Instead of mapping all physical memory 1:1 into core/kernel's address space,
this commit limits the 1:1 mapping to the binary image, and I/O memory
regions used by the kernel only. All subsequent memory accesses of core
are done by mapping the corresponding memory on demand, and not necessarily
1:1.
This commit has several side effects:
The page table code had to be revisited completely. The kernel inserts no
longer anything into the page tables, apart from the initial translations
to have the core/kernel image available when enabling the MMU. The page
tables and higher level translation tables are no longer named Tlb, but
Translation_table instead. There is no indirection class required to define
the translation tables of a concrete SoC, the appropriated ARM specifier
is sufficient.
The ability to map core's memory the same way like it's done for all other
protection domains, makes a special treatment of core's threads (no context
area) obsolete.
Ref #567 (partly solves it)
Fix#723Fix#1068
Removes the generic processor broadcast function call. By now, that call
was used for cross processor TLB maintance operations only. When core/kernel
gets its memory mapped on demand, and unmapped again, the previous cross
processor flush routine doesn't work anymore, because of a hen-egg problem.
The previous cross processor broadcast is realized using a thread constructed
by core running on top of each processor core. When constructing threads in
core, a dataspace for its thread context is constructed. Each constructed
RAM dataspace gets attached, zeroed out, and detached again. The detach
routine requires a TLB flush operation executed on each processor core.
Instead of executing a thread on each processor core, now a thread waiting
for a global TLB flush is removed from the scheduler queue, and gets attached
to a TLB flush queue of each processor. The processor local queue gets checked
whenever the kernel is entered. The last processor, which executed the TLB
flush, re-attaches the blocked thread to its scheduler queue again.
To ease uo the above described mechanism, a platform thread is now directly
associated with a platform pd object, instead of just associate it with the
kernel pd's id.
Ref #723
Kernel::resume_thread was restricted to core when the targeted thread was in
another domain. Now there are two kernel calls, resume_local_thread and
resume_thread, where the former is never restricted and is provided via
public kernel/interface.h and the latter is always restricted to core and
is provided via core-local kernel/core_interface.h.
ref #1101
Kernel::pause_current_thread can be implemented much simpler and is not
restricted to core threads, in contrast to Kernel::pause_thread which
also benefits from the split and can be moved to core_interface.h.
ref #1101
In most cases an error report is not necessary in the kernel as the problem
does not affect the kernel itself but the according user-land context. Thus
we can also do a warning that is not printed in release mode and hence safe
execution time.
ref #1096
This is needed as soon as we do inter-processor interrupts to
inform a processor about a remote modification in its scheduling plan.
In this case we can not explicitely decide wether to reset timer
or not. Instead we must decide it according to the choices of the
scheduler before and after the modification.
ref #1088
As synchronization of signal contexts is now the users business instead of
cores and the signal framework ensures that every context of a receiver gets
synchronously destructed before the destruction of the receiver itself
synchronization and thus blocking at the destruction of a kernel
receiver-object isn't necessary anymore.
ref #989
Kernel::signal_context_kill can be used by any program to halt the processing
of a signal context synchronously to prevent broken refs when core destructs
the according kernel object. In turn, Kernel::bin_signal_context doesn't block
anymore and destructs a signal context no matter if there are unacknowledged
signals. This way, cores entrypoint doesn't depend on signal acks of a
untrustworthy client anymore.
ref #989
Stefan Kalkowski
Martin Stein