
in the initial objects of the init process.
The Boot FS subsystem provides access to the files loaded during the platform boot (or available in ROM). These files are either linked into the boot image or loaded via a flexible boot loader, such as GRUB.
The subsystem provides an L4Re::Namespace object as directory and an L4Re::Dataspace object for each file.
By default all files are read only and visible in the namespace rom
. As an option, files can be supplied with the argument :rw
to mark them as writable modules. Moe will allow read and write access to these dataspaces and make them visible in a different namespace called rwfs
.
An example entry in 'modules.list' would look like this:
The logging facility of Moe provides per application tagged and synchronized log output.
The scheduler subsystem provides a simple scheduler proxy.
Moe's command-line syntax is:
moe [--debug=<flags>] [--init=<binary>] [--l4re-dbg=<flags>] [--ldr-flags=<flags>] [-- <init options>]
<debug flags>
values are a combination of info
, warn
, boot
, server
, loader
, exceptions
, and ns
(or all
for full verbosity).--debug=
.pre_alloc
, all_segs_cow
,and pinned_segs
.--
option are passed directly to the init process.