Because the template instantiation rules of C++ do not deal well with
null pointers specified as '0', the constructor of 'Local_addr' was
instantiated for [T = int], which does not make sense. To avoid the
warning "cast to pointer from integer of different size", we need to
explicitly state that '0' is a pointer. In C++11, there is the 'nullptr'
keyword, but until we switch to this version, we have to state (void *)0.
When L4Linux tries to allocate a dataspace of the size of its physical
memory, this allocation can fail, because the 'l4re_ma_alloc()' function
in the 'l4lx' library always tries to allocate a contiguous dataspace of
the given size and there might be no contiguous free area left.
With this patch, memory gets allocated in chunks: if the size to be
allocated exceeds the configured chunk size, a managed dataspace gets
created and filled with multiple memory chunks of at most the chunk size.
The chunk size is 16M by default and can be configured in an l4linux
config node:
<config args="...">
<ram chunk_size="16M"/>
</config>
Fixes#695.
The new core-internal 'Address_space' interface enables cores RM service
to flush mappings of a PD in which a given 'Rm_client' thread resides.
Prior this patch, each platform invented their own way to flush mappings
in the respective 'rm_session_support.cc' implementation. However, those
implementations used to deal poorly with some corner cases. In
particular, if a PD session was destroyed prior a RM session, the RM
session would try to use no longer existing PD session. The new
'Address_space' uses the just added weak-pointer mechanism to deal with
this issue.
Furthermore, the generic 'Rm_session_component::detach' function has
been improved to avoid duplicated unmap operations for platforms that
implement the 'Address_space' interface. Therefore, it is related to
issue #595. Right now, this is OKL4 only, but other platforms will follow.
The CPU session interfaces comes with the ability to install an
exception handler per thread. This patch enhances the feature with the
provision of a default signal handler that is used if no thread-specific
handler is installed. The default signal handler can be set by
specifying an invalid thread capability and a valid signal context
capability.
Furthermore, this patch relaxes the requirement of the order of the
calls of 'exception_handler' and 'set_pager'. Originally, the exception
handler could be installed not before setting a pager. Now, we remember
the installed exception handler in the 'Cpu_thread' and propagate to to
the platform thread at a later time.
This patch reflects eventual allocation errors in a more specific way to
the caller of 'alloc_aligned', in particular out-of-metadata and
out-of-memory are considered as different conditions.
Related to issue #526.
With this patch clients of the RM service can state if they want a mapping
to be executable or not. This allows dataspaces to be mapped as
non-executable on Linux by default and as executable only if needed.
Partially fixes#176.
